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 The previous version was outdated and no longer supported.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

Insufficient fuel from tank to carb ?

The good news, is that the cut-dead on acceleration at the top of 3rd is gone. :)

OK, so everything is together and now with the extra narrow custom needle, she starts sounding very deep, boomy and rough from the mid-range on up.
As I understand it, this is what 4-stroking sounds like.
You can sort of ride through it, but it gets worse then better then worse and finally cuts, as if the spark is being snuffed out.

Back off, and you get a run-on sound...

Going to see if the dyno guy here is up and running and carefully drop the main a bit. Still on 430.

T
 
@Fire:
Hmmm, will open up and have a poke inside to see if I can see anything.
Its a new MZB with lighting coil - so hope not.

Will have to open up for the dyno man anyway.

keep everyone posted later this week

T
 
Off to the dyno tomorrow evening:

1. Confirm no coil breakdown
2. Confirm fuel flow to bowl
3. etc

Hold thumbs. Will post results and the good, the bad and the ugly as it happens.

T
 
HI All

Well, its slightly better overall, but I still have the funadamental issue that the bowl drains too fast/doesn't refill fast enough/ has the wrong fuel level.
So I am still looking at the float lever arrangement.

My manual shows the following:

Husqvarna500XC-Ownersmanual40mmMikunisetup.jpg


but the measurement of the 17mm, is this from the upper edge, or the recessed edge in the carb.

How do you guys measure ?

Also, anyone had to change the needle and seat arrangement ? Mine is a 3.3.

Lastly, what altitude are you guys running at ?

Please post so I can build the overall picture.
 
That measurement may be different if your running the 40mm carb. I set my float level in my 83 500 with the arms level, parallel with the float bowl mounting surface as shown above. If the the fuel level is getting too low when running hard you may have too small of inlet orfice in the needle and seat valve. I was hoping Scooot would chime in as he runs a couple of 500's near me and has them very dialed in. He owns the Starvation Ridge and Eddieville MX tracks in Goldendale Wash. There may be a contact info on his website. I haven't seen him on here in awile.
 
Reading the parts manual again, it shows a main jet of 340.

I am at 1500m altitude.
This is 4920 feet.
This means at least 2 sizes down on the main.
This means a 300 main....

I am currently on a 420, which means I am at 140% of what I should be on ?

So here's the confusing part:
The 430WR is listed as having a 430 main to start with.
I would have expected the 500XC to have the same size or bigger, not 30% smaller than the smaller motor.

Am I smoking the good stuff ????
 
Started by fitting a 340 main.
She's a ripper - still draining the carb too quickly, but a helluva lot better all round.

Next will be a 330 and test carefully.

A buddy who used to ride Maico's in the day took it for a spin down the road.
Picked up in 1st, 2nd and 3rd - this is more like what I was expecting... :)
 
I agree you may want to check your needle and seat. there should a rated flow for the seat number(3.3) you are using. I know this is the case with dellorto. when i was getting my 510 going i had 2 x 40mm dellorto carburetors to make 1 good one , and the later model husaberg 501 carb. had a bigger # needle and seat which is what i used.
I have a 40mm mik. carb in the shed i will check the # and let you know.
I take it you have removed the needle and seat and checked there is no crud or corrosion behind it?
 
@SA63, all clean and checked. I did replace with new for good measure too though.
Today I'm going to match up a simple ball-valve for the fuel tap, see if that makes any difference.
That should straighten out the fuel flow too.
 
Finally sorted !
The last key to the puzzle.

307492_10150407548079343_522719342_9859971_1362481308_n.jpg




Thanks to everyone all across the world that has helped me with ideas, suggestions and actions.

Now we are in business !

Trevor
 
i had a similar thing happening on my cr500 . long run up hill int 3rd or 4th it would go flat . turns out there is a reason the fual tap and fuel inlet on the 44mm are about 6 mm . put 6mm id line on it and a equal size filter and it fixed it straight away
 
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