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Author Topic: How loud are Wiseco pistons?  (Read 3075 times)

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Offline nobrakese28

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How loud are Wiseco pistons?
« on: October 10, 2011, 11:41:59 AM »
So I thought I had transmission problems but after some investigation the transmission is fine, I think.  I removed the top end and inspected the parts.  I discovered, with help of a friend that the ports on the cylinders were not chamfered.  I believe the ring was catching on the exhaust port.  So I filed all of the ports down.  I put the bike back together, it started.  The noise was greatly reduced.  Although the engine is still rather noisy.  Like a metallic "clinking" sound.  I had the cylinders measured, they were about .002-.0025 inches of clearance to each piston.  Although there was a bit of wear from the piston ring rubbing. 

The right cylinder was smoking much more then the left side.  I hope this is  not a result of the minor damage from piston ring hitting


So I have heard that Wiseco pistons are loud.  How loud are Wiseco pistons?


Offline GSXRDman

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Re: How loud are Wiseco pistons?
« Reply #1 on: October 10, 2011, 12:17:17 PM »
My bore specialist says 0.003" (3 thousands) is the clearance he bores too for wiseco pistons (he was pretty firm on that...no question here).  You don't want to end up seizing w/ too tight clearance (as many have). 

Take the top end and pistons off and let the bore guy take a look and see what he says.

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Offline Tz250racer

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Re: How loud are Wiseco pistons?
« Reply #2 on: October 10, 2011, 04:04:56 PM »
Louder then your stereo.  :)
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Offline Coyote

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Re: How loud are Wiseco pistons?
« Reply #3 on: October 10, 2011, 05:26:25 PM »
My bore specialist says 0.003" --SNIP--

Seriously Kevin, Bore specialist.
Hey, I'm one to talk, but "Bore Specialist"  :sigh:
.
I am going to ask my tire inflater if that is a even a real job title.
.
Actually my significant other is a bore specialist.
I guess I take that back..

Dave
Wow, that could be taken a few different ways.
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Offline Kraven Morehead

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Re: How loud are Wiseco pistons?
« Reply #4 on: October 10, 2011, 06:37:19 PM »
87.6 decibels...with the rubber fin inserts 66.2.   In all seriousness though, we have Wisecos in the 74 and Pro-x in the 75 and the Wisecos do make more top end noise.  I don't know why that is but I've just excepted it as normal. 

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Offline MarkT

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Re: How loud are Wiseco pistons?
« Reply #5 on: October 10, 2011, 07:30:15 PM »
I've built several air-cooled two stroke engines with forged Wiseco pistons.  They do have a different shape than a cast piston...  the "egg shape" is more pronounced than it is with a cast piston and they do seem to make more noise than cast pistons.

I know a lot of people recommend really loose clearances with Wiseco.  But I followed Wiseco's recommended clearance specs and never had any issues.  You could call Wiseco and get the recommended clearance, but my guess is you are close at 0.0025.

The saving grace of a Wiseco is that you can run REALLY loose clearances that would shatter the skirts of a cast piston.  But does that mean you should?

(Harry Klemm of Klemm research is who I used to take my cylinders for boring...  I think he wrote an article on the "myth" of Wiseco piston clearances some years ago...  Klemm did a LOT of testing and I never had an issue with a Wiseco piston using their recommended clearances...)

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Offline Vintage Smoke

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Re: How loud are Wiseco pistons?
« Reply #6 on: October 10, 2011, 09:58:37 PM »
My bore specialist says 0.003" (3 thousands) is the clearance he bores too for wiseco pistons (he was pretty firm on that...no question here).  You don't want to end up seizing w/ too tight clearance (as many have). 

Take the top end and pistons off and let the bore guy take a look and see what he says.

Like I have said before...a little bit of knowledge is a dangerous thing.
Forget the "bore specialist" crap.
Find a competant shop or someone with the right tools and experience to correctly measure clearance and you will be fine. I have heard that some people recommend running Wisecos a little looser in an air cooled application, but your safest bet would be to contact Wiseco directly or an experienced engine builder on that one.

Yes....Wisecos rattle more than cast pistons(especially when cold) because they are run looser. This is normal. How much rattle is ok will depend on an experienced ear. It is impossible to get a definitive answer about how much is too much on the internet.

When in doubt consult someone who actually knows. If you do the exact opposite of, or at least completely disregard anything Kevin(GSXRDman) says, you will more than likely be better off.
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Offline Vintage Smoke

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Re: How loud are Wiseco pistons?
« Reply #7 on: October 10, 2011, 10:04:14 PM »
Also...I almost forgot...if you are smoking a lot more from the right side you may have one or more bad crank seals. The seal on the left side is open to the air while the left side has trans fluid on the other side. Often times when an engine is smoking more on the irght it is sucking in trans fluid through a bad seal.
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Offline MarkT

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Re: How loud are Wiseco pistons?
« Reply #8 on: October 10, 2011, 10:13:06 PM »
Here's an excerpt from an article written by Klemm.  Not the one I remember but it does talk about Wiseco pistons.  I ran the recommended Wiseco clearances on several race engines and never had an issue...  YMMV. 

http://klemmvintage.com/breakin.htm

"About Wiseco Piston Break-in -  There are an abundance of two stroke enthusiasts that speak with very little enthusiasm about Wiseco pistons.  The common response is “you have to give them lots of clearance … otherwise they seize”.  We couldn’t disagree more … and here is why.

