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Modify trials bike for beginners

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Just a quick question, as is often the case we are having an influx of new beginners to our trials club and its hard finding the young ones bikes,ie 13 yr olds

How easy is it to de-tune / de-power bikes Im finding myself against my better judgement putting people on bikes that are two powerful, but i guess if you can slow it down there is no problem is there any easy fix solutions that anyone has had a degree of success with.

gas gas, scorpa and sherco are most common brands here, i would love to here your storries :thumbsup:

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Jono - not too long ago - couple months? there was a thread on limiting the throttle position. Basically adding a piece of tubing inside the carb (above the slide)to restrict the slide travel. (the throttle cable runs inside the tube)

This was primarily to reduce the chance of whiskey throttle problems, but may be a good mod depending on the skill level of the rider.

Good luck

:thumbsup:

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Hi Jono,

Apart from modifying the bike, I like to set up cones in between tape (did it for myself when starting a few years ago!) so the only way to ride through is by using the clutch to control the turns. I think the finger on a clutch as a get out of trouble device is so important and this helps get the rider used to it. Good luck. Lucky you getting lots of new riders.

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thanks for that feedback so far, That clutch idea is really very good but i'm also really keen to get a good grasp on some of the things you can do to de-tune a bike or make it more manageable. Someone said to me you can mess with the timing has anyone ever done that.......:thumbsup:

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a slow throttle tube also,messing with the timing works but you eliminate the woodruff key by doing so and the fly wheel could move later on.head spacers?best thing is to put em on the bike and ride it if they crash they crash

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thanks for that feedback so far, That clutch idea is really very good but i'm also really keen to get a good grasp on some of the things you can do to de-tune a bike or make it more manageable. Someone said to me you can mess with the timing has anyone ever done that.......:banana:

Yes I do it routinely. Pull the flywheel (assuming it's external), mark the position of the stator on the crankcase so you can put it back to stock if you want to, loosen the screws that hold the stator and move the stator 1-2mm in the direction of crankshaft rotation. Do NOT remove the flywheel key!

You can experiment with different positions. You can file the slots in the stator for more movement if needed.

This is a free mod that can be easily undone. As a bonus, with retarded timing your bike will probably run on lower octane gas.

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Yes I do it routinely. Pull the flywheel (assuming it's external), mark the position of the stator on the crankcase so you can put it back to stock if you want to, loosen the screws that hold the stator and move the stator 1-2mm in the direction of crankshaft rotation. Do NOT remove the flywheel key!

You can experiment with different positions. You can file the slots in the stator for more movement if needed.

This is a free mod that can be easily undone. As a bonus, with retarded timing your bike will probably run on lower octane gas.

I believe the newer Gas Gas bikes from 2002 to present do not have a movable stator plate. You would HAVE to remove the woodruff key to rotate the flywheel on the Pro model Gas Gas Bikes... But that's an extreme measure.

Use the vinyl tubing trick on the throttle cable just above the slide like Laser said. After that, you can see if it's possible to add flywheel weight. I know it is on the Gas Gas because I added weight to my Wife's GG 200.

Then there is the slow turn throttle. I added THAT to my Wife's bike also.

And THEN, if it's a Gas Gas, you can order head shims or spacers from LewisportUSA to drop the compression without affecting the port timing.

Another trick to keep the speed down a little is one tooth smaller on the counter shaft sprocket (front sprocket). However, without reducing the power by other means, the lower gearing means a slower speed at any set RPM, but more mechanical advantage for the engine with more jerking if the rider is sloppy on the throttle. BUT, slower speeds without as much need to slip the clutch..

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great 2-ply !combine everyones opinions and put em all together,do the hokey pokey....saves reading time!!!!!!!!

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great 2-ply !combine everyones opinions and put em all together,do the hokey pokey....saves reading time!!!!!!!!

That's right! otherwise this thread will go around and around over and over... Get the facts all neatly packed in one post and then we can get down to crackin jokes and stuff.. :banana: or not.. :lol:

However, I left out one trick to slow the bikes down for beginners:

Pull the spare tire out of the car or truck..... or out of the neighbor's car or truck and tie it to the bike.. Don't have a spare? then just tie the bike to the bumper of your daily driver.. THAT should do the trick. Not foolin, I once pulled my old air cooled VW Van 1/2 mile with my SWM 350, with the van in second gear and the other two bikes and bodies still attached to the van... I made a mistake and tried to drive through a flooded neighborhood and drowned out the van and then ran the battery dead... But the SWM got us running again!!! :banana:

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