Two Stroke Motocross

Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: cnrcpla on May 13, 2012, 07:54:17 PM

Title: How much power does carbon rob?
Post by: cnrcpla on May 13, 2012, 07:54:17 PM
A bit of a  pointless question, but I am itching to get back on my bike after a week of not riding in this beautiful weather. I am just curious as to how much power about 1/8 of an inch of carbon build up in the expansion chamber can take away? Is it even going to be a noticeable difference? I sent the pipe to be heat tanked to get it all out, and I am hoping I get it back this week  ::)
Title: How much power does carbon rob?
Post by: Premixed on May 13, 2012, 08:16:44 PM
better to ask yourself not how much power the spooge robs, but rather, how much power the poor jetting that caused the spooge robs.
Title: How much power does carbon rob?
Post by: cnrcpla on May 13, 2012, 11:26:09 PM
I am re jetting as soon as I get the pipe back. I have a new plug and a few jet sized a bit leaner I want to try. We shall see how it goes.
Title: How much power does carbon rob?
Post by: eprovenzano on May 14, 2012, 05:43:14 PM
Just a note of wisdon, as the cylinder ages / wears, it makes it seem as though the jetting is off...  the reality is the jetting may be correct, the the engine is worn.  After rebuild stay with current jetting, until after the top end is broken in.  If you feel the jetting is still off, then change one thing at a time.  I've seen it a thousand times, people will change two or three things at the same time, and they can't understand what they can't get the bike to run properly.  Change one thing at a time so you know what works and what doesn't, and please, please write down current jetting settings, (needle number and clip setting, air screw, pilot and main jet numbers before making any changes.
Title: How much power does carbon rob?
Post by: cnrcpla on May 14, 2012, 05:46:06 PM
My engine has about 2 hours on it not including break in and it is still spooging a bit. But, I did discover that the air/fuel screw was off about a quarter turn maybe more, so I re set it and I will see what happens. If it still spooges then I will re jet and plug chop accordingly.
Title: How much power does carbon rob?
Post by: eprovenzano on May 14, 2012, 05:51:53 PM
Sound good.  Let us know how it goes 
Title: How much power does carbon rob?
Post by: cnrcpla on May 14, 2012, 06:25:16 PM
Will do. I have a hunch it might have been the air/fuel screw because I had it jetted perfectly a while ago.
Title: How much power does carbon rob?
Post by: Coop on May 14, 2012, 11:08:47 PM
Two experiences with pipe obstruction come to mind I'd like to share.

1) I had a mouse nest (complete with dead mouse) inside a KX125 pipe after sitting all winter. That robbed A LOT of power.
2) 1997 PW50 had so much carbon in it when I bought it for my nephew I thought it was blown up. Cleaned out the pipe and that bike ripped up until the day we sold it. I also re-hooked up the oil injector as the previous owner was mixing it at 16:1 because he didn't trust the oil injection.

So yes obstructions in your pipe will rob power. But as mentioned find out what caused the issue and fix it.
Title: How much power does carbon rob?
Post by: cnrcpla on May 14, 2012, 11:30:09 PM
Quote
So yes obstructions in your pipe will rob power. But as mentioned find out what caused the issue and fix it.
I am almost positive it was a rich air/fuel mixture hahaha, I like to mix rich, but I'm thinking that it isn't worth all this trouble. Thanks for the input guys  :)
Title: How much power does carbon rob?
Post by: evilscientistmoose on May 15, 2012, 12:56:17 AM
This doesn't have anything to do with that old 'if a woodchuck could chuck wood...' song, does it?
Title: How much power does carbon rob?
Post by: cnrcpla on May 15, 2012, 02:34:49 AM
What?  ???
Title: How much power does carbon rob?
Post by: Premixed on May 15, 2012, 04:09:49 PM
I think it ties in with "if a 89 YZ250 falls in the forest, and no one is there to hear it..."
Title: How much power does carbon rob?
Post by: eprovenzano on May 15, 2012, 04:42:06 PM
Premixed, I think you're having riding withdrawls... and spending tooooo much time on the internet...   8) To help with the riding withdrawls, you need to get on your Katoom, (yes even with the engine not complete) and start making braap sounds...   :D
Title: How much power does carbon rob?
Post by: cnrcpla on May 15, 2012, 07:49:44 PM
Quote
if a 89 YZ250 falls in the forest, and no one is there to hear it..."
I'm not sure about an '89, but I know that when my '92 fell (on me) in the forest, I sure as hell made noise, I think it was a "F*ck F*ck F*ck!" sounding noise.
Title: How much power does carbon rob?
Post by: cnrcpla on May 15, 2012, 09:45:53 PM
Couldn't help but post this... I can't wait to slap this baby on