engine isue ...

[michael-nadav]

hi there:
i recently renovated my 1963 cb77 , the problem i am encountering now is that the engine can not go over 5000 rpm at 3rd and 4th gear unlike before
however it does start easily and works great in gear upto 4000 rpm and then it start vibrating and making some funny noises
timing , ignition , valves and carburetor are all clean and tuned
i checked the spark at the top of the plug and it look quite strong ...
what might be the reason for that ???
thanks..
M.

[Dgormley]

Hmmmm, vibrating, funny noises????????????????????? its gettin ready to blow up............D

[Dana01]

Hi Michael,

Try this: drive it up to 4k rpm and let it sputter for a bit, pull in the clutch and kill the engine. Coast to a stop with the clutch in and check the plugs.

Is there unburned gas on the plugs??

(welcome :)

[56_oval]

Hi Michael,

Try this: drive it up to 4k rpm and let it sputter for a bit, pull in the clutch and kill the engine. Coast to a stop with the clutch in and check the plugs.

Is there unburned gas on the plugs??

(welcome :)

I was actually thinking too lean... I built a 2276cc engine for my Karmann Ghia a few years back running dual Weber 40mm carbs off of my 1835cc engine. I had totally forgot about jetting when I took her out for the first time. I wrapped her up with load to about 4k and she sputtered and had no power. She was running out of fuel at higher rpm. After reaming the jets to a larger size (one step at a time and testing), she ran great with power up to 8k.

[Dana01]

aha! ... so what size main jets do you have?

[e3steve]

Hi Michael,

Try this: drive it up to 4k rpm and let it sputter for a bit, pull in the clutch and kill the engine. Coast to a stop with the clutch in and check the plugs.

Is there unburned gas on the plugs??

(welcome :)

I was actually thinking too lean... I built a 2276cc engine for my Karmann Ghia a few years back running dual Weber 40mm carbs off of my 1835cc engine. I had totally forgot about jetting when I took her out for the first time. I wrapped her up with load to about 4k and she sputtered and had no power. She was running out of fuel at higher rpm. After reaming the jets to a larger size (one step at a time and testing), she ran great with power up to 8k.

Seems like a weak mixture to me, too.

[Snakeoil]

Dontcha think that "renovated" should be clarified before you all start jumping to conclusions. Does it mean a clean up, oil change, total rebuild, tune-up.... what??

Just sayin'....

regards,
Rob