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GEBE exhaust / muffler mod

J

JemmaUK

Guest
I am not sure where to put this, and as its a pic - I though here would be ok..

I have done a couple of rides now, and the term 'buzzing' is about right - and after a while it can get a little annoying and lead to the start of a headache...

So I went to the local model shop and had a look what they had in the area of exhaust parts... I was looking for a expansion box.. but what with being in the UK and not being sure what would fit and what wouldnt, I thought I would make something a little like the old 'thin pipe' exhausts on bikes like the cyc-auto.

This effort cost me £8.50 and about 10 or so minutes..

Parts used..

2 x Flexible rubber exhaust elbows.
1 x brass pipe.
4 x cable ties.

I have cable tied the bottom of the exhaust to the rear extent of the deraillier control cable with alot of free play - just as a locator really..

It doesnt seem to have dropped performance any but is that a possibility?

Jemma xx
 

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bamabikeguy

Active Member
Joined
Sep 30, 2006
Messages
1,929
Hey Jemma,

Didn't know you were a gebe'r :rolleyes: (so many posts nowadays, I barely have time to peek around ).

Maybe drimpact could snip this, bring it over to Rack em, Hive will be very interested in your muffler modification.

The rubber works??? You blokes must have better rubber trees than us'ns...
 
J

JemmaUK

Guest
Hi Bama,

Given the temperature these things throw out, I wouldnt recommend normal rubber ... The rubber bends I got are specifically designed for exhaust use in model planes etc running .80 - .140 engines.. so they can take the heat.

It does quiet the engine down some and I will take a short run out to see if it hurts speed any but it didnt seem to - although the test slope outside my flat isnt really a fair test..

EDIT: just found this - http://www.davesmotors.com/store/pocketbikeexhausts.html - the silicone tubing would be perfect for a flexible exhaust routing - or for bends/joints.

Jemma xx
 
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bamabikeguy

Active Member
Joined
Sep 30, 2006
Messages
1,929
Good deal....

When you test, is there anyway to take a temp (Farenheit for us idiots) near the end of that exhaust?

Just wondering, air cooled and all, what the temp of the far end of the metal reaches, whether the rubber absorbs a lot of the heat, then the pipe, if finagled/manupulented, could serve as "dual use", allow more modification.

When you think about it, esp. if the pipe circumference was larger, or some kind of "double walled" piping was used, that could make a different angle, and serve as a "frame modification". As a support, as a place to clamp on a red reflector/blinking light...etc etc etc.

Nothing says it has to go straight, does it? A zig here, a zag there, and it might keep one side of my saddlebags away from the rear wheel/chain workings.

(oh, and I think you have to send a pm to drimpact, request pruning this thread into Rack em, we can make it the "be all to end all" exhaust modification thread, cuz we don't have the answers yet !)
 
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G

gone_fishin

Guest
a cheapo conduit bender might could be handy for someone doing this stuff, no?

'UK, i moved this into the "rack 'em up" techie area, it'll prolly be more effective here...good info, thanks.
 
J

JemmaUK

Guest
Good deal....

When you test, is there anyway to take a temp (Farenheit for us idiots) near the end of that exhaust?

Just wondering, air cooled and all, what the temp of the far end of the metal reaches, whether the rubber absorbs a lot of the heat, then the pipe, if finagled/manupulented, could serve as "dual use", allow more modification.

When you think about it, esp. if the pipe circumference was larger, or some kind of "double walled" piping was used, that could make a different angle, and serve as a "frame modification". As a support, as a place to clamp on a red reflector/blinking light...etc etc etc.

Nothing says it has to go straight, does it? A zig here, a zag there, and it might keep one side of my saddlebags away from the rear wheel/chain workings.

(oh, and I think you have to send a pm to drimpact, request pruning this thread into Rack em, we can make it the "be all to end all" exhaust modification thread, cuz we don't have the answers yet !)
I dont have a method for temp testing - but I know the top end of the pipe gets skin fryingly hot... although it doesnt seem to melt anything...

Im not sure what you mean by dual use... I think things could be clamped onto it, but only if they arent heat sensitive and not too heavy..

