I am redoing the top-end on a YZ85 for my sons buddy. Problem is there is no marking left on the cylinder to tell me if it is A, B, C, or D. So, I pulled the cylinder to look at the piston. It too has no letter designation, but it is not stock. The piston has numbers in the top of it (may be a Wiseco) anyway, it all looks to be in much better condition than what I expected (based on condition of the rest of the bike).
I have a re-build kit "B" from the dealer but the piston is way too small for the cylinder. I tried to mic both the piston and the cylinder but my meter shows them both being around 42.5 mm and the book says they should be 47.--....
So, my questions are
1. How do I find out what cylinder I have without the marking?
2. The B piston is way too loose in the cylinder to work..I don't think the thing has been bored. It should be pretty obvious right? The dealer says to put the B in and run it, but man it is a lot more play than the wiseco piston....what do you guys think?
3. The numbers on the top of the piston are 805M04750 and 85S7B ---update...I found that this is the standard wiseco piston size at 47.50 mm. Which is bigger than the D piston in the manual (47.472).
Any help or advice would be great. This kid wants to ride with us this weekend and I would like to take him. His mom is divorced and he doesn't get much "guy" time. After replacing the swing arm/linkage bearings, brakes, fork seals I am ready to be finished with this thing!! LOL
I have a re-build kit "B" from the dealer but the piston is way too small for the cylinder. I tried to mic both the piston and the cylinder but my meter shows them both being around 42.5 mm and the book says they should be 47.--....
So, my questions are
1. How do I find out what cylinder I have without the marking?
2. The B piston is way too loose in the cylinder to work..I don't think the thing has been bored. It should be pretty obvious right? The dealer says to put the B in and run it, but man it is a lot more play than the wiseco piston....what do you guys think?
3. The numbers on the top of the piston are 805M04750 and 85S7B ---update...I found that this is the standard wiseco piston size at 47.50 mm. Which is bigger than the D piston in the manual (47.472).
Any help or advice would be great. This kid wants to ride with us this weekend and I would like to take him. His mom is divorced and he doesn't get much "guy" time. After replacing the swing arm/linkage bearings, brakes, fork seals I am ready to be finished with this thing!! LOL
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