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 The previous version was outdated and no longer supported.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

1982 250WR...for vintage motocross?

420 doesnt sound too big. different motor but my 88 250 takes a 460. the smaller bores tend to take bigger mains in these bikes. would go bigger on the main till it loses power then go back a size. i only say to settle on the main first as it tends to throw your needle settings out the window, but changing needle setting wont affect your main jet choice.
 
Okay...spring has sprung and I am back on the race track. And back to jetting. I went from a 420 to a 430 to a 440. The plug is somewhat darker, but I would still call it 'yellow' rather than brown. I am running race fuel, Golden Spectro 55-1. Wondering how big to go with the jet? I have to order them, so wondering if I should skip the 450 and go higher?
 
You go big on the main till it's blubbery, too rich. Then go down one size till she responds clean and crisp. How's your pilot and balance screw?
 
First your float level is the correct height, the needle and seat isn't leaking.
I set the balance screw between 1 to 2 turns open were it's smooths out, 1 1/2 turns out is perfect if that's were the pilot jet balances. I put the needle in the third slot. Then it's the main jets turn. I go larger till it's blubbery then go smaller till it's smoothed out. Now it's the needles turn. Up or down till the slide movement is clean not rich, not lean. The slide should move up bringing up the rpm's with no hesitation. Now it's the pilot skews turn again to clean up the bottom. Now your carb jetting and setting is correct.

Note, as your balancing the screw for the best idle if it's a higher rpm, lower the slide by the idle screw for the best idle. You don't want the slide to be higher so the needle and the main jet effects the pilot jet and idle setting.

It takes some time to learn jetting 101 but it's not hard to learn.

Installing the UFO in the bottom of the slide does change the jetting. But it smooths out the reaction of the engine as the throttle is turned. The UFO is a ramp that installed in the uneven bottom of the round slide. Without the UFO installed the gasses hits the wall on the bottom of the slide. It causes a turbulence that effects the rest of the gas flow that's below the slide opening too.
 
I went from a 420 to a 430 to a 440. The plug is somewhat darker, but I would still call it 'yellow' rather than brown. I am running race fuel, Golden Spectro 55-1. Wondering how big to go with the jet? I have to order them, so wondering if I should skip the 450 and go higher?

The plugs only going to get darker, if your increasing the size of the main. Larger the number the bigger the
opening. Husky always put in overly large main jets in, so they wouldn't blow up no matter what premix ratio you were running.


BigBill hit the nail on the head, it's not that hard to figure jetting out..

Look at it this way, if the bike starts easily, idles & runs decent in the low RPM range (below 1/2 throttle)
your main jet still hasn't come in play yet. So increasing the main will partial foul the plug, as your not
above 1/2 throttle that much usually, and then running it around at lower throttle cleans it partial back again.

Also if you motor is stock, which it sounds like it is, why are you using Race Fuel?
Race fuel runs cooler which sometimes means richer running. Does your car run fine on regular, then putting
Premium in it is a waste.

420 is too large for a A/C 250, as there much more peeker then the later model motor are. Go the other way, try a 400. My 84 had a 430 in it, I played around with different size jets, til I wound up with a 380.

Take small steps, change one thing at a time, never change the pilot & the main together, etc. , + write down every thing.

Husky John
 
But the pilot jet gets addressed first. Once the balance screw is near 1 to 1 1/2 turns and we have the best idle. Then go to the main. The balance screw must have some adjustments to go either way to tweeking the last setting when the main jet and needle is set. Sometimes we need to do it twice if something was way off. We can get it adjusted to about 90% that last 10% is the hardest.

Check the float level first.
Make sure the needle and seat isn't leaking.
Make sure the air filter is clean.
Make sure the intake boot isn't cracked
Make sure the reeds are good and sealing, if open flip them.
Make sure there is some play in the throttle cable.
Make sure the throttle goes to wide open(static test) visual.

Now your ready to jet.
 
Bigbill said:
But the pilot jet gets addressed first. Once the balance screw is near 1 to 1 1/2 turns and we have the best idle. Then go to the main. The balance screw must have some adjustments to go either way to tweeking the last setting when the main jet and needle is set. Sometimes we need to do it twice if something was way off. We can get it adjusted to about 90% that last 10% is the hardest.

Check the float level first.
Make sure the needle and seat isn't leaking.
Make sure the air filter is clean.
Make sure the intake boot isn't cracked
Make sure the reeds are good and sealing, if open flip them.
Make sure there is some play in the throttle cable.
Make sure the throttle goes to wide open(static test) visual.

Now your ready to jet.
Click to expand...
 
Okay...this update!

I've raced this old Husky a few times now...took the advice and went back to regular fuel and a 420 main jet. Can't say that I notice any difference in power...and much less expensive!

I've had the Ohlins shock rebuilt and had the spacers removed. Swapped out the rear fender for a CR fender and most folks think its a CR.

Now...what is next?

I would like to look at the gearing. First is very low, second is good...but third seems pretty tall, or at least quite a jump from second. Any thoughts on experimenting with different sprockets?

Thanks.

Kent
 
Okay...the winter has passed and racing season is underway. The Husky seems to run strong...I re-packed the silencer and, unless it is psychological, I think that made a difference. I do want to tackle the gearing next!
 
Motoduc84 said:
Okay...the winter has passed and racing season is underway. The Husky seems to run strong...I re-packed the silencer and, unless it is psychological, I think that made a difference. I do want to tackle the gearing next!
Click to expand...
packing a silencer can make a big difference..better flow. when packing is loose or missing, flow goes out of the core into the packing area instead of passing thru. an extra bonus is better sound and lower decibels..
 
You must log in or register to reply here.
Back
Top