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 The previous version was outdated and no longer supported.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

CR 500 jetting issue

i did a little kdx 200 years ago, an 87 a/c model. put a new slug in it, gutted the pipe and put an allow muffler on it. ran sharp but on its second ride i took it to the beach:banghead: Idiot!!. got about 300 metres down the beach and heard the noises, felt the slight drag so i locked the back wheel on full throttle, too scared to roll it back through the needle jet. let it cool for a bit and it fired up and was fine after that. i dropped the needle clip and that helped. back home i went up a couple on the MJ and that sorted it. Stripped it down at a later date and there was minimal damage c/w what i thought had happened.. lucky escape!
 
Piston clearance depends on the piston material so the clearance from the motorcycle manufacturer is only correct if you are using the OEM piston. Any other piston should use the piston manufacturers specs at least as a starting point. The person in the link you posted was most likely working on a Japanese motorcycle which all come with cast pistons and he was using a Wiseco piston. OEM Japanese pistons are cast, which dont expand as much as the forged Wiseco so the Wiseco is going to require more clearance.
 
IMG_6139.JPG


Gutted to say, she seized up(milk crate) yet again in qualifying at Farleigh. The good news the spare (silver bike in the picture) rode like a dream and got me to 15th overall from the second row of the grid. So its' back to the drawing board.
 
you didnt try changing them both at the same time right? 370 would be the next step, and that change alone.
 
just a outside point...i had a mate who had several seizures on a 250 and it was the middle head bolts being too long by a poofteenth and bottoming out in the cyl before tightening the head down sufficiently... took some pistons to sort that out.
 
There was a Husky service bulletin about those head bolts being too long. It's something I check on every motor I build. One would think the issue had been solved by the time the 500 came out, but I'd rather check than bet.
 
husqyhamm said:
This engine is 4hrs since rebuild. Used for asphalt circuit trackdays and flat tracking. Pressure tested for 10mins at 15psi from where carb goes into manifold to exhaust port blanked off.
Fuel supply increased through carb as well.
VM 40
Pilot 35
Needle 7dh3 middle groove.
Emulsion tube AA5
Main 420 and it can go bigger.
Run at 4000ft altitude. It idles in the line-up for 15 mins and then accelerates through all 6 gears without a cough or splutter all the way to 7500rpm where it can sustain.
Fuel is 95 octane and full synthetic at 25:1
Click to expand...


I forgot about this post from husqyhamm. Notice the main jet size.
 
Four corner seizures are usually (but not always) caused by the piston expanding too fast for the cylinder during warm up. Its interesting that it does not appear to be seized above the ring. Other than running it too hard before it is thoroughly warm, which I do not think an experienced rider like yourself would do, I really dont have any ideas.
 
That hurts.
Looking at piston ring in frontal part of seizure, you can see it did not seat properly with cylinder causing blowby and a hotspot beneath it.
Cylinder likely out of round.
 
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