Help needed! extreme bogging and terrible performance :(

[ghost_Shark]

I can't see any damage on the stator, it looks clean, and i've tested the spark and it's better now, nice blue powerful spark. I think valve clearance is next on the to do list, what do you think?

 

[my67xr]

Yeah do the clearance's, then adjust the carby to suit.

 

[ghost_Shark]

i've adjusted the clearance's (quite poorly) and it's way better, can pull upp hills and it idle's so it's definently better, but i didn't have any .003 so i had to take the .004 and .006 option. Do you think there would be more performance from the .003 and .004 option?
I still have to adjust the carby better, so maybe that's the problem now, the thing is, when i'm cruising along and just slightly throttle up, it pulls for a second then looses power and regains it after 2-3 seconds, it's not undrivable but it's a bit annoying, if i throttle more it's fine, also when idling it will jump from say 1500rpm to 1600rpm, then drop down again after a second. i think that's the carby tho.

So i'll adjust the carby, change the needle position as the clip is all the way down now, hopefully that cures it

 

[my67xr]

Sound's like you are getting close to it running sweet now.


I don't think you'll really notice the difference if you adjusted the clearance's from .004" and .006" down to .003" and .004" on a 50cc engine.
But you could adjust both to .004" though, and see if it's any better
Or even adjust the bottom/exhaust clearance to .004" , and do the top/inlet at a slightly tight .004" so it drag's a little when you move the feeler gauge between the rocker arm and valve tip.


Yeah,
once they are set, adjust the carby like i described in post #11 above.

When you pull on the throttle and it looses power for a couple of second's does it sound deeper through the exhaust or sort of the same sound ?
When you cleaned the carby did you pull the mixture screw, spring and o ring right out and spray cleaner through it all ?
It may have some dirt etc stuck in there and is blocking the fuel flow for the pilot jet ?

Also when the jet's were out, did you remove and clean the long emulsion tube where the main jet screw's into ?
The main hole through the middle and the tiny one's across it, then blow out the tube and carby well ?

The other thing is the float level may be adjusted wrong too ?
With the carby upside down, and with the float arm tab in the middle only just touching the pin on the lnlet needle, the top of the float should be sitting roughly square with the base of the carby
The centre tab on the float arm may have been bent at some stage?
This will affect the float level and the mixture's but more when you are holding the throttle open at 1/2 or more

 

[ghost_Shark]

i will check the carby, i cleaned the carby as best i could (took everything apart that can be screwed out), i used brake cleaner as i couldn't find anything else, and i know how good that stuff is at cleaning things.

It doesn't look like i can adjust the float level, but i will check if anything is bent, it shouldn't be though, the carby is brand new.

When i did the clearance's i made both fairly tight, that's why i think it might be a bit poorly done. I haven't done this before, but i've watched a fair bit of people doing it so i know how it should be done. I think i will try to set the exhaust to .004 and the inlet to a tight .004 (don't need to do this one really )

And of course adjust everything first to see if it isn't the carby.