carb question

[300rman]

well, i bought a 38mm keihin carb off ebay. it came off a cr500, its been running great, starts right up, and seems to run great. plug color is a good tan/brown.

think is, i havent touched the jetting on this thing. got it, put it on thinking i would need to lean it out, and it ran great.

only thing is, when i first start it, it will not rev past half throttle. even after it runs awhile, it will not. i have to hammer it a few times to get it past that halfway point, and after it raps out a few times, it is perfectly fine and wont do it any more. but it will not get past this "halfway point" unless i hammer the throttle a few times.
when it does this, it doesnt smoke excessively like its too rich or anyhing
it just revs up to its halfway point, and wont rev past this, just kinda stays at that rpm, might sputter a bit, and then stay at the same rpm still. i dont really know how to describe it.
maybe like a funny "hollow" bog-sound when it hits its halfway point.

when i tore the motor apart to go get ported, it had about....10 hours on the top end. the cylinder had some vertical lines in it, but were not deep or anything, just some light scuffing, if you want to call it that.
is that normal? i have heard people tearing their motors down after a few months and the cylinder being in great shape.

can we define "great shape'. i am trying to figure out if she's running right.

the plug is a good color, but i mention in my other post that maybe a rich premix could cause a false plug reading? i have no clue, and want to make sure it gets back together right this time and that it will run great for years.

[TwoHundredEx]

Mines been doing this too ever since I put the motor in the trike.
Before that it never did it.
It's exactly as you described, it doesn't really bogg, just kind of stops, like it's hitting a limiter or something.
If I pin it for a couple seconds it'll "break through" and rev fine for the rest of the day.
I'd really like to know what it is.

[300rman]

Mines been doing this too ever since I put the motor in the trike.
Before that it never did it.
It's exactly as you described, it doesn't really bogg, just kind of stops, like it's hitting a limiter or something.
If I pin it for a couple seconds it'll "break through" and rev fine for the rest of the day.
I'd really like to know what it is.

exactly. you have to hit the throttle hard and quick to get it to break through. makes zero sense.

[TwoHundredEx]

Bump
.....

[300rman]

bump.....noone has a clue?

[MTS]

What ratio are you running your oil at???... you let it warm up for 5 mins befor you pin it???...im leanin towards a worn out needle+seat + to fat a piolet, that have a fuel or air screw on it?

[300rman]

What ratio are you running your oil at???... you let it warm up for 5 mins befor you pin it???...im leanin towards a worn out needle+seat + to fat a piolet, that have a fuel or air screw on it?

im running a 20:1 ratio. yes, i let it warm up a bit before hammering it. but 3/4 throttle isnt really hammering it, it just kinda wont go past half till i jack it off for a minute. then its fine for the rest of the day/until it cools off again.

but i would think a worn out needle/seat would cause problems all day, not just at the first rev-up?

it probably does have a fuel/air screw. should i lean it out or richen it up and givr a try?

[TwoHundredEx]

im running a 20:1 ratio. yes, i let it warm up a bit before hammering it. but 3/4 throttle isnt really hammering it, it just kinda wont go past half till i jack it off for a minute. then its fine for the rest of the day/until it cools off again.

but i would think a worn out needle/seat would cause problems all day, not just at the first rev-up?

it probably does have a fuel/air screw. should i lean it out or richen it up and givr a try?

I'm running 32:1 and I let it warm up too. The longer I let it warm up, the better it is, but still does it.
The odd part about mine is that it only started doing it when I put it in the trike. Never once had this problem when it was in the bike frame.

[MTS]

im running a 20:1 ratio. yes, i let it warm up a bit before hammering it. but 3/4 throttle isnt really hammering it, it just kinda wont go past half till i jack it off for a minute. then its fine for the rest of the day/until it cools off again.

but i would think a worn out needle/seat would cause problems all day, not just at the first rev-up?

it probably does have a fuel/air screw. should i lean it out or richen it up and givr a try?

well, depending on , if its a air or fuel screw, is it at the front, or rear of the carb? kinda sounds to me like a normal a/c bike, they need alota heat when wore out to run clean, even fresh they do, i would start droppin piolet jets and see where that gets you, its hard to diagnose this stuff over the net, not gona lie, as fpr the200x,,, thats pushin alot more weight than a bike,,,imo,,,,:beer

[ants84olds]

I think its just because it is cold. Let the bike warm up for a while and then see what happens. Its hard to burn the oil on a cold motor.

[300rman]

i didnt think it a serious issue, just want a few opinions on it to make sure its not serious.

but as for warm being the solve it, if i take it and hammer it as soon as its started, its the exact same. it takes the same 15 seconds ish of hammering it/leting off/hammering it to get it to break through. letting it pre-warm up doesnt seem to help.

im a bit wary of messing with the jetting because i couldnt ask for it to start any easier unless it started itself.

just wanting to make sure that its not like a "sign" that something is deathly wrong and it could let go any second lol.

[MTS]

lean out your oil mix to like 40:1 with a good synthetic and see where that gets you, jetting is nothin to be fraid off, it runs like *Edited**Edited**Edited**Edited* now, just jet down till it runs good, and fatten it up a bit, Warm mind you,,, it sounds to me like a normal ac 2 stroke,