LtWtRR-digest Monday, May 26 1997 Volume 01 : Number 021 ---------------------------------------------------------------------- Date: Sun, 25 May 1997 13:29:40 -0800 From: "Michael Moore"Subject: LtWtRR Posts to the list I see that some of the list members are making LWRR list-appropriate posts to the race and 2smoke lists, but not to the LWRR list. Feel free to post the message here too, as there are probably some people here that aren't on the other lists who may have info that you need, or can benefit from your info. It just seems odd that when you've got a list specific to the lightweight roadracer topic (and there seemed a lot of interest in it when I proposed starting the list) that you'll post to the other lists and not to this one. With puzzlement, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ Date: Sun, 25 May 1997 16:53:49 -0800 From: "Michael Moore" Subject: LtWtRR Oh No! Another vintage road race project Hello, My name is Michael, and I'm a projectaholic. While at Craig's shop the last two days I did a deal with his friend Marc to buy his MotoBi (also known as Benelli) horizontal-cylinder 250cc four stroke stuff. This is a fairly complete chassis with presumably running engine and 2 additional engines. It appears that all the bikes are 4 speed transmission models. In the spares is a new race kit head (with "RR" lettering stamped below the exhaust port on the underside of the head) that looks to have much bigger ports than the standard head. There is also a new camshaft with "S" designation, but we don't know if that stands for Sport, Speziale, or Standard (maybe spatzle? - probably not since it is an Italian engine). Craig and I spent about 40 minutes looking at the parts and scheming on what to change. The crankshaft is not a real impressive looking item. It has the same stroke as an XR200 Honda single (and is about the same width), and the mainshafts on the Honda crank are enough bigger that they could be turned down and modified to work in the MotoBi. This would also give a bigger crank pin. The 4(!) ring piston isn't very impressive either, but it is the same bore as an XL250, and they are both flat top pistons so that is solved too. The Honda piston uses a 1mm bigger wrist pin, but since the deck height is a little lower that would probably be taken care of by ordering a slightly longer Carrillo rod to the appropriate length/ID dimensions. Megacycle is supposed to have a master for the factory race kit cam, so I'll contact them for timing specs on that to see what cam I've got, or if the race kit cam will be at all suitable. Craig looked through some catalogs and found some 5.5mm stem titanium valve blanks in appropriate sizes, and I'm sure that R/D Spring will either have a suitable valve spring set or can come up with one once I send them a head. This time I won't worry about trying to come up with replacements for the OEM parts as I did for the Laverda - whatever retainers they've got on the shelf are what will be used. Craig said the intake port didn't look too bad, but the exhaust is one of the wretched flat ports that the Italians seemed to love to put in their engines. I see a bit of TIG welding in the exhuast ports future. Ivar very kindly took some time send me some MotoBi information. He told me that the factory bikes had trouble with the side thrust from the helical primary gears (much as do Ducatis - Nova sells a straight cut primary set for the Ducs) so this is going to have to be addressed. The transmission is the other sticking point. All of the engines I got appear to be 4 speed boxes, which strikes me as less than optimum for a 250 race bike. 5 speed models were also sold in the States, but Ivar tells me that all the factory racers used 4 speed transmissions. The standard 5 speed has a wider overall spread than a Ducati 5 speed (and we won't even mention how it compares to an Aermacchi race gearbox!), and the top gears aren't very close together. The immediate conclusion was to find another transmission to install (since I know of another Italian 250 racing bike that is running a CR125 6 speed). But wait - the MotoBi uses an English-style transmission with a mainshaft/layshaft setup (power comes in and goes out from the mainshaft), not a typical Italian/Japanese indirect crossover type box where the power comes in on the main shaft and leaves via the countershaft. The 4 speed cases are fairly narrow inside as well. Hmmmm, this is going to require more thought. I've been emailing with a fellow in Australia who has some of