upgrade ttr 250- a bigger engine..

**niels** · #1 14 Mar 2005

hi,

just got an idea by reading this forum..
can i put a bigger engine in my ttr 250 (like for ex a 600?) or an engine from another bike?
wicked question, i know..

thanks for your reply
greetz
niels

**FredXTZ** · #2 14 Mar 2005

I think your best [read : easiest and cheapest] bet would be to rebore your cylinder to the biggest bore possible, keeping in mind what piston you can use. Then get the biggest air filter and exhaust you can get, preferably a Laser Duo-Tech, and test and adjust the performance and air/fuel mixture on a good test bench.

------------------
Fred, XTZ660, Holland.

**Matt595** · #3 15 Mar 2005

TTR frame is not made for a 600 torqy engine, a bike is an all together and you'll need to change many other parts if you transplant an engine.
Then in some countries it won't be approved legally, insurance will not be valid if you crash etc.
It will cost you way more than buying an old 600 bike instead.

Matt

**niels** · #4 15 Mar 2005

thanks for the replies guys...

if i bore the cylinder, it makes it illegal to i suppose, i mean for the assurance and so on..
greetz
niels

**Steve Pickford** · #5 15 Mar 2005

Fiiting a 600 cc engine, even if possible could work out a great deal more expensive than buying a 600 in the first place.

You'd need the whole engine, plus carb, exhausts, electrics, bigger battery etc. You probably couldn't service the top end without first removing the engine. I doubt that any of the engine ,ounts would line up, serious engineering & ££££ to do a good job. Exhaust & airbox routing problems would also present additional difficulties.

Unless you're an experienced engineer & mechanic with a fully equipped workshop, I'd just buy the 600.

If you bored your 250 to 280-300, how would anyone ever know, they'd have to strip the engine & measure the piston to find out.

**Fish** · #6 16 Mar 2005

Hi Niels, I don't really know about fitting a different engine (XT350 maybe?) but there are some other things you can do. I think the biggest you can make the standard engine with no crank case modification is a 270 kit which is actualy 263, there are or where a 325 and 350 kit in the US it means a different barrel/piston and the crank cases have to be machined aswell.
If you have'nt already through away the snorkel from the airbox intake as it strangles the engine and a step further is to modify the airbox intake hole by almost doubling the size of it.
Then theres always one of the CRD exhaust systems (header and muffler). A couple of web sites of interest:-

www.ttr250.com

All the info on mods

www.groups.yahoo.com/group/TTR250

more info and a forum.

Cheers Fish.(hows the battery holding out)

[This message has been edited by Fish (edited 16 March 2005).]

[This message has been edited by Fish (edited 16 March 2005).]

[This message has been edited by Fish (edited 16 March 2005).]

**Fish** · #7 16 Mar 2005

Sorry I could'nt get one of the above links to work so try this one:

http://autos.groups.yahoo.com/group/TTR250

Cheers Fish.

[This message has been edited by Fish (edited 16 March 2005).]