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 The previous version was outdated and no longer supported.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

OK, so I decided to change only 1 variable at a time.

Tested with the flattened float lever.
On the side-stand, there are a few drops out the overflow - which tells me the fuel level is now quite high.
I set it to the 17mm, as opposed to 18mm or 19mm to give me the max available within spec.

Hard up into 3rd, and she still goes lean.
Gentle in 3rd, keeping a constant 3/4 throttle, and she runs fine till she suddenly goes lean at the top, takes off , then does the bonnggg bong, be-bong story again.

This is definately the best so far - but not quite right.

PS. One covers ground quite rapidly now !

Next step:
Pull that petcock and measure the inside diameters.

Anyone got a petcock and a fuel tank handy - keep to compare flow-rates for 250ml.
 
I am going to start looking into mine this week. My first item will be the petcock, seeing how I drained all the gas last week to run in my Maico project.
 
Try cutting the top "shield" down by half on your needle jet. That will change the vacuum signal to the needle/main jet and increase flow at high RPM. It also helps the midrange. I have never tried it on a 500 but works awesome on my 250 and 430. Other thing is make sure you carb vent lines havent shrunk with age causing a vacuum in the float bowl- displacement-replacement issue.
Just thought of one more thing! Slide is going to full open/throttle isnt it? Suprising how many I have seen in both bikes and cars that was an issue.
 
Sorry had a brain fart here. 27 years ago this what we had to do on the 40mm and 44mm carbs.
Need BB-0 needle jet (richer)
7F7 needle,(leaner to start with then the taper goes richer, use dykem measure up 10mm from tip put needle in a drill press. Hi speed on drill press Use fine cut file, file to a point ( not quite a needle point more like fine ball point pin) from the 10mm line down. Cilp in middle to start.
between 430-450 main. This was with race gas mixed 50/50, spectro oil at 52 to1.
This works or put 38mm carb on it.(too expensive).
It will rip
Later George
 
Thought of another test which I will also try.
The air-cleaner is fresh, but does have the secondary coarse red foam sleeve on it.
(But running out of air it will feel like its starvig itself and not sound lean....I expect)

Will check silencer for loose material and the like. I had to have one made as it was missing. Will post specs tomorrow.
If anyone has OEM dimensions handy - please post them for comparison, but I will search in the meantime too.

I now recall a period article about the needle mods - will go search = thnaks Uptite

This is becoming obsessive, so don't rule out the 38mm carb :)
Also going to try get some onboard footage so you guys can judge.

Thanks again for all the help - this is really great !
 
No thats the problem just try it. What we had to do back then. Did all the other things first larger pitcock nipples, float levels, of course made different exhaust systems. But this what worked, then started lowering compression for more top end 119-124mph for 30-40 miles and not a blip to throttle and no seizers.
Later George
 
HI

Silencer dimensions
inner = 29mm
outer = 76mm
length = 300mm

Please can someone measure up their and post dimensions as a comparison.
 
Thanks Up-tite for your guidance - off to start grinding now :)
Will also see if I have a spare needle jet to try Husq.fleet's suggestion too.
 
Have Boyesen reeds in there - shouldn't be a problem right ?
Probably put stock in till it runs correctly then test them again....
 
Discovered something else:
The petcock has 2 fuel filters. I visible into the tank, and the other from the bottom into the body of the tap.
The second one looks like it was in deep space for a while. Vacuum collapsed.

312373_10150375094039343_522719342_9676505_1135295066_n.jpg
 
I take the petcock filters/screens out and run a good high flow fuel filter. Everyone used to make fun of the "big" filter on my bikes calling it paranoid filtration. It was for flow. I had a tank painted once and spent some quality time in the desert with one finger plugging the petcock hole in the tank while I tried to clean the screen. The painter had gotten overspray in the tank and the race gas made it come loose. I had paint flakes plugging the screen. Ended up ripping the screen off, one handed and tried to get petcock back in before all the fuel ran out. Of course it had a full tank of gas and even having the bike on its side didnt help much. Sorry, got sidetracked as usual.
 
Latest news:
  • drilled the fuel cap breather to 5mm, was 4.4mm
  • Removed the 2nd fuel filter as pictured above.
  • drilled the pet-cock into the fuel tank hole out to 8mm
  • removed the 2nd red air-filter foam layer
Observations from today's run:
  • Sometimes when hot, I need to put the choke on to start. Sounds like a flame-out.
  • Accelerating hard, at the top of third, she still runs into a wall and basically dies.
  • Accelerating slowly, as you reach top revs in 3rd, she seems to go lean, suddenly revs up and then does the boing, be-boing be-be-oing noise...
Next steps:
I have a spare 7DH3 needle, so am going to try and get specs for the 7F7 needle to see if I can grind it using the 7DH3 item as the base.
 
photo_su4E1.JPG
Needle Taper Diameter Dimension Chart
(a)=Needle Length (mm)
(b)=Length between points (x) and the taper point (Y)
1=10mm
2=20mm
3=30mm
4=40mm
5=50mm
D-1, -2, -3, -4, -6 are the actual taper diameters at those
given points in millimeters
 
OK, need to think this one through:

A B D-1 D-2 D-3 D-4 D-5 D-6 D-7
7F7 72.3 33.1 2.99 2.99 2.99 2.8 2.54 2.28 2.02
7DH3 72.5 28.1 2.98 2.98 2.96 2.8 2.47 2.11 1.76
This tells me the 7F7 needle is fatter (larger diameter) all the way down. I know George suggested we grind the needle, but natively, the 7DH3 seems to be thinner, hence allowing more fuel and makinh ot a richer needle.

So by grinding, then the custom needle will be even thinner, and allow more fuel - making it a richer needle.

With the grinding only taking place towards the sharp point, it's at high revs that there will be more fuel.
 
This is the standard float lever:

293684_10150383282729343_522719342_9726450_1551098976_n.jpg


then my modified float lever to get the correct 17mm horizontal measurement:

316522_10150383278224343_522719342_9726434_1131419974_n.jpg


and

316846_10150383283374343_522719342_9726456_1480717871_n.jpg


Reckon we are getting there.
Either to the solution, or the end of my rope :)
 
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