the 5 speed engines, but even there new gears would have to be made, though this might be less trouble in the long run than finding a different transmission to swap into the engine. Then again, most of the tracks over here don't have (m)any first gear corners, so if I could build a dry clutch that would tolerate a lot of slipping on the start a close ratio 4 speed might be tolerable. I don't know yet if Zanzani or others made straight-cut gear conversions or different transmission ratios, but I'll find out. I now have a (presumably) good address for Werner Maltry, who developed a lot of the factory racers and his own LinTo-type 500 twin based on the MotoBi single, so I'll drop him a line and see if he recalls any helpful information. I'll build a new chassis for it. Ivar told me that Zanzani made a space frame for sale for the bikes, and I see no problem doing a replica of that or a LinTo 500. The lower rear motor mount appears to be usefully wide, but the top mounts are only 30mm wide and about 60-70mm apart. Hmmmm, maybe a bit more TIG welding will be called for here. The engine has a pretty narrow chain line with about 10-15mm clearance to a 3.00x18 Avon tire, so it may need to be slightly offset in the frame to allow a 90 or 100 section tire. I think that a set of late model external-damper Guzzi GP pattern leading link forks are likely, or maybe some Reynolds type LL forks, whichever seem to be more appropriate for the link geometry that I decide upon. Before you know it (well, maybe late next year) I may have a perfect replica of the MotoBi racer that everyone wished they were riding in 1965. As you might guess, any bits of MotoBi lore, legend or engine components are desired - you know where to find me. I guess I need to see if the Benelli club caters to MotoBi - or maybe I'll have to start a MotoBi club myself (in my copious spare time - right). Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ Date: Mon, 26 May 1997 20:49:09 -0800 From: "Michael Moore" Subject: LtWtRR SS1 Dell'Orto Manual Moto Italia has a couple of pages from an SS series (remote float smooth bore) Dell'Orto manual on their website at: http://www.aa.net/~garage/motoital/dellorto.html This is some good information that I hadn't seen before. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ End of LtWtRR-digest V1 #21 *************************** LtWtRR-digest Wednesday, May 28 1997 Volume 01 : Number 022 ---------------------------------------------------------------------- Date: Tue, 27 May 1997 14:58:06 -0700 From: Jason Van Slyke Subject: LtWtRR SRX250 To Bill: Your nospam system didn't like my original message, so this message is now for everyone: I, too, have an SRX250 that I have been trying to make faster and handle better. KEEP the recommended tire sizes---DO NOT CHANGE SIZES UP! It makes the turn-in a lot slower. I used to have a somewhat restrictive filter and I actually saw 105 (the speedometer needle buried against the stop and rpms rose), then I put in a Uni filter and it suffered severe stumble from 2-5K, then seemed to come on stronger at higher rpms. I put in two 3mm spacers on each needle jet to raise them and it cured the stumble. Got more induction noise and a little louder exhaust (now probably to 89dB from 88) but would only wind out to perhaps 102. There are no exhausts available, as you may well know. Michael has given me information on new carbs, and I'm very interested. What would really help is a brace going from the head to the swingarm mount to give it a lot more stability. I saw a guy who had a solo seat conversion which is really cool. I have the manual and bought it last October---it is a reprinted copy from a Yamaha dealer which looks like a Kinko's special. But the point Michael brought up is where do you stop with something like this bike? Putting on good rubber may be about the best thing you can do, because the general consensus seems to be there is severely diminished returns from doing any modifications on this bike. Good luck, Jason ------------------------------ Date: Tue, 27 May 1997 10:24:17 -0400 From: Bill Subject: Re: LtWtRR SRX250 Jason Van Slyke wrote: > > To Bill: > I, too, have an SRX250 that I have been trying to make faster and handle > better. KEEP the recommended tire sizes---DO NOT CHANGE SIZES UP! It > makes the turn-in a lot slower. > I used to have a somewhat restrictive filter and I actually saw 105 (the > speedometer needle buried against the stop and rpms rose), then I put in > a Uni filter > and it suffered severe stumble