Topic: Jetting issues

[davidstipek]

I had to move the Carb on my project (hitting Tank) I know about intake and exhaust Pusle waves on 2 cycle engines and I modified a total of 9 3/4 inches (includes velocity stack) stock jet was a #95.  I am going to have to order upgrades... so question is what does everyone think a good range to purchase would be (where to start)?  Since I am going o have to wait a week to get them. Needle is in 3rd position and air jet is 17.5

Engine is a 80cc Y80 Yamaha 2t, semi automatic.  gearing is stock 14/37  I am thinking about going to 14/27 as engine will be able to pull it. For road cruising.

Engine is .50 over, stroked, head has been shaved to increase compression, head studes are oversize, auto oiler works fine! using Shell 2T Oil. intake and exhaust have been ported and polished to the Max. Using crank driven fan from a Yamaha Mate 111 Super as a cooling device for head. Engine runs fairly cool on 93 Octane, have Aviation Fuel Available and with oversized tank (Honda Phontom) so hve plenty of time to refill. (Even have Octane Booster if warranted)
David

[lucky]

You threw in ALL kinds of data in that does not matter. Very confusing.

80cc Y80 Yamaha What year??
What kind of exhaust???
Intake 9-3/4 ,did you lengthen the intake track? Velocity stack.
#95 main jet.
Needle position middle.
Idle jet size?


What was the stock main jet, and stock idle jet?
Are the crankshaft seals fresh?
Is it a port timed engine or is the intake on the cylinder ?

[davidstipek]

1986 Yamaha Y80 Belle was stock bike before proceeding.
Exhaust is 2t for yamaha mate111, expansion chamber and can. Pipe size went from 7/8" to 1 1/4" size

yes lengthened intake track and added velocity stack with 1/4" foam (oil trap) filter

Yes stock jet was a #85 (main Jet), Also question about Needle jet, carb manual said it should not have any side holes in it for 2t application. When drilled it is a 4t part???

yes, clip position third from top

I believe idle jet is #15

I had increased main jet to #95

Sill have to manually choke carb to get to fire (Hand over venturi)

[davidstipek]

Oh I forgot,  2t engine, reed cage is on cylinder

Yes crankcase seals are fresh.

Sory for delay in answering you, had to go to Mae Sun as Goverment wanted to get our opinion as they were relocating river bank back to original location to save everyones land from washing away, after last years flooding.

I'm back now
David