Need advice on performance 83 250 XC

[Ron]

Have you run the bike again with the cap vent open? Did it make a difference?

The liner gets bored to the next oversize piston. Wossner make several oversizes larger than the original Mahle's and they are a lot less expensive.

Stay away from Wiseco. Supposedly the new pistons are better, but you don't know if your getting someones old stock and they were definately prone to siezing.

Wossners pistons are good, but I am setting my 77 250CR up a little loose at .003" piston clearance. Wossner says .002", otherwise it will take a lot of break in miles before you can really run it hard.

I just siezed mine on four corners with less than 2 hrs on it. It was to tight at .002" IMO. Although I admit, I was screaming it to death right before it siezed. 5 miles into the race, bikes and riders were scattered all over a hill and I just screamed mine to the top first try. But it cost me a new piston, a DNF and my $90 entry fee.

After you do the top-end do a leak down test, to make sure you don't have any air leaks.
You might wants to changes the crank seals anyway. They're cheap and easy to get to.

 

[cgmjr]

*jots* Perfect, thanks @Ron. If it is necessary to bore, does one take the jug with liner to any machine shop, or does it take special jigs and such to do the job? If there is a minor enough ring groove, can one just hone it out themselves and skip the boring?

Haven't been able to test her with the cap vent open yet; work intrudes. I hope to do so in the next couple of days.

 

[adam6402]

No, the liner is bored, you will just need a new base gasket, piston kit, piston, ring, bearing, pin, and clips. Plenty of new kits for sale on ebay or from husqvarna-parts.com or Halls Cycles http://www.halls-cycles.com, which is a Cafehusky sponsor. They are great to work with as well.

 

[adam6402]

Hadn't heard about the Wiesco issue. I'm running a Wiesco on mine. I ended up at .0025 piston clearence.

Any competent machine shop should be able to handle the job, you will need to take them the whole jug and new piston, just make sure they understand the tolerances. I recently bought an '84500CR, brand new bore job and piston. Decided to take it apart and check things out. Yes brand new piston kit, but the cylinder was over-bored substantially. Now going to have to get a new piston kit and go to a 87MM bore.

 

[2premo]

what were

Hadn't heard about the Wiesco issue. I'm running a Wiesco on mine. I ended up at .0025 piston clearence.

Any competent machine shop should be able to handle the job, you will need to take them the whole jug and new piston, just make sure they understand the tolerances. I recently bought an '84500CR, brand new bore job and piston. Decided to take it apart and check things out. Yes brand new piston kit, but the cylinder was over-bored substantially. Now going to have to get a new piston kit and go to a 87MM bore.

what were the clearances on yours?

 

[adam6402]

what were


what were the clearances on yours?

.015, once I had the head off, and noticed the jiggle, new something was off.

 

[2premo]

.015, once I had the head off, and noticed the jiggle, new something was off.

where you check the clearance on these is the skirt clearance the tops seem loose
the only way to check it is to remove the jug and piston
and the specs are looser than you would think on these 500's

 

[cgmjr]

No, the liner is bored, you will just need a new base gasket, piston kit, piston, ring, bearing, pin, and clips. Plenty of new kits for sale on ebay or from husqvarna-parts.com or Halls Cycles http://www.halls-cycles.com, which is a Cafehusky sponsor. They are great to work with as well.

Wow, I don't get Hall's ordering site. I acknowledge that Hall's has a good reputation, but I gave it the part number and it gave me a $303.50 price, but no explanation of the article. That seems high to me.

Husqvarna-parts.com has a kit of $170, but I don't know the brand. It says "Made in Germany;" is it the Wossners?

 

[adam6402]

where you check the clearance on these is the skirt clearance the tops seem loose
the only way to check it is to remove the jug and piston
and the specs are looser than you would think on these 500's[/quote/]

I know, that measurement is at the skirt. While I didn't say it, yes I took the entire jug off. I must have measured it 10 times in disbelief!

 

[adam6402]

Wow, I don't get Hall's ordering site. I acknowledge that Hall's has a good reputation, but I gave it the part number and it gave me a $303.50 price, but no explanation of of the article. That seems high to me.

