gobigorgohome

Looking for any help on this.

I have a sv 50cc twin that I am currently breaking in. It has approx 1 gallon of fuel through it now. One side seems to be spurting out blackish oil. I know that i am running rich right now and will not be switching to synthetic or a higher mixture ( currently 32:1 ) until i get another gallon through it at least. But my question is why one side is doing this so much more than the other.

I am not new to gas engines but am new to the twins. Is this normal until i lean it up a bit?

Any insght is appreciated on this.

Edwin

My Feedback: (2)

I'd try new plugs first. Then verify that side is truely firing. If not, swap sides with the ignition module. If it is, it could be the other sides ring set faster, wild speculation on my part. I'm not ready to point to a ring failure yet.
Edwin

Tired Old Man

My Feedback: (1)

I'll hold debate on the part about not being new to gas since you are running rich. We'll revise the word "new" to not overly experienced. It explains why the engine is running rich and wet.

Tune it for the best performance, use the oil you intend to fly with at 32-1 for the break in which will last about 15 hours of run time, and go fly. Synthetic or mineral matters not. The engine will continue to emit black residue until it completes the break in process.

The design of the crankshaft counter balances and case in an opposed twin assures that if only using one centrally located carb the engine will run richer on one side than the other. The best you will be able to hope for is to strike a balance.

Edwin

My Feedback: (2)

I step aside and bow to greater experience. Listen to T.O.M., his experience is pretty much without question.
Edwin

ggraham500

My Feedback: (4)

Interesting. So is it better to have a carb on each cylinder? Or sharing one carb input?

Excellent discussion. Thanks.

Edwin

My Feedback: (2)

I have a GT80 that I havent run yet. It has an intake manifold. I mistakenly assumed that was the standard carb setup. I bought that engine 2 years ago, too good a deal to pass up. Figured I could use it in the future.
Edwin

Tired Old Man

My Feedback: (1)

MVVS and the Zenoah GT 80 do things are lot more efficiently in thier use of an intake manifold. The MVVS version is better than the GT 80 but both offer far superior combustion performance to a single case mounted carb. The other option would be to use cylinders with an intake port and run one carb per cylinder. Those designs used to be pretty common but were discarded in favor of the central case method. Some performance WAS sacrificed but only a rare few know that. The rest, having never run one, have never missed the difference.

Just tune what you have for the best performance, assure the lean cylinder (relatively speaking) is not running too hot, and enjoy. If you keep the hottest cylinder below 150C-155C during the hottest part of a run you'll be good to go. Tuning will not be the "be all and end all" of running temps. Baffling may also be necessary for proper cooling. A 20c spread between cylinders is not uncommon.

gobigorgohome

Sorry it took so long to get back. Thanks everyone for your help, i have a gallon of fuel run through it now and have picked up some prm. It seems to be breaking in very nicely. I have had no dead sticks and no problems with power.