As to using thicker gauge/bore piping, I dont know as that would work because of the complications of fitting it to the stock silencer out-port... I am no metallurgist unfortunately..

the more flex points the better for routing - or you could just use the silicone pipe and thats all..

just some thoughts

Jemma xx

EDIT: well, that was fun - speed tested and speed might be down a bit - but I was being more careful. Up until the engine threw the exhaust on a bump... scratch one elbow ... have replaced that (and cabletied it this time). It should be ok & it does seem quieter.

Joy of joys almost suffered the bane of GEBE - tinkling noise on the move turned out to be the front locking nut on the engine mount... now tightened...
 
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bamabikeguy

Active Member
Joined
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Messages
1,929
MB edit:

Just read your intro, which answered most my questions, cept the girlie part.
Glad to have you !


http://www.motoredbikes.com/showthread.php?t=6728

Jemma 2 items

Hive tried something a month ago with copper, but when it didn't work out like he wished, he deleted the pictures, think he said "never mind".

Could you edit the thread title, sumpthin like "GEBE exhaust/muffler mod?"

Second, you didn't mention if you ripped out the screen/spark arrestor on the end of the exhaust?

If you did, great, but we'll just mention it here, so a reader will see it.

If you didn't, and you have 7-800 miles on it, that is where the "hiccuping" comes from.

When did you get the engine? Which drive gear are you using? Have you been avoiding ethanol in the UK?

You'll be a valuable Gebe'r, once you get thru my interrogations !! :rolleyes:

Welcome aboard !
 
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bamabikeguy

Active Member
Joined
Sep 30, 2006
Messages
1,929
Hive,

When you find this thread, AND combine it with framemounting, where a fastener could be added to the newer/securer mount system, (heck, thread the pipe thru an eyebolt, it'll NEVER come loose)...

Anyway, framemounting is the answer to securing that pipe AND thinking about putting 5 foot of "back and forth" conduit on that side of the bike, a few clothes pins and you could hang your laundry to dry while you ride !! :cool:
 

bamabikeguy

Active Member
Joined
Sep 30, 2006
Messages
1,929
Back to Jemma, (pardon my enthusiasm, I like making a good thing puzzling)

As to using thicker gauge/bore piping, I dont know as that would work because of the complications of fitting it to the stock silencer out-port... I am no metallurgist unfortunately..

the more flex points the better for routing - or you could just use the silicone pipe and thats all..
Okay, think about Augies conduit, two peices, connected with a tee. The Tee sits midway up the mount, the conduit horizontal, about a foot down from the engine

A "dead end" fastened on the side, under the seat, similar to Hives simple support brace.

The back end of the conduit, which you've fed the copper exhaust piping, extends all the way out past the back of the tire.

Okay, back adds a double walled "muffler", can hold a reflector.

Deadend front provides side support for either saddlebags or in the auxillery tank ideas on 35 R/S.

Hope you engineery guys can envision it.
 
J

JemmaUK

Guest
Bama,

I got the engine about 2 years ago - it has the standard gear and no I am not using ethanol - I know to use what the manfacturer says in engines, a detonating 40 year old 1.6 litre motor thats rarer than hens teeth taught me that..

I understand what you are saying about the sidemount thing, it makes sense. Trouble is I dont have the tools to do that sort of work and putting any sort of pipe on a rack mount has issues because the only way of routing it so it doesnt poke out the back and look like something you nicked of a spare german V-1 is running the pipe straight down and having a short tail angle. the in-frame mounting is much easier to do as that was the way the old cyc-autos and such were set up.

I have about 650 miles to go before I have any problems with coking up... the engine isnt even run in yet..

I have had a look at changing the thread title and I cant seem to find a way of doing it... im pretty much a newbie at forums and such..

on your question about temperatures. I can tell you that on a 7-8 mile run the top of the metal part is ouchie hot (hotter than the outside of a boiling kettle )and the bottom is about the same temperature as lukewarm water...

As to lights... on mine I have fitted a cateye LED front and a combined stop/tail/indicator setup on the back with a LED flasher to the bottom left on the other side from the exhaust. I havent used it at night yet but will let you know what happens when I do..

with the exhaust there does seem to be some backpressure as you get a slight squelch noise just after you have kicked over the compression...

If I put this kit on another bike - assuming I ever get that far - I will go for suspension - hard-bikes *hurt* - 30+mph across terrain is not condusive to kidneys staying in the right place - it also isnt kind on the wrists...

Jemma xx
 
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