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View Full Version : what color is your pipe?


Kenstogie
07-09-2020, 03:08 PM
What color is your pipe.....err exhaust pipe i mean. :hmm:

what color should it be?

Is it indicative or your fuel/air mixture (too lean for example)

what else does it indicate?

mine is below and is the ever present aftermarket special..... and i rode it around for about 100 miles yesterday in the 90 degree heat (apprx 70/30 road trail) it never gets cherry red or orange but is getting that shiny purple rainbow thing going on...

Wild Dog
07-09-2020, 03:27 PM
If you changed the whole exhaust but you didn't rejet the carb, then you will be very lean... Those carb are already lean from the factory...

It should turn browninsh when everything "normal" but if you get a deep blue like the bluing used on old guns then you are quite lean.

Bruces
07-09-2020, 03:34 PM
In 1983 I was a mechanic at the local Kenworth ,Peterbuilt dealership ,and we would get our rear ends handed to us if we didn’t wipe down the stainless exhaust before starting an engine .The truckers were convinced it had to do with oily fingerprints that turned those pipes blue and honestly those guys would know since I was doing engine rebuilds at over a million miles with the pipes being clean like new .

franque
07-09-2020, 03:35 PM
You're probably lean, but also many bikes with chrome plated/stainless pipes do that from the factory (one reason why Harley puts chrome covers on their pipes).

Kenstogie
07-09-2020, 03:41 PM
i did rejet it 110 or 115 main but was thinking of upping it ....

franque
07-09-2020, 05:27 PM
It's more likely to happen at idle, what was the pilot jet at?

TheChairman
07-09-2020, 09:20 PM
A little color change is going to be normal, especially considering the quality metallurgy of that aftermarket exhaust.

What you don't want is blue, or even worse blue with yellow spots. That doesn't look too horrible. Just a little blue up by the flange where it's the hottest. Some minor adjustment should clear that right up.

Deckard_Cain
07-09-2020, 09:29 PM
Mine is still black. Still OE exhaust...only 70 miles on it though.

Kenstogie
07-10-2020, 07:58 AM
It's more likely to happen at idle, what was the pilot jet at?

i left that stock and what that is i don't know it is an amazon special but has good reviews (Hwbnde VM26 Carburetor (https://www.amazon.com/Mikuni-Carburetor-200cc-Motorcycle-Motorbike/dp/B07CN36W65))

.... but it does seem to come more alive at 1/2 and up on the throttle..... and is a little tame or lame at 0 to about half.... i do have a tendency to stay at the below 50% throttle in an attempt to be nice to it...

any recommendations on the "correct" size or at least a ball park? i am pretty sure i have a jet kit floating around

thanks and cheers!

Kenstogie
07-10-2020, 07:59 AM
Mine is still black. Still OE exhaust...only 70 miles on it though.

yea that thing chokes the air to much.... unless you gut the cat...

Deckard_Cain
07-10-2020, 10:02 AM
yea that thing chokes the air to much.... unless you gut the cat...

Yep... you can feel the extra heat coming form the cat itself too. The rest of the pipe, even right at the head is nowhere near as hot as that restrictive cat converter.

Then I had read/heard from a few people (admittedly not many) that it didn't make any difference.

I'm just wondering if cutting a window, gutting it, and welding it back together is worth it, or if I should just buy the silly $100 exhaust and be done with it.

I like how not-loud the stock exhaust is, not how restrictive it is though.

JerryHawk250
07-10-2020, 10:35 AM
Yep... you can feel the extra heat coming form the cat itself too. The rest of the pipe, even right at the head is nowhere near as hot as that restrictive cat converter.

Then I had read/heard from a few people (admittedly not many) that it didn't make any difference.

I'm just wondering if cutting a window, gutting it, and welding it back together is worth it, or if I should just buy the silly $100 exhaust and be done with it.

I like how not-loud the stock exhaust is, not how restrictive it is though.

I'm still running the gutted header pipe on my Hawk for over 3 years. I removed the stock muffler and replaced with an Ebay muffle that someone gave me.

franque
07-10-2020, 01:07 PM
i left that stock and what that is i don't know it is an amazon special but has good reviews (Hwbnde VM26 Carburetor (https://www.amazon.com/Mikuni-Carburetor-200cc-Motorcycle-Motorbike/dp/B07CN36W65))

.... but it does seem to come more alive at 1/2 and up on the throttle..... and is a little tame or lame at 0 to about half.... i do have a tendency to stay at the below 50% throttle in an attempt to be nice to it...

any recommendations on the "correct" size or at least a ball park? i am pretty sure i have a jet kit floating around

thanks and cheers! Just check the Hawk 250 thread, it's the same motor, the VM26 was a popular swap for a long time.