Porter

I was planning on changing my front shock oil yesterday using the tips from this board using the niffty vacuum pump and 8mm drilled out bolt...but...
riding home yesterday I hear some pops and the exhaust sounds flat.
Upon inspection I see that the Y-pipe from the rear cylinder is completely cracked. (The whole way around at the crotch of the Y).

Remove the pieces, cleaned and welded them back together. I still have to get some gaskets and clamps from the dealer to complete the installation. I checked on this board and there were a few notes to not even weld it and just get a new one, because it will crack again. But if the OEM part keeps cracking or is prone to crack what is the point?

I can think that the heat stress will make weld a weak spot after the pipe has been through so many heating cycles.

I guess my question (and I know it is subjective) is: Are the statements that "it will just crack again" meant to say that the weld repair will fail in a few days of use or after several months? How fast would you expect it to fail?
The bike was used when I bought it and it did have those "wraps" around the pipes and I suspect after seeing some posts that those probably shortened the life. It is just that the pipes still have a thick wall and there is very little corrosion at all. Only the crack that is very jagged, with would indicated brittleness, I guess.

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BOBFLHTC

Just a comment regarding the fork oil change. I tried the vacuum method and it worked very well for me. I used the plastic fitting that came with the hand pump with a clear tube in a jar with the pre-measured amount of oil. My better half had to keep the vacuum going while I replaced the screw otherwise the oil just comes back out. Next time I was thinking of using a kitchen baster with a clear tube suspended about the inlet and wondering if I could pick up a bleed screw with the proper thread. Sorry I can't help with your main concern.

Porter

Thanks.
My plan (for the fork oil change) was to use a ketchup/mustard bottle. You know the kind that come to a point. Fill it up with a premeasured amount, disconnect the pump, connect the bottle and turn the valve.

As for the y-pipe, I am going to start calling around for prices on a new one, just to see how much the total will be with all the new clamps and gasket. Plus, I want to really inspect the front cylinder pipe as well. I haven't found any threads talking about that one cracking, but if I decide to order stuff (if it is not in stock) I might as well order a front pipe if it looks questionable.
If I remember, the torx exhaust clamps cost about $10 a piece from the dealer. $60-$70 in single use clamps. Maybe I just answered my question and should just buy a new one....

dhorne

I welded my Y pipe as well and so far so good , I have gone around 5000 miles , I did buy another one and was thinking of reenforcing it to avoid another dissapointment

Doc45

The problem with trying to re-weld the pipe is the carbon buildup inside the pipe. Even if it looks clean, the carbon is there. All the other stuff that is burnt inside the chamber is all over the inside also and makes for a very poor weld. The weld will more than likely fail because of the different heat ranges in the weld joint.

I hope that I am not offending you, but I have no idea of how long you have been welding. I have been at it for over 25 years and have never had much luck welding on used exhaust systems, they are just too dirty.

If it was my bike, I would buy a new system.

glider

I would buy a new pipe for reasons mentioned above with the welding. That is a stress point of the system, due to design. The later bikes have a mount behind the rear cylinder to give some additional support.

dhorne

Oh okay , mine broke on the Y closer to the passenger peg on the right hand side , being in venezuela I didnt have a choice , I had to weld it , I do have another set on the way , I was thinking of reenforcing it to prevent breaking again

Makes sense thanks Doc

Porter

Thanks Doc45! No offense taken!
I have been welding for 7 years. (mostly TIG 316L and 304L stainless steel)
I am pretty persnickety about cleaning prior to welding stainless. Your point and your experience is well taken.

I am probably going to break down an get a new pipe, just because I don't want to spend double the amount of money in clamps if it only lasts a month.
But also because you said if it was your bike, you would replace it.

I think the fiberglass wraps that were on the pipes probably contribued to an early demise. But again, the pipes are discolored, they are not rusted or thin in any areas. Just the crack. I guess the high heat, maintained by the wraps may allow carbon to "soak" in over time, increasing the brittleness. Add the heat cycling and vibration and there you go....

Thanks again to all for your input and opinions....

TQuentin1

As Glider mentioned above, this is a stress point and many of us have had the cracking problem (yes, me too!). I went ahead and replaced mine. Obviously new gasket, but I do try and reuse the TORCA clamps. I feel that if I soak the bolt and nut well in penetrating oil, and then "sneak" up on the torque setting using the max minus 5 ft-lbs. as my target, I can safely reuse them. Now I do this with a grain of salt. If the clamp is one of the originals and is really rusty, I trash it. But if it is one that I have put on in the last few years and still looks OK, I try to reuse it. But always have a couple of spares in the box in case you shear off the bolt!

TQ

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Porter

The Y-pipe is back ordered until November 20th....
Looks like I am bolting on the welded one for now.
No way I am not riding in the Fall.....
Hopefully it will hold until November.