How To Make A Gasgas 125 More Powerful.

[yzeefoureight]

Hi,

thanks i will tell my dad when he gets home and see what he says.

Thanks

sam

[yzeefoureight]

Sam

It has two base gaskets for a reason!

That reason is taking one out to tune the engine.

Of course it changes the squish BUT so does swapping for a modified higher compression cylinder head and people do that!

If it were me!

I would do the following in the order as I write.

Take the cylinder/jug off

Remove ONE BASE gasket

Put the jug back on!

THIS NEXT STEP VERY IMPORTANT!

When putting the cylinder head back on and after torquing down cylinder head and jug/cylinder REMOVE SPARK PLUG AND TURN/PUSH START LEVER SLOWLY.

This will verify that the piston is not hitting the lowered ( lower due to removing a base gasket) cylinder head!

If it does NOT hit then proceed with re-assembly and then start bike as usual.

You may have to increase the octane of the petrol

If this first step works let us know and we can walk you through the next steps.

Good luck!

BillyT

[yzeefoureight]

Your spot on Billy T,

I have put a new Wosner piston kit in this morning, nearly half the price of the GasGas S3 piston kit, cleaned the ex port up & removed the thinner of the two base gaskets.

The bike is now running better than ever. I put Boyesen reeds in over a year ago & they made a worthwile difference.

On the subject of race fuel, I once bought & ran some VP race fuel in a std YZ125 motocross bike, It made no difference to the performance, I mixed it with shell optimax.

I found with 2 stroke mx bikes without engine work, different pipes, silencers, reeds & altering jetting would only alter the power one way or another top or bottom end, realy to suite the power delivery to the individual.

I use to use Silkolene octane booster at 100ml to 5 litres of Shell Optimax & it was noticeable, the bike noticeably ran cleaner & crisper off the bottom.

Unless an engine has had head & compresion mods to increase the power output I don't think the race fuel is worthwile other than to prevent detonation, a mate of mine years ago used to mix aviation gas (av gas ) with his petrol to stop detonation on his CR250 mx bike in the winter. Maybe simpler to go up a couple on the main jet or lift the needle !

Anyway thanks all for the advice & in depth debates ! verry good reading.

Any advice on how not to fall of a Scorpa on rock sections would be gratefully received.

Thanks, Nigel, Sams Dad.

[jse]

Hi everyone,

thanks for all the replys. Really useful. My dad can set it all up for me its just that we didn't know what would be the most beneficial and easiest way of gaining more bottom end power. There are loads of ideas on the topic but which do you think is the best? My bike has 2 base gaskets on it and my dad thought of taking one off as BillyT said but we asked at our local biike shop and said that it had been set up in the factory for the squish band, so I don't know now. What should I do?

Thanks

Sam

Sam,

I kinda wanted to stay out of this discussion, but in my experience, the bike shop is giving you good advice. The 2 gaskets (some engines come with one or rarely three, the thickness of the gasket(s) is much more important than the number of gaskets, which come in various thickness spec.'s) are used by the assembling tech at the factory to set squish band minimum clearance. If you remove one you may run into the problem of reducing the squish clearance to the point that, under operating condition temperature and material growth, you may have contact between the outer piston crown and the head. Contact at the outer crown will reduce top ring land clearance and cause the ring to seize in the groove, causing blowby and a spike in piston skirt temps and skirt deformation. Things go rapidly downhill fast from there.

Jon

ps. Forgot to add that it would be a good idea to check the squish clearance just to be sure. Soft solder works well and to be really accurate, use two pieces, front and rear, which will compensate for piston rock. Generally accepted clearance is about 1mm (.039"), but the 125 can get away will a little less as smaller cylinders have a little less temp growth of components.

Edited April 12, 2010 by JSE

[houseape1000]

Any advice on how not to fall of a Scorpa on rock sections would be gratefully received.

Headfirst is always a good way to not fall off !

[billyt]

Sam

What is the latest with the 125cc project?

How is the bike running now since the changes?

Hopefully you are a satisfied lad? LOL.....

BillyT