Difference in header pipes

[KA1J]

I've been trying to find an original set of pipes & mufflers for my XJ11 with only moderate success. I've been able to find a pair of XJ11 mufflers for it that are missing the crossover pipes. I figure I can get that repaired at a welding shop. It still though needs the headers.

I've looked at the cross references for the pipes and I'm finding the XJ11 is only partly interchangeable with the XS11 parts. Here's what I've found so far & I'll finish my question after the "facts":

Data from: http://www.yamaha-motor.com/sport/parts/home.aspx

Right side outer pipe (10M-14625-00-00) only fits the XJ11

Right side inner pipe (2H7-14631-02-00) is the same for:

XJ1100J 1982 1100 XJ1100 Street
XS1100E 1978 1100 XS1100 Street
XS1100F 1979 1100 XS1100 Street
XS1100G 1980 1100 XS1100 Street
XS1100H 1981 1100 XS1100 Street
XS1100SF 1979 1100 XS1100S Street
XS1100SG 1980 1100 XS1100S Street
XS1100SH 1981 1100 XS1100S Street

Left side inner pipe (2H7-14621-02-00) is the same for:

XJ1100J 1982 1100 XJ1100 Street
XS1100E 1978 1100 XS1100 Street
XS1100F 1979 1100 XS1100 Street
XS1100G 1980 1100 XS1100 Street
XS1100H 1981 1100 XS1100 Street
XS1100SF 1979 1100 XS1100S Street
XS1100SG 1980 1100 XS1100S Street
XS1100SH 1981 1100 XS1100S Street

Left outer pipe (10M-14615-00-00) is the same for:

XJ1100J 1982 1100 XJ1100 Street
XS1100SG 1980 1100 XS1100S Street

So I continue...
The parts diagram does not give dimensions or the reasons for the variations. Looking at photos of different XS11 & the XJ11, they look to be the same except for the appearance of the mufflers. All the headers pass around the frame in the same way and since the engines are pretty much the same except for the XJ11 YICS passages & some ignition differences, the physical engine plant looks to be the same. Since all the engines are designed to work with the BS34 carbs and the restriction characteristics of the Yamaha muffler, I have a few things to ponder to know what might be easily possible.

I wonder if the differences in the headers comes down to aesthetics? Perhaps the headers are really the same but with a different flange or some minor cosmetic issue and any of the XS11 headers would work?

Also by that same thought, it seems like the mufflers would be the same restriction wise and perhaps all that's needed is a different bracket or a minor bend and any would work?

At this point in time I haven't seen much original exhaust offered for the XJ11 & while I'd like to have the original parts on it, I'm not going to be showing this bike and if something's not 100% XJ11 but works perfectly and looks clean, I'm happy.

So what's the differences in the headers and pipes that make interchanging parts a negative other than loss of originality?

Idears?

[crazy steve]

All the header pipes are the same, as is the collectors where they wrap around the frame. But from that point on, you've got three distinct variations and they won't interchange. Where the collectors end and Yamaha welded on the remaining parts is where all the differences lay. Your XJ has separate mufflers (and is the only model that does), all the rest have these welded to the collector. If you've got the XJ mufflers, you could use any set of head pipes/collectors with suitable mods. By grinding away the welds at the last joint on the collector and removing the mufflers, you could fabricate the intermediate piece needed to use the OEM XJ mufflers and weld that to the collector. This would be finicky work as you need to save as much of the collector as possible when removing the standard/special mufflers.

Your best choice would be the Special head pipes/collector if you can't find XJ parts, as these have removable heat shields to give you access to the joint (and will help cover it when done). The standard pipes would work as well, but you'd have to cut the stock shields off and reweld them back on. Lots of die grinder work...

[Jamie]

If you need me to, when my stock exhaust gets back from being ceramic coated, it will still be seperated and I can take some pics for you. Just let me know if that would help in any way. You can also go to www.nichecycle.com and get any of those slip-ons too, but if you're headers and collection aren't any good that won't help.

Good luck
Jamie

[crazy steve]

So what's the differences in the headers and pipes that make interchanging parts a negative other than loss of originality?

Idears?

After re-reading your post, I'll add this..