Husqvarna-parts.com has a kit of $170, but I don't know the brand. It says "Made in Germany;" is it the Wossners?

Halls does not have a very good web site,when wanting something I just call them, ask for parts department.

Husqvarna-parts.com pistons are Wossner.

 

[adam6402]

Wow, I don't get Hall's ordering site. I acknowledge that Hall's has a good reputation, but I gave it the part number and it gave me a $303.50 price, but no explanation of of the article. That seems high to me.

Husqvarna-parts.com has a kit of $170, but I don't know the brand. It says "Made in Germany;" is it the Wossners?

Yes, they are selling Wossners.

 

[cgmjr]

@adam6402, thanks for the info. I've spent quite a bit with Philip at Husqvarna-parts.com already, and he hasn't disappointed. Not the most talkative in emails, but brevity is indeed the soul of wit, eh?

Any other good suppliers? Any in the Dallas, TX area?

 

[adam6402]

@adam6402, thanks for the info. I've spent quite a bit with Philip at Husqvarna-parts.com already, and he hasn't disappointed. Not the most talkative in emails, but brevity is indeed the soul of wit, eh?

Any other good suppliers? Any in the Dallas, TX area?

Philip is a good guy to deal with, I specifically mentioned Hall's be cause they support this website. If not for the sponsors, this great place might no exist.

I'm not aware of anything in the Dallas area. I don't recall the exact website addresses, but Husky Junk, Huskydoggg, Husqvarna Outlet, HVA (Britain), Vintage Husky/Husqvarna.

Huskydoggg really has nothing on his website, but he has lots of vintage parts, e-mail or call, owner is Steve.

 

[cgmjr]

After you do the top-end do a leak down test, to make sure you don't have any air leaks.
You might wants to changes the crank seals anyway. They're cheap and easy to get to.

@Ron, two questions:

1.
2. How does one perform a lead down test?

 

[cgmjr]

Philip is a good guy to deal with, I specifically mentioned Hall's be cause they support this website. If not for the sponsors, this great place might no exist.

Then I will indeed find a way to support Hall's too; this site/community has been a blessing, even in such a short time.

 

[86 400 XC]

Check out this guy, not close but awesome prices.
He has mega pistons and stuff in stock.

http://www.huskydoggg.com

 

[Ron]

@Ron, two questions:

1. View attachment 22718
2. How does one perform a lead down test?

Yes, that's one of crank seals. There's another one on the primary side. They fit into a holder that attaches to the case with a gasket and 4 screws.

To do a leak down test you need to plug the intake and exhaust and then pressurize with air. General rule is 6 psi and no more than 1 psi per minute leak down. I use an expansion pipe plug found at hardware stores and I made an adapter for the intake side with a guage and shraeder valve. Pictured below.

 

[cgmjr]

Nice fabrication! What is that silver cylinder for your intake adapter/gauge? I presume you insert that into the intake manifold and c-clamp it tight, eh?

Should one run the engine to let the rings seat before this leak down test?
Gah! Got a thousand questions, but I'll stop pestering you soon!

 

[1982 XC 430]

As mentioned above I'd like to know how Clean the Pipe is. I bought a Maico in Michigan a wile back and when I turned the Pipe on end I filled a 5 Gal Bucket full of Grain. I must of stolen the whole winter supply for a family of mice.

 

[cgmjr]

As mentioned above I'd like to know how Clean the Pipe is. I bought a Maico in Michigan a wile back and when I turned the Pipe on end I filled a 5 Gal Bucket full of Grain. I must of stolen the whole winter supply for a family of mice.

The pipe was full of squirrel , acorn caps, moss, etc. The airbox too. I blew the pipe out with compressed air and loosened the internals with some shaking and banging. I have no silencer on it now, so it is straight pipe from cylinder to ears

I -did- have two rust spots that I had to patch. I used my Dremmel to grind the spots to good metal, then stripped away rust on the outside. I used some screen wire and JB Weld to patch. I'll smooth out the patches with the Dremmel once I start the cosmetics part. See attached.