Engine Trouble High rev problem

[goodtime65]

If you feel that the carb angle is not an issue than I would be more inclined to look into your fuel valve on the gas tank. Iv'e come across this problem a few times and found out there was not enough fuel flow from the valve. To verify this you can replace the valve with a straight fitting and try it out

 

[motorpsycho]

Hey Motorpsycho, It does it with the gas cap off too. And I am taking every bit of advice and gonna go do most all of it right now. Gonna level out the carb and use a gas resistent hose for the intake to avoid vibration. I think yer right about most everything, from the angle of the carb to the vibration causing it to foam. ANY foaming, with the carb not being able to fill all the way, Would cause it to get more air than fuel.
So, I'm headed out to the shop right now to find out. Wish me luck.

Just for the record, it was gearnut who mentioned the gas foaming, not me.

 

[motorpsycho]

If you feel that the carb angle is not an issue than I would be more inclined to look into your fuel valve on the gas tank. Iv'e come across this problem a few times and found out there was not enough fuel flow from the valve. To verify this you can replace the valve with a straight fitting and try it out

or a simpler solution is to just pull the fuel line off the carb, and open the valve letting fuel run out of the hose into a gas can. look at the stream of fuel and you'll know if it's flowing well or not.
This is easier than replacing the valve right from the beginning.
if the flow is very wek, let the tank drain empty (you'd have to drain it to replace the fuel valve anyway). pull the old valve out of the tank and look at the screen on the end. Take the screen off, and that may solve the fuel flow proble, (if there is one).

 

[Big Red]

Well guys, I've been out in the shop most of the day AGAIN. I've got it reving with no load but bogs out with load. Also, it acts like it's out of time or something couse it's spitting a gas fog out of the carb intake. How can this be? I thought these engines were factory set for timing. I've tried different muffler setups for some back pressure. I think I might still have a fuel flow problem plus a timing or carb problem. What the H E double hockey sticks? I've NEVER had this much trouble with a little china girl in my life. You guys have got me this far and I really apreciate it. Any more ideas out there?
Thanks,
Big Red.
Hey bro's. Right after I posted this I THINK I figured out my carb blow back problem. I think I'm using WAY TOO BIG of a hose for my intake. The engine was not made to take in that much volume. What don't get sucked in has to go somewhere, and thats back out of the carb right on my UPPER leg. A little too close to my n^%,s. Yeah, thats right, I smell like gas and my leg is burning. I'll check back when I get out of the shower.
Thanks guys,
Big Red.

 

[Big Red]

Just for the record, it was gearnut who mentioned the gas foaming, not me.

Yer right bro. I did level out the carb as you suggested. I think that was at least 50% of my problem.

 

[motorpsycho]

Well guys, I've been out in the shop most of the day AGAIN. I've got it reving with no load but bogs out with load. Also, it acts like it's out of time or something couse it's spitting a gas fog out of the carb intake. How can this be? I thought these engines were factory set for timing. I've tried different muffler setups for some back pressure. I think I might still have a fuel flow problem plus a timing or carb problem. What the H E double hockey sticks? I've NEVER had this much trouble with a little china girl in my life. You guys have got me this far and I really apreciate it. Any more ideas out there?
Thanks,
Big Red.
Hey bro's. Right after I posted this I THINK I figured out my carb blow back problem. I think I'm using WAY TOO BIG of a hose for my intake. The engine was not made to take in that much volume. What don't get sucked in has to go somewhere, and thats back out of the carb right on my UPPER leg. A little too close to my n^%,s. Yeah, thats right, I smell like gas and my leg is burning. I'll check back when I get out of the shower.
Thanks guys,
Big Red.

well, the timing on these engines is keyed, it's either right or 180 degrees out. there's no way to adjust the timing unless you cut a new notch in the magneto for the woodruff key.
gas spitting out of the carb is normal on these engines because there are no reed valves, just ports in the cylinder.
the size of the intake tube has nothing to do with how much fuel gets taken in by the engine. The amount of fuel that gets taken in by the engine is regulated by the main jet. The amount of air that gets taken in is regulated by the size of the carb throat.
so even if you had a 3" diamater intake tube the same amount of fuel and air would be sucked into the engine with the stock carb.
If you put a carb off of a 250 c.c. motorcycle on it, then you would get major blowback out the back of the carb because there would be too much fuel going into the engine for it to burn all at once. the engine probably wouldn;t even run with a carb that big, but i'm just using a 250 cc carb as an example.
the only thing intake diamater and length affects is the rpm range where the engine makes the most or least amount of power.

 

[Big Red]

Intake

So I'm guessing that the factory boys already have it all worked out. How long the intake is and the I.D. are at optimum for the best power at most RPM levels. Then what would one do, as far as intake goes, to get best power at higher RPMs?
This is my first offset carb build and It's not going as planned. I don't give up easy though so I'll be on it again tomorrow.
Thanks,
Big Red.

 

[cloud_2901]

I read somewhere the rule was shorter intake = more top end power, longer intake = more bottom end, think it was jaguar who said it somewhere in these forums. No idea how the diameter would affect ideal flow ratios, some here seem to think it wouldn't matter at all for the flow, but bigger/smaller, one of the two, don't know, could end up with less impedance? thereby not really increasing the flow, but making more of said flow enter the cylinder? Is that possible or am I talking out my arse here?

 

[Big Red]

Intake

Hey Cloud2901,
It seems to me that as long as you don't make the intake any larger than 66/80cc capacity then the cylinder should be able to take in the entire fuel discharge from the carb. I think also if the intake is the size of a house, (yeah, stupid I know) There's no way much of the fuel mix is gonna reach the cylinder.
Anyway, like I said before, The factory boys must have worked this out already so I'm gonna go with tubing as close to the stock size as possible.
So I'm off to the shop to try it again. Hope I have better luck today.
Thanks,
Big Red.

 

[Lazieboy]

Ammemendment rights

Hey Lazieboy. No air leak, no pinched line. I do have the tank setting above, but close to the carb. So perhaps there is not enough gravity involved to help keep the bowl filled. combined with the angle and the vibration I might get this figured out today.
I went to the links you included thinking it had something to do with my carb problem. Imagine my suprise when they turned out to be about getting stopped by the police, And pot. I've only been on this site a few months, but don't those belong in another forum. I have no problem with the cops and I don't smoke weed, (anymore). I think it should be legal but that is for another forum, don't ya think?
Thanks for the input anyway, ALL suggestions about how to get my engine running right are welcomed.
Big Red.
Oh yeah, I forgot to add, Brand new Muffler.

It's not about Illegal substances, but that WE have rights and even a square like you dont have to let your property be searched illegally. Cops are not always honest and will try to Intimidate people to get what they want to build a case. I dont hate em though. O ya bike running ok still in break in. 27 mph. so far.