from 2-5K, then seemed to come on > stronger at higher rpms. I put in two 3mm spacers on each needle jet to > raise them and it cured the stumble. Got more induction noise and a > little louder exhaust (now probably to 89dB from 88) but would only wind > out to perhaps 102. So the uni filter HURT performance? > There are no exhausts available, as you may well know. I have considered making one from tubing, I've done this before but it's a lot of work.... > Michael has given me information on new carbs, and I'm very interested. I am interested in better carburation, but only if it's worth the $$$, without a cam and exhaust, I think it may be a lost cause. > What would really help is a brace going from the head to the swingarm > mount to give it a lot more stability. > I saw a guy who had a solo seat conversion which is really cool. I have > the manual and bought it last October---it is a reprinted copy from a > Yamaha dealer which looks like a Kinko's special. I'll ask at the other Yamaha ha ha dealer if I can get a manual. > But the point Michael brought up is where do you stop with something > like this bike? Putting on good rubber may be about the best thing you > can do, because the general consensus seems to be there is severely > diminished returns from doing any modifications on this bike. Do you mean that this bike is pretty close to the best it can be or that it is too limited to be worth spending money on it? > Good luck, > Jason I heard rumors that the motor in this bike is the same as the off road 250 4 strokes, can anyone confirm or deny this? I have to change the clutch soon but I don't recall where to put the bolts to keep the clutch pack together on a yamaha, I haven't seen one in a while. Anybody remember the procedure? Bill * If everything is going well, you don't know what the hell is going on. ------------------------------ Date: Wed, 28 May 1997 16:52:52 -0800 From: "Michael Moore" Subject: Re: LtWtRR SRX250 > > But the point Michael brought up is where do you stop with something > > like this bike? Putting on good rubber may be about the best thing you > > can do, because the general consensus seems to be there is severely > > diminished returns from doing any modifications on this bike. > > Do you mean that this bike is pretty close to the best it can be or > that it is too limited to be worth spending money on it? > > I heard rumors that the motor in this bike is the same as the off road > 250 4 strokes, can anyone confirm or deny this? Hello Bill, The off-road engines are basically the same, and my friend Craig says that it looks like the TT350 is a pumped up 250 since the valves are a bit small. An SRX250 would be a fun project to drop a grand or two into. . . Unfortunately, project bikes often seem to cost the same for the same results, no matter what the original bike was. You might find that after coaxing a relatively big amount of bhp out of the engine that the chassis is now not as adept as it was with less bhp, and then you start spending money on the chassis, wider wheels, better brakes, modified chassis, etc. You might look to see if you could swap a 350 motor into your bike. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ End of LtWtRR-digest V1 #22 *************************** LtWtRR-digest Friday, May 30 1997 Volume 01 : Number 023 ---------------------------------------------------------------------- Date: Thu, 29 May 1997 20:26:51 -0800 From: "Michael Moore" Subject: LtWtRR Kicking people off the list > By the way...did you throw me off all of your new lists ... I > haven't gotten any mail for awhile. I checked and you aren't currently subscribed. Some ISPs seem to bounce up and down, disappear for awhile (as far as the mailing process goes), can't recognize their own subscribers, people go away on vacation and their mailboxes get full, etc. I think this is a fairly widespread problem. I'll let a subscriber go for 2-3 days of bounces, but after that I presume that the email address is terminal (usually after trying a direct message that gets bounced) and unsubscribe the person. If you are in digest mode on my lists you should be getting a couple of digests a week minimum, so if you don't get anything after a bit you might drop me a direct email to check. I've had my ISP contact me to have people unsubscribed when the bounces get very heavy (ie lots of list traffic). Sorry for the inconvenience, but MY mailbox starts getting filled up with bounce messages, and I have to look at each one to see if they are different people or just one. I now have instructions on subscribing for all five lists on their own page on the web site. I'll see if I can come up with an easy way to get the digests on the web site, but you can always mail me and let me know the last digest/message you got and I'll send you the digests you missed. