idle start run fine, nut hit the gas .......see video. or my build threadinfo

[rjz5400]

I got the tank back on and sealed it all up and she fired up kick number two.
It runs great but it doesn't rev above 5500. I cleaned and set the timing but that is about it. No air filter and stock carb
so where's my number one geuss ? Advance timing? Bigger main jet? Raise needle?
Or is it possible the dead battery is keeping my sparkabilitu down?

so i can actually ride it and i did, i went for a bout twenty minutes and when i was at idle and hit the high beam, it stalled with no headlight it runs up to 5500 or so and the wont rev higher, it misses and will die if pushed

bike is a 1973 cb125s with stock 22-mm kehin, no air filter stock exhaust clean jets and good gas and a generic coil with newish ngk plug
and an old 6v battery
everything works lights blinkers taillight horn but it works slowly or dim.

if possible for a battery to do this i will buy one today but i just dont want to throw money i dont have at it.


ideas for the number one culprit????!!!

sorry about the video i just got this iphone. wont happen again.
the turning!

 

[bobjohnson]

No filter and stock carbs, culprit is its running lean. No 2 ways about it. Dont run it too much until you get that sorted, you can really damage the engine by running it lean, and in short order. Pull the plug i bet its all white or maybe even blistered.

Solutions? Get some airfilters. If you get the stock box, you wont need to rejet. If you get K&N's or some other kind of filters, youll need to rejet.

No way around this at all, the stock jets/needles dont have enough adjustability to adjust for no filter or even K&N's.

 

[rjz5400]

Re: idle start run fine, nut hit the gas .......see video. or my build threadin

word. i have the stock box and its all hooked up there is just no element in there.
ill sort one and pull the plug in the meantime

 

[crazypj]

Re: idle start run fine, nut hit the gas .......see video. or my build threadin

word. i have the stock box and its all hooked up there is just no element in there.
ill sort one and pull the plug in the meantime

Yep, get filter and put fender back on, it will handle like a 3 legged camel without some sort of fork brace, they are real flimsy forks.

PJ

 

[rjz5400]

Re: idle start run fine, nut hit the gas .......see video. or my build threadin

i wish PJ, it had some cheng shin dirt bike knobbies and on it with no fender and i think one of the mounts had been snapped off.
probably from a g out while pretending it was a motocross bike.!!!
i was thinking about drilling or machining a fork brace for both my cb550 and this cb125 cause i got no fenders for either.

 

[bobjohnson]

With a jigsaw and a drill, and a block of steel you could probably come up with a pretty bad ass fork brace. Just need something in there to keep the forks from twisting.

 

[crazypj]

You want something like this,
I've made a few of them for different bikes over the years (this one is for CB360)
I havent taken any pictures of it finished (not polished yet)

 

[rjz5400]

Re: idle start run fine, nut hit the gas .......see video. or my build threadin

I get the idea but wher does it go? On thrip of the lowers I geuss? I wonder if a straight brace will clear the tire?
Thanks fir the pics very usefull

on the running issue here is the plug

and it stalls like hitting the kill switch if I touch anything electrical like the horn or the headlight.
I think I have some bad electrical component. I am charging the battery now

 

[tonuppirate]

You want something like this,
I've made a few of them for different bikes over the years (this one is for CB360)
I havent taken any pictures of it finished (not polished yet)

PJ, you sellin those cb360 fork braces yet? I'll take the next one you make. PM me the price, thanks,
tp

 

[rjz5400]

Re: idle start run fine, nut hit the gas .......see video. or my build threadin

I update the problem solving, i pulled the super rich looking plug an i charged the battery up.
i am leaning towards the timing, i cleaned and reset the timing before i fired it up for the last time so i think maybe either the point gap is too big or the plate is too far retarded or advanced or something.
it runs great just up to about 5500 it sputters

also i am gonna check the valves, i have not done that yet.

 

[crazypj]

Fork brace clamps around fork top, remove the dust seals/covers.
I may be selling the one shown but it's for CB360 (probably fit late model disc brake CB350) so doesn't help you out
Use spacers to lift cross piece for tyre clearance (they are not in pic)

PJ