Exhaust Clearance at rear pipe mount

[REVERUP]

Over the last few years of racing Gas Gas 300's I've had a real problem with exhausts rubbing into my Gas tank at the upper pipe mount. One tip over on the exhaust side, pipe not even dented, but yet, now the upper pipe mount is out of the recessed area of the gas tank and digging into the tank.I'm talking a few mm out and its digging in. Part of the problem is the back of the mount is not flat but actually protrudes out, and has some sharp edges. The other problem is the recessed area of the tank gives little tolerance to movement if things do get a bit out of wack, cause the recessed are is not very wide. It hasn't made that much of a difference what pipe or guard I've used. But I will say the stock 06 pipe with the stamped GG logo stayed true longest.
Anyone else experience this and if so were you able to figure out a way to prevent it from rubbing. And yes, I know I need to quit crashing!

Les at LTR said he thought a CR 250 mount might ad some clearance, he is gonna see what he can do to help alleviate the problem while he is going through my bike from top to bottom getting it ready for next season.I decided I won't be gettin a new scoot for 07 just a revamped 06.Cant wait to see the 08's!

 

[Boomhauer]

I bent the mount on my pipe out in a vise to fix mine. You might want to try it.

 

[PEB]

I don't run the upper mount on my bike. The mount on my old bike tryed to chew through the tank so I got removed. I had tryed to isolate the tank from the mount with a bit of rubber but the mount ate through it in a handfull of rides. With my newer bike I took the pipe off, discared the mount and reinstalled the pipe without the mount. Works fine no problems and no potential hole in fuel tank.

Paul

 

[Hawkeye]

My brother heated up his tank with a heat gun and pushed the plasitic in a bit for clearance. Worked for 2 years at least, since it was fine when he sold the bike.

 

[highspeedsteel]

I fashioned up a small piece of tin that I glued in place where the mount rubs. Stops the mount digging a hole in the tank and you can't see it when the bike is assembled.

 

[REVERUP]

I knew I wasn't the only one living with this problem.Thanks for all the great suggestions on how you all have addressed this issue.And please keep em coming. I'll let you all know what Les does to help prevent it from happening.

You know it isn't a huge problem if you tip over on a trail ride cause you have time to survey the damage and make sure there is adequate clearance, and if not tweak the mount out. In a race you just don't have the time, or at least I don't. I'm not that fast! So the rest of the race, that is in the back of your mind is that mount rubbing my tank again?

prevention = reliability = consistency = top of the standings!

Later, Roscoe

 

[motorhead]

I used a dremel rotary toll to grind the protruding edge flat and ground the protruding threads halfway down than swapped to a shorter 6mm bolt then went to my local japanese mega dealer and asked if they had any of that thick plastic in the garbage that the japs use in the crates of quads and such to keep the plastic from getting scraped=bingo,free gas gas fuel tank scratch eliminator.

 

[GMP]

I did exactly that, ground the clip nut to a lower profile and made a plastic guard. No problems.

 

[REVERUP]

After brain storming this problem, Les decided to put a threaded insert into the exhaust pipes tab itself and run the upper exhaust mount on the outside of that pipe tab, instead of inside as it comes from the factory. Doing away with the cheesy sharp threaded OE clip all together, plus gaining the additional width of the pipes mount not being inside rather outside.
So no more protrusions on the tank side behind the tab but a couple of threads from the bolt that would have stuck out anyways. Thus creating A few millimeters of clearance gained toward the tank and fore and aft in the molded gas tank slot.
He also added a larger spacer to the rear sub frame mount which further helps pull the exhaust away from the gas tank. Looks like a good set up!
The only draw back to it would be, if I do smash my pipe, which is pretty probable. I will need to have a new threaded insert installed to keep it set up that way. I do however have the OE clip so I can run a new replacement pipe back stock in the event I smash Les's modified one until I can have him install a threaded insert into the new one. I can now crash and continue the race confidently, not worrying if my pipe mount is rubbing through or gouged through the gas tank and it will continue to hold fuel on to the finish.

 

[gasmonaut]

away it did go. (the upper pipe mount)
i use onlu the lower mount and flange springs to keep the exhaust on place and it just work fine.

i think it put a little more stress to the muffler mount .

the 2007 has that same issue but the muffler mount is much more rigid so maybe it will hold better.

 

[Dave]

You could tack weld a button head machine screw to the back of the mount. This would provide a stud for mounting the pipe.

 

[Brian VT]

I fashioned up a small piece of tin that I glued in place where the mount rubs. Stops the mount digging a hole in the tank and you can't see it when the bike is assembled.

I took kinda the same approach.
I used a 3/4"x2 1/2" strip of sheet metal with a bolt hole in one end. Place the end with the hole between the bracket and the "nut" and then run the bolt in. Then fold the sheet metal down over the back of the "nut". It provides a smooth surface for the tank to rub against. I did also file down the back of the "nut" a bit too.

 

[jefgil123]

Brand new 2001 EC 300, I had to cut off the FMF pipe mount and re-position and reweld it to line up with the tank dent. P.-I.-T.-A$$

I replaced the hanger with a Kaw part made of steel and rubber as the stock alum. part broke after a fall. I guess I really didn't need it from what some have said above.