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 The previous version was outdated and no longer supported.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

clearances on bore job..

justintendo

justintendo

klotz super techniplate junkie
hello all...doing a freshen up on my 83 250 and am installing a 2nd over wossner kit...at the machine shop they ran into a question..
in order to provide the spec clearance, it appears the bore will be over 70.5mm, when the kit is listed at 70.46..they say the wossner coating is adding about .001" on top of the 70.46 the piston measures. basically are you guys measuring the bore clearance on top of the coating and counting the coating as part of the piston? is the .06mm the right clearance to run? they say if they do this it will be a touch over 70.50mm. thanks for the help!
 
I had all the same questions with my Wossner Piston to untill I read the Instructions that come with the Piston wich should be in the Box. Then there was the thought that an Air Cooled Iron lined Cylinder should have a diffrent clearance than a water cooled Plated, there is no mention of this in there instructions. Then there are the people who don't like the coating and clean it of before installing it. I came to the conclusion I was making it to complicated and just went by the Instruction Sheet. If You don't have the Instructions I might be able to find mine, or they may have them on there Web sight.
 
instructions? hmmm, never saw those in the box...in fact, i was sent the wrong piston and returned it to get this one. neither had instructions...
 
I've got a new Wossner piston in the box right in front on me for my 430 & there NO instructions, thought the side the of box says .08mm clearance

Husky John
 
ruwfo said:
I've got a new Wossner piston in the box right in front on me for my 430 & there NO instructions, thought the side the of box says .08mm clearance

Husky John
Click to expand...
interesting that ones .08....mine says .06, but if that tolerance is used, it will be bigger than 70.50mm..just wondering what you guys have had good success with....
 
Does it matter if its bigger than 70.5mm? I just have the cylinder bored to the clearance I want and dont worry about what the actual bore size turns out to be.
 
Kartwheel68 said:
Does it matter if its bigger than 70.5mm? I just have the cylinder bored to the clearance I want and dont worry about what the actual bore size turns out to be.
Click to expand...
I'd agree doesn't matter about the bore diameter , as long as you get the proper clearances. The difference in clearance sizes is more then likely because your piston is a 250 & mine is for a 430, larger bore may require more clearance according to Wossner.
 
If you are going to the next size overbore, you dont bore the cylinder to a size first, you bore it until you get the clearance you want for the piston you are using. In this case it might mean the bore is 70.47mm or dead on 70.50mm or it might be 70.53mm, thats kind of irrelevant as long as the clearance is correct. If you are putting another piston of a different brand into an already bored cylinder, there can be enough difference in piston size to be a problem, either too much or not enough clearance.
 
You should have the piston in hand when you take the cylinder to the machinist.
If he's is familiar with motorcycles, he should know how much clearance the piston will need.
Cast or forged pistons will require different clearances and he should know that.
If he doesn't, take it somewhere else.
 
yes the piston is at the machine shop before honing...was rough bored to determine which size was needed. i guess ill just have them finish hone it to have the .06mm clearance. where it falls doesnt really matter, i agree. just was wondering if the wossner clearance was good. it should be or they wouldnt have put it on the box i suppose.
 
I'm dropping mine off for boring this week, so keep us posted on how your runs afterward. One thing i notice on mine, is though the wrist pin hole, & ring area is in the same location, but the piston is machined in areas to lighten it. Modern tech for some Vintage parts, the lighten piston should
make it rev faster.
 
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