Transmission jamming

Here is the problem, I parked the bike and when I went to start it the starter turned once then hung. I pulled the starter, not the problem. I pulled all spark plugs and manually turned the crank shaft. It took a little moving back and forth to get it moving but after that no problem. All the valves and pistons were moving fine. I left the spark plugs out and tried to start it(I didn't want any force to cause any more damage)I heard a sound like something moving in the gearbox and then it hung again. The bike ran great up until this point. Is this something that might be a broken spring or something or is this something that might get expensive really quick? I appreciate all your help.

 

We need a little more info. Does it do this with the clutch pulled in and with the bike in neutral? Does the clutch feel the same when you pull it in? Does the tranny shift with the bike off or does it have resistance?

 

Might be the "bag of marbles" sound made by the starter clutch is it?

 

I get something similar to that on my MaximX. What I've discovered is that putting it in gear and rocking gently usually gets the motor past that "hang-up".

I'd be surprised if it's the tranny if it does it when you're in neutral and/or have the clutch pulled in...

 

It does it in neutral and with the clutch pulled in. It is not the starter due to the fact that when I removed the starter it was still jammed. It is almost like something has come loose or broken and jammed the engine. It shifts just fine just something is hung somewhere in the transmission housing or in the bottom of the engine. Any ideas?

 

The starter doesn't engage directly with the engine, there's some gearing/clutch assembly in between. That's the part I think they're talking about. The transmission wouldn't have an effect on the motor turning over if the clutch is pulled in.

 

Check the primary drive chain. I read something about that once I think.

 

Likely your starter chain tensioner blade fell apart and the pieces have locked up your tranny. Gotta split the case on that one. $25 part, ridiculous amounts of time to pull, strip and reassemble the motor.

 

I would say your on the right track Robert, it is possible to pull the left hand engine cover off, and there is a small hole ( about the size of a nickel ) in there which you *may* be able to pull the piece of chain guide out of. I did it for a friend of mine, pulled out a piece of rubber a bit bigger than a dice. However, there is no way to know if another piece will break off a week from now and jam you up again. It lasted the whole season for my friend.

So the right way is as Robert said to split the cases and replace the guide, the quick and somewhat easier way is to pull the engine cover and remove the piece.

 

When the Guide separates it usually sends chunks into the Shift Cam causing the Shift Forks to be unable to change Gears ... not causing the Engine to "Hang" necessarily.

This sounds to me more like the Rear Cam Chain Guide escaped. If it did ... you'd get about a revolution and three-quarters before the engine locks-up.

Pull the ignition cover and see it you can get several full revolutions opposite the engines normal direction ... like you would when setting the Cam Chain Tensioner Manually ... if you do ... you need to check to see that the Rear Cam Chain Guide is still secure within its Hold-down notch.

You can pull the Cam Cover and do a lift of the Cam Chain as a preliminary test to rule-out the escape. If the Cam Chain is tight across the Guide Bridge ... the Rear Guide is likely to not have escaped. Get hold of the Rear Guide and try lifting it straight up. If it moves you might get out of this mess with the Gods looking down upon you favorably.

If the Rear Guide is snug in its anchor notch and the Cam Chain is tight across the Guide Bridge ... what ever it is that is causing you the "Hang-Up" isn't going to be an hours work to correct.

 

Rick, when I pulled the cover off I was not able to rotate the engine in the normal direction, but when I did as you suggested, it moved backwards and then I was able to move the engine in the normal rotation. It did hang again after ten to fifteen revolutions. Does this sound like the cam guide to you?

Thanks for all your help

 

Not ten or fifteen.
When the bottom of the rear chain guide is out it locks-up within two.

This is not to say don't check it. You'll be on your way by that thing if you have to get in to that engine some to find-out whet the heck is going on.

There are several things that come to mind. Like your whole Clutch Basket being loose in there and slipping off the main shaft.
You might have a gear broken.

Typing about it isn't going to really help us figure it out ... This is one of THOSE Cases where "Hands ON" is really the only way to determine what it is.

I could have the bike right here in my living room with me and not be able to figure it out until you discover what it is during the tear-down investigation.

 

Yikes!
Rick is right, there is no substitute for "hands-on" in the presence of the patient. The suggestions to date are likely candidates for the problem but I'm now firmly planted in the "pull-the-engine" camp. There is something way wrong in Paradise and there is no easy way around it.

