Missing Crossover pipe.

So during my last ride, my exhaust note changed and I had a noticeable lack of power. I managed to get home but was in pretty bad shape the last couple blocks. My bike sounded like a Harley exhaust and it was fairly obvious that one or more cylinders were not firing correctly.

After ruling out compression, fuel and spark plugs I found that the crossover pipe between the mufflers was mostly missing. It either rotted out or something hit it on the road and knocked most of it out.

I am working on the best approach to get this fixed and am having a bit of trouble determining if the crossover pipe can be replaced by itself or if it is more involved.

looking at this diagram it appears the crossover pipe may be integral to the right side muffler. Does anyone have any suggestions on the best way to approach this? Do I need a new right side muffler? Should I just bite the bullet and replace the whole system? The mufflers and headers seem to be in decent condition.

Any ideas would be appreciated.
Thanks!

 

Take a picture or two for us so we can have a better reply for you.

 

Here are some pics of what I am working with.



http://imgur.com/a/maI67

 

Don't think a patch would work or work long on those pipes, too far gone. Time for new exhaust system. You can usually find a MAC system on ebay for a decent price.

 

I dunno, it looks like a pretty clean break and the surrounding areas don't look to be excessively rusted away or anything.

The original crossover pipe is indeed part of the RH muffler assembly; replacing the whole thing would be the easiest way to go except for: finding one; and how much it might cost.

You might consider dropping the whole system and having a look at replacing the missing piece with an appropriate piece of tubing welded in place on the one side and clamped on the other just like it was to begin with. It looks like there might be enough solid metal left to accomplish that.

 

I'm thinking that if it's rusted bad enough to break away, it'll break away again. It might hold for a while, maybe long enough to find another system. This is the best time to buy one cause of the season.
How good are your fabbing skills? You might find a DIY kit for cheap.

 

best bet for a stock replacement would probably be a used parts bike.

CN

 

the cross-over pipe is actually a two-piece pipe...... the majority of it is on the right muffler, but there is a smaller part of it on the left muffler. There is a slip joint between the two with a collar and clamp.

If you have the left side intact, you may be able to weld a replacement section on to the right side. If there is not enough metal to weld to, you'll have to find a replacement.

Best of luck to you.

Dave F

 

x2

 

Thanks for the ideas everyone. I am thinking I will just use this as a sign and source a replacement exhaust system. Off to scour the cycle salvage this weekend.

 

Ok guys. I have a follow up question on this. I haven't had much luck sourcing a replacement system locally. I also talked to a welding shop / exhaust shop and it looks like it might be a bit tricky to get a replacement crossover pipe fabricated that fits the dimensions and bends of the stock one. (namely because I can't get the bike to the shop along with the pipes).

Doing some research on a MAC system to replace it, I see that the 4 into 2 systems do not have a crossover pipe. If I was to have the welding shop close up both mufflers and turn them into separate systems would this affect my performance? Would it cause problems with the scavenging and would I need to rejet?

 

Hard to say; but I don't think you'd need to re-jet. Generally speaking a "balance tube" type pipe like that is primarily for noise control.

I think the main thing that will happen is an increase in sound level.

 

Can't you have the shop weld a short length of pipe to each side, and you fit them together at home with flexible exhaust pipe?

 

I like this idea but ended up opting to just seal them up and go with a two piece system. Both for convenience and I was a bit curious how it would perform.

Once I replaced the exhaust gaskets (which were so bad they were probably original) and got the pipes back on it became obvious that I have had some undiagnosed exhaust leaks for quite a while. I am not done getting the fuel mixtures properly set but it is already a world of difference from what the performance was.

The bike is a bit louder without the crosspipe but doesn't sound bad at all. The only con I have found is that the 5K rattle has gotten a bit worse.

Thanks for the help and input everyone.

 

Get your valves in spec and vacuum sync your carbs before tweaking the mixtures. The "5K buzz" can be greatly alleviated.

 

I agree with Fitz. Some of the change may be due to a change in scavenging because of the lack of a crossover pipe. They do make a difference beyond just the sound (though not nearly as much on some machines as on others).

 

I did my valves about 1500 miles ago but I think I will give them another once over and do a sync and fuel mixture set from scratch now that the pipes are in tact. I think I was compensating for a lot of unknown gremlins with my previous tuning caused by the exhaust leaks.