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Scorpa Problems/concerns


fedralseth666
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ive just recently started trials on an 03 scorpa sy 250 which i got second hand from a farmer off ebay. id like to know the following:

there is a dent and some small cracks from where the kick starter at some point has hit the engine side casing. it doesnt seem to leak, is it worth getting it welded next time the casing has to come off to do the clutch?

looking at the bike i know the scilencer wont have been cleaned out, how do you clean scorpa scilencers/middle box? havnt they got ceramic plates in them or something? all the mx scilencers ive done have been a simple repack job but this one is welded shut. ive read the tech advice on here and it recomends burning the oil/carbon out but it also says that the high temperatures used to do this can melt aluminium. its suggests soaking it in strong chemicals, which chemicals? can someone shed some light on this?

My gearbox worries me, its not like an mx bike, it doesnt seem to like to change gear on the roll, ill fully pull the clutch in and pull the lever up and instead of going from first to second easily sometimes itll go into neutral, then when its in second it might jump back into neutral. im sure it dropped out of third and into second the other day. if you select second gear you sometime get a clattering sound befor it drops into gear, its like you really have to exagerate your gear changes, unlike on an mx bike where its a little tap and its in. im not sure if its me changing gear wrongly or just not used to how far away the shifter is. i also got told to use the clutch every time i change gear where as on an mx bike you normally dip the revs and nock it up a gear. should i be worried or am i just a total noob!

Many Thanks for any advice, Tim.

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1..Gear changing difficult. Sounds like someones been changing gear without the clutch!!!!! Don't even think about it. Get it checked by someone who knows what they are doing.

2..There is nothing in the middle box to repack.

3..Repacking the silencer is a problem. Just doing mine at present. It needs cutting open and repacking then welding up. Might be easier to buy a new one.

4..Cracked casing. If it doesn't leak leave it.

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Try changing the gear box oil before doing anything else to do with the gears if hes a farmer i doubt very little maintenance has gone into the bike dont get me wrong it might have though.

I know you motorcrossers dont always use the clutch either not advised every gear change use the clutch unless you want to be paying out for a new gearbox.

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I've found that trials bike gearboxes can be a little tempramental, but I've generally found that it is when the clutch drags slightly when you are stood still and the gearbox is tight that changing gear is difficult. I also believe that trials bike gearboxes must be meade of stearner stuff than they appear to be because on my old bike I got false neutrals a couple of times and cound hear the gear rattling about before dropping in somewhere with a loud clunk, but I've as yet had no lumps in my oil except occasioanlly some clutch material.

Don't test your gearbox though, use the clutch, an oil change for some good thin oil would be what I would try first in your situation. Use something thin, and do it whilst the engine is warm.

Bob

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cheers guys, after my first outing on the bike i changed the gear box oil, i use the same motorex light gear oil (10/30w)as what i put into my 06 yz 125. the only difference ive noticed so far is that when cold the clutch sticks/drags.

when i first start the bike i have to pump the clutch and then nock it into a gear, and hit the rear break to free it up! im told this is a common problem with trials bikes. if it were a motocross bike id change the clutch basket but people say its pretty common with trials bikes.

ive tried to free the clutch without the engine running by pumping the clutch and rocking the bike in gear but it doesnt seem to work. have you got any sugestions?

Ive been told to zip tie my clutch lever to bars while the bike is stood during the week to let the plates separate, is this a good idea? wouldnt it strain the springs and put excessive pressure on the hydraulic clutch?

cheers, Tim.

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Pumping the clutch lever does nothing but build arm muscles.

Leaving the clutch lever pulled in when you are not riding it sags the clutch springs.

To free the clutch, there are two easy options:

Option 1 Without starting the motor, change into 6th gear, hold the clutch lever in and rock the bike.

Option 2 (if you have the riding space available) Start the motor in neutral. When you are ready to go, push off with one leg and select first or second gear while it is still moving. Change up gears until you are in a high gear and then pull the clutch lever in and ride around a bit like that till it breaks free.

You can fix the problem by:

Roughening the steel clutch plates (bead blast or coarse abrasive paper both work fine) and removing any wear grooves from the fibre plate tangs against the basket fingers. Both fixes are temporary if you are hard on the clutch (probably the same as you've seen with MX bike clutches).

What people have told you is right. It is a common problem with trials bikes. Most people don't bother to service their clutches because once the clutch is freed it works fine till next time.

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cheers for that advice, ill try bead blasting the plates when i have the clutch cover off next.

i dont think im that hard on the clutch, i hardly ever slip it like i would on my mx bike as the trials bike doesnt seem to have any sort of power band or top end power which you need to slip the clutch to get to quickly. i guess time will tell.

does the clutch stick because the oil between the plates is keying them together (like slip blocks) or is it more likely a nackered basket?

cheers for all the help,

Tim.

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The Scorpa SY250 motor eventually suffers from both shiny plates and grooves in the basket fingers. The shiny plates mean there is no way for the air to get in between the plates when the clamping pressure is released. Roughening the plates provides a path for the air.

I successfully filed the fingers smooth on my TY250Z (which has the same motor as the Scorpa SY250). Baskets are very expensive so it is worth filing them a few times before replacement. It needs to be done very carefully to prevent bending the fingers and keeping the engagement surfaces on the fingers flat and square.

From how you describe your riding style it sounds like once you fix your clutch it will stay good for a while. Have a look at what the top level riders do with their clutches when jumping up big obstacles from a standing start and you will see that they cop lots of hard use ie full throttle, peak RPM, drop clutch in third gear. I've heard that the clutch in your Scorpa SY250 shares a clutch with an early 1990s Yamaha YZ125 so it is designed for a bit of abuse.

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Early 90's YZ125 clutches were prone to dragging. But the problem stemmed from release mechanism issues. If left unrepaired the steel plates would blue and warp, making the problem worse. Maybe bleed the clutch. If it is better for a while then starts dragging again perhaps the clutch system needs to be disassembled serviced.

Paul

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  • 13 years later...
 

You're going to have to explain the problem better.

What year is the bike?

Does it go into gear with the engine off, if you rock the bike fore and aft a bit?

Does it seem to click into gear but nothing happens?

Can you see the clutch arm on the engine moving when you squeeze the clutch?

The way you asked the question is like, "My car isn't working right...how much do you think it will cost to fix it?"

 

 

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