fxstbi

Thanks to Chylowen's written instructions about how to put a 240 pipe on without removing the head. While I did it I took these pictures to supplement his instructions. The last picture shows the inlet resting on the down tube, a little push and it cleared. It took longer to remove the necessary parts than to put the pipe on. Very easy to do. Thanks Chylowen!

Thank you very much for that detailed explanation. Time to open it up!

I have an '82 240 and am doing maintenance during the pause in our riding season. I've had several people tell me that it's important to cut the pipe open and replace the internal packing. I don't have a problem doing the work but I can't get anyone to tell why it needs to be done. I understand why I need to repack the muffler but the pipe makes no sense. I can push a piece of tubing clear through. Anyone have an explanation?

My "lean but it's not" issue is about 90% gone. I'm not sure what I did to help it but I did do the following: Pulled the pipe and cleaned the carbon out of the header. I scraped and used steelwool in the exhaust port so it's very clean. I went back to a 115 main jet and left the 52 pilot. Needle clip is in middle position. I put in an NGK Iridum plug. I put a new cylinder and air box intake boot in too. Its much better than it was, unfortunately I don't know what "fix" fixed it. Thanks all for the replies!

I'll give that a shot, waiting on a part right now. Sigh....

Good suggestion. I'm in Texas so about 400' MSL and the temperatures are in the 60(f)-70's here in winter. My carb is a new OKO and I run a fuel filter.

Huski, thanks for the reply, that's interesting to know. Up to this point: I have re-jetted to the where the bike wants to blubber and not clean out and still the same. I've tried some 104 race gas, same thing. I did try using brake cleaner sprayed on the flywheel and intake tract as it ran and it's all good. I put in a NGK B6HS and that seemed to reduce the knock some, I think. I'm going to pull the pipe and make sure everything is ok there. I have a new NGK iridium plug that I'll try after the pipe is checked/cleaned. I'll clean the exhaust port while I'm there. If anyone else has a suggestion please chime in. My old TY 175 is looking pretty good right now! ?

The clip is in the second notch from the top. The bike runs and starts great (with the 115 main) with the 118 it doesn’t want to clean out. It falls to idle quickly as soon as I chop the throttle. It just bangs like detonation when the throttle closes. I just read about deceleration knock, “pipe bangs” some call it. I haven’t had an opportunity to research it yet but the one short article I read describes what I think I’m hearing.

Line away, I did go up to a 52 pilot and I have the 118 main in it now with an NGK B6hs plug. After all the testing I’ve done the (what sounds like) detonation is still there. It’s only about half as much but still present. With the 118 it’s not reving out clean at w/o throttle so I might need to step down one there. Do you think it could be coil or ignition related or stay with the carb and go up more on the pilot? Any and all advice is greatly appreciated!

Thanks everyone for the replies. After extensive checking and testing I haven’t found anything wrong so I went back to the carb and increased main jet size to 118 and put in a new NGK B6HS plug. It actually runs better! It still has a little lean sounding knock or ping at almost full throttle. I’m going to go up to a 120 main and give it a try. I would have never guessed that I would increase jet size so much. Like Alberto indicated above, my bike came with a 105 installed. I was surprised when I was told 112 is the correct size. Thank you all for the help.

That’s a good idea and easy to try. Thanks!

Unfortunately I don’t have any past history for the bike. Is there any way to check the seals? Perhaps some sort of leak down? I’ll try the bigger pilot, thanks for the tip.

My bike is sounding lean at about 2/3 and up throttle. (It almost sounds like detonation.) I’m running an OKO 26mm carb, 48 pilot and 115 main, needle clip in the second notch from the top. The main is one size bigger than required. I don’t think it’s a carb problem anymore. I checked my timing and it’s right on. I checked my pipe and it appears clear and the muffler is a new Wes. I’m running the stock champion plug. Any ideas or suggestions?

Good idea, welding on top of the frame instead of a butt joint. That’s a simple way to get a custom location. Thanks for posting! Edit: I just looked and removing the peg mount and adding an overlay like b40rt shows the new peg mount can move down and back without having to move the kickstand. Thanks for sharing your ideas.

It looks like it would be easy to make and weld a wedge as shown and weld on the peg holder. I could gain an inch of drop but nothing back. I also have a ‘17 Montesas 300 and I found that the pegs on my Fantic are 1” further back than the Montesa. No point, I just thought it interesting.