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ Date: Fri, 30 May 1997 21:59:24 -0800 From: "Michael Moore" Subject: LtWtRR Lots more pictures on the web site The latest addition is an entire section devoted to some of the 2, 3 and 4 wheeled racing vehicles (and a 120 mph race-vehicle transporter) constructed by former GP sidecar racer/constructor Rudi Kurth. There are Kurth CAT sidecar outfits with BMW twin Rennsport four stroke and Crescent and Yamaha 3 cylinder (yes, Yamaha) two stroke engines. The solos are Yamaha and Crescent triple powered semi-kneelers, and the four wheelers include Alfa and Fiat racers, as well as the CATVAN and several solar-powered racing vehicles. I've also set up a separate page for the line of composite chassised bicycles that Rudi makes. Cool stuff - check it out. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ End of LtWtRR-digest V1 #23 *************************** LtWtRR-digest Sunday, June 1 1997 Volume 01 : Number 024 ---------------------------------------------------------------------- Date: Fri, 30 May 1997 21:59:25 -0800 From: "Michael Moore" Subject: LtWtRR Eat your hearts out! I've excerpted a section from a message sent to me by Ivar. Not only did he do this last weekend, but he should be at the Isle of Man now! Enjoy reading it - I did. Cheers, Michael ********************************************************** Ivar wrote: Last weekend I went to the CRT races. They ride in 6 classes, 50/125/250/350/500 and sidecars. Each class, but especially the 50, has very interesting racing bikes, all classes have production racers in them, some have factory racers competing. In the 50cc class some old G.P. riders from the seventies ride their bikes, like Aalt Toersen on his 50cc Kreidler. He rides like a rocket and the Kreidler is really extremely fast. Three or four other van Veen Kreidler's compete, together with a batch of sixties Kreidler's, Jamathi's (!!), FB Minarelli's, Sachses, and some home-made racing bikes like a Hercules (with very intersting light-weight leading link fork), Garelli, Moto Guzzi and Gilera. The bigger classes are interesting as well, seen can be a extremely nice and fast 125cc Villa racing bike, ex. factory, who competes in the 250 since it is so bloody fast. He competes often with a Yamaha 250 factory racer, which once belonged to Phil Read. It's nice to see the rider makes a difference as well. Many Aermacchi Ala d'Oro's can be witnessed, many carry a Metisse frame, in the 350 an ex. Sid Lawton Aermachi competes, with it's distinctive light green colour. These bikes are real fast and very well handling as I could judge myself during a test spin. The 500 is very interesting. Some Crooks-Suzuki's, Yamaha 500's, and a bunch of hopped up Goldstar's, 50's Gilera Saturno's, a Vincent Comet (Grey Flash replica), Ducati single's compete enthousiastically against each other. Most times the battle is against a Yam. 500, a Crooks Suzuki and a hopped up Duc. 450 (non desmo). The Ducati rider sweeps with the bike in a way which is not to be expressed in words, FAST! On straights he loses, but he makes it more then well in corners, and just after corner's torquey accelaration. Indeed, the rider makes the difference. He carries still stock brakes, naturally with non stock linings. "It's a hobby", he always says when someone asks him why he doesn't ditch the old brakes. The CRT races are always fun, and atract a crowd as well. ------------------------------ Date: Sun, 1 Jun 1997 10:40:07 -0800 From: "Michael Moore" Subject: LtWtRR Determining rear damper length I initially wrote this to send to Alec Millet in Australia, who is trying to decide what dampers to buy for his Ducati 350 road racer. I thought that it might be of use to someone else. This is a pretty basic treatment, and if you are running a 100 bhp bike this procedure may require a bit of modification on the final setup. ******************************************** Before buying your rear dampers do this: Pull off the dampers and let the tire rest inside the rear fender. Measure the center-center distance on the damper mounts, then add 1/2" to that for fender clearance and record this dimension. Be aware that fender clearance can vary with chain adjuster