Husaberg 660

Ouch. Is it just a simple task of replacing the woodruff key, or are there further implications?

A backfire caused mine to shear, took a long time to work out what was wrong! Just replaced the key and all was good, yours should be too.

Seeing as how the spark was weak and intermittent I decided to swap the stator. I was at the last step of reinstalling the flywheel (the stator on this old engine is mounted to the right side engine case and the flywheel goes on the outside unlike the setup in canolman's bike) and I just couldn't find the woodruff key to align the flywheel. That sucker sheared off so cleanly that I had to take an extra close look just to find it (had to put the extra powerful reading glasses on).

The good news is that I had my old 501 engine on the work bench in order to cannibalize the stator from it so I just grabbed the key from that engine. Quick and easy. Of course, it was at this point that I decided to use a 6-way Deutsch connector at the end of the stator wires to clean up that whole situation...and then I decided to run the wires for a regulator and headlight in case I want to do some night riding with this bike. So the snowball was rolling at 11 PM last night and I didn't get it all buttoned up. Hopefully that'll happen tonight and I can see if she runs so I can get back to the engine break-in.

Hopefully broken woodruff keys won't be a thing with this engine given the extra snappy nature of this rotating assembly.

I guess that I'm starting a collection of sheared flywheel keys...



Broke another today. Got only 1.5 laps on the Hangtown practice track.

I'm starting to wonder if the quick revs (especially when returning to idle like when going off a jump) are causing the flywheel to loosen the nut which loosens the taper fit to the crankshaft. Then all of the torque goes directly into the key.

I'll admit that my idle is too low to the point that the engine actually stalled in the air a couple of times. I'm still dialing in the carb settings and was intending to get in a couple of laps before going back to the truck to let it cool and make some adjustments. But I ended up having to bring the truck to the bike! I imagine that the inertia of the flywheel working against that big piston at 13.5:1 compression when there's just not enough rpm to keep it running can be a bit of an impact...or maybe I'm just grasping at straws.

If any of you long stroke, big bore, light rotating assembly guys are out there, have you experienced problems like this? Bushie? Anyone?

I'm running out of flywheel keys. I have one...maybe two left. I'd like to try it again with a higher idle and maybe retorque the nut a few times but I'm afraid of having to push it back to the truck...again.

I used to have similar issues with the keys on my old 490. I sold the bike and acquired my FE501 which solved the problem, but not a solution for you I'm afraid.

My VOR went through a phase where the flywheel nut kept coming loose and the flywheel was coming off and destroying the flywheel key. The flywheel keys should be standard metric keyways available at any hardware store. Ace hardware had them, I believe they were $1.50 or less.

I solved my issues with the flywheel nut coming loose by lapping the flywheel to the crank with valve lapping compound. Sometimes the taper of the crank and the taper of the flywheel do not match exactly, resulting in less contact area. Use fine lapping compound and spin the flywheel on the crank in one direction, until the flywheel and crank have uniform surface areas. Blue loctite and torque the flywheel nut to spec, I’ve had no problems since. May be worth a try.

Thanks VOR! I will try just that. Was your VOR a wet stator or dry? When I got this engine back from Thumper Racing, I noticed a large hole that had been drilled into the crank case below the stator. I confirmed with Travis that this was intended to convert it to a wet stator for cooling purposes. He also left the right side crank seal out so the flywheel end of the crank has been getting bathed in oil during my initial break-in cycles. I'm sure this has aggravated the situation if the flywheel and crank tapers aren't a perfect match.

ditto what VOR says and also, are you sure that the crank was for the early flywheel? I know that there is a difference between pre and post 98/99 cranks or flywheels? I'll have to trya and sort that one out but they don't swop generations easily.

Taffy

Keep in mind the key is only a ‘locator’. It’s not for holding the flywheel. That’s the job of the taper. If it’s taking out the key with the correct torque applied there is something not right with the taper relationship.

If you don’t have a crank seal installed (and even if you did really) you are going to have to be extremely careful not to get any valve lapping compound into your new motor...

Maybe install an old seal, before doing the procedure.


