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 The previous version was outdated and no longer supported.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

Finding TDC

390wr Jon

390wr Jon

Husqvarna
AA Class
This is probably a stupid question so please don’t hammer me on it.


I’m in the process of installing a Powerdynamo system in my 1980 390WR using a dial indicator through the spark plug hole. When the piston nears TDC there is a slight resistance when turning the flywheel. The dial indicator then stops, whereby I can rotate the flywheel back and forth ever so slightly without moving the dial indicator. When I continue turning the flywheel toward the downstroke, there is a similar slight resistance.

Note that there is no slop in the connecting rod to crankshaft bearing or connecting rod to piston.

So is the correct procedure is to set the timing on the downstroke as soon as the dial indicator starts to move again? I plan on retarding the timing about 1.8-1.9 mm. Is this done by removing the flywheel at its TDC and rotating it counterclockwise (without moving the crankshaft) to achieve the 1.8 mm retarded timing setting?

I used to be reasonably good at this stuff but I guesss my gray matter is going south as I get older…..
 
I used to be reasonably good at this stuff but I guesss my gray matter is going south as I get older…..
Click to expand...
I'm right there with ya brother. :oldman:

I've have zero experience with aftermarket ignitions but I do have a fair amount of timing experience with a Femsa and Motoplat. An ignition fires before TDC. So, using your dial indicator find TDC then rotate the crank backwards the recommended timing amount which you indicate is 1.8-1.9mm BTDC. At this point a mark on the flywheel must align with the a mark on the stator. This is where the plug will fire.

As for moving the flywheel back and forth one millimeter at TDC without moving the dial indicator, IMO thats normal. The resistance you mentioned isn't something I'd say is normal. I will say that there may be a different feel to turning the crank past TDC but there certainly shouldn't be resistance. If this was my project, the head would be removed for a visual inspection.
 
I have Power Dynamo on both my 78 390 Huskys.
If you set the stator plate in the middle of its slots and get the flywheel generally in the right place you should be able to fine tune the 1.9mm with moving the plate in the slots.
I have found with both mine that 1.9mm is the sweet spot.
Don't push the flywheel on too hard as you may want to pop it off to move slightly. Make sure it is lapped in too.
It's a great ignition system. My 390WR has run one for 10 years and the Auto for 9 years. Never an issue.
 
grouty said:
It's a great ignition system. My 390WR has run one for 10 years and the Auto for 9 years. Never an issue.
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Does this ignition add any noticeable gain in engine performance? Data says it puts out 4x the current over the stock ignition.
 
I have one on my 450CR and I like it. Easy Starts even though I'm old and tired. With a single pull comp release even I can start this beast.
Mine is a Vape. Great Luck
 

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Crash, you won't notice any "extra power" other than it will start easier and run clean and consistently.
The spark will probably be stronger and help with the clean running.
It won't destroy your engine like my old Electrics World did :-(
If you run lights like I do then most of that extra generating capacity goes to making almost road bike like lighting.
 
grouty said:
Crash, you won't notice any "extra power" other than it will start easier and run clean and consistently.
The spark will probably be stronger and help with the clean running.
It won't destroy your engine like my old Electrics World did :-(
If you run lights like I do then most of that extra generating capacity goes to making almost road bike like lighting.
Click to expand...
Might I ask why the Electric World ignition destroyed your engine? Only asking cos just installed one on my '82 XC
 
When I eventually got an answer out of Electrex (that was hard work and nigh on impossible !). It seems there was an internal fault. It was running on full advance most of the time. It was random though.
You get what you pay for at the end of the day.
The Power Dynamo / Vape was worth every penny.
 
grouty said:
When I eventually got an answer out of Electrex (that was hard work and nigh on impossible !). It seems there was an internal fault. It was running on full advance most of the time. It was random though.
You get what you pay for at the end of the day.
The Power Dynamo / Vape was worth every penny.
Click to expand...
Okay thanks, let's hope I have more luck. But I'm having the Motoplatt repaired just in case!
 
Here’s the latest update:

1. Installed new intake manifold
2. Installed new gaskets between intake manifold and cylinder
3. New NGK BR8ES spark plug set at 0.018 gap
4. Checked compression - 90 PSI
5. Reset VAPE timing to 1.85 mm BTDC

Result: No ignition whatsoever, but a robust and healthy spark when holding the spark plug against the cylinder.

I also tried a very small squirt of ether to make sure it wasn’t a fuel issue, but still absolutely nothing. I then tried setting the timing at the Husqvarna owner’s manual setting of 2.18 mm and still no success whatsoever.

Needless to say, I’m thoroughly frustrated.

Any other suggestions on what I might be missing or other troubleshooting suggestions?

I still think it’s a timing issue (Grouty/ DFA - Do you have any other suggestions since you both run a VAPE system successfully?).

Thanks in advance,

Jon
 
90psi Is very low is that with the throttle wide open with multiple kicks in a row?
Try ATDC you might be looking at it in reverse!! Ask me how I know!
Try to start it with the pipe off
A squirt of either befor ya kick in the plug hole
Keep at it you'll figure it!!
 
Yes, 90 psi to too low if you have checked it correctly. You should be up at 150/160 psi minimum.
Pop the head off and check for bore/piston wear.
 
So by way of background, I did a hare scramble last fall using the original Motoplat ignition with its anemic spark. Plenty of power but an absolute bear to start. Hence the change to the VAPE system in hopes of easier starting.

The cylinder and piston looked fine since I had it bored 1 oversized with a new piston many years ago before I parked it.

I’ll try another compression test, but will 90 PSI prevent it from running at all? Also, the 90PSI was with the throttle closed after about 2-3 kicks.
 
The compression test must be done with the throttle wide open.
Yes, if it is 90 psi it will be a pain to start. I had that with mine a while ago. When I pulled the cylinder the piston and bore were very worn. That explains why it was a pig to start. I now have a NOS cylinder and piston. Starts easy now.
Be aware you may have to jet slightly richer at the top end if you change from a Mototwat to a Vape. The spark will be stronger at higher revs and therefore burn the fuel better. Otherwise you could be looking at a lean situation at full throttle.
 
DeathFromAbove said:
90psi Is very low is that with the throttle wide open with multiple kicks in a row?
Try ATDC you might be looking at it in reverse!! Ask me how I know!
Try to start it with the pipe off
A squirt of either befor ya kick in the plug hole
Keep at it you'll figure it!!
Click to expand...
Here‘s the latest update:

Compression is 115 PSI with throttle wide open after 4-5 kicks.

Tried 1.85 mm ATDC ( in case I was looking at it backwards) with a squirt of ether in the plug hole and the pipe off but absolutely nothing.

I’m ready to jump off the nearest bridge
 
Something useful when trying to diagnose ignition problems - an inline spark tester (pic below - $5.29 at Harbor Freight or at your favorite auto parts store). Even if a spark is good holding it on the side of the cylinder, screwed back in the head and under compression it may have a weak spark. Even if it doesn't solve your immediate problem, you will know that a weak spark is not contributing to your not starting. It is a handy tool to have in the tool box.

63590_W3 - Copy.jpg
 
Jon Check all the wiring again.
Disconnect the Kill button and isolate it.
Also pull the front motor mount and clean to shiny the frame and mounting plate. Might not be a good path to ground.
Re torque the head to see if compression comes up some. And Change the Sparkplug!
When I get to the Shop I'll look for the install directions and post up some pics of mine.
Maybe we can see a difference.
Never easy diagnosing on the internet!
 
On the way to the shop I was thinking you had a feel of resistance as the piston passed tdc.
Are you sure your piston isn't touching the plug and closing the gap?
 
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