[sqf]

Of course I jinxed myself.  Had no problems and I'm sure this one isn't too hard to figure out once I get into it but of course these things happen on my way into work so I have to suffer all day until I can get home to inspect things.  So here is the deal, I have had no riding issues at all before this morning (including yesterdays ride to and from work).  About a mile into my ride (07 military, 7k miles 50 degrees out) I started from a stop got about 50ft and BANG it sounded as if someone whacked the primary with a hammer.  It did this under moderate throttle.  As I babied it the additional ten miles to work I checked and "felt" what I could.  If I accelerate very slowly it doesn't do it.  If I accelerate harder (not real hard I didn't want to break anything) it will BANG be fine and BANG....  It did it in 1st and second gears more than in higher gears, in 5th gear only when going up a hill.  It feels to me like when an automobiles clutch slips and re-engages although it was only one bang at a time instead of many (a function of RPMs perhaps).  I kept pressure on my gearshift lever and I couldn't feel it doing anything odd, the engine sounded fine and didn't seem to notice anything was happening.  I changed the primary fluid mabout 1500 miles ago (along with gearbox oil).  
Any suggestions before I get the chance to delve further?  As always, I know I am blind posting and fishing and I willl look at the Snidel manual and further research the problem when I get home.  I'm just too impatient to wait that long for ideas other than my clutch one.......  

Mike

[The Garbone]

Does it act funny when in neutral and reved?    Can you coast in 1st with the clutch pulled and not have it happen?

Sounds like chain slap.

I would pull apart the primary case and have a real close look for loose bits etc... Could be as simple as a loose primary chain.  I would worry about little sprag bits getting into the works with the primary chain causing a little binding and chainslap on the case. No matter what you have to take a look, I can't imagine it will get any better.  

Also check your drivechain tension and if your chainguard rear bracket is broken and the guard is bouncing on the chain.

[Chasfield]

If it was just clutch slip you wouldn't be getting any bangs - the engine would just surge with, no increase in road speed, at high levels of engine torque.

[single]

I am sorry but I can not determine the cause of your problem with the bike.I also would check into the primary.Gotta start somewhere.But the fix for the work thing,I have gotten pretty well worked out:RETIRE !

[sqf]

Thanks guys,
The ideas are helpfull.  It drives me crazy that I can't go out there and start looking into it right now!  My boss wouldn't be too happy if he came outside and saw me working on the bike LOL.  I'm lucky I get to pop on the internet for a few minutes each day.  I'll definately pull the primary cover off when I get home. 

I will look at the rear chainguard now when I go out to my car, as far as "acting funny in neutral and revved I don't know.  I'll see about that when I get ready to go home.  It definately doesn't do it while coasting or downshifting, only while accelerating.  It downshifted perfectly. 

Thanks again, having ideas helps keep what sanity I have! 

[1Blackwolf1]

  If you have 5 minutes you can check for chain slap in the primary on a n iron lung.  Remove the fill plug on the primary, with the engine OFF..you can stick a finger in and feel how much slack you have on the top run of the chain.  That'll let you know how important it might be to adjust the chain before you try to ride home.  Busting a primary case may get a little expensive.

  Will.

[sqf]

I checked the primary chain before leaving work and there was only about 1/4" play at the top run of the chain.  I got it home but it was not a happy ride.  The motor seems fine, the clutch seems to work fine, the gearbox seemed to shift fine but I could not accelerate at all.  The bike would "lurch" and make unhappy growling noises in all gears. 

I babied it home and pulled the primary, clean as a whistle, no obvious problems present. 
No shavings, no bits, the fluid is clean and clear as the day I put it in. 

I peered into the gearbox through the inspection plate and don't see any carnage there.  I spun the back tire in several gears while looking into the gearbox and there are no bad noises, no visibly broken gear teeth or anything. 

I looked at the primary sprocket and it looks good. 

I'm hoping to get time to delve into it more later but it will most likely be a day or two.   The one thing I did notice is that there is way too much slack in the rear chain.  Almost 4 inches of travel on the center stand.  I know I checked the chain not even two weeks ago when I changed the oil and it was only about 1 1/2" then. 

I will try and adjust the chain and see if that fixes the problem.

[ace.cafe]

It does seem odd that the rear chain would go so slack in such a short time.

I'd have a look at the rear axle area, to see of the axle slipped forward in the swing-arm or something like that, just to be safe.

Growling and lurching can be caused by a slack chain.
But you need to find out why it got so slack.

