Total Motorcycle Community Forums

I started this over in the maintenance forum but thought it fit better here.

http://totalmotorcycle.com/BBS/viewtopic.php?t=20998

I am in the process of building a Busa powered formula car, the car is in my shop and the engine is on the way.

This is the car
http://i101.photobucket.com/albums/m57/ ... 500001.jpg

This car has rubber pads for suspension which I will replace I am planning to use GSXR 600 or 750 springs and shocks for the suspension.

Does the 600 and 750 use different spring rates and valving? I see them listed on ebay as fitting both, but ebay is not a great source for proper fit information.

Also can they be used in a horizontal position? the fronts are inboard and horizontal.

does anyone know of a clutch master cylinder that has a remote reservoir? I will be mounting the clutch lever to the steering wheel in a vertical position so I think I need a remote reservoir.

Those are the questions that are top of the list for now.

Thanks for all the help.

Brian

1) They are two different shocks, and while they are mechanically interchangelable I do not believe they are valved or sprung identically. Additionally they will be different between years.

2) They can work in the horizontal position if they are mounted correctly. I'm not sure they will be able to support the weight of a car though.

3) I think mounting a hydrolic clutch to a steering wheel is a bad idea. If you press the clutch at the wrong time you'll end up with air in the system and have to bleed the whole thing. But I believe goldwings have a remote reservoir.


Good luck.

Just some random thoughts on your car....

It's really just a big go-cart, isn't it? It looks like a freakin' blast too, BTW

So it has cantilever front suspension, even at a straight 1:1 leverage rate (and it's probably not a straight rate, but progressive) the wheel travel will translate into what? An inch or 2 of shock piston stroke? Probably less, due to the ratio options cantilever arms allow. Most of a GSX-R shock will be wasted with that limited amount of stoke, and valving could be tricky. A fair bit of weight and expense over what's there now.

The car was raced in the past. Was it raced with the rubber suspension elements it has now? If so, they probably work at least acceptably for now. Once you have it up and running and out to the track a few times, you can see what the others are running might be helpful.

Does the car even have a full steering wheel rotation from lock to lock? I would guess not. So you might get away with a M/C on there and avoid it sucking air when activated upside down. Many sportbikes with full fairings and hyd. clutches have remote reservoirs, it shouldn't be hard to find one at a wreckers. What kind of set-up was in it before?

Another thought. Those 3/4 scale oval track cars, Legends, I think they are called, use motorcycle engines. Somebody is supplying that market with options to make those clutches work. A Google should tell you who.

Anyways, I could be way off base, I know Jack about race cars, really. But there you go......

Sev wrote:1) They are two different shocks, and while they are mechanically interchangelable I do not believe they are valved or sprung identically. Additionally they will be different between years.

That is what I was thinking, so I need to get them from the same bike and year.

Sev wrote:2) They can work in the horizontal position if they are mounted correctly. I'm not sure they will be able to support the weight of a car though.

Would that be with the reservoir in the up position? They should be able to support the car, I am shooting for a wet weight with driver of 900 to 1000 Lbs. so it will only have 350-450 Lbs. on the front or 175-225 per spring, my concern would be they may be to stiff, but I can change the mechanical advantage by changing the bell crank dynamics.

Sev wrote:3) I think mounting a hydrolic clutch to a steering wheel is a bad idea. If you press the clutch at the wrong time you'll end up with air in the system and have to bleed the whole thing. But I believe goldwings have a remote reservoir.

Good luck.

Would this be the case with the remote reservoir? I really don't have a choice on mounting locations for the clutch, I have to get some narrow form fitting driving shoes to drive this thing, my feet hook on each other with normal shoes, there is no way to get another pedal down on the floor and with the shifter mounted on the right side of the cockpit I should keep at least one hand on the wheel during shifts.

That is why I am thinking of the remote reservoir. eventually I want to fully automated shifting with paddle shifters but that is later.

Brian

BuzZz wrote:Just some random thoughts on your car....

It's really just a big go-cart, isn't it? It looks like a freakin' blast too, BTW

A go-cart on steroids, it's 4 1/2 feet wide and 10 feet long so it's a bit bigger than a go-cart plus it has independent suspension "freakin' blast" might be an understatement.

BuzZz wrote:So it has cantilever front suspension, even at a straight 1:1 leverage rate (and it's probably not a straight rate, but progressive) the wheel travel will translate into what? An inch or 2 of shock piston stroke? Probably less, due to the ratio options cantilever arms allow. Most of a GSX-R shock will be wasted with that limited amount of stoke, and valving could be tricky. A fair bit of weight and expense over what's there now.

Granted, I might need a softer spring for the front, and I can change the mechanical advantage to match. maybe I need a rear off of a 250 or smaller for the front. the 600 size should work on the back, it has trailing arms and the shock will be mounted about the same as it is in the swing arm.

BuzZz wrote:The car was raced in the past. Was it raced with the rubber suspension elements it has now? If so, they probably work at least acceptably for now. Once you have it up and running and out to the track a few times, you can see what the others are running might be helpful.

This car isn't going to be legal in any road race class, I'll be using it for Auto Cross and hill climbs which takes place on much rougher surfaces than a road race track, thus needing a better suspension. and I'm not a young pup anymore so I want to keep the physical abuse down to a minimum.

BuzZz wrote:Does the car even have a full steering wheel rotation from lock to lock? I would guess not. So you might get away with a M/C on there and avoid it sucking air when activated upside down. Many sportbikes with full fairings and hyd. clutches have remote reservoirs, it shouldn't be hard to find one at a wreckers. What kind of set-up was in it before?

The steering wheel rotates about 100 Degrees each way from center. I need to find a local wrecker and go shopping... In stock form they used a snowmobile 500cc engine and CVT so it didn't need a clutch, I want engine braking so the CVT is out of the question.

BuzZz wrote:Another thought. Those 3/4 scale oval track cars, Legends, I think they are called, use motorcycle engines. Somebody is supplying that market with options to make those clutches work. A Google should tell you who.

Yes, they have room for a clutch pedal.

BuzZz wrote:Anyways, I could be way off base, I know Jack about race cars, really. But there you go......

Not a problem and I don't think you are off base, I'm not on a motorcycle forum to get information about race cars, I'm here to tap into the vast knowledge of bikes and bike hardware that is available here, then it's up to me to incorporate it into a car. I like to through out ideas for others to think about and get differing opinions and viewpoints, someone else may see a different solution than I do. I'm always open to ideas.

Thanks

Brian

Another question, What fuel pressure does the FI run at on the busa motor? I'll have to get a fuel pump for it.

Brian

Update and questions

I can't use the stock oil cooler in the car so until I put together a cooler that will work, I was thinking about blocking off the limes at the engine so I can keep working on the car. Looking at the engine lubrication diagram in the manual it looks like I should remove the restricter orifice in line with the oil filter. Is this correct? I will probably use a screw on adapter and remote mount the oil filter and cooler so I think this needs to be a permanent mod, what do you guys think?

Also there is a small hose coming off of the the thermostat housing, where does this go to? I don't have a bike to look at and the manual doesn't seem to cover this hose.

Also here about the car build progress, if anyone cares to look at it.

http://ultimatecarforum.com/smf/index.php?topic=2538.0

Thanks for the help,

Brian