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Nate R

XL600 Hi-Comp Piston?

10 posts in this topic

Wiseco makes an 11:1 compression piston for the XL. Anyone have any idea how much power gain I'd see out of this? How much harder will that be to start?

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Hi,

If you can wait a few weeks I'll be bale to tell you as Im just building an XL with that piston!

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Nate R,

I have a Wiseco 11-1 piston with 200 miles on it if you're interested. It still looks new, only a little brown on top. 1 mm overbore (101 mm). Bruce

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Ive chosen it cos I always used the wisecos for racing. I find them to be very strong and good value.

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Now, why would you have that? pulled it out and put in an xrs only piston???

:thumbsup:

No, smart ash, that's not what I did! lol Here's the story.

I bought this bike, it ran good but had top end oil leaks. I pulled the top end apart to repair the leaks and while it was apart I decided to pump it up a bit. So, I bought the Wiseco , a Megacycle cam, had the rockers hardwelded and so on. Reassembled it and it ran great, only now it sprung a leak out of the main cases!:busted: So, I pulled it back down. In the meantime, I came across a bunch of '93 XR650L stuff. The engine ran great, so I installed it, the wiring harness and front end onto the XL600. The 650L engine has always burned some oil so now I'm gonna pull it down and try to install my dual-carb top end on it. I can't use the piston because it's for a 600.

So there you have it, the abbreviated version.:busted: Bruce

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No, smart ash, that's not what I did! lol Here's the story.

I bought this bike, it ran good but had top end oil leaks. I pulled the top end apart to repair the leaks and while it was apart I decided to pump it up a bit. So, I bought the Wiseco , a Megacycle cam, had the rockers hardwelded and so on. Reassembled it and it ran great, only now it sprung a leak out of the main cases!:busted: So, I pulled it back down. In the meantime, I came across a bunch of '93 XR650L stuff. The engine ran great, so I installed it, the wiring harness and front end onto the XL600. The 650L engine has always burned some oil so now I'm gonna pull it down and try to install my dual-carb top end on it. I can't use the piston because it's for a 600.

So there you have it, the abbreviated version.:thumbsup: Bruce

Zrxer,

Both the XR650L and XL600 pistons are 100mm in diameter. I think that the wrist pin diameters are the same, but I'm not sure. The difference is in the distance from the wrist pin to the top of the piston. I'm thinking that the distance in the XL piston is greater so it might go past the top of the cylinder.

I'm pretty sure that the XL combustion chamber is smaller. This will up your compression. Just guessing it will be about 9.5:1 to 10:1.

I think that the issue is going to be the difference in diameter of the head bolts. This might make the locating pins different in diameter between the XR650L head and the XL600 head. If this is the case try using the cylinder from the XL on the XR650L crankcases and see if that works. Might have the same issue with the locating pins between the XL600 cylinder and the 650L cases.

That dual carb XL head will get you at least 10% more power if not 15% or 20%.

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the locating pins could be trashed, and left out. couldnt they? havent had the cyl. off mine yet but the xl head sounds interesting to me.

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