Dented Front Pipe !

[marky g]

Anybody got tips on how to get dents out of the front exhaust pipe of my TYZ Yam ? the pipe is seamed and there are about 4 big dents all over the pipe a couple of the dents are on the seam.

I've been told to weld both ends up and heat the 'dent' up with a blow torch, and also to weld a nut on the dent and use a slide hammer to get them out etc etc.

I'm not too bothered about a perfect finish as long as it looks better than it is now..any thoughts ??

[g4321]

I've been told to weld both ends up and heat the 'dent' up with a blow torch, and also to weld a nut on the dent and use a slide hammer to get them out etc etc.

As far as I remember the way a mate used to do it on MX bikes was similar although he had an air valve fitted to one end. The pipe was pressurised - dont know how high!. The area of the dents was then heated with a blowtorch or welding torch.

[alan bechard]

Have done those several ways, although I have never actually welded up the end of the pipe nor seen it done that way. We had shop made tools that pinched the sides of the pipe with 3 bolts and then screwed an endcap onto the end of the pipe to make it air tight. Welding would work, and if you had to do just one it might be the most practical way but I would not do it.

If you go to a plumbing store or whatever you guys call it where the commercial plumbers buy there stuff you can get a variety of plugs and test fittings with common shrader valves in them. Short version is that you close both ends of the pipe, and have a shrader valve and a gauge inline. Apply about 50 psi to the pipe and heat the area that you want to come out with an acytelene torch.

Some words of caution here, often if there is goop in the pipe, as it is heated it will start expanding and overpressurize and blow your caps off. This is scary. If you go to someone that rebuilds automotive engines (at least here in the US) they will have a box to superheat this part and turn all that oil and grease to ash and blow it out. It only costs a couple of bucks and is well worth it. Also sometimes you can get the area too hot and it all blows out in your face, This is REALLY scary! Dull red usually makes it go. Be wary of what is going to come apart and try and stay clear of any flying shrapnel. One of the things we added in was a pressure relief valve from a hot water heater to keep from overpressurizing if we were not paying attention.

I did one or two TY pipes and the seam always gave me fits and never came out real well. It would blow apart or leak or whatever and never really come back into shape for me. I think on one I ended up drilling some holes, and putting in a dent puller, pulling into shape after some heating and welding the holes back closed. I was never over impressed with my work on these, the results always worked but nowhere near the work we did on on the MX bikes.

I would suggest talking to some MX guys. Last time I was playing that game with Bobby (going to the tracks doing mobile Machine and welding) the big guys had taken Bobby's deal and were doing it, FMF, and Pro Circuit both, someone else was there selling pipes for like $50 and that was impossible to compete with. Point being, if you go to a large MX you may find someone in the pits set up with the stuff to do this, and the practiced eye that it takes to do a nice job.

[monty-python]

Alternatively, keep you looks, save yourself 3rd degree burns, and buy a new pipe!!

[bob]

I have seen blow out kits on this website

racespec

you'll have to have a look around but they are definately there.

bob

[kevin j]

I have done several TY headers using a bent piece of 1/2 inch round rod about a foot long. Shape it into the curve you need to reach the dents in question. Might need several bent to different shapes to reach various spots. I think I also flattened off the end to make a spoon shape.

Stick the rod into the header, and heat up the dent area say 1 inch square. By prying slowly and gently on the rod (the fulcrum point is where the rod pivots at the flange on end of the header) the spoon pushes the dent out. Don't try and get it all at once, or the metal stretches. Work the sides of the dent, then center, etc. A dull red heat makes it real easy to push around.

This is much more predictable than air pressure, as you control the force precisely. Only down side I recall is as you go deeper into the pipe the lever gets longer and the leverage force gets less. There wer also some spots I could not reachno matter what.

End result: quite rippled, but they work ok. Maybe you could then tack weld on a curved section of auto exhaust pipe on the outside to mask the bent spot. This was a (Chris J?) mod to protect the header bend before it got bent in the first place, but it would also hide the repair.

kcj

[marky g]

Cheers for the replys guys, here's a couple of pics just to show you how bad they are.

Someone has suggested drilling a hole opposite the dent then knocking it out from that side and then welding the hole up ! I can see me trying all of the above mentioned methods before I fork out the

[alan bechard]

That one is going to be rough no matter how you go about it.

I would pursue finding someone in the MX field that does it regularly and see if they would takle it at a reasonable cost.

I could point you to some folks in the US, but that would not be a lot of help.

[marky g]

Cheers Alan, I'll put the feelers out, it is quite bad isn't it

Beats the hell out of me how folks can get the things into such a mess in the first place ! looks like it's been thrased with a hammer

[steve shakeshaft]

I'd say that was beyond repair myself. But before I paid

[monty-python]

Or you could try some of the specialist off road breakers. May not be priistine, but could be better than the one you have! It may be an easier bet to start repairing one which isn't so badly dinged, and will be less than 350 squids.

[g4321]

That is not a bad 'ding' going by what I have seen fixed on a scrambles bike by using pressure and heat. I remember seeing a pipe which was flat and did not allow bike to run at all repaired back to nearly perfect condition.

Try speaking to your local MX riders and dealers, someone locally is bound to be able to repair this at a reasonable cost. They will have the equipment to repair this sort of thing and more importantly know how to do it!

Good luck!

[kevin j]

ouch.

can't reach those using my rod method.

I think I'd try the suggestion above, but instead of a punch, cutting a one inch hole on back wall, against engine or over near the front left cylinder hold down bolt in the picture. Then work through that hole with a rod. Use heat to soften and work out the dents. Patch it later and the patch on the inside won't show.

Wont' be pristine, especially in the seam, but it would be a workable pipe.

k

[jer]

I've fixed an old, twin shock ty similar to the above method. Drill a hole on the opposite side to the dent, put a metal bar through this hole and gently tap out the dent. Maybe put a sandbag or similar under the dent. Cut a patch and braze it over the hole. It didn't look too bad when finished, a lot cheaper than a new exhaust.