jamie.s Posted March 19, 2007 Share Posted March 19, 2007 will an xs400 engine fit a xs250 ?or even can the 250 be bored out by much ? it needs new piston rings any way so might as well bore it out / get 400 bores put on the 250 engine and put all new pistons on it. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 19, 2007 Moderator Share Posted March 19, 2007 will an xs400 engine fit a xs250 ?or even can the 250 be bored out by much ? it needs new piston rings any way so might as well bore it out / get 400 bores put on the 250 engine and put all new pistons on it. I assume your talking about the 2A2 engine, as there was a later dohc engine which won't fit. the xs400 will slot straight in and is in fact lighter than the 250 (bigger bores I assume) you can't just overbore as the valves are a lot smaller and uses a different carb 32mm-250 34mm-400. I think even getting a 400 barrel onto a 250 bottom end could cause the liner to foul the crankcase mouths (not tried it, but i'm guessing) I bought a 400 engine off ebay for £50 and carbs for £20, then you need the rubber between each side of the carbs for the bigger mouths. Well worth the hassle though as mine motors up to 85 and great on the twisties. a custom model will fit as its only got a rounded barrel as opposed to a squared off one. Be careful of the 12n model as they have "rear sets" which If yours hasn't then you need to figure this into your equation. BTW loads of stuff in germany, but be carefull with carbs and camshafts as they have restricted (27bp) engines drewpy Link to comment Share on other sites More sharing options...
jamie.s Posted March 19, 2007 Author Share Posted March 19, 2007 thanks for the info , just to check that a 400 will fit in this , right ? my bike Link to comment Share on other sites More sharing options...
Moderator YamaHead Posted March 20, 2007 Moderator Share Posted March 20, 2007 I've had a coupla 400's in the past....& shoehorning a 400 lump into your 250 would make a nice little sleeper there Jamie. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 20, 2007 Moderator Share Posted March 20, 2007 thanks for the info , just to check that a 400 will fit in this , right ? Looking at your bike....yes with no mods. Link to comment Share on other sites More sharing options...
Recommended Posts