How to adjust the jets on motorcycle carburetors

This is a brief introduction to the fairly touchy process of re-jetting your carbs. The techniques discussed here are fairly universal to most carburated motorcycles, but not all, so your first step in performing carb tuning should be to consult your repair manual and online forums. Hopefully this video can demystify a lot of the process for you, so that you have the courage and interest to do this yourself. Let me know if you have any questions.

Category:

Autos & Vehicles

Tags:

• kawasaki
• suzuki
• honda
• yamaha
• bike
• moto
• motor
• carb
• jet
• main
• pilot
• needle
• venturi
• float
• bowl

[KEEPNITPG]

I have a cb650sc im making into a cafe have all upgrades and mod'd myself it looks sick and thanks to you i understand more than i did the crude animations helped soo much'

[mrmaxstorey]

@KEEPNITPG Cool glad to help

[altlandf]

By the way my bike is stock. It has the OE air cleaner and exhaust. Most times I used 93 or 92 octane but the problem is back again.

[mrmaxstorey]

@altlandf The majority of problems starting which present as the weather turns cold come from vacuum leaks and weak batteries. I would like to encourage you to watch my video on how to check for vacuum leaks, how to diagnose battery problems, and finally how to select the best fuel octane for your bike. Let me know if I can be of further help or if those videos are unable to direct you towards a solution.

[nikola25spasic]

Max, looking at the jet sizes for the main on my BS34ss carb the stock is a 130 and it goes up to 132.5, 135, 137.5, 140, etc. Are those jets ending in .5 half size increments? I figure they are but want to get that 2.5 base after adding the pod and work from there.

[mrmaxstorey]

@nikola25spasic You got it, they are very precise. I would suggest getting a set of 132.5 and going from there, you may need to tinker with needle height or even go to 135, its not an exact science.

[KEEPNITPG]

THANK YOU SOOOOOOO MUCH

[altlandf]

I live near Harrisburg, Pa. I am having a problem with my Honda CM250C starting when it's cold out. I don't think my bike likes the cold. Most times after the bike warms up it runs pretty good. But today wasn't one of them. It was about 35 degrees out and the bike idles good but when I put it into gear and try to take off it won't go and starts to pop and carry on. To make matters worse we have ethanol in the fuel. If there's too much in the fuel the engine will run lean. What do I do?

[krayziesensei]

Wow! Very well done and easy to understand.

[mrmaxstorey]

@ilikesuzuki Sounds rich, altho it could b either. Pull the plugs and look at em, should tell for sure if you are running rich or lean.