Wiseco

[IGASAURUS]

Anyone ever had any issues with Wiseco products? I had just threw a fresh top end into my 125, only to have my bike die. Tore it apart today and found out the damned ring broke, so of course my piston and cylinder are f.cked now.

Just curious if this is common with Wiseco or just a fluke. Also, anyone have experience with the Athena big bore kits? I want to 144 it :thumbsup:

[Falcon991]

I've heard good things about Athena but no personal experience with them. Wiseco seems OK to me, but I have always felt they were maybe a little lower-quality. I've done plenty of rebuilds with them though and no ring issues like you report. It was probably just a fluke.
If you go for a standard-bore rebuild, try Cometic's hard parts brand... uh... the name slips my mind. Pro- something. They are decent. OEM is best for durability though.

[IGASAURUS]

Was hoping either you or 757 would reply, I think you guys are the only 2 strokers :lol:. But yeah, I knew it was bad when I looked at the spark plug and it was all tore up.

I think it would end up being about the same price if I were to just repair it with standard stuff vs. getting the Athena kit which includes all that I'll need. That's the only good thing about having bike problems...gives you an excuse to get cool new stuff! :rockon:

[copsey]

If your exhaust port is bridged a Weisco piston will try to seize without many, many short heat cycles (like 4 tanks according to them). Athena has decent products but I've seen issues with their Nikasyl.

[757]

I was running the nik's Pro-X pistons in my YZs and never had an issue with them. I would abuse the hell out of my top ends and usually would only change them once a year. This was in both the 125s i had (01 and 06) and I raced the 01 for 3 seasons in 02, 03, and 04. and the 05 250 that I ran for 2 full seasons in 06 and 07. Come to think of it, we never even put a top end in the 250 after the one we put in when we picked it up. Definatly good stuff and was very reliable.

[Falcon991]

Pro-X! That's the brand I was trying to remember. Good stuff.

Remember, Wisecos are forged pistons. Forged aluminum has a faster rate of thermal expansion than cast aluminum. What this means is, although the two pistons will end up being the same size at full temp, the forged piston gets there faster. This is a problem when the cylinder is engineered for a cast piston (as are all OEM cylinders/sleeves.)

Can you guess the problem?

Yep, forged pistons will get bigger than the cyclinder they reside in if you pour a lot of heat into the motor quickly. Heat seizure! In other words; warm the sucker up really well before riding with a Wiseco. You shouldn't have any problems if you do.

[Fearo]

Pro-X make some great products indeed, and they are pretty cheap, at least here in Belgium.

The absolute best quality pistons we have ever used in my 144, are definitely Vertex, though.

[Sam137]

Pro-X make some great products indeed, and they are pretty cheap, at least here in Belgium.

The absolute best quality pistons we have ever used in my 144, are definitely Vertex, though.
Pro-X can do some impressive things with a 85 and still legally run stock class.

[MXDave]

Old post I know, but bored. I have always been advised to steer clear of Wiesco products Pistons and Cranks. This has come from two well know engine builders. Lower quality and other issues.

[RAD]

Pro-x I like allot better, never had any problems with them and I ran lots of them. Good or better than stock. Had a lot of issues over the years with Weisco, especially with wrist pins seizing. Did you check the end gap on the ring and file it to tolerance listed in the Weisco instructions, before you installed it.