A forum for owners of Yamaha TTR250 trail and enduro bikes!

spit · Veteran Member

280 kit, review?

TTRfan · Super Guru

Hi Mark

It's a straightforward rebore to the biggest oversize. No need for re-sleeving the barrel or opening out the crankcases as there is with the 325 conversion.

I have been running this for quite a while now but it doesn't anywhere near give the seat of the pants improvement that the 325 does.

However, if your TTR needs a rebore then the extra cc will never go amiss!

Brian

JDM_stig · Veteran Member

is there an idiots guide to this ?
or any information on re jetting if you went down this route.

TTRfan · Super Guru

Most of the work is covered in this guide http://www.ttr250.com/Removing_Cylinder_Head/TTR_head_removal.htm

You just go one stage further by lifting off the barrel and taking it to an engineering shop to get it bored out to take the new piston such as the 2mm oversize piston kit available here

The next time I remove a barrel and piston, I will take some pics to insert into the thread.

If you don't alter anything else then the standard jetting is fine - it's working well on mine biggrin

Brian