Elimination of 2 center pipes???

[CBWELLS]

Just a hypothetical question for consideration. I'm looking for any thoughts on the following;
Has anyone out there ever removed the two center exhaust mufflers from any of the GT series 3-cylinder bikes, blocked off the original "center-Y" exit ports so as the center cylinder exhausts out thru the cross-over tubes to the outer mufflers? At this point I'm just "wondering" if anyone thinks there would be any "back-pressure" issues reflected to the outer cylinders, or risk factors to consider.

My reason for the question is 2-fold;
1] One of my center pipes has no baffle any more & is internally damaged so as to be useless & I suspect the other is probably all clogged up & I can't get the baffle out of it.
2] Removing the two muffler assys would remove about 10 lbs of weight.

I'm not into "hi performance" nor am I too anal about minor nuances of operation or appearance. Let me know what your thought are.
Thanks

[oldjapanesebikes]

Interesting idea I'm not suggesting that the engine would not run - it would - but given 2 strokes depend on back pressure and resonance for performance and engine health (holed pistons come to mind) it isn't something I'd try personally if only because of the sharp right angle corners in the gas flow. I'm sure others will jump in with additional comment

[CBWELLS]

Just and addendum to the original post.
I got a lot of "lookers", but only one "responder" to my original post! Thanks to "Oldjap..." for that! I guess I just felt like experimenting, so I went ahead & did the dirty deed. I had an extra center header to play with, so I cut two 1/2" thick "pucks" from a 1-1/4" aluminum bar stock. These fit nicely into the exit tubes of the "Y" split & I pop-riveted them in place. So far, the effect has been favorable! I notice a small reduction in exhaust noise, probably as much a result of better sealing at the remaining joints along with elimination of a pipe that was missing the baffle, AND a minor improvement in the "feel" of the bike. Seems to run a bit smoother & have just a bit more torque. I don't have any particular explanation for that, but it's what I sense. I've driven it around town & a couple short back-road drives for a total of about 200 miles. No problems so far! I used an infra-red non-contact digital gun type thermometer to check the temperature of the jugs just above the exhaust ports several times during some rides. They all are similar (+/-20F) in the 240F range. I don't really push it too hard & the weather has been a bit cooler than a normal summer, so maybe that is helping somewhat. Whatever works I guess! I'd welcome some more comments if anyone has anything to add or any 1st-hand experience with such a "mod".

[pearljam724]

Huh, that's a neat share. How about you post a video of a walk around without the lowers or better pictures ? It would be cool to see and hear. Keep us posted on how the bike continues to run. I would have not done so, but I like to see what people do with their bikes. I would have not risked the experiment as even though exhaust will exit the cross over tubes. I'd imagine TOO MUCH exhaust would bounce directly back into the cylinder. But, that's what I'd imagine. You shaved a lot of weight, but is that and the look worth the cost of a motor ?

[oldjapanesebikes]

I suspect that at moderate loads and moderate usage it should be OK - just keep a close eye on the colour of your plugs. As I offered before - given a 2 stroke depends on pipe resonance for performance and also engine health, the issues I think would kick in at higher speeds and loads - while I can see that you could have gained on the bottom end of the range, I suspect you will have lost most of the top end performance and potentially will risk doing some damage if you try having a heavy throttle hand too often. Someone like Richard (TZ375) is better qualified to comment.

Interesting experiment though

[Coyote]

I am not qualified to comment, but I can't see how that would work very long. Also I would think at WOT it would fall flat on its face and possibly hole the center piston while it's at it.
2 stroke exhausts are a major part of the overall performance and tuning. That's why you can't run 4 stroke exhausts. They are not made with the proper configuration to 'extract' the pulses of the motor like a 2 stroke.
The center cylinder can't possibly do it's job correctly with that 'dead end'.

[GT750Battleship]

+1 to the above,two stroke exhaust systems play a huge role in how they perform...I had friends in the 70's with GT750's,who fitted a 3 into 1 "Bromlech system" the bikes went & sounded terrific...but it affected top speed performance,started running out of breath around 100mph,,probably could have been solved by get the jetting right with the carburettors..?
Cheers.
GT750Battleship.

[CBWELLS]

FROM THE ORIGINATOR: First off, SORRY for that ratty picture! I've attached a better shot to this post. Thanks for all the replys. I'd still welcome any other's input. It's about what I expected to hear, although I think there's a lot of speculation involved with the predictions of doom. I have no doubt that it's probably NOT the way to go for maximum performance or for pushing the envelope to the edge. Those are things I'm not interested in since I generally drive below 60 & rarely go over 70mph. If I want to scare myself, I take out the Vmax for some exercise. I can surely to get the willeys creepin' in with that thing!
I shot a video of it idling in my driveway, but it really doesn't sound significantly different than normal, so it isn't worth the download. It's just a bit quieter than it had been & seems to run slightly better as I described before. As I use it more, I will continue to monitor the jug temperatures & check the plugs as suggested. More & longer road time will be the final determinant if there is any value or detrement to the bike, but I do like the way it runs

[oldjapanesebikes]

[pearljam724]

Thank you for sharing. Good for you, if it continues to work out. I like the look. Where did you get that carry bag on the luggage rack and who makes it ?

[CBWELLS]

Thanks again for the comments & feed back. Good to hear other's thoughts & opinions.
As for the little bag on the back, I don't even recall where I got it. I think it's an insulated fabric lunch "box". Probably got it at a yard sale or flee market for a couple $. I've had problems with loosing things off the back (even a large trunk similar to a GIVI), so this one has a plastic plate all across the inside bottom & is bolted in 4 places thru the luggage rack. Not easy to remove, but it stays PUT!