Help diagnose a sputtering bike?

[UltraLife]

I have a 2006 Bajaj Chetak which has served me well for a long time. I rarely start it during the rainy Seattle winters, but drive it a lot in the spring and summer. I went to start it up the other day and it starts and idles fine, but when I turn the throttle, it sputters and has very little power. I made a video so you can see what happens.
Can someone help diagnose this?
Big thanks in advance!
Adam

[UltraLife]

I'll try here and will also put the link in my profile

[Ebuddy]

My first impression is that this could be a vacuum leak. At idle, the carb can keep up but under load, it's sucking in too much air somewhere. I'd check the lines as well as the carb. Pinhole leaks are the worst.....

[UltraLife]

Originally Posted by Ebuddy

My first impression is that this could be a vacuum leak. At idle, the carb can keep up but under load, it's sucking in too much air somewhere. I'd check the lines as well as the carb. Pinhole leaks are the worst.....

Ugh, for a pretty untechnical guy like me, that sounds like a nightmare. So I should look closely at all the tubes and hoses? Any best practices for troubleshooting that type of thing?

[Ebuddy]

Well… It depends upon how “untechnical” you are. ;-)

Rather than recreating the wheel, here’s a site that has some good information:

http://www.mopedarmy.com/wiki/Vacuum_leak

I’d just stick with Method 1 to start.

After that, I’d replace all of the vacuum and fuel lines anyhow. This is a cheap, easy task that should probably be done on a ’06 if it’s never been done before.

Failing that, I’d start looking at the petcock/fuel pump, auto enricher (if equipped) and the carburetor (in that order).

Best to try one at a time so as to not be overwhelmed.

If after all that there’s still an issue, perhaps the valves need to be adjusted.

[UltraLife]

Super helpful, thanks! I am going to try this out with a friend soon!

Originally Posted by Ebuddy

Well… It depends upon how “untechnical” you are. ;-)

Rather than recreating the wheel, here’s a site that has some good information:

http://www.mopedarmy.com/wiki/Vacuum_leak

I’d just stick with Method 1 to start.

After that, I’d replace all of the vacuum and fuel lines anyhow. This is a cheap, easy task that should probably be done on a ’06 if it’s never been done before.

Failing that, I’d start looking at the petcock/fuel pump, auto enricher (if equipped) and the carburetor (in that order).

Best to try one at a time so as to not be overwhelmed.

If after all that there’s still an issue, perhaps the valves need to be adjusted.