position so to check that out move the adjusters full forward and full aft to see if the minimum clearance changes. Now put the bike back on the stand (still without dampers) and let the rear wheel droop. I don't know if you still have the passenger peg mounts, as they are often used as an exhaust mount on the Ducati singles, but let the wheel go down until you start to see the chain interfering with the top of the swing arm pivot or other parts of the bike. Measure the damper mounts again. Now align the c/s sprocket, swing arm pivot and rear axle on the same line. Measure the damper mounts again. This should be the tightest point on the chain, and the chain will loosen as the rear axle moves up or down. This is a good time to set your chain tension. When you get a final setting on the damper lengths you can measure the chain slack at full extension of the rear suspension and record that figure for later use. This is much easier than pulling the dampers off every time you want to adjust the chain! You now know the potential maximum and minimum lengths of the dampers. Try to get a 4" travel damper, as the Ducati dampers are not heavily leveraged on the swing arm and 4-5" of travel is pretty nice to have on a road racer, especially on a bumpy course. I think that both my Laverda and the Honda run close to 5" of travel in the rear suspension. The longer travel lets you run a little more sag, allowing the rear wheel to move down into dips in the road instead of leaving the ground when encountering the dip. The longer travel will also let you run a lighter spring. Sometimes the dampers come with shorter travel done by adding spacers on the shaft, and I've successfully cut these off of Girlings/Hagons (the Hagons are plastic) to increase travel. Don't confuse these spacers with the rubber bump stop. Always presume the bump stop will compress to zero when figuring the actual shaft travel of the damper. Consider making the travel symmetric about the "3 points in a line" figure, as that will keep the chain tension most constant. Record the max/min damper lengths that this gives you, and compare with the potential max/min lengths you measured earlier. I'd recommend biasing the length a bit towards the long side, as that will steepen the front end a bit and give some more ground clearance. As long as you aren't having massive chain rub on the swing arm pivot you probably don't need to worry much about excessive anti-squat in the rear end (besides, it doesn't seem to make a great deal of difference in our small displacement low-powered vintage bikes). You now have a good idea of what damper length you need for your bike, which may well be different than the length of the OEM damper, or what your local "never seen one of these bikes, mate" parts guy will recommend for your bike. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ End of LtWtRR-digest V1 #24 *************************** LtWtRR-digest Saturday, June 7 1997 Volume 01 : Number 025 ---------------------------------------------------------------------- Date: Sun, 25 May 1997 16:38:39 -0400 From: Bill Subject: LtWtRR Tires? Hey, I am looking for an appropriate tire for my SRX250. I am thinking about the Bridgestone BT39SS or BT90 but I can't seem to find these. Thanks, Bill ------------------------------ Date: Sat, 7 Jun 1997 16:48:53 -0800 From: "Michael Moore" Subject: LtWtRR MotoBi pictures I've added several photos of the MotoBi 250 team at Daytona in 1962 (thanks to Michael Green for making them available) and a photo of Kurt Liebmann winning a 200cc race in the early 1960s. They are on the graphics page on the website - the MotoBi photos now have their own section instead of being in with the other vintage roadracers. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ End of LtWtRR-digest V1 #25 *************************** LtWtRR-digest Tuesday, June 10 1997 Volume 01 : Number 026 ---------------------------------------------------------------------- Date: Sat, 7 Jun 1997 20:57:15 -0800 From: "Michael Moore" Subject: LtWtRR Another photo I've just added an action shot of a 50cc Honda CR110 road racer at Brands Hatch in 1966. It is located at the top of the "vintage Japanese" section on the graphics page. