• Husqvarna Motorcycles Made In Sweden - About 1988 and older

  • 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 The previous version was outdated and no longer supported.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!

What Caused This Burned Piston?

That looks like detonation.... See pistons like that in our sleds. Either bad fuel, or bad jetting. Hard to tell on jetting due to lack of wash, rich oil mix can hide that quite well. Definatly REPLACE crank seals during the rebuild, will help eliminate a potential source for air.
cheers
 
That looks like corrosion from a coolant leak. Magnesium is not all that corrodes from water or improper coolant
 
I had the cylinder bored and installed the new piston and a new air filter. Just waiting for some cooler weather to inspire me to finish it. Maybe a new crank seal and clean the carb. Check this out, looks familiar.
 
Maybe a good theory for modern highly tuned engines, but in the old days lots of street bikes and enduros were two stroke and didn't seize up from constant throttle. I rode those old bikes like the Kawasaki H1 triple, the Yamaha twin R5 and a few Japanese and European enduros with license plates on them. I still ride a 1986 KDX200 C1 with a license plate and cruise it around the mountain highways. A friend of mine has a newer 220 KDX that has been ridden on many a dualsport ride with a large amount of pavement. double rings, lower compression and more mild tuning go a long way in preserving the top end, I guess.
 
maddog82 said:
I had the cylinder bored and installed the new piston and a new air filter. Just waiting for some cooler weather to inspire me to finish it. Maybe a new crank seal and clean the carb. Check this out, looks familiar.
Click to expand...

There is probably some truth to that but I doubt that engine design is 100% responsible. Most that run hard on and off the throttle don't take the time to perfect the midrange jetting and then when the need to cruise at part throttle comes up they are running lean on the needle for too long and it catches up with them. Getting a woods bike perfect through the entire range is no easy task for even the most skilled tuners and just when you think you've got it the air density altitude changes and you are back messing with the air screw and the main at the least. Just my 2 cents.
 
I finally got off my lazy @!# and got it running. Started 3rd kick and runs well. Feeling good about it.
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That piston damage is from a lean condition. Bad crank seals or base gasket or reed cage not sealing or all of the above. You will need to do a total rebuild (crank bearings and seals, rod kit / bearings top and bottom over size piston) as the motor is full of metal. After the rebuild you should do a leak down test on the motor and check your jetting .
 
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