OMG another piston q

[redwheeliemonster]

So I will try to make this as specific as possible to avoid the long debate.

Last year I installed a new piston kit and was persuaded by the local shop to use namura. Now I have about 30-40 hours on it. And want it out.

While the jug is off I am reinstalling with the 05 thinner base gasket. And phatheads hi compression head.

So considering I am after a low end power band. Would I benifit more from wiseco gp style single ring piston. Or a traditional 2 ring.

[shrubitup]

Neither will make more low end focused power but the gp piston will rev faster due to less weight. Could rev so fast that you just skip past the low end power range unintentionally.

[redwheeliemonster]

Would the single ring help improve throttle response or what is the benifit to using one

[adam8781]

So I will try to make this as specific as possible to avoid the long debate.

Last year I installed a new piston kit and was persuaded by the local shop to use namura. Now I have about 30-40 hours on it. And want it out.

While the jug is off I am reinstalling with the 05 thinner base gasket. And phatheads hi compression head.

So considering I am after a low end power band. Would I benifit more from wiseco gp style single ring piston. Or a traditional 2 ring.

Congratulations on making it to 40 with a namura.

Compression is lowend powers best friend. And lowering the ports with the thinner gasket gives more lowend. So yes You will gain a lot of low end with the thinner base gasket, and phat heads head. You will need 100+ octane fuel from stacking the 05 gasket with the head. the head is designed for the stock base gasket. With the thinner gasket the stock head gets a bump in compression (very common mod) and with the high compression head, it does the same thing.

The only real difference between between the single and dual ring is drag, the single ring piston has less, it revs faster. The downside is the piston rocks in the bore a bit more and the single ring needs to be replaced more often. dual rings don't need Tobe replaced as often, and they rock less in the bore. but rev a tad slower. Most don't notice the difference.

Edited July 12, 2013 by adam8781

[redwheeliemonster]

Thanks for the responses. I will be going with oem I guess. Is it vertex or pro x that makes the all the oems?

Ya the namura seemed like a no brainer talking to the local parts guy. I'm glad I am reading otherwise instead of finding out myself.

On a Sid note magura sent me the wrong clutch kit. They sent on for 08 and up crf450. They said I could either send it back or they could give me a good deal on the proper one. He says to me how about 150$. So I took it.

What's the difference between the two. Would the 450 kit have worked.

And anyone want to buy a hydro clutch new in the box? Lol

[adam8781]

Pro x is the oem-a-like piston.

I would use forged if it was my bike. I have had bad luck with cast in my 02 cr250. Went to forged. Stopped melting the pistons at the exhaust port bridge.

[redwheeliemonster]

Well here we go again. Considering the significant increase on compression. Is a cast piston up to the task. Or forged becoming a requirement at this point.?

The phathead dome I was going to use recommends 95 octane. Shouldn't 100ll be enough even with the thin base gasket

[adam8781]

100 should be fine, And both cast or forged would be just fine. I just prefer forged pistons if you go cast replace it every 40hrs max. The hot exhaust port bridge kept smearing the cast pistons. I went to a wiseco and the problem went away.

i bought the bike used in 04, pulled the cylinder found the stock piston smeared all over the port

I had the cylinder replated to fit a oem cast piston perfectly. 15 hrs later it did the same f**kin thing. had it repaired again, went to wiseco. looked at the cylinder with the head off 2 seasons later when i was getting it ready to sell. No more problems around the pesky exhaust port.

Edited July 14, 2013 by adam8781

[redwheeliemonster]

Thanks for the info. I already picked up a prox kit. So I will run that this season. Next rebuild will get forged.

The current namura piston replaced the oem. Is am curious to see what it looks like compared to the original. Bu I guess skirt failure just happens with no sighns of wear or stress?

Edited July 14, 2013 by redwheeliemonster

[adam8781]

Thanks for the info. I already picked up a prox kit. So I will run that this season. Next rebuild will get forged.

The current namura piston replaced the oem. Is am curious to see what it looks like compared to the original. Bu I guess skirt failure just happens with no sighns of wear or stress?

Yes, never see them coming. Im still impressed you got 40 hrs out of the namura!!

[shrubitup]

I'm still impressed you got 40 hrs out of the namura!!

Then you should worship me as I've gotten twice that interval from these Taiwanese pistons. ?