As far as performance/tuning, there shouldn't be any differences between any of the stock exhaust systems. A complete '79-81 Special exhaust system will bolt onto your XJ with no mods, with simply a differently styled muffler. A standard exhaust will also fit, but with its longer mufflers and not being angled up, you'll have to fab an 'extension' to support the mufflers. Same thing goes for aftermarket exhaust; if it fits a Special, it will fit your XJ.

[KA1J]

Steve,

As long as it looks like it pretty much belongs there, I'm OK with a different exhaust system. I'll expand my search for a 79-81 Special exhaust system and I can be happy with that, especially if it's just a bolt on situation and the only notable difference is the way the muffler looks at the end.

Think I might have better luck finding this set.

Thanks

[yamahansolo]

If your interested I have an xj partsbike besides my dos 79's...

The crossovers are rusted and broken apart... I took th header pipes off and if I remember they were in decent. Shape??? Id let them go for a reasonable offer.

[KA1J]

If your interested I have an xj partsbike besides my dos 79's...

The crossovers are rusted and broken apart... I took th header pipes off and if I remember they were in decent. Shape??? Id let them go for a reasonable offer.

This might well work. I just sent you a PM.

[Kit]

..when my stock exhaust gets back from being ceramic coated...

Not meaning to hijack the thread, but I'm curious what that is costing you. I got a quote a while back from a local shop (the only place locally that can do it) for approx $375, and I'm wondering how it compares to other places.

[natemoen]

Not meaning to hijack the thread, but I'm curious what that is costing you. I got a quote a while back from a local shop (the only place locally that can do it) for approx $375, and I'm wondering how it compares to other places.

that's not a horrible price but I think WWW.jet-hot.com is cheaper.

[Kit]

Yeah, from what Jamie and a couple of other people have said, it's looking the quote I got was kinda high. I was just hoping to not have to ship them somewhere.

[crazy steve]

You might ask if they were going to try to coat the inside too. I don't see these coatings as being anything more than cosmetic if you have attached mufflers, as it'll be impossible to clean/coat the interior of the mufflers with the various baffles, and you may run the risk of it partially clogging them up. The big advantage to Jet-hot if I understand it right is they coat the inside of the pipe too and that helps with heat transfer and rust prevention.

You might look at powdercoating; they have some exhaust-rated powders out now that may be cheaper.

[Jamie]

Yes, they are ceramic coating on the inside also, just don't know if they are doing it once or twice. For those pessimistic on ceramic coating, this is about as rustproof as you can get and very durable. With the difficulty in acquiring a good "quality" XJ exhaust, this may be the very best solution. Jet hot was way more expensive than the other quotes I got.

Now, back to the original post, sorry Ka1J, let us know on how you make out with the new headers and mufflers for your build.

[Stralya]

All the header pipes are the same, as is the collectors where they wrap around the frame. But from that point on, you've got three distinct variations and they won't interchange. Where the collectors end and Yamaha welded on the remaining parts is where all the differences lay. Your XJ has separate mufflers (and is the only model that does), all the rest have these welded to the collector. If you've got the XJ mufflers, you could use any set of head pipes/collectors with suitable mods. By grinding away the welds at the last joint on the collector and removing the mufflers, you could fabricate the intermediate piece needed to use the OEM XJ mufflers and weld that to the collector. This would be finicky work as you need to save as much of the collector as possible when removing the standard/special mufflers.

Your best choice would be the Special head pipes/collector if you can't find XJ parts, as these have removable heat shields to give you access to the joint (and will help cover it when done). The standard pipes would work as well, but you'd have to cut the stock shields off and reweld them back on. Lots of die grinder work...

Forgive me asking this so long after you posted the reply, but I have a complete XJ exhaust system here in very good condition. My question is, what do I have to do to bolt this Maxim exhaust up to my '78 standard. Is that even possible?

Dan.

[motoman]

Forgive me asking this so long after you posted the reply, but I have a complete XJ exhaust system here in very good condition. My question is, what do I have to do to bolt this Maxim exhaust up to my '78 standard. Is that even possible?

Dan.

The 78Standard has a bit different rear peg mount piece than either of the 81models or XJ. This just changes muffler hanger location on muffs. Also, IIRC, the head stud lengths are different between the years/models. Both an easy fix, then whole exhaust system is plug'n'play.

[DiverRay]

Both an easy fix, then whole exhaust system is plug'n'play

NO! IT'S NOT!! The center stand and cross over are different, and you WILL have problems, I know, BTDT! It WILL work, but you MUST remove the center stand.