• 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 The previous version was outdated and no longer supported.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

hvaloz3 said:
Going to have to look at my notes for my 84 jetting ... that had a 40mm .... as you know steve the streak had the 44mm .View attachment 82575
Click to expand...



Hello Mate,

I've spoken to Andy and I'm having it honed out to 95micron clearance (approx. 0.0004") I think part of my problem is that I used to run the 500's on a blend of 60% 97 octane with 115% Octane Sunoco fuel to give me 105 octane. The 115% Sunoco stuff has lead in it, which helps keep it a bit cooler. I stopped using it as it was bloody expensive, but I might have to have a re-think.

I've got a 44mm carb on my Silverstreak, but I've not ridden that baby yet (probably wont ever ride it lol)

Steve
 
ive seen a heap of 500 woosy's seize on the box specs. i also note that they were fairly new engines (1 or two tanks) put into high load situations. deep mud, lonnng straights not enough enough jetting time etc
 
silverstreakNZ said:
What sort of clearance is need in a 82 500 with a Wossner. Stock everything else . Ran fine . Just worn out the old piston
Click to expand...



I've been told to use 95 micron (0.0004") clearance on the Wossener pistons. Ive also ordered some more leaded Sunoco 115 Octane fuel to hopefully cure my issues.
 
May want to move that decimal point over one. To .004 Because of heat of texas bored out a bit more .0045 now

So Steve are you saying you are adding a overbore or honing out to .0005 more to clean it up?

I was amazed also when I had the timing just a bit past or advanced on how hot bikes run
 
Timing being just a little bit too far advanced can a lot of heat for no real performance gain. On a water cooled bike it can dissipate most of it, but it can be very bad for an air cooled bike.
 
Bigbill said:
Too much retarded on the timing causes more heat as it exhausts. I'm going to run stock timing. Clearance around .005" my 390cr had a light seeze at .0045". There's no mistakes when the pistons ar $200. I figure the UFO installed and start off with stock jetting, the bottom should be rich with the UFO. Since I can't hear that good I purchased a hand held tach. I want it right because we don't baby these bikes.

I wish we knew what the piston clearance is for desert racing?
Click to expand...
sounds like different advice than what most of us do. but our bikes still live somehow.
 
GaryM said:
May want to move that decimal point over one. To .004 Because of heat of texas bored out a bit more .0045 now



So Steve are you saying you are adding a overbore or honing out to .0005 more to clean it up?



I was amazed also when I had the timing just a bit past or advanced on how hot bikes run
Click to expand...

I'm just honing to clean off the aluminium coating I got when she nipped up. The thing only seized at the end of a long straight. By the time I knocked her out of gear and got the kick start out she kicked over again and fired up. I have always run stock timing, but I will double check that I'm on the dial. Plus as I said I'm going to run blended leaded fuel. It's going to be a couple of long nights to get her built back up before we leave for the biggest twinshock event in the world on Thursday...Farleigh Castle Vets Des Nations.:applause:
 
Bigbill said:
Too much retarded on the timing causes more heat as it exhausts.
Click to expand...

The exhaust will run hotter but not the engine because retarded timing has the fuel charge still finishing combustion after it has been pushed out to the header. Timing that is too advanced has the fuel charge burning and expanding too soon before TDC which puts the heat into the engine, not the exhaust.
 
Bigbill said:
Why are there so many seezed ?
I think we're getting mixed up. Advanced is before top dead center, retarded is after top dead center,
Click to expand...
yup, thats advance and retarded spark timing.....you could be getting mixed up, im not sure. many of us retard our bikes a bit for several reasons. saying it makes the engine run hotter is not a grasp of 2 stroke operation theory. there are few seizes here on cafe, mostly because we usually dont report "hey my bike ran its 10th tank of fuel no problems again" for no reason...but if someone has engine troubles we talk about it i guess..
seizes are usually jetting and bore clearance imho. i run my stuff somewhat hard and have never had it happen.
 
Anyone who's worth using will know what to bore it to regardless . Problem solver . Let the engine builder do the engine building
 
Bigbill said:
Why are there so many seezed ?
I think we're getting mixed up. Advanced is before top dead center, retarded is after top dead center,
Click to expand...

No one is confused. His point is you say retarded timing causes excess heat, which is only true if you are talking about exhaust temps, which is irrelevant to piston seizures, too much advance causes ignition of the fuel charge too early which dramatically increases cylinder head and cylinder temps which is directly related to what we are talking about with seizures.

The single most common cause of a seizure in a two stroke, of any kind, is an air leak which probably covers 75-80% of them, the remaining are jetting, ignition, tolerances, etc.
 
No don't use the advice of most engine builders. Do use the advice of Husky engine builders.

Most of top posters here build their engines and most tell the machinist their needs based on
true experience

So sorry - say it ain't so Joe - you will be missed
 
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