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Taffy, this engine started out as a '96. That includes the crank. Only problem is that I have 4 or 5 of the early flywheels and there's no telling which one I ended up using. I'll bet that the original to that crank wouldn't be having this problem. Note to self to keep flywheels and cranks a matched set. Hopefully I won't be seeing any problems with the primary gear. So far so good on that.

Once again, VERY good point VOR. I do have a crank seal installed now but I'll definitley take considerable care with the lapping procedure.

I've also heard that a little red Loctite on the taper will help ensure that the flywheel doesn't move. Just gotta remember to apply some heat before trying to remove it.

So, it's been a few months and you'd think that I would have hours and hours on this engine. Well, I don't. I consider it broken in though but have been having a bunch of small issues. First, it appears that the lapping of the flywheel to the crank has worked. No more issues there. Then I was dealing with a significant low throttle position stumble which I recently fixed with a swap to a fatter needle (fatter diameter, not fatter jetting).

I did a little riding last weekend but this was on tight singletrack where a 660cc motocross bike is severe overkill. Suffice it to say that I still have no idea how it runs at full steam...but I can say this. It's smooth and fairly easy to ride. The lightness of the rotating assembly has not made it significantly more stall prone. There is no need to use the clutch to bump the engine up into the meat of the power when exiting a corner. The meat of the power is EVERYWHERE! Also, as expected, the close ratios of the FC engine, in conjunction with the fat torque curve, give me my choice of 2 to 3 gears that I can be in for any given situation. If I'm feeling fresh and have no arm pump I can, for instance, use 2nd gear in a turn and absolutely destroy any berm that might be there. Usually I'd choose 3rd for the same turn and would probably end up being much faster because it'll still destroy the berm but I won't have to shift immediately after coming out of the turn. Or, I can choose 4th gear if I'm tired or feeling really lazy and it'll chug along nicely through the corner.

Now, take all this big bore, long stroke Husaberg engine yumminess and realize that it gets even better. Here's how. I have a number of different bikes and, among them, is a 2015 Beta Xtrainer. When pushing the Xtrainer across the garage, it feels light and easy to me. Well, pushing this 660 has been a pain. There's a LOT of wheel friction coming from somewhere! I've tried on several occasions to get new wheel bearings for this bike over the last few months but the bearings I'm able to obtain from my local dealer (which just so happens to be Dan at MotoXotica) are always the wrong size (turns out my wheels appear to be from '94 or older bikes which have different bearings). So I finally got off my ass and popped the bearings/seals out of my hubs (I also have a spare wheel with bearings so old that I can't make them spin at all!!!) and measured them. Come to find out that the wheel I've been using has been missing the bearing spacer. So, when I crank down on the axle nut, that force squeezes the **** out of the inner races of the bearings, causing them to be misaligned with the outer races which are firmly seated on the shoulders in the hub. There's no telling how much horsepower I've been losing to this condition!

Needless to say, bearings are on order, wheels are disassembled, and I'm hoping to get it all back together for a trip I'm going on next weekend to go camping in the high desert where I can really let this beast rip.

Stay tuned!

I think I just got a little tickle of excitement in my stomach

Here's some good video. On this ride, there were 7 riders including me and we covered terrain ranging from technical rocky single track to wide open roads. Since I was the only one with any idea where I wanted to go, I was in the lead and the 660 was exactly what the doctor ordered. I only had one issue which was a flame-out due mainly to altitude. We were approaching about 8000 ft (2400 M) elevation and I know my jetting is off there. If I hadn't been having so much fun, I would have thought to turn on the Go Pro for some of the faster sections so you can get a feel for how awesome this bike is. Of course, the conditions were perfect as the high desert we were riding in had gotten a good soaking the night before but there were still plenty of horsepower-sapping sandy corners where, on any other bike, I would have had to be in exactly the right gear to be in the meat of the power and then be ready to shift up immediately after the corner. Not on the 660! I could choose a gear higher than usual, maybe use a little clutch...maybe not. Didn't matter. Just twist the throttle farther if you want to come out of a corner faster and then let her rev out into the next corner.

Enough talk!
https://photos.smugmug.com/Walker-R...8/i-3qwgRNF/0/dfaa8506/1280/GOPR0973-1280.mp4