A couple of years back I bought a complete set of coated Weisco pistons w/rings,pins,bearings and circlips for a rebuild I was into put them in and ran them,it was the cheapest way to get my engine back together.Last season I had crank problems which ended up taking out a cylinder and piston so when I put the engine back together I used the 2 Weisco's and an oem in combo with the oem in the center.I didn't especially want to do it this way but it was pretty much the end of the season and I didn't want to spend any more on it at the time.I got one run on it and had to put it away as it rained that very night and ended sledding around here for the year.Now I'm thinking I should replace the 2 Weiscos to get the engine balance back as the oem pistons are noticeably heavier but wondered if it would really make that much difference with a trail ridden sled.I know that Weiscos wear out faster and all I'm just looking for opinions on the balance issue.Has anyone else ran a similar combo?
daman
New member
pull her down and get all oem's in there for sure..
That is my first instinct and I do actually have the parts on order from Port Yamaha just waiting for them to get here so I can put them in.
While I'm not arguing that the OEMs are the best replacement, Wiseco's are not direct replacements and require different cylinder to piston clearances. This is most often overlooked and is why Wiseco's get such a bad rap. Folks don't follow the recommended clearances and just slap them in. If you did not overbore the cyclinder when you installed them last year, installing new OEMs in thier place would be a direct replacement and would be recommended. In my experience, Wiseco's outlast any cast OEM piston by a long shot as long as they are installed correctly and proper warm up is followed prior to holding the loud lever WOT. Had an XCR with over 7000 miles on .020" oversize Wisecos without issue.
horkn
New member
I have had great success with wiseco pistons as well.
there is no need to bad mouth them, but no, I would never run 2 different pistons in any multi cylindered motor.
there is no need to bad mouth them, but no, I would never run 2 different pistons in any multi cylindered motor.
srv540
Member
Oem are great, but I have had luck with my wisecos in my SRV 540 since 1998 and still going strong to this day.....jugs were bored to wiseco specs. and warm sled up for a minimum 10 minutes before WFO runs.
snomofo said: