Pre 76 XL250 to 350/360 stroker

[Husados]

Just seen the latest issue of VMX with a C&J honda 250 stroked to a 360

Can this be done with standard XL 350 parts...........? Rod and crank.?
Can a 350 top end be coupled with a 250 bottom end.............?

Help me out i need to know

[MX?]

Dunno the answer.
But it sounds interesting! I also read somewhere that the cam is interchangeable between the two (very different lift and duration), and have been trying to find what difference/affect this may have as well....to no avail at this point.
I'd imagine there are folks here that should know this.

[Tim754]

Gees just bolt the complete XL350 engine straight in even the same cables and electrics!!!! and will save a lot of bullshitting around.  Machining and fitting this top end to that, stroking cranks, new sleeves Bah! use the easiest method when it is available,then  get out there and ride/ enjoy

[cyclegod]

Gees just bolt the complete XL350 engine straight in even the same cables and electrics!!!! and will save a lot of bullshitting around.  Machining and fitting this top end to that, stroking cranks, new sleeves Bah! use the easiest method when it is available,then  get out there and ride/ enjoy

Most of the bullshit is to drop the 15Kg difference between the two motors so I'm told 

[Tim754]

9.30 kgs difference without oil or carby. Used to race both had engines on bench and weighed ,still written on shed wall. If you want to do that caper fine,enjoy
From experience a 250 properly and cleanly fitted with a 305 kit fitted with electronic ignition that you can still find was worlds better than the 342cc stroker we had made. 305 Revved quick made usable power over a fair range, did not shit gearboxes and was so reliable ! Stroker was ho hum for all the work and setting up and naturally it went the big bang as of course parts all had to be made. Even the >>>fat lump<<< 350 with an aftermarket 420 kit we had was a better racer and well heaps more enjoyable. But like I started out saying all this is only based on experience having competed on these for fun with an eye on the budget as always in the 1990s   Cheers Tim

[firko]

In my old Champion framed XL I tried a number of combos including a very highly modified stock bore/stroke 350, a mildly modded 11-1 comp 420 and a 12-1 compression 305. The 350 was by far the quickest but the 305 cut equally as fast lap times due to it being so easy to ride. The 420 was a torquey bugger that was prone to wheelstanding and breaking third gear due to the extra torque. If I was building another XL I'd build a 305, if only to get some life out of the gearbox.

I'm actually negotiating to buy my old XL 350 back. In fact the whole Champion Honda is (or was) for sale but I don't want to go down that path again.

[Husados]

use the easiest method when it is available,then  get out there and ride/ enjoy 

Every chance i get, But you need something in the shed to play with.............

Cheers, thanks for the info