• 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
     WR = 2st Enduro & CR = 2st Cross

  • Hi everyone,

    As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.

    When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.

    Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.

    Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.

    Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.

    Thanks for your patience and support!

125-200cc Piston knocking

Mr_X

Mr_X

Husqvarna
A Class
Hey guys,

Need help again. My new piston on my WRE125 2008 is making a lot of knocking noise during engine braking. :( Is this because of a wrong size?

I found 3 sizes of Pro-X piston off the web:

53.94mm
53.95mm
53.96mm

Which one should i use now? Thanks...
 
what you should use is.....a wrench to tear her down and gauge the bore and piston. then consult the SM for more info (hours, tollerances, etc). no one can accurately diagnose an engine noise over a keyboard, are you sure it's the piston and not the chain/rr caliper slapping while backing into corners due to wheel-hop? dont order parts till you know what you need.
 
pvduke - How much should you allow for clearance?

Mr X - are they the same piston as wr's? I know where you can get good quality WR 125piston
not sure about Pro - x do you know if they are any good?
 
The piston to cylinder clearance should be around 0.04mm-0.06mm and absolutely not more than 0.08mm. While best to do this with a bore gauge and calliper, you can measure it using a feeler gauge between the cylinder and piston. Insert the gauge with the piston down to about where the wrist pin hole is. Start with a .05mm gauge. The piston should require a small amount of effort to move it (maybe 4 to 6 Newton’s or about a pound). It should not be able to move under gravity.

The ring gap should also be between 0.26mm-0.6mm.

Also, check to see if there is any radial play in the crank-rod-piston assembly before you remove the piston. To do this, get the piston to TDC (no cylinder of course) then use a small soft wooden wedge between the crank lobe and the case to keep it from shifting. Carefully try to move the piston up and down (not side to side) directly along the line that passes through the wist pin and the center of the crank. You should feel no play at all.

Finally, check the side clearance of the connecting rod in the crank. It should be less than 1mm. Remove the piston and rotate the crank so that you can see the widest part of the gap between the lobes (TDC again). Just use a feeler gauge between the crank and con rod.
 
thanks - would be good to see this info in a detailed top end rebuild tips thread
Ive just donme a rebuild and my conrod had some play but couldnt get up and down movement
I am not sure about my piston now as the compression is only up a little to 150 lb - need to check it again after ive ridden it , I will take the head off to check again (seemed like a nice fit though )
 
rockdancer;131385 said:
pvduke - How much should you allow for clearance?

Mr X - are they the same piston as wr's? I know where you can get good quality WR 125piston
not sure about Pro - x do you know if they are any good?
Click to expand...

i always consult the service manual for service limits and spec's, and, measure according to the manual otherwise the data will be flawed. on cast pistons even if they look ok they hour out. replace them. they are not made to last forever. they have cycle limits and work-fatigue and can fail even though they look fine.

pro-x is a japanese (mostly) made piston to oem spec, cast mostly in that regard. i've never used them as i've used wiseco forged if oem aint avail.
 
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