 

Yeah, Rick your explanation sounds better, I was reading it as more of a transmission jam rather than an engine jam :S

 

It would be helpful to know what service or maintenance was done recently that might contribute to the cause.

Did you adjust valves or do anything to the clutch?

 

I haven't done anything with the clutch or valves yet. I was planning on doing a valve adjustment this winter but now I have bigger fish to fry. When it jammed it ran well to the store but when I came back out to start it made about 1 rotation then hung. Does this shed any light? I had resigned myself to the fact that I was going to have to tear into her and I appreciate the tips on where to start.

 

There's at least a dozen reasons why you'd suddenly jam-up.
That's why we really can't give you much of a diagnosis typing about it.

THIS is one of those situations where you need to actually lay a wrench on the Bike and jack it through whatever motion you still hsve left and feel and listen for what's holding it back.

I threw a Valve Shim, one time ... awhile back, and the Cam Couldn't make a revolution past where the Shim was flipped outside the Bucket.

We have to consider everything like that and "Go Looking" for it. All we really know about you plight as far as dealing with it in The Forum is that you have an Engine that locks-up and won't fully rotate.

We want to be able to help you.'
But, you got the Bike.
All we got to go on is what you've been writing for us.
That leaves everything we might consider still being "Guess work"!

 

Thanks Rick, I'll hopefully be tearing into her shortly. I will let you know what I discover. Again thanks for the help.

 

I like for it to be something that isn't going to involve having you do a full scale splitting of the cases. That's work!

But, if it is and you find-out what went wrong while on the way in ... don't think you HAVE to rebuild that engine.

I'm sure you can find a decent whole engine to swap in there without looking too far at all. In my opinion ... if it comes down to something that means having too take your engine all the way down ... you might be better off finding a low-miles complete engine to swap in there ... AND THEN ... take your sweet time overhauling the one you have ... IF ... the situation is such that the problem is easily resolved.

If you get into it and find something that will allow you to save your current engine ... you make the call about what you are willing to sink into the project.

I'm don't endorse going only as far as you need to go ... (i.e. just replacing a broken second gear) ... and fixing that ... thinking that the Starter Clutch, Chain Guides or Gear Dogs don't need a critical inspection and possible replacement ... WHILE you are already inn there.

You could get away with a component replacement only ... if the engine was just a few years old.

But, with age and age-only ... things deteriorate and NEED to be replaced when the opportunity presents itself!

 

Amen Brother!

 

Shooting from the hip here but could it be that the primary guide is jamming the primary chain? Remember that the guide is mounted on a metal plate which it seperates from when it goes bad. The metal piece could be bent and causing some trouble also. If so then pulling the oil pan would dislodge the remaining pieces and would help diagnose the problem before tearing further into the engine.

 

It could be that and several other things, too.
But, it sure would be worth investigation the easy way rather than have him pull an Engine and start taking it all down to brass tacks.

That's one of those things I was talking about when I said that we really need to have our hands on the Bike.

Everything we have to say about it is an educated guess. Something we know about or have heard about of experienced it ourselves.

No matter how we cut it ... it's still way out of the ordinary and finding it is going to take an afternoons worth of sleuth-wrenching ... that's for sure!

 

Well, guys here is what I have found. After pulling the motor and really getting into it, turns out the guide for the starter chain (plastic) had disintegrated and hung up the starter chain. It doesn't look like it will be too hard to get to and replace and thankfully the part is only $22. I plan on working on the valves and carbs while I have it in pieces. Rick what else do you recommend checking while I am this far in? The cams look brand new, no grooving or scratches. The frame will get a good sanding and repainting while she's naked. I'll post pics on the rebuild. Thanks for all your help guys. Thankfully, this turned out to be minor other than the splitting of the case.

 

I wouldn't hesitate to do a Starter Clutch Overhaul. It's easy as pie when you have the access to remove the old pins and springs.

You can either get an Overhaul Kit ... OR ... a whole New Starter Clutch. Which ever way you want to go, depending on what you see ... I wouldn't fail not to do that bit of prevent.

That's a "Peace of Mind" Job!!!

 

Glad to hear you have things well in hand and there is no damage to any thing. Do follow Rick's advice, "a stitch in time..." Another point to touch upon is make sure you replace the o-ring for the oil passage between the case halves. It is a case of good sense as well.