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Front sprocket came loose

IIRC the rear engine/trans mount is about level with the oil filter and behind it making it part of the lower crank case/transmission case. I wonder if it would come off while in the frame? Because its pinched between the frame that could make it serious PITA! However, the crank would stay with tension of the rods and timing chain, the input shaft for the trans and clutch would stay as they are in the upper case so maybe it could be done???

Working upside down with oil in the face might be worth the hassle of pulling the engine. . . Worth looking into I suppose?
 
The wet rag trick might be good enough to protect that seal

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It wouldn't take much of a weld to take care of the problem as the splines take the brunt of the torque. The weld would just keep the sprocket up against the shoulder of the shaft.

If welding, I personally, would get everything super clean and have a helper push the sprocket flat against the shoulder with a screwdriver (with the chain on) and tack it in a couple of spots.

Spin it and verify its on straight and doesn't wobble. Then have the helper spin the the rear wheel (which spins the sprocket) at a medium speed while holding the welder tip at a close distance to the sprocket/shaft and put one bead down while rotating... The weld doesn't need to be super heavy, just some good penetration. My Hobart 140 110 volt welder would easily be big enough for the job...

Then gently apply some water down the aluminum engine case to keep the heat from transferring from the shaft to the seal.

If done correctly, the weld would look like the welds on the ends of your car's drive shaft(s).

When I worked in a machine shop, we custom shortened/welded drive shafts in a lathe with a MIG welder in the same manner. The tubing was considerably thinner and looked bone stock. In fact they were truer than factory when checked with a dial indicator gauge.
 
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How about something like this as an alternative to welding?
ROCKSETT,2 OZ - Flexbar
I don't have any experience with this product, but just putting it out there to think about.

That might work if the threads wernt messed up, but if the threads wernt messed up he wouldn't have to worry about welding it in the first place. Ive never used it but from what it looks like its similar to jbweld/locktite mix

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lol, read the product review.

"Great Product"

Andrew Whitaker on 10/9/2011 11:15:27 AM


Comments: This came packaged in a safe container in a timely manner and worked better than expected. You can adhere any type of metal with this, but you cannot adhere a G.I. Joe doll to the back of a squirrel to create a low-budget horror film. All in all, this is a great product
 
Something that came to mind re welding should you go that route...

Even thou the ECU and battery are disconnected for safety, you may not get a good ground, grounding to the frame, etc, especially while spinning the sprocket to run a bead. I'd be afraid of a ground arc in the engine screwing up a bearing as electric trys to jump keeping a ground.

Should you go the welding route, it would be better to either ground the welder to a vise grip clamped direct to the output shaft or run two half welds on the sprocket again using the above grounding method.
 
Sorry for the lack of updates. I'm not a very heavy forum user and it didn't occur to me to let you guys know how it went.

I used the welding idea. Clamped the ground to the bottom of the sprocket around the chain, then just dropped a spot weld at the top, hit it with the wet rag to cool off, then spun the chain around and did a spot weld on the other side, then hit it with the rag. I did that until I had a continuous weld the whole way around the sprocket. Figured that would minimize the heat to the oil seal there, so it might be the world's ugliest weld, but so far it's done the trick.

I've moved from Houston to San Antonio since then, so it's made several highway trips back and forth with no problems yet.

Thanks so much for the advice, I'm not sure why welding didn't occur to me before, but with the move coming up at the time, I couldn't afford the time or parts to replace that shaft, so this really saved the day for me.
 
Good job getting her going, the wet rag trick I was referring to was to tie the wet rag around the shaft so you. Oils make one continuous weld, but hey if it works it works great to hear
 
Glad to hear it worked out for you, saved a bunch of $...

+1 on the wet rag behind the sprocket, but its working now, so excellent!!!


When its time for a new sprocket, get out a small grinder and dig into the welds!!

And yes, most regulars were very curious the outcome..
 
I'm curious how replacement will go also. Guess you can't mess it up anymore. It could be a good learning experience if you tear it down and fix it yourself :thumbup:
 
On my 04 FJR, some of the bikes (03-05) were having problems with the exhaust valve guides failing("the dreaded tick"). The bike is currently way out of warranty however on the FJR forum, its said that Yamaha will still fix the bike (free) as it was a known problem... Mine doesn't tick so I can't verify that personally...


What is this dreaded "tick"? My '04 FZ6 ticks a little bit. Not sure what it is.
 
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