LocostUSA.com

so has any one broke there gear box from spinning they car backwards ?
i was at lime rock last season and spon the car at speed coming down the down hill .
i'm not sure just at what speed i was going one i never look at my speed-o and two this car has no speed-o in it but i was just going into 5th gear when the 180 happend .
i finished the day and than ran the car with that motor at a test day at the end of the year and again the gear box was shifting fine .
i put that motor back in the car for the last event with the COMSCC this season at NHMS .
i went on for the 1st morning run and 5 laps into the session all i felt was a big bang and no forward drive . the 1st thing i thought of was the chain snapped . no every thing there was good so i checked the rear end all good there two . i go my car back to the shop and pulled the motor to find the shaft were the nut that holds the clutch basket on was snapped in half .
the only thing i could think of is it was damaged when i spon the car ?
now i have only used this motor 7 times or so and i did take it from a totaled 2002 GSX-R 1000 with bent forks and frame so i don't know what life it lead before i got it . other than the spin i had i can not figure any other way a shaft would brake like that .

I'd say that's a pretty good guess based on your description. .. I recommend checking for cracked/damaged teeth on the fifth gear cluster and the primary reduction gear set as well.

_________________
"There are times when a broken tool is better than a sound one, or a twisted personality more useful than a whole one.
For instance, a whole beer bottle isn't half the weapon that half a beer bottle is ..." Randall Garrett

So that sucks! Too bad.

I'm going to guess you got on the brakes quickly when you spun, so going backwards shouldn't be a big factor. We don't have a big history with the bike motors on this site yet. The car weighs more then what the motor was designed for. Maybe it was prior use though. There is a place that makes final drive sprockets for motorcycles with a little rubber in them. They are for competition use, I think. I have no recollection of who though. Stock bikes usually have something for this anyway so maybe it's for Bike engine in car use...

Do you shift without the clutch?

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

I've heard several stories of people destroying bike starters or the crankcase attachment points from spinning and the engine rotation reversing. The starter is always engaged to the crank but a one-way bearing keeps it from being turned when things are working normally. When things reverse the starter has to spin or something has to break.

It causing drivetrain damage seems totally plausible.

_________________
-Andrew
Build Log
Youtube

well i tor down the motor today and the center case is cracked also .
when i spon the car at LRP the assend jumped in the air 3 time . at the end of the down hill ( track out ) there is no run off room on the inside so hell yes i got right onto the brakes .
when you spin on a bike you just go over the high side in a car it's a hole other thing so on a bike the motor never see's reverse damage .
the gears them selfs look ok with no galling to them i still have to remove them from the shaft . i will do that once i get the new shaft ordered and here at my shop .
there are some motors that it will eat the starter motors when you spin and yes my motors will do that i went thru 2 starters before i found that speed partz makes a srtarter saver for that .
i am now about 2 hours into designing a drive gear that will free wheel in reverse and lock in forward drive . i'm thinking it should hold about 250 FT LBS torque ? i have a built NA motor that puts out 229 HP and 103 LBS torks . if i start to sell them i want them to handle higher hp and torque motors .

I'll be impressed if you pull that off. You won't be able to do it with a sprague clutch or the like 'cause the direction of torque transfer with an engine driving the axle forward is the same as with the axle driving the engine backward. In both cases, the top of the chain loop is in tension.

_________________
Locost builder and adventurer, and founder (but no longer owner) of Kinetic Vehicles

my design i have now is not counter rotation . it's 7 inches wide that makes the offset from the counter shaft of the motor to the rear Diff to great making the diff offset way to the left side in the chassis that in turn makes the half shafts two deferent sizes .

Well that sounds like it would do it, quite a ride! I can see that causing some damage...

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

you have run at LRP i don't know how fast we are going but it's quick .

i'm getting very tired of this car ! 2 plus years of R and D just when i think it's all good to go the POS brakes again . 1st it's eating clutches so i design my own cable ,peddle and clutch cam and get rid of the master and slave set up the motor comes with . then the barings in the out put shaft ( counter shaft ) extension start to get crap out every event . redesign that . then it starts eating chains 14 of them so i drop the motor in the chassis and move it all the way over to the right side to fix that . and that was after trying drive shafts and all other types of crap . then it lead into it eating the rollers on the chain tensioners . so i went to a gear that just lead into eating the chain again . so i tried a aluminum gear then a delrin gear then to a roller that is used on dirt bikes . then made my own roller out of 3" round stock of delrin . that worked i am now getting many events out of the chain and roller set up . did i leave out that i had to design a new chain tensioner too after moving the motor the last time the stock tensioner would no longer tension the chain at full compression of the suspension .
if any one wants to turn a bike motor sideways in a chassis on mid engine rear drive car for get it ! it's a dumb idea there is just no plus to do it .
i took today off from work to start the new back half on my chassis so the motor sits in it the way it should .

