Flex Pipe undertail exhaust review and pics.

F

Fear My Twin

Chicks hate my bike.
Well in case anyone was following this, its works pretty damn well. As guessed, no power gains noticed. NO POWER LOSS NOTICED EITHER.

However, I did notice the pipes were extremely cooler to the touch from where the pipes turn vertical until the tip. I guess the added surface area of the flex pipe helps with heat disappation. That means that by the time the pipes reach the carb/electronics they are warm to the touch. It was time consuming but I did fab up some heat shields just in case with one hand which was not easy

Took a couple hours to get the pipes mounted/ clamped/ routed/ mounted to tail. I didn't have time to mount the tips before having to go to work.

Soapy water test proved no leaks at the clamps or in the actual pipe.
She sounds and runs like a ----d ape with the new jet kit in. Took her for a little spin, looked alittle odd splitting lanes with a blue cast and but oh well.

Not too bad for a $15 undertail.

Excuse the pics, I forgot to upload them at home and had to have the fiance upload them at home. These are mock-up pics.
 
That's actually kinda neat. Do the pipes run all the way to the back of the seat? It's hard to tell in the first picture. If I wasn't going to use just straight pipes on my scoot, I'd consider it. I mean, you could heat wrap that, and no one would ever be able to tell. Just a thought. Cool idea though, very tactful.

Steve
 
how flexi is the flex tube? could you take that off and bend some pipe using that as a template? with the popularity of the honda twins you could probably make up the cost of everything by selling a few on ebay.
 
Heh...great minds (or equally damaged?) think alike!

I've got a 500T sitting here that needs an exhaust to finally be done and I'd considered doing something like that and tucking a pair of small Harley take-off (hooray eBay!!) mufflers under the seat. I agree on the heat wrap too. In my case I happened into a pair of TT pipes from a cb450 K? that tuck under the engine nicely so I'll probably build from there and run the pipes in a similar manner.

I may try stuffing a Radian swing arm (after a bit of machining) on it, I should be able to tuck the pipes inside the swing arm......

Nice job!

ps: hey...what 'jet kit' did you use?
 
Thanks for the comments guys!

1st. The pipes are two 3 foot sections. 1 3/4". The pipes only go to the metal hump under the seat. Thats for a reason though. I was going to use either a muffler or some tips to extend out past the seat. Then maybe a slash cut. I dont know yet.

2nd. The pipe is hella hard to remove without bending it out of wack. I may just have to bend some up and ebay them! Thanks for the idea!

3rd. Swagger, I was trying to hunt down a set of CL450 pipes but gave up, thats when I had this idea. My jets. I had a hell of a time hunting down the proper jets for my bike. Which explains why the PO drilled out some spare 65's and used those. You can search my name for the thread on what kind you need. I was able to find OEM keihin 145's though. They seem to be working good up to 70 which is about all I can do with a cast now lol.

Ill post some good pics when I get home from work tonight.
 
Glad you found those 145's.Question, will this system heat your ass for cold weather riding?? ;D
 
I'll be honest: I think it's ugly.

And then today I was thinking, "Oh, you could just cover it with header wrap!"

Looks like someone beat me to the punch. Really cool idea, but would be really awesome with some header wrap.

Props for some ingenuity, for sure. ;D
 
I like the concept, but I'm not liking the execution.

The flex pipe does nothing for me, though, if you use it as a model to have a professional exhaust guy make up a pair of custom chrome pipes, or as suggested above to wrap them, then it'd look better. It's a gorgeous bike, but the flex tube just looks cheap. I know it is cheap, but it shouldn't look it ;)

I wonder about three things:
1) Heat. Pipes get hot ... real hot. That close to your electrics and your ass may show some issues you hadn't thought of before. I've seen a similar kind of treatment on some street fighters, and the main issue for them is that the bitch seat gets really hot. Speaking of which ...

2) Brake light. I see turn signals but no brake light. You sorta need one of those to be legal. Not sure where you can put it without melting it.

3) As mentioned above, rear wheel clearance. The street fighters I've seen with the same kind of treatment have ridiculous amounts of wheel clearance between the mufflers and the rear wheel. Sitting on the ground without the stand, how much clearance do you have? Would you be afraid of bumps?
 
sorry to cut in, but on the subject of wheel clearance, i was wondering when i put my battery box under my seat if there would be enough clearance during big bumps, i still haven't been able to test it out yet.
As for your exhaust, its an idea, but the long gradual curve looks a little fake, maybe if it followed the lines of the frame more,
 
First off guys, Of course I was getting header wrap. I thought that was a cafe given lol. I just kept forgetting to state that :)

Second of all heres some pics with the tips and mounted to the old rear fender mounts. Glad I didnt chop them off!

Plenty of rear tire space. The tips are higher than the stock rear fender for sure seeing as they use the same mount. All together im into the entire undertail for $40. As for under the seat, I dont have pics yet but I made a heat shield which seperates the pipes from wiring/ electronics. I stuck on some of the heat tape foil stuff from the hardware store ($4.99) and plan to rivit it in place tomorrow. I think/hope that should be safe.

Any yes, I plan to high temp the rear mount black.

Thanks for comments and tips guys, thats exactly why I posted here!

Another semi-problem surfaced though. My left cylinder is firing at the same time as the right but isn't as strong. With my hands behind the tips I can easily tell the difference. Why would that be? You can tell from the video that im shooting flames from the right :) Sorry for no sound. I didn't realize the camera didnt have a mic!

Excuse the insane garage, we just moved in.
 
Dood...i think that looks FUCKING SICK!! That should keep some cagers off your ass...otherwise they're gettin double barreled in the face!! I like it..and as long as the heat issues are good, headerwrap it and bobs your uncle!
 
Sorry guys, the video took 11 hours to load with no sound!

[youtube=637,575]NIkhJaInbdg[/youtube]

Baby flames at 30 seconds in.
 
That's a 270 degree crank, right?
Shouldn't be firing together at all.
Flames are prolly from timing issues, but maybe a bad exhaust valve/rich in that carb?
(mine flames on the left side...)
Are the valves clearances set right?
I've got to go over mine (again) as I let it sit for months on end due to scheduling my life around my other life and my other life, and my wife...
 
^Thank you sir!

Well I let the bike warm up today. Left cylinder was very cool. While the right was pretty warm, not like skin boiling hot, just warm.

I did pull the plugs and take pics but forgot them at home. I can load them tonight.

The left plug is a nice dry soot.

The right is a dry soot with a grey/ burnt tip.

Also, I noticed that the flames arent on decel. all the time. Just if I really crank it up say to 6k and then let off.

Besides that I should have mentioned earlier that I am pretty sure the 500T is a DOHC 180 degree twin. Should the cylinders be firing at the same time? Or is this a timing problem. Here is what I found on the 500t:
IN common with all previous Honda twins the CB500T used an 180° crank, as opposed to the traditional British 360° setup. Bear in mind that a 4-stroke cylinder fires once every 2 revolutions (720°) of the crank.

Sounds like I might need to finally learn how to set timing. Pug, please, please, please do a CB500T write up with pics. I will help out all 3 500T owners here lol.
 
Last post. Promise.

Heres the 100% cleaner way to mount the barrels. Clamped to the splash gaurd mounting tabs. Just need a spare seat pan to mount the cowl to.
 
Nice, super clean.

Hurry up and get some header wrap on those so we can all forget it's flexpipe and oggle the beauty of it all.
;D

** EDIT: DAMN that looks good with that seat cowl! **
 
Wow, that's looking great with that seat cowl. I thought about doing something similar with mine, but settled on the old gas tank method. Looks great.

How did you mount the cowl on, by the way? And are you hacking off any of the frame that sticks out?
 
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