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ Date: Tue, 10 Jun 1997 11:37:11 -0400 (EDT) From: "Mark J. Andy" Subject: LtWtRR '94 RS-125 stuff for sale Howdy, Got some extra parts left from my '94 RS-125 that I need to sell: (ML == MotoLiberty price) new head (ML$135) $70 new CDI (ML$165) $100 used peg hangers (ML$60 & $58) $50 (both) (excellent condition) Package deal $200 for all. Mark ------------------------------------------------------------- The 1997 M and N Racing Team Team Owners: Laura Maynard-Nelson, Paul Hoyt Nelson Riders: Paul Hoyt Nelson (WERA/CCS/NASB Expert #81) Mark Andy (WERA Expert #3) Tuner: Connie S. Brooks Manager: Laura Maynard-Nelson ------------------------------------------------------------- ------------------------------ End of LtWtRR-digest V1 #26 *************************** LtWtRR-digest Monday, June 16 1997 Volume 01 : Number 027 ---------------------------------------------------------------------- Date: Wed, 11 Jun 1997 17:13:25 -0800 From: "Michael Moore" Subject: LtWtRR Aermacchi Transmissions If anyone out there has an Aermacchi 4 stroke single I'd be very interested to hear how the clutch and countershaft sprockets are located in the engine. The pictures (all of which have the side cover on) that I have make it look like the clutch and c/s sprocket are both mounted on the same shaft (at opposite ends of the shaft). If so, this would be the same set up as my MotoBi, and means I need to start looking at Aermacchi transmissions for possible use in the MotoBi racer project. Thanks, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ Date: Mon, 09 Jun 1997 19:22:31 -0400 From: Bill Subject: LtWtRR Race Tires for small bikes Hi all, I am looking for appropriate tires for my bike. It is an SRX250 and I slide it around alot ( tires are rocks ) I have decided that I would like the Bridgestone BT39SS or BT90 tires but I cannot find them. Sizes are F= 90/90-16 R= 100/90-18 Min speed rating required is S (105 mph) If you have another good suggestion for a light bike like this, please tell me about it. Thanks, Bill 1987 Yam SRX250 race toy 1994 BMW R100M new streeter 1975 BMW R90/6 old faithful ------------------------------ End of LtWtRR-digest V1 #27 *************************** LtWtRR-digest Thursday, June 19 1997 Volume 01 : Number 028 ---------------------------------------------------------------------- Date: Tue, 17 Jun 1997 16:54:56 -0400 (EDT) From: SCOTTA336@aol.com Subject: LtWtRR Reed calculations Folks, I found some interesting info on the Boyesen web page, in particular an article by Kevin Cameron on reed theory. He says Yamaha figures that for best power the natural frequency of the reed ought to be 80% of the engine's speed in RPM. He goes on to give the equation for the fundamental frequency F=(3.52/2pi)* (Eb^2g/12DL^4)^.5 where E is Young's modulus, b is the thickness, g gravity, D the density of reed material, and L the free length of the reed. Then he goes on to simplify for steel material, F = 32900B/L^2 Here's where it falls apart for me. I plug in Young's modulus and the density of steel, change the units just like they taught me in engineer's school, and I get nothing like his simplification. Anybody else want to take a crack at this? ------------------------------ Date: Tue, 17 Jun 1997 16:58:31 -0500 (CDT) From: "Paul C. Kurth" Subject: Re: LtWtRR Reed calculations On Tue, 17 Jun 1997 SCOTTA336@aol.com wrote: > > F=(3.52/2pi)* (Eb^2g/12DL^4)^.5 > > where E is Young's modulus, b is the thickness, g gravity, D the density of > reed > material, and L the free length of the reed. > > Then he goes on to simplify for steel material, > > F = 32900B/L^2 > I don't know why that gravity term is in there, but if you use B^2 instead of B^2g you will get Cameron's reduced frequency calculation. I got F = 32781B/L^2 by using D = .73E-3 and E and 30E6. Make sure that your units are correct. E is usually given in inches and pounds, while density varies from pounds per cubic foot to pounds per cubic inch, depending on your reference. Cameron PS I just derived the natural frequency equation, I sure would like to know why he stuck that gravitational term in there. ------------------------------ Date: Fri, 20 Jun 1997 09:52:56 +0800 From: Matthew Carter Subject: LtWtRR RS125 Tyres Sizes Hi, Still looking for some info on '91-'93 RS125 tyre sizes. I've got an '89 but with 17" wheels. 