Low idle, reduced power

[stwaxy01]

Closing the loop on this one. I took the bottom carb apart and realized the issue was user error. I didn’t have the Needle Valve Assembly screwed all the way in which didn’t allow the needle to work properly and must have held the carb open. I fixed and reinstalled. All carbs were synced. No more leaking carb.

After I reinstalled I got it up to 5200 RPMs (which is the most it has gotten up to). A few minutes later (I barely touched the tilt) it dropped to 4600 RPMs and stayed there steady the rest of the trip. I tried readjusting tilt all the way down, up some, etc. but never got back up past 4600 RPMs so I don’t think it was tied to trim.

This happened last time I put carbs back in. Does 5200 for first 5 minutes then seems to drop to 4600. Grateful for any suggestions.

[99yam40]

your 1st post said 5500, now you say the most was 5200.
which is it?

something is not right if RPM dropped and could not get it back by moving the trim back to where it was when you were able to hit the 5200.

change plugs maybe.
trash plugging off a jet maybe or one of the other carbs has something that came loose.

I had a rubber plug come out of the idle jet hole before on my C40.
might cause too much fuel if that happens and cause a cylinder to not burn properly.
Something to look into

[99yam40]

+1 ^^^.

With the fuel literally running out the carb, that cylinder is flooding out, thus the lower RPM's(way too rich).

If you look at his last post he found what the problem was with that flooding carb and fixed it.
at least that is what he wrote.
then he had some RPM drop he is asking about

[TownsendsFJR1300]

If you look at his last post he found what the problem was with that flooding carb and fixed it.

Darn you 99!

I missed that in post #13..

Deleted my entire post there (as he obviously addressed it), thanks...

[99yam40]

towns I sent you a PM

[TownsendsFJR1300]

towns I sent you a PM

Yep, I responded. Holler back if it didn't go thru...

[99yam40]

Yep, I responded. Holler back if it didn't go thru...

got it and replied, thanks

[stwaxy01]

Thanks 99. I'm sure i estimated the first time (i.e. 5500 RPM). This second time I made note of exact RPM (5200) limits and drop (600). It sounds like it's likely still a carb issue. I'll take a look at them again this weekend. Thanks again.

[TownsendsFJR1300]

Just a quick note...

I know you re-built the carbs but it is IMPERATIVE
THAT YOU REMOVE ALL JETS and verify that YOU CAN SEE THRU THEM.

The orifices are soooo small, its very easy to miss something...

A shot of carb cleaner don't count either.. When you see light, your good!

Good luck..