It still seems to me the version of bike motors in Jetskis or snowmobiles without a transmission and then hooked up to a 930 transmission might make sense. I'm a long way from getting around to try it though, and I think those motors are in much shorter supply.

It's too bad the car has been so difficult, hope I get to see it next year.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

i got the new back half layed out and tack welded as much as i could . i'm waiting for my tubing supplyer to drop off the tubing i need to really get the new back half going .
in the meen time i got my car stripped down to just a bare chassis yesterday .

i like the bike motored cars . the motors really need to sit in the chassis the way they do in a bike that is the reason i'm going a new back half .
i have been thinking of this for some time now so last night i set up the jigs on my celette bench to build a new chassis for a diasio body using a totaled porsche boxter S i have .
my plan for that is to use all the porsche suspension , motor , trans and steering mated up to a tube chassis and a diasio body .
i don't know were the car would be classed ? under the new rules comscc has on the table it would be in SU ?
my guess is that the cars weight will be in the 1200 LBS range with with the 3.4 L i think the motor put out about 290HP ? so power to weight should be about 0.241 ?

4.13 lbs/hp, that looks like you ran the math backwards. ..
1200 / 290 = 4.13 __________ 290 / 1200 = 0.24167

I'd expect a weight closer to 1500 lbs with a full porsche suspension and drivetrain, still an extremely respectable 5.17 lbs/hp.

_________________
"There are times when a broken tool is better than a sound one, or a twisted personality more useful than a whole one.
For instance, a whole beer bottle isn't half the weapon that half a beer bottle is ..." Randall Garrett

my math could be wrong ?
i went to easycalcultion.com and used there form and thats the numbers they gave me for hp to weight LBS .
i don't know what the parts weight is yet i have not scaled them they are still in the car .
i know the weight of the body i have now it 's weight is 341 LBS and the chassis is just at 401 LBS with the front suspension in it .
so i maybe in the 1500 LBS range ? this chassis will be a little deferent built more like the real 962's rather than the diasio 962's . so most things like weights are just a guess .
tonight i start yarde just dropped off alot of the materials i have been waiting for .

Please don't take this badly, but I get the impression you're all about getting on with building things and not so much about doing the research. I highly recommend slowing down and taking your time to really get the foundation of what you're doing in place. For example, before even starting to build the car you should have a good idea of what it'll weigh and its CG. Yes it'll take digging but it's just one example of how you're making decisions based upon expectations and not fact. Much of building a car is research and even though there are no sparks flying or holes being drilling, it's at least as important, and probably more so.

_________________
Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

i don't take things badly !
i build chassis for a living that is my business i own a body and chassis shop .
the new back half took about 40 hours to design as for the porsche 962 style monocoque this will be the 14th one i will be building .
so will the monocoque handle 300 hp hell yes they are built to handle 900 plus HP .
as for the chassis measuring points thats ez celette has them for every car made . as for the jigs they are just bolted to the celette frame bench .
there is no black art to it at all .
i'm replacing a 935 power plant with the boxter one . i can't say just what the weight of the drive line is as it is still in the car and will need to be scaled when it comes out of the car .
so there is no way to calculate in the 100% accurate weight at this time bacause the drive line is still in the said car . but if it's plus or minus 100 LBS OF my guess on weight it will be just fine . i have not ordered any shocks or springes yet as the chassis is not finished with body on to get the 100% accurate dry weight .
now because i have had the boxter here all summer i have also been playing with the design all summer on and off . .
the design system i have tells you most of what you need to know and the chassis system i have for all cars also tells you every pickup point that is needed like motor monting points suspension mounting points and steering mounting points. so then you set up the bench with the right jigs and build the chassis to the jigs after your finished all the parts just bolt on as they would to a boxter's chassis .
if i were trying to do this on a build table it would take weeks longer to build than on a celette bench .