• 4 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
     TE = 4st Enduro & TC = 4st 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 The previous version was outdated and no longer supported.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!

Help! Exhaust valve stuck open!

S

stan23

Husqvarna
C Class
Hi,

I have an '06 SM510R with 8K miles. The big end was recently rebuilt (new piston/springs/crank/bearings) about 500-miles ago.

Bike runs great - oil super clean - and very fast. Valves are in spec.

I start it up today like normal and rode about 1 mile from my house and the bike just stopped. I pulled over, thumbed the starter - no go. Just a clicking noise. I suspect something was wrong because If I try to push start it, I would hear some clanking noises from the head.

I truck the bike home.

I pulled the plug and verified I have good spark. I can thumb the starter and physically see the piston move up and down. That's good, right?

I pulled the valve cover off, and noticed the exhaust valve closest to the decompression lever is stuck open. The spring is fully compressed, and the decompression lever if pulled is not hitting the cam to open it.

I suspect the valve is bent, and may or may not be hitting the piston (which would suck, since it's a new piston)

Just wondering if 8K on the valve train caused this? I have yet to verify if the timing chain jumped since only one valve seems to remain open, and none of the other valves look affected.

Anyone else had this problem?

Thanks!
 
Assuming you don't have a bent valve. Have seen this many times.
This can happen if bike was washed and not run long enough to burn out moisture in motor or in muffler packing.
This being the case what has happened is the exhaust guide has rusted and the valve is held open.
Take off the exhaust spray the valve and guide with PJ nut buster let it set.
Go back up on top and make sure the shim is still in place, turn the motor over several times keep watching the shim as it can be spit out. Keep spraying on the PJ it will usually pop loose after a while.
Sometimes have to position cam so can being carefull not to side load valve use small tire iron or curved screw driver under cam to flex valve up and down.
Once it pops go ride it for several mile then check it after it's cooled down.
Later george
 
Well, the worse is here.

Removed the header, and you can see one exhaust valve sitting there sheared off, and the other one looks like a Z shape.

No doubt the piston slammed onto the valves -- hard!

Looks like at the very least the head needs to be done, and a a new piston.
 
Curious as to why the valve broke?
Bad cam timing, wrong choice in head gasket thickness, over-revving?
 
Tensioner loosened off? Im pretty leery about OEM tensioners for race engines.
Call Jeff @ Halls Cycle for head rebuild info.
 
You must log in or register to reply here.
Back
Top