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mounting question for Jemco 3-into-1 on GT750

Posted: Fri Aug 14, 2015 10:48 am
by jabcb
How much clearance should there be between the Jemco 3-into-1 and the center stand bracket?

I did a Google search for examples.
On this pic from oldjapanesebikes.com, it looks like part of the bracket may have been cut off.
Image

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Fri Aug 14, 2015 4:01 pm
by Alan H
I had to adjust the Piper 3-1 for the 550 with a medium percussive instrument as it just fouled the centre stand bracket.

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Fri Aug 14, 2015 4:29 pm
by Vintageman
Once upon a time I cut off the center stand bracket. I cut it carefully in case I ever wanted to weld it back on. I have since forget what save place I put it :lol:

If the mounting bracket hanger was tweaked do you think it would clear? Did you ask Jemco if they knew of this.

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sat Aug 15, 2015 6:39 am
by jabcb
Vintageman wrote:Once upon a time I cut off the center stand bracket. I cut it carefully in case I ever wanted to weld it back on. I have since forget what save place I put it :lol:

If the mounting bracket hanger was tweaked do you think it would clear? Did you ask Jemco if they knew of this.
I had seen pics of the 3-into-1 on GT750s & GT550s prior to purchasing it.
Some had the stand bracket & some had it removed.
I didn’t notice that the bracket was modified in the above pic.

I talked with the Jemco guys when I made the purchase, but don’t remember what they said.
Just assumed that people cut the bracket off for cosmetic reasons & we all know what assume stands for.

The 3-into-1 is now on my bike but I worry that the bracket is so close that it will wear a hole into the pipe.
But the problem will be solved next weekend.
Showed it to a mechanic friend who prompting said that its ugly & offered to cut the bracket off.

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sat Aug 15, 2015 6:46 am
by Alan H
Don't take it anywhere.
Just put a small dent in the pipe so that it misses the bracket as I suggested above.
One day you might want to fit a stand again, or a different exhaust.

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sat Aug 15, 2015 7:08 am
by Vintageman
Maybe put a higher temp rubber stopper, late 90s 583/670 MXZ Doo sleds for example had one between pipe to muffler if recall into eye of the mounting bracket. This may help stiffen the pipe mount if pipe vibrates side to side a lot (sometimes they do)
jabcb wrote: its ugly & ... cut the bracket off.
When you get it on give us a review of how it performs. I sure would love to hear what it sounds like, maybe taken off normally as you go through a few gears.

Has Jemco been a little more supportive of why people are interested in these pipes.

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sat Aug 15, 2015 11:08 am
by yeadon_m
Like Alan, when I fitted a Piper to a GT550, I had to bash it in a number of places to avoid it hitting the gearbox drain plug, the mainstand mounting lugs etc.
So if ever you wonder why a Piper 3:1 has so many dents in, the answer is, none of them fit the bike they're made for. Not until you use a BFH and a drift.
Mike

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Mon Aug 17, 2015 2:24 pm
by jabcb
Any suggestion on which paint to use to touch up the frame after the bracket is cut off?

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Mon Aug 17, 2015 2:35 pm
by rngdng
Vintageman wrote:Maybe put a higher temp rubber stopper, late 90s 583/670 MXZ Doo sleds for example had one between pipe to muffler if recall into eye of the mounting bracket. This may help stiffen the pipe mount if pipe vibrates side to side a lot (sometimes they do)
jabcb wrote: its ugly & ... cut the bracket off.
When you get it on give us a review of how it performs. I sure would love to hear what it sounds like, maybe taken off normally as you go through a few gears.

Has Jemco been a little more supportive of why people are interested in these pipes.

Actually, the 3 into 1 that Omar's was selling in the end was from Jemco (thanks to me when Omar's supplier crapped out). A 3 into 1 is still a 3 into 1, they are fine for low-end torque, but restrict RPMs (a mechanical rev-limiter) and limit power. They sound cool, but if you want to do more than 6K RPM, go with 3 into 3. Jemco 3 into 3 I will recommend with my last breath....


Lane

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sun Aug 30, 2015 8:37 am
by jabcb
Removed the side stand bracket & the pipe now fits nicely.

Now on to the next issue — adjusting the oil pump, which I put in another topic:
viewtopic.php?t=11662

I was aware of the rev-limiter feature of the 3-into-1 & am fine with that given what I’m going to use the bike for.

The Jemco 3-into-3 look like nice pipes.
A GT750 with them was at a show I was at a few days ago:
viewtopic.php?t=11645

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sun Aug 30, 2015 11:18 am
by Alan H
http://www.kettleclinic.co.uk/kcforum/d ... &mode=view" onclick="window.open(this.href);return false;"- clicky for picky.
Currently I'm on the Isle of Man for tbe Classic TT and went round part of the unrestricted mountain course two days ago.
Pulled 8000 rpm in 4th and 7000 in 5th on standard gearing on the GT550K, so it's not really restricting performance anyhow.
It was still going but there are bends and such which tend to restrict speed........
So much for 3-1 restricting performance then.
Must admit it is bloody noisy though!

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sun Aug 30, 2015 3:14 pm
by jabcb
Alan H wrote:http://www.kettleclinic.co.uk/kcforum/d ... &mode=view" onclick="window.open(this.href);return false;"- clicky for picky.
Currently I'm on the Isle of Man for tbe Classic TT and went round part of the unrestricted mountain course two days ago.
Pulled 8000 rpm in 4th and 7000 in 5th on standard gearing on the GT550K, so it's not really restricting performance anyhow.
It was still going but there are bends and such which tend to restrict speed........
So much for 3-1 restricting performance then.
Must admit it is bloody noisy though!
That’s a nice GT550. What 3-into-1s are those?

I think the 3-into-1s provide maximum coolness, which is what I was after.

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Sun Aug 30, 2015 5:29 pm
by Alan H
jabcb wrote: That’s a nice GT550. What 3-into-1s are those?

I think the 3-into-1s provide maximum coolness, which is what I was after.
Thanks, I believe it's a Piper, but not certain. It's light and about 35ish years old.
The chrome was totally horrible, so I had it ceramic coated (great), it doesn't cover the crap original welding though!

Re: mounting question for Jemco 3-into-1 on GT750

Posted: Mon Sep 07, 2015 4:41 pm
by jabcb
Think I’m just about done.

With the old pipes there just wasn’t much power below 4k rpm.
Now can pull out up hill from a stop sign at around 2k.
Compared to my stock red GT750, its definitely peppier at 3k rpm.

Pic with center stand bracket removed.
Image