XR400 Kickstarter woes

[LeftTurnOnly]

The kickstarter on my XR400 quit working one day after my son rode it. I pulled the case off and discovered that the pinion gear and idler gear aren't meshing together, but grazing the top of the gears - which seems to explain why it doesn't work anymore

 

This is my first dive into the cases of an XR engine. What I found doesn't look right..

 

Anyone have a similar experience? And, anybody out there have some good parts they'd like to sell? 

 

The metal shavings are another cause for concern. Am I out of my mind to try and save this engine?

 

[Baja trail Rider]

Send pictures if you can

[LeftTurnOnly]

Pinion gear and idler gear not meshing...

 

[Baja trail Rider]

Start removing parts,to see what went wrong.

[lanz]

Mine broke off the end of the countershaft which supports the gear. $100 from Honda, split cases big job. Be caerful buying on ebay , Honda made several sizes countershaft and you might buy one that does not fit. I put on a XRs only Mikuni pumper, starts one or two kicks all the time. 

[Trailryder42]

That's strange. Yes, the idler gear teeth look a little worn but not enough that the gear meshing would be that far off.

Are you the original owner of this bike?

My first thought is that if the idler gear meshes properly with other related gearing besides the kickstart gear, then someone installed the wrong kickstart assembly. I can't remember what other gear the idler gear meshes with. Anybody? I'm thinking it meshes with a gear on the back of the clutch basket, but I've had so many bikes I'm unsure.

Definitely keep us up to date as to what you find.

[LeftTurnOnly]

@Trailryder42 - great point! I'm the third owner of the bike - the first owner did a lot of the mods on the bike (pumper carb, Scott's upper triple clamp, etc.). I got a bucket of parts from the second owner that was passed along to him, including a bottom-end from a 400.

 

Guess what's missing on that bottom end? The kickstarter assembly! 

 

I've looked at OEM parts for the bike, and there are several different idler gear and pinion gear options even within the same year. This could be the problem?

 

And, I thought myself the gears didn't look too worn, and none broken. 

 

I'm just baffled that, if it wasn't the right size gear to begin with (either one), why did it work, and why did it quit working?

[LeftTurnOnly]

So after taking some time to look things up - the idle and pinion gear are common to several different XR400 years. That doesn't explain what happened. 

 

It does make sense that the two gears should be meshed together, right??? 

[Trailryder42]

I should have posted a picture from the shop manual to show you what its meshing should look like. But yes, they are normally tightly meshed together. The wear on the idler gear looks like the two might have been barely meshed together at one time.

[Oil Baron]

What shaft does the idler ride on?  Can you wiggle the idler to make it mesh? 

 

The countershaft on the early XR4 is known to break.  The good news is, it can be upgraded to the later and larger countershaft.

[LeftTurnOnly]

The idler is on the countershaft. 

 

I'm going to tear down the engine further this weekend. The idler gear doesn't seem to be out of place. Will know more soon.

[Still-learning]

Take a very close look at the bearing behind the idler gear. I have stripped two XR4 engines, one had a broken counter shaft, both had a worn bearing there, one which had collapsed. I think it must be the last point of the engine to receive oil & if the oil is low at any time it can cause the bearing to wear quickly. if this is the case, the bearing can only be purchase from Honda as it's an odd size (that's the case in Australia anyways) So my theory is if that bearing collapses, the shaft can lift up enough to lose contact with the kick stater gears but being a slight incline from the bearing on the opposite side of the counter shaft the internal gears will remain meshed to a certain degree. Put the bike in gear & rock it back & forth, it may just slip back to where it's supposed to be if that is the problem .

Hope this helps

[LeftTurnOnly]

Ok, so I finally got back to this project, and found a broken countershaft. Pretty much what I was expecting.