'02 400 gearbox problems

I picked up this 400 last fall. It was not running and, consequently, cheap but it had motard wheels, complete with cush drive, which my brother has always had an interest in trying on his 550 so I bought the bike. To my surprise, it also had a 41mm Keihin FCR MX on it for an extra bonus.

I seem to recall a previous owner posting here about this bike because it had evidence that one, or both, of the cam sprocket bolts had come loose (and I remember this story from somewhere on the UHE). The head and rocker cover were grooved and exhibited some cracking. The bike was sold to another guy who bought a head for it off of ebay but then lost interest so now it's mine.

I cleaned the aluminum out as well as I could, bought a bunch of parts from Taffy (cam, dvsk, gaskets, timing chain, tensioner blades, etc) and put it together with the new head and the original rocker cover. Oh yeah, I had the frame powder-coated yellow and replaced the black spray painted plastic with some new parts and some old that I had laying around, laced up a front wheel from an old hub and I'll do a matching blue rear when bank account recovers a bit.

Here's what she looks like today:



I got her running a few months ago and she purrs quite nicely. Problem is there's a bunch of clattering from the transmission. When in neutral with the engine running, lean the bike to the left and it clatters. Lean it to the right and it doesn't. Clatters in first while riding. 2nd, 3rd, and 4th are fine. She's difficult to shift into 5th and then pops out of 5th quite readily. It's hard to get into 6th and she pops out there as well. With constant pressure on the lever, I can hold 5th and 6th but, remove the pressure and it drops into a false neutral every time. With the engine off and the transmission in neutral, lean it to the left and it'll catch a gear and need the clutch pulled to push across the driveway. Lean it to the right and she'll maintain neutral.

Whenever I've had a Husaberg engine apart, and all of my experience is with 1996 and older, I've made a concerted effort to just leave the transmission alone because there always seemed to be a lot going on there that I had no understanding of.

Question 1: Any guesses as to what's going on here? Bent/worn shift fork? Shift drum shimmed wrong? Damaged shift drum? Chunk of aluminum stuck somewhere it shouldn't be? I should mention that, once running, I saw a CONSIDERABLE amount of aluminum flakes floating past the oil sight window (but I didn't notice this until after some 15 or 20 minutes of riding) so I drained the oil. The oil screen was caked in aluminum shavings but doing a pretty good job because the pleats of the oil filter had almost none.

Question 2: I've seen it mentioned that the transmissions are interchangeable from about 1997 to 2008. I have 1995 and 1996 engines sitting on a shelf in storage. Can anyone tell me what is different between the older engines and this 2002? Can I cannibalize one of the old engines for possible solutions?

This is a fantastic bike and would make a perfect addition to my stable once functioning properly. Then I would have the '02 400, an '01 501, an '03 with a '94 600 engine, and my '94 FC with the 660 cc big bore. Basically, a bike for all occasions.

It probably isn't the gearbox. talk about "give a dog a bad name".....

probably one of two things or a combo.

one, the gear selector fork is jamming back due to 'blunting' damage by the selector drum pins smashing it up. this stops the claw passing the base plate.

two, the by far most probable problem is the selector star is out by one position. My tip for that is to just take the left cover, clutch, selector arm and selector star off and then using your hand on the rear tyre and the other on the selector drum just chug the rear wheel too and fro whils selecting clockwise, clockwsie (yawn), clockwise till you can go no further.

this is technically known as "first gear"
'snick' (yes, an american word there) back a little and you should be able to hold the front shaft while spinning the wheel.

this is now known as 'neutral'. now remount the star in its NEW (yes) position.

you can chamfer the edges of the selector plate by dismantling but leaving the top plate dangling on the spring. I use the sidewall of my bench grinder and the jobs a good 'un!!!

regards

Taffy

PS. I love the look of the bike. can't wait for that rear rim. mudguard looks like a Yammy?

Ok. I'll give your process a shot as that's definitely a lot cheaper than tearing the whole thing apart to replace internals.

The mudguard, fender brace, and headlight housing are 2009 Husaberg. The color is a bit darker blue than the rest but it doesn't bother me.

A little update here.

I tore into it today. Removed the clutch cover, removed the clutch, the shift detent, shift star, and the shift lever assembly.

The shift claw had slight burrs on it, but nowhere near as bad as my '94 FE600 when it wouldn't shift at all. I filed off the burrs anyway.

Next, I followed Taffy's advice above to find neutral. While turning the shift drum, I noticed that there is a very large amount of axial slop, maybe even as much as .5mm! I didn't measure it. Maybe I should have.

Then I started reassembling everything and noted the stepped spacer under the shift detent arm. The stepped end should fit inside the hole in the detent arm...





Now, I could be wrong but, when I took it all apart, I could have sworn that the step was facing the engine case. This is wrong. I also noticed...



The detent arm was bent! I straightened it in the jaws of an adjustable wrench and put it all back together. Started it up and...still clattering!

I've taken a few other older Husaberg engines apart to the point where I was fiddling with the shift drum and I don't remember any of them exhibiting as much axial slop as this one. Is there a thrust washer in there somewhere that could be missing?

I haven't ridden the bike yet and am hoping that maybe I've at least fixed the 5th and 6th gear issues because I really doubt that the detent was engaging the shift star properly. I will update the thread as things develop in case anyone else has a similar issue.

So, Here I am finally updating this thread almost a year later.

The shift detent arm was, in fact, the culprit for the difficulties with 5th and 6th gears so the step in the spacer does, in fact, interface with the arm and not against the engine case. However, the transmission still clatters. Still no idea what causes that.

I've made a number of changes to the bike to make it better for my intended purposes. I switched to an '07 radiator with the hole for the thermal fan switch and the holes in the fins to mount the fan. I mounted the Spal fan that was factory in '08. Because the '02 fuel tank didn't provide enough room for the fan, I found an '08 tank for it. I recently received a care package from Taffy with some graphics, a seat cover and new yellow shrouds. I finally got a matching blue rear rim laced up and am running 13/52 gearing. I installed a Rekluse auto clutch and have been getting it dialed in.

I'll post some photos in a bit.

Some may wonder what my intended purpose is for this bike given the modifications I'm making. Well, I have a 9-year-old daughter who loves to ride so, to keep the bike from overheating while putting around with her, the gearing is low and the fan comes on at 180 degrees F. I also intend for this bike to be my go-to for very difficult trails such as Foresthill Trail 6 (a somewhat famously difficult local trail) or the Rubicon Trail. There, the auto clutch will be a nice addition. I have other bikes for other types of riding - dual sport, high-speed desert, etc, so this one can be very specialized.

Anyway, there's your update in case anyone is researching similar problems with their bikes.

Dirty, but here's the latest look...



Upgrades...





Discovered this as I was installing the Rekluse...

they all do that. convert to 2003+ and allen screws if it worries you Thorgan.

cheers

Taffy