[sqf]

Found the problem.  After dinner I got an hour to go see what I could find (thanks to my lovely wife that put all five kids to bed so I could go play).  I started at the rear as Ace suggested.  I immediately noticed that the cotter pin was missing from the castle nut.  After investigating I called the shop that completed my yearly state required inspection last week.  "Hey, it's Mike, did you guys have to do anything different with the bike when you inspected it this year", shop owner said he would ask the mechanic that did mine......(elevator music),  "The mechanic says he adjusted the slack out of the rear chain but everything else was fine". 

It turns out the mechanic adjusted the chain (that didn't need adjusting), lost track of what he was doing, never tightened anything beyond the one nut beneath the castle nut (castle nut and drum nut weren't tight at all) and sent me on my merry way.  It was fine for three days and today it just happened that the axle started sliding forward. 

I reset the chain and drove it and it drives just peachy now.  I did go speak with the shop owner who is ordering and paying for a new rear sprocket because two of the teeth on mine are sheared off.  I know I did this while babying it home but hey, he offered and I'm not turning him down.  I will order and pay for a new chain because I figure I may as well replace them both (get a new fancy o-ring chain). 

Thanks for all who posted during the day when I was stuck at work and unable to troubleshoot.  Virtual troubleshooting is always fun! 

[r80rt]

Glad you got it figured out, it's a shame to have something like that done to you though.

[sopwithdriver]

It has been said that the most dangerous time to fly an airplane is right after the mechanics are done with it. glad you figured it out on your own.

[1Blackwolf1]

  Ah the simple beauty of mandatory state inspections and the helpful mechanics that do the repairs.  Thankfully we don't have such regulations here.  But at least you found it before something worse happened.

[Blltrdr]

Found the problem.  After dinner I got an hour to go see what I could find (thanks to my lovely wife that put all five kids to bed so I could go play).  I started at the rear as Ace suggested.  I immediately noticed that the cotter pin was missing from the castle nut.  After investigating I called the shop that completed my yearly state required inspection last week.  "Hey, it's Mike, did you guys have to do anything different with the bike when you inspected it this year", shop owner said he would ask the mechanic that did mine......(elevator music),  "The mechanic says he adjusted the slack out of the rear chain but everything else was fine". 

It turns out the mechanic adjusted the chain (that didn't need adjusting), lost track of what he was doing, never tightened anything beyond the one nut beneath the castle nut (castle nut and drum nut weren't tight at all) and sent me on my merry way.  It was fine for three days and today it just happened that the axle started sliding forward. 

I reset the chain and drove it and it drives just peachy now.  I did go speak with the shop owner who is ordering and paying for a new rear sprocket because two of the teeth on mine are sheared off.  I know I did this while babying it home but hey, he offered and I'm not turning him down.  I will order and pay for a new chain because I figure I may as well replace them both (get a new fancy o-ring chain). 

Thanks for all who posted during the day when I was stuck at work and unable to troubleshoot.  Virtual troubleshooting is always fun! 

Good thing you found the problem before something catastrophic happened. I don't think an o-ring chain will fit without rubbing.

[The Garbone]

Oh, that is so uncool in so many ways, gives me an ulcer just thinking about it..... Glad you found what happened and it was an easy fix.

[Leonard]

Good thing you found the problem before something catastrophic happened. I don't think an o-ring chain will fit without rubbing.

I'll second that.  I've even seen the chain rub if you put the master link clip on the outside.

[1Blackwolf1]

  Wonder since it sheared two teeth off the rear sprocket if it may have damaged the front sprocket also.  Just thinking out loud..hope I'm wrong.

[sqf]

Thanks for the info on the o-ring.  So much for adding modern technology!  I guess I'll buy another can of chain wax.....
I checked the front sprocket and it doesn't appear to be chipped, warped or warn in any way.   I think the rear sprocket took the brunt of the slap and that is why it snapped those two teeth.  The chain itself doesn't look like it sustained damage but I want to replace it just in case, plus having the new chain with the new rear sprocket can't hurt.  I considered replacing the front sprocket as well but It looks fine and I don't want to have to pull the cases if there isn't a need. 

[single]

I am really coming to the conviction that one needs to do ones' own wrenching.It is your life on the line with a bike.I have not had a bad experience myself,but others sure have and it makes you think about,no?I really don't fear the roadside fumble with something simple,but when I split lanes between 2 semis........Friend of mine had one of his wheels pass him on the e-way after leaving a tire shop.Others were all loose.