3.15x17 and 3.00x17 What tyre sizes would be suitable? I've currently got 90/575 and 105/585 Bridgestones. I think I can go wider on the rear (115)as it wears to the edge while the front is nowhere near. Ta, Matt - --------------------------------------------------------------------------- Matthew Carter mjcarter@cyllene.uwa.edu.au Robotics Laboratory, Ph (09) 328 7740 (Hm) Dept of Mechanical & Materials Engineering, (09) 380 3051 (Lab) University of Western Australia - --------------------------------------------------------------------------- YOU WANT INTERNET INTERACTIVITY? http://telerobot.mech.uwa.edu.au/ ------------------------------ End of LtWtRR-digest V1 #28 *************************** LtWtRR-digest Saturday, June 21 1997 Volume 01 : Number 029 ---------------------------------------------------------------------- Date: Fri, 20 Jun 1997 10:11:57 +0800 From: Matthew Carter Subject: Re: LtWtRR RS125 Tyres Sizes Whoops! Should be 2.15x17 and 3.00x17 >I've got an '89 but with 17" wheels. 3.15x17 and 3.00x17 Doh! Matt ------------------------------ Date: Fri, 20 Jun 1997 13:35:09 +1100 From: Daniel_Builth-Snoad@wlgore.com Subject: Re: LtWtRR RS125 Tyres Sizes Hi Matt, I'm running a 92 with Machesini 3.25 & 3.00 x 17 over in Sydney and I've tried a few tyre combos. Currently I'm running a 120 Michelin rear but it would be a little too big for your 3.15 I would say (which is a shame because the Mich's are great but have limited sizes). Prior to that I had a 115 Yokie which worked well for the rim size and would be the size for you to go for. Hpe this helps, Danny >Still looking for some info on '91-'93 RS125 tyre sizes. > >I've got an '89 but with 17" wheels. 3.15x17 and 3.00x17 > >What tyre sizes would be suitable? > >I've currently got 90/575 and 105/585 Bridgestones. I think I can go wider on the rear >(115)as it wears to the edge while the front is nowhere near. > >Ta, >Matt ------------------------------ Date: Fri, 20 Jun 1997 13:34:49 +1100 From: Daniel_Builth-Snoad@wlgore.com Subject: Re: LtWtRR RS125 Tyres Sizes Hi Matt, I'm running a 92 with Machesini 3.25 & 3.00 x 17 over in Sydney and I've tried a few tyre combos. Currently I'm running a 120 Michelin rear but it would be a little too big for your 3.15 I would say (which is a shame because the Mich's are great but have limited sizes). Prior to that I had a 115 Yokie which worked well for the rim size and would be the size for you to go for. Hpe this helps, Danny >Still looking for some info on '91-'93 RS125 tyre sizes. > >I've got an '89 but with 17" wheels. 3.15x17 and 3.00x17 > >What tyre sizes would be suitable? > >I've currently got 90/575 and 105/585 Bridgestones. I think I can go wider on the rear >(115)as it wears to the edge while the front is nowhere near. > >Ta, >Matt ------------------------------ Date: Sat, 21 Jun 1997 20:43:21 -0800 From: "Michael Moore" Subject: LtWtRR Another photo I've just uploaded a picture of some modern girder forks that Tony Foale made for a customer. Tony was surprised at how well they worked, and thought they had some advantages over telescopics. It's at the top of the "Tony Foale" section on the graphics page of my web site. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ End of LtWtRR-digest V1 #29 *************************** LtWtRR-digest Friday, June 27 1997 Volume 01 : Number 030 ---------------------------------------------------------------------- Date: Sun, 22 Jun 1997 12:04:59 -0800 From: "Michael Moore" Subject: LtWtRR Vintage Japanese site URL This looks pretty interesting - a fellow in the Netherlands passed the url to me. >>Perhaps you've found it already, but there is a Japanese site, with a huge picture gallery on Japanese classic racers up to 125cc. I found it amazing (never seen 23 Honda CR110 racers in one picture): http://lump-proof.com Paul Kellner>> Check it out if you haven't already. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ Date: Fri, 27 Jun 1997 10:17:39 -0800 From: "Michael Moore" Subject: LtWtRR Lots more photos I've just added a number of photos to my web site's graphics page. Included are shots of one of Tony Foale's racing sidecars, details of the Q2 rear axle setup, and shots of a FF bike to which Tony assisted the owner in fitting one of his QL front ends. There are some new photos of Ollie McKagen's alternative front end dirt bikes, and one of his projects with a space frame and old-fashioned telescopic fork. I've also (over the last few days) added pictures of various small Italian ISDT bikes, a page for my Laverda 150 vintage MX project, and some other stuff that escapes me at the moment. Cheers, Michael Michael Moore Euro Spares, SF CA Distributor of Lucas RITA and Powerbase products Sole North American source of "The Racing Motorcycle: a technical guide for constructors" http://www.eurospares.com AFM/AHRMA #364 ------------------------------ End of LtWtRR-digest V1 #30 ***************************
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