Machine shop/rebore questions

[xscafe]

First off I want to see if there are any members on here who are machinists that can resleeve my engine. If not maybe a suggestion to a place I can ship. I was looking at L.A. Sleeve but I have no experience. My machinist won't do bike engines. (I've used him for car stuff).

Second I want to see what you guys think of what I'm planning on doing. I'm planning on running XS650 liners bored to 77/78mm and raptor 250 Pistons in 10.5:1 comp. (if the starter can turn that) I'm also planning on either regrinding the cam or using a "performance" one if I can find one. I also want to go a little bigger on the valves and put new springs on.

I've done a bunch of research on the piston sleeve combo but all I've seen so far is "it should work" but nothing about it being done. Will it work? I've yet to look too far into valve train.

Thanks

 

[xschris]

You will never fit a xs650 sleeve in a 400 block. If you want a 650 size motor get a 650 size bike.
http://www.xs400.com/threads/holy-grail-of-xs400-big-bore-pistons.9388/ Check out this thread.

 

[xscafe]

You will never fit a xs650 sleeve in a 400 block. If you want a 650 size motor get a 650 size bike.
http://www.xs400.com/threads/holy-grail-of-xs400-big-bore-pistons.9388/ Check out this thread.

I've seen that thread. That's where I got the idea for the raptor Pistons.

I saw this post where the guy talks about boring the cylinders bigger to take xs650 sleeves. He has other posts talking about bigger sleeves for big Pistons.

http://forums.sohc4.net/index.php?topic=9766.0


Also if you read the chart posted in the thread you quoted it says that xs650 liners can be used for 75-77mm bores.

 

[xscafe]

Well much apologise. I guess I should have read past the first page. That forum is a little screwy on my phone and the next page button was missing.

 

[NewHavenMike]

That seems like a big step up for an engine that was built to be 250/360/400CCs. Id think something would be out of balance or at least, exposing a very big weak point in the engine which is almost always the rods.

Id probably try it anyways though

 

[xscafe]

After more research, I think I've decided that I'm going to go with XJR1300 rods and possibly xt225 pistons or possibly GS500 pistons. I'll probably stay around 70 to 71mm. That way I don't have to replace the sleeves. As far as compression goes I think I'll probably try to stay around 10:1 I may or may not regrind the cam to get a little bit more lift and duration and put some bigger valves and stiffer springs in it, and put some bigger valves and stiffer springs in it, but if I don't need to modify the crown on the piston, I'm not going to bother with fly cutting for bigger valves and more lift. I did a lot of thinking about it and I'm not really wanting to make a hot rod out of it. It's just the hot Rod her and me trying to do as much as possible with it. Realistically I just wanted to run a little bit better. I can do the tunnel on it and I don't really care for going that fast so I don't really need to go any faster. Really I just want to be able to get there faster.

 

[BBS360]

I seem to recall the xt225 pistons and probably the gs500 pistons had different crown heights and shapes, requiring some machining to fit.

 

[xschris]

http://www.xs400.com/threads/lets-go-racing.15270/ This member did a bunch of engine mods. He had some mixed results from them.

 

[xscafe]

I seem to recall the xt225 pistons and probably the gs500 pistons had different crown heights and shapes, requiring some machining to fit.

From what I read the 225 pistons are 1 mm shorter from Crown to Center of wrist pin. And the XJR rods are 1 mm longer. So theoretically it should match up pretty well. Also what I read is that the GS 500 Pistons require recrowning to work with the bowl.