Bending Exhaust. A few questions.

[Wrench]

Yuckfoo, have you installed the drive chain and rear sprocket to make sure you have a straight chain line?

yuckfooo is making a Motorized Fat Tire bike I don't think he's got that far yet. I think he's still installing the Jackshaft

 

[Ralpho]

yuckfooo is making a Motorized Fat Tire bike I don't think he's got that far yet. I think he's still installing the Jackshaft

Cool, first order of importance is straight chain line to bottom bracket from shaft and straight chain line from engine to shaft. Until then still don't have much idea where the exhaust needs to be. Of coarse there are plenty of methods. Wrench, I think if you've seen the inside of these mufflers you would understand what I mean.

 

[Wrench]

Cool, first order of importance is straight chain line to bottom bracket from shaft and straight chain line from engine to shaft. Until then still don't have much idea where the exhaust needs to be. Of coarse there are plenty of methods. Wrench, I think if you've seen the inside of these mufflers you would understand what I mean.

Yuckfoo has another thread about this build that show the bike with the exhaust on. Maybe ya can look at

Test Fitting The Engine - A Big Hurdle Cleared!

motoredbikes.com

 

[Sidewinder Jerry]

yuckfooooo's pipe only needs a slight dent .


Yes yuckfooos pipe don't need to be bent much. I guess ya can take a chance and hand bend the pipe without sand, but...
When bending the pipe with heat it's recommended to make a Sand Bend. The pipe keeps it shape or it can buckle kink
When hand sand bending a pipe use Builders Sand and it must be dry and packed in the pipe
Of course the muffler would be blocked. The sand would only be in the pipe,
The sand should be dry so it creates no steam Ya wouldn't want to pop a hole in the pipe.
How to plug the pipe - Secure a piece of a rag to a coat hanger and push it it with a flexible rod then cap the flange

Tip: Draw the bend radius on the floor, slightly over bend because when the pipe cools it will pull back slightly


yuckfoos pipe don't need to be bent much I guess ya can take a chance and bend it with a hickey
A hickey pipe bender is for soft metal pipes
IDK how hard the metal is on the China 2 stroke exhaust pipes. But chances are it's a soft metal.
M/C exhaust pipes are made made from harder metals

youkfoos pipe only needs a slight dent

Galvanized rigid conduit isn't soft. To make such a bend with no kinks you'd have to keep each bend around 2-3° before slightly sliding back to the next bend. Fortunately like you said you don't need much.

I could do it but I wouldn't advise an inexperienced person to try it.

 

[michael whiteman]

There's really no good way to do the sand bend with the muffler installed. This type of bending is usually done during assembly before adding the flange and muffler. In your case you would still need to heat the pipe with a torch and that is going to discolor the chrome. If it was mine, I would make a cut near the flange about 90% of the way through and bend the pipe away from your frame. Then weld up the cut. You'll mess up the chrome in that area but that's going to happen either way. Although putting a dent in the pipe will work, it will give you some restriction and will the clearance really be enough. There's no going back with that mod.

 

[Chainlube]

Cool, first order of importance is straight chain line to bottom bracket from shaft and straight chain line from engine to shaft. Until then still don't have much idea where the exhaust needs to be. Of coarse there are plenty of methods. Wrench, I think if you've seen the inside of these mufflers you would understand what I mean.

Getting a straight line with the jackshaft shouldn't be an issue, they make them long enough to have at least a half inch left over.

Never put sand in an already made exhaust for a 2t, it's the nature of the beast to draw back fumes from the pipe and any sand with it.

Get a short piece of wood, inch long should do it, whittle a curve in one side, put the pipe and wood in your vise and give it a little squeeze. DONE!

 

[Sidewinder Jerry]

With the hickey bender you could wrap the area to be bent with rubber insulting tape to keep from marring up the chrome while doing the bend. Then you can get exactly what you want with no damage to the pipe. As little as a 1/16" of separation from the frame would be enough.

 

[Sidewinder Jerry]

Have either of you put a slight bend the CG exhaust pipe like your describing?

I've only suggested what I thought would work,
I never had a China Girl 2 stroke, I've never bent an already made China Girl exhaust pipe

Let's say ya want to put a large bend in the CG pipe or even a small bend
Do ya think the sand would still be an issue, even if the pipe was plugged to prevent sand from getting into the muffler.
Then after the sand is dumped out blow it out with compressed air from the muffler end. (or is there something I should know about this muffler)
Ya also could put a rag on a coat hanger and wipe it out while blowing it out with compressed air.
I was worried if the pipe was heated to cherry red and bent without the sand it might kink or deform somehow especially now that it will have a large bend. What's your opinion on making a large bend

Large bends requires a special shoe for that kind of pipe. You can see them in use at muffler shops.

 

[Wrench]

With the hickey bender you could wrap the area to be bent with rubber insulting tape to keep from marring up the chrome while doing the bend. Then you can get exactly what you want with no damage to the pipe. As little as a 1/16" of separation from the frame would be enough.

Yes a Hickey will put a slight bend in the pipe? I've bent 1" rebar with a Hickey
Do ya think you can put a large bend in the CG exhaust pipe with a hickey?
Are ya worried that the pipe might crack or get kinked?

 

[JerryAssburger]

Something I picked up from Ralpho's first comment- So the stock China-Girl Exhaust has some sort of emission control-device in it? I was wondering what sort of baffling is in one of those.... without cutting mine apart*, has anyone done that? Photos?

*I am a CHEAP S.O.B. !