‘09 Suzuki RM 85 piston choices?

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1/23/2018 5:53 PM

Vertex, Namura or Wiseco. Cast or forged. Been reading all I can find on pros/cons of them and see benefits from both but really, what’s the general consensus guys?

TIA.

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1/23/2018 9:27 PM
Edited Date/Time: 1/23/2018 9:28 PM

That has epic potential of getting the perpetual circle of responses from unwitting posters. Let the games begin!

ty (in advance)

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much ty. How to spot a paid forum poster/artificial forum traffic producer (see list of actions/phrases below):

Copius pattern amounts of phrases like “Anyone have”..., “Anybody know?”.... and their variations.

Thoughts?
Any help is appreciated!
Thanks in advance!





1/23/2018 9:29 PM

In my opinion OEM is always a safe and smart choice.

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1/24/2018 1:07 AM

Wiseco forged.

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2009 Kawasaki KX450F
2009 Kawasaki KX250F
2002 Suzuki GSXR 600

1/24/2018 1:43 AM

Bman_145 wrote:

In my opinion OEM is always a safe and smart choice.

Not on a Honda. Vertex is the right choice for a piston.

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1/24/2018 8:04 AM

Thanks for the input everyone.

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1/24/2018 8:22 AM

Bman_145 wrote:

In my opinion OEM is always a safe and smart choice.

My findings as a 30 year motorcycle mechanic

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1/24/2018 10:04 PM

Namura doesn't even belong in a list of other pistons. They belong on a list of things like cancer, socialism, being dropped from an airplane without a parachute, leprosy, etc.

When my son was racing RM85's, I found the OEM ones to be super consistent on sizing, easy to find, and reliable enough given our change regimen (ring every 5 hours, piston every 10). I had Millenium re-do the coating and they sized it for the OEM pistons. Worked great.

Forged is better if you want to really stretch the limits of piston replacement, as they are much less likely to shatter if you keep them in so long cracks begin to form.

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1/25/2018 1:42 AM

OEM or Vertex cast, replace at sensible intervals and you cant go too far wrong.

Forged pistons are good, but if you go that route you need to make sure you, or who ever rides the bike knows that it needs to be warmed up well before going WFO. Or it could potentially cold seize.

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@russ_69

1/25/2018 4:29 AM
Edited Date/Time: 1/25/2018 4:30 AM

Matt Fisher wrote:

Namura doesn't even belong in a list of other pistons. They belong on a list of things like cancer, socialism, being dropped from an airplane without a parachute, leprosy, etc.

When my son was racing RM85's, I found the OEM ones to be super consistent on sizing, easy to find, and reliable enough given our change regimen (ring every 5 hours, piston every 10). I had Millenium re-do the coating and they sized it for the OEM pistons. Worked great.

Forged is better if you want to really stretch the limits of piston replacement, as they are much less likely to shatter if you keep them in so long cracks begin to form.

This is what I needed to hear. Thank you! The bike will be lightly (?!!!) used for woods riding and spirited fire road rides and won’t be on a track. The cold seizing thing is concerning but I definitely understand why it happens.
I saw a seized Namura piston and ring setting on a parts counter recently and examined it closely. Exhaust port side was properly scored and ring was impressively captured within the ring groove!
Once again, thank you to all who contributed with opinions.

T.

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1/25/2018 9:24 AM

Might want to check the squish on the head. I found that the stock gap was pretty big, and reducing it to something like .030" to .035" will help in getting better throttle response, easier jetting, more bottom-end. Having the head cut is a cheap way to improve performance.

If you like to have overextended maintenance schedules, probably shouldn't get the squish reduced. Carbon build up along with a worn crank and bearings can result in the piston smacking the head due to excessive play in the bearings from being old. If you do a good job of maintaining it, you'll likely have no issues and will simply enjoy the added performance.

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1/25/2018 10:46 AM

Matt, I don’t expect trying to fudge on service intervals or anything like that, but it’s definitely not going to be on the limiter 98% either. Knowing this, I’m expecting some carbon to be found as well as the power valve kinda gummy when I pull it apart.
51* out today and I rode it on the road a bit. It stayed very cool temp wise in the scooter’s cooling system so I did not crank it, all the while trying to be quiet and not pi?? off the neighbors. It was loaded up by the time I got back!
Thanks much.

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1/25/2018 3:49 PM

Matt Fisher wrote:

Namura doesn't even belong in a list of other pistons. They belong on a list of things like cancer, socialism, being dropped from an airplane without a parachute, leprosy, etc.

When my son was racing RM85's, I found the OEM ones to be super consistent on sizing, easy to find, and reliable enough given our change regimen (ring every 5 hours, piston every 10). I had Millenium re-do the coating and they sized it for the OEM pistons. Worked great.

Forged is better if you want to really stretch the limits of piston replacement, as they are much less likely to shatter if you keep them in so long cracks begin to form.

He has Namura to a T. Biggest POS pistons on the market. Stay away from them and Hot Rods crank related products.

On our KTM 85's I have always ran Vertex(OEM) & usually ran Wiseco on the YZ85's we had & CR125 mainly due to they have specific pistons that the bikes used. I really don't think you are going to see a massive difference in any quality brand. We run 20hrs usually in the 85's and have never had a piston related failure no matter what brand (except when a buddy tried running a Namura). The whole "warming up" thing has kind of gone away with the advent of plated cylinders. You don't have the big steel sleeve expanding slower and causing an issue.

I set squish, timing and deck height on almost every rebuild. Each smal detail in itself might not make a big difference but added up they do.................

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1/25/2018 4:51 PM

Tracktor, thanks for that heads up too. Wasn’t aware of Hot Rods longevity, or the lack thereof. I just got this bike about two weeks ago and it had been gone thru with a new piston and ring. Can’t remember what brand is in it though. He said the crank was fine, and they usually are just before they let go. A bit paranoid not knowing just how many hours the rod has so I’d say later this year maybe I’ll have the rod serviced. That’s a job in and of itself I’m not willing to buy the proper tools and do myself. This is my first newer 2-stroke since my ‘82 250 Husky! The RPMs this thing turns, scratches an itch I’ve had for YEARS and the 4-strokes just don’t do it for me anymore.

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1/25/2018 7:06 PM
Edited Date/Time: 1/25/2018 7:07 PM

There is a guy in another thread that has some experience with rats nests. If you need help with such a thing.

thanks much (in advance)

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much ty. How to spot a paid forum poster/artificial forum traffic producer (see list of actions/phrases below):

Copius pattern amounts of phrases like “Anyone have”..., “Anybody know?”.... and their variations.

Thoughts?
Any help is appreciated!
Thanks in advance!