20mm Walbro on a China Girl
- Thread starter FFV8
- Start date
The intake mounts at the same angle as the cylinder port - you can look straight through the carb in to the cylinder
Add the crankcase pulse line
I laser cut the carb flange to include the bracket for the cable,and cold formed it to locate the cable & return spring
Even the stock intake nuts still fit.
Add the crankcase pulse line
I laser cut the carb flange to include the bracket for the cable,and cold formed it to locate the cable & return spring
Even the stock intake nuts still fit.
skitchfish
Member
FF, That is nice work and excellent pics! I hope you do a follow up on your linkage and throttle. I feel that this is the downfall of the Walbro carb, unless your racing, the feel of a less than 1/4 turn throttle doesn't get it with me.
The tuning aspect is unbelievable from bottom to top and in my own opinion is the best that can be had with such ease. I even used a old piece of excercise equipment to run my back tire under load in the garage. No four stroking anywhere, no screwing around!
I will be very interested to see what you come up with for your throttle as i can not seem to eliminate it's total crap feel. Thanks, Skitch
The tuning aspect is unbelievable from bottom to top and in my own opinion is the best that can be had with such ease. I even used a old piece of excercise equipment to run my back tire under load in the garage. No four stroking anywhere, no screwing around!
I will be very interested to see what you come up with for your throttle as i can not seem to eliminate it's total crap feel. Thanks, Skitch
The biggest problem with the throttle cable is a lack of a proper return spring.
Trying to use the OEM spring on the butterfly will only lead to frustration. Without enough spring pressure the cable drags in the housing & feels mushy.
I use a return spring with an adjustable preload, and fabricate the cable attach parts for the butterfly arm - smooth, consistent throttle operation is the result.
.
Trying to use the OEM spring on the butterfly will only lead to frustration. Without enough spring pressure the cable drags in the housing & feels mushy.
I use a return spring with an adjustable preload, and fabricate the cable attach parts for the butterfly arm - smooth, consistent throttle operation is the result.
.
graydog8josh
Member
where is the rest of your cylinder?
It's laying right here. I just took it apart to port it, makes it easier to reach the transfers.
SpecializedMountainMoto
Member
your kidding right
This has to be the best idea i seen in a long time, with all the carb trouble people are having. Jet changing, moving C clips, trying two or three different carbs ( none fast then the other ). Don't have a china engine myself,but have others. And have used chain saws for years and never had trouble tuning like the guys do with china tuning, and they can be run on 4 stroke as well. Just turn the high and low jets a little for fine tuning. The big thing about 2 stroke is measuring the gas right and the same every time you fill ...........Curt
sbest
Member
Cutting an old cylinder in half is an excellent learning tool.
This was a Yamaha Blaster cylinder cut apart as a learning tool:
From what I learned from it I stuffed it with several tubes of JBWeld epoxy in this manner (photoshopped):
Which in real life looked like this comparison:
The result was easier carb jet tuning because of fuel staying in suspension, wider powerband and of course, more power.
All gleaned from studying a sectioned cylinder.
Steve
This was a Yamaha Blaster cylinder cut apart as a learning tool:
From what I learned from it I stuffed it with several tubes of JBWeld epoxy in this manner (photoshopped):
Which in real life looked like this comparison:
The result was easier carb jet tuning because of fuel staying in suspension, wider powerband and of course, more power.
All gleaned from studying a sectioned cylinder.
Steve
cannonball2
Well-Known Member
You can also use the carbs with the internal pulse passage just by Dremeling a small channel/port into the manifolds carb mounting flange to allow the pulse in the intake to reach the port on the carb.
Porting the pulse circuit in to the intake is not the best plan.
The fuel pump was designed to work with the crankcase pressure pulse as well as the intake vacuum. That drives the diaphragm both directions.
With vacuum only, you get a half stroke of the fuel pump. This can make the high speed tuning very sensitive as the fuel pressure drops at WOT.
I have carbs and manifolds on the shelf. Just finished making a new batch of throttle arms too.
The fuel pump was designed to work with the crankcase pressure pulse as well as the intake vacuum. That drives the diaphragm both directions.
With vacuum only, you get a half stroke of the fuel pump. This can make the high speed tuning very sensitive as the fuel pressure drops at WOT.
I have carbs and manifolds on the shelf. Just finished making a new batch of throttle arms too.
mike carter 2
Member
cool kit . are you still makeing them?