Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: danabritton on March 08, 2011, 08:07:08 AM

Title: Pipe slightly touching frame - '01 CR250
Post by: danabritton on March 08, 2011, 08:07:08 AM
Is this something I should be concerned with due to the heat of the pipe possibly tempering and weakening the aluminum in that spot?  I plan on replacing the pipe soon but I'm not sure how soon I should do it.  This might be irrational fear but I don't want the frame strength to be compromised.
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: downonmonday on March 08, 2011, 08:13:37 AM
Is the pipe bent? I have a 2000 Cr 250 and thinking if mine touches? I don't think the pipe gets hot enough to hurt the structure of aluminum. It has to be pretty hot!
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: danabritton on March 08, 2011, 08:21:38 AM
Yeah it's bent. I didn't think it would get hot enough but I'm no metallurgist and I don't want to inadvertently ruin my frame.  I just recently bought the bike and am trying to spend money where it is needed most first.
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: downonmonday on March 08, 2011, 08:29:51 AM
Yeah, I'm no expert either. lol
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: ford832 on March 08, 2011, 02:23:51 PM
Take your muffler off then loosen the mounts on your pipe-both pipe side and frame side and move it away  from the frame then tighten them.You can get a fair bit of movement this way.Reinstall your muffler and see where it sits-you may end up elongating the holes a bit.
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: danabritton on March 08, 2011, 04:11:00 PM
Take your muffler off then loosen the mounts on your pipe-both pipe side and frame side and move it away  from the frame then tighten them.You can get a fair bit of movement this way.Reinstall your muffler and see where it sits-you may end up elongating the holes a bit.

Thanks ford, I'll definitely see how much wiggle room is there.
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: SachsGS on March 08, 2011, 04:14:44 PM
That steel pipe will wear a thin spot in the CR's soft aluminum frame in no time and could cause a "stress riser" (crack).It may sound crude but I've taken a 1" by 4" wooden board and bent the pipe away from the frame on bikes numerous times.Try it,it works. :D
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: monsteryz125 on March 08, 2011, 04:56:02 PM
From what i was told (on this site actually) that aluminum starts to change at 400? but i agree with the post above as far as the steel weakening the aluminum
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: rbigair40 on March 08, 2011, 07:21:34 PM
That steel pipe will wear a thin spot in the CR's soft aluminum frame in no time and could cause a "stress riser" (crack).It may sound crude but I've taken a 1" by 4" wooden board and bent the pipe away from the frame on bikes numerous times.Try it,it works. :D
YES
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: ford832 on March 09, 2011, 03:56:00 AM
That steel pipe will wear a thin spot in the CR's soft aluminum frame in no time and could cause a "stress riser" (crack).It may sound crude but I've taken a 1" by 4" wooden board and bent the pipe away from the frame on bikes numerous times.Try it,it works. :D

As per the new Maico setup manual  :D ,Not that I haven't used the wood fine tuning method myself from time to time ;D
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: MyckMcClung on March 09, 2011, 06:08:56 AM
The wood tuning method works well, and so does the mount adjusting, and if thats not enough, since the pipe is already f'ed, mark the spot that is touching the frame, take off the pipe , and knock a dent in it where it touches.
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: danabritton on March 09, 2011, 06:43:49 AM
Great advice guys, thanks!
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: ACMX on March 10, 2011, 09:30:39 AM
Mine's bent too >:( But it's not touching my frame. It's touching my clutch cable. Which I didn't find out about till I took it off and found my clutch cable melted on that spot. Anyone got a spare 03 Yz125 clutch cable tube?
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: MyckMcClung on March 10, 2011, 07:07:42 PM
just get some heat shrink tubing a little larger than the cable diameter, take the cable off the bike, cut it a few inches longer than the burn, slide it over the cable and center the burn in the tubing, hit it with a hair dryer or heat gun, then cut another piece an inch shorter, slide it over the other piece hit it with a heat gun and put it back on the bike,
Title: Re: Pipe slightly touching frame - '01 CR250
Post by: ACMX on March 14, 2011, 03:22:33 PM
thanks  :D