Hi All,

I have just bought my 15yr old daughter an '05 Gas Gas 125. She loves it, but I was after a little advice....

i) it needs a new chain. The rear sprocket does seem hooked, but the snail cams are in their longest setting. The chain tensioner sits against the swinging arm. I looked at removing a link, but their isnt quite enough length to accomplish that. So, what is the standard gearing, and what pitch is the chain? Is it a 520? Will i need to replace sprockets too, or just the chain? Who makes a good chain for a small trials bike?

ii) it has a Domino throttle with a black tube. How can i tell if its a slow action throttle or not? my Beta has a slow throttle and it seems to have a similar amount of angular rotation.

iii) which is the easiest fltwheel weight to fit? I wasnt keen on heating and then shrink to fit actions, or the tack welds. Does anyone have any experience of a simple to fit flywheel mass?

iv) its got AJP brake and clutch master cylinders. The rubber boots that seal the actuation pin are a little perished. Can you but them separately in the UK? If so where from? My Beta has Grimeca brakes and has a similar problem and i havent been able to source the boots separately from a service kit!

many thanks

Ian

All parts available from Gas Gas motors uk (do web search).

520 chain - correct.

Re: flywheel weight, most bolt on. My S3 flywheel weight on my 280 gasser is bolted in with 2 Allen key bolts, I'm fairly sure it's the sane on a 125.

thats great, thank you! off to look now :-)

Ian

Hi Ian,

i) Check that it is a 520 chain, a few riders on 125's have fitted 420 chains & sprockets. The number on teeth on the rear sprocket will let you know, standard on the Gas Gas 125's with a 520 chain I believe is a 44, or if it is running a 420 chain it will be about 58 tooth.

Renthal R1's are the highest quality chain, but are more expensive: http://www.splatshop...-104-links.html

Regina standards are a good quality cheap chain: http://www.splatshop...-520-chain.html

If the sprockets are worn, I would recommend you replace them at the same time as the chain, else you will wear your chain quicker.

http://www.splatshop.co.uk/talon-front-sprockets-gasgas-pro.html

http://www.splatshop...-sprockets.html

ii) Black tube Domino throttle is the slow action throttle. white for the fast action.

iii) The S3 flywheel weight is bolt on, and comes with everything you need, including the flywheel puller.

http://www.splatshop.co.uk/s3-gasgas-flywheel-weight-with-puller.html

iv) RQF make an aftermarket rubber boot pin & spring that fits: http://www.splatshop...ubber-boot.html

Cheers,

Tim

Edited March 15, 201313 yr by splatshop

Hi Tim,

wow thats splendid!

thank you very much

regards

Ian