Sign in to follow this  
Followers 0
WR400Droid

Problem With Fifth Gear

9 posts in this topic

I have a 2000 WR 400, it's got YZ Cams, an FMF Q Pipe and about 100 hours on it. For about 30 hours now it has been exhibiting an odd slipping sensation, but only in fifth gear. All the other gears pull great. It only happens under load, not when coasting.

I replaced the clutch basket, clutch boss, friction plates and clutch plates with springs. This did not fix the problem. What could it be?

My suspicion is that fifth gear itself is damaged, or possibly a shift fork? But I don't want to crack the case until I've eliminated everything else.

Any help would be greatly appreciated.

Share this post


Link to post
Share on other sites
I have a 2000 WR 400, it's got YZ Cams, an FMF Q Pipe and about 100 hours on it. For about 30 hours now it has been exhibiting an odd slipping sensation, but only in fifth gear. All the other gears pull great. It only happens under load, not when coasting.

I'd bet that one of your dogs is broken off 3rd gear. 3rd gear drives fifth.

My bike showed the exact same symptoms, and this was the result.

broken gearbox

Share this post


Link to post
Share on other sites
What was the replacement cost? Is this an expensive fix?

about $AU500 if I remeber correctly, but I changed a few other gears that were worn at the same time. Yamaha payed for all the 'broken bits' because it died the 1st day I had the bike :cry: (bought 2nd hand from a dealer)

I opted to do the work myself which was a much safer option than letting some 1st year apprentice loose on my baby.

Share this post


Link to post
Share on other sites

If you had a chipped or broken tooth on any of the gears, you would hear it, and feel it.Chipping and clunking away in your tranny. If you are really feeling a 'slipping' when in 5th gear, then maybe it is your clutch. Check all the dimensions and clearances of the basket, pressure plate, springs, even clutch plates and the shaft they all are mounted to.

Make sure you are using NON-Energy Conserving Oil with NO anti friction additives.

Share this post


Link to post
Share on other sites

All of the tolerances check out, according to the Yamaha owners manual. I've been using Rotella T 10 30 Synthetic oil, it was what the previous owner used. I've since heard that I should drain it, and switch to a dedicated 4stroke oil, like BelRay or Hinson oil.

Share this post


Link to post
Share on other sites

I had the same problem. Its your 3rd and 5th gears. The dogs/lugs that engage the gears (3rd drives 5th) are worn on the edges and slipping under load. I was trying to shift from 4th to 5th while wheelieing and didn't get a good engagement. After that, 5th would slip if I get on the gas (1st - 4th works fine). Sorry about your luck! You will have to split the cases and replace those 2 gears.

WR450 supermoto :cry:

Share this post


Link to post
Share on other sites
If you had a chipped or broken tooth on any of the gears, you would hear it, and feel it.Chipping and clunking away in your tranny.

Unfortunately you arent correct on that matt. Mine was as smooth as silk in all gears, even fifth, but to the untrained rider it appeared to be slipping in 5th. If the clutch was that bad that it 'free reved' in 5th, it would be noticeably slipping in 4th aswell.

You need to understand how the gearbox works to see how this can be the case. As the dogs wear, they round out. This round edge causes the gears to 'ramp out' After they have ramped out enough times, the dogs break off.

Alternateively, the dogs can just fail.

I have heard comments on this forum like 'shifting too hard without the clutch causes the gearbox failures' :cry: I think not.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0