In the 1970s, we made many attempts to use Wiseco pistons in two-stroke race motors…with very poor results.  The truth is that Wiseco (at that time) had numerous materials and design issues that needed resolving.  However, Wiseco has done a great job of evolving their materials and designs since the 70’s, and today’s Wiseco Pistons are an excellent choice for most high-performance two-stroke platforms.  All that said, Wiseco pistons do have one design issue that they have intentionally have not tried to resolve … longer than average piston-ring break-in times.

  The forged material that Wiseco uses for their forged pistons does require “a little” more clearance and a little longer break-in that typical “cast” type pistons … but that is not the unresolved design issue…. It’s the rings.  The piston ring material that Wiseco uses is a very tough material that takes much longer than average to “seal” to the bores.  While the Wiseco pistons themselves are not a particularly close clearance fit to the bores, the Wiseco rings are.  In truth, the Wiseco rings are made brand new with an end-gap that is much too small for full temperature high rpm operation.  However if a Wiseco equipped engine gets the slightly longer than average break-in period it deserves, the outer-skin will wear off the rings to result in an ideal “running” end-gap that will give excellent long term wear and service.  If however, you try to run Wiseco piston rings prematurely hard, those rings will quickly expand until the ring ends make contact and literally “bite” the full bore diameter in the ring path.  Some engine builders incorrectly give Wiseco pistons excessive piston clearance in an effort to resolve this ring end-gap issue.

  We respectfully submit that Wiseco pistons can be fit with very close clearances, and offer great service … as long as you let the rings have their break-in time.   Our 8500rpm Kawasaki Bighorn road race bikes are equipped with 82mm Wiseco pistons fit at .0035” clearance.  These pistons never showed the slightest sign of piston scoring, even after 25+ hours of racing, dyno-passes and high speed testing.  You cannot abuse a piston harder than we abused these…. But we did give the rings a long gentle break-in."

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Online JA-Moo

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Re: How loud are Wiseco pistons?
« Reply #9 on: October 10, 2011, 11:54:33 PM »
Bore specilist = guy that can read the side of a Wiseco box......... :jerkbag:

 How many miles do you have on the motor? have your ridden it hard yet? I had a customer trash a set of rings in under 300 miles from a bad chamfering job. You might want to check your compression for possible ring damage.

 Wisecos are pretty noisy as stated above, the main thing, is to let them warm up before thrashing on it. The pistons expand more, so the pistons have to be at operating temp to reduce the extra clearance. Reving out when cold will beat the piston skirts up.
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Offline dxrat

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Re: How loud are Wiseco pistons?
« Reply #10 on: October 11, 2011, 01:37:11 AM »
Bore specilist = guy that can read the side of a Wiseco box......... :jerkbag:

Funny you say that because I was a bore specialist at my local motorcycle shop for a few years. I always went off of the box or piece of paper with the piston. Sometimes people would ask for a special clearance. But if not they got what the piston specialist asked for :lol:.
Dave,
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Offline nobrakese28

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Re: How loud are Wiseco pistons?
« Reply #11 on: October 11, 2011, 09:30:20 AM »
Thanks for the replies guys. I hope the seal isn't bad, I replaced all the crank seals with the exception of the "crank seal o-ring", the rubber o-ring with the woodruff key cut out.  I will do a compression check when I get home tonight.  Dang, I really don't want to split the cases for a bunk seal.  But I don't see why the seals would be bad if they were brand new. 

Thanks. 

Offline jrodenhiser

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Re: How loud are Wiseco pistons?
« Reply #12 on: October 11, 2011, 10:38:04 AM »
Wiseco 2 stroke clearances



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Offline dxrat

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Re: How loud are Wiseco pistons?
« Reply #13 on: October 11, 2011, 10:53:27 AM »
Thanks for the replies guys. I hope the seal isn't bad, I replaced all the crank seals with the exception of the "crank seal o-ring", the rubber o-ring with the woodruff key cut out.  I will do a compression check when I get home tonight.  Dang, I really don't want to split the cases for a bunk seal.  But I don't see why the seals would be bad if they were brand new. 

Thanks.

I don't think a compression test will tell you much. You need to do a leak down test.
Dave,
San Pedro, Ca

Online JA-Moo

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Re: How loud are Wiseco pistons?
« Reply #14 on: October 11, 2011, 10:23:27 PM »
I don't think a compression test will tell you much. You need to do a leak down test.

 The compression test is to see if there was ring damage from the ports not being chamfered......
Just because you almost won once at Operation, doesn't qualify you to do actual surgery..........