Some ZS167FML questions for racing sidecar

Jibberwobble · 09-19-2013, 11:06 PM

Well after a nice long w/e in Wales we had two days of sun and one day of wind and rain on race day.

The long manifold was causing problems in that it was creating this back flow thing and belching out a huge cloud of vapour that was soaking my arm and cleaning/dissolving Chads visor when he was out for the right handers! first thing was to rule out jetting and the new lower altitude in relation to the tank so we ran it with the fuel turned off and let it empty the float bowl. Even when it was starting to pick up revs at tick over due to getting lean on an empty bowl it still pumped out the plume when the throttle was twisted.

I used the top half of the manifold which is similar in shape to the old blue silicone tube elbow that was on there before and remounted the carb in it's previous position. The belching cloud was gone and we no longer had a racing tricycle steam train. So I can only imagine that the large volume manifold was storing some higher pressure mixture which then backflowed after the intake valve shut and then back flowed out of the carb picking up a second dose of fuel as it passed the tube. Some research needed me thinks.

It was running nice after remounting the carb and quali was looming so we left it be after that. Qualified 3rd which is our best yet and knocked 0.6 sec off our previous best lap time at this circuit with a 58.6 second lap on a 3/4ish mile track.

First start went well... up to second then nearing the end of the race laying in 3rd we broke the chair wheel axle and spun off. Second start went well with a similar result but we were on the wrong tyres and dropped back to 4th at the finish. Last race, did not start, we suffered a split chair wheel tyre and only noticed it on the way to the holding area :(

The zonger is pulling well against the other more modern engines, think it's still the slowest out there but not by much. Our outfit is the heaviest at 110kgs too but we arent exactly total fatties so we end up in the middle somewhere when you look at combined weight.

Going to give her a little run at an indoor track this w/e and may try that other carb. We will then look at what the next step is with the motor for some winter modifications.

09-19-2013, 11:06 PM	#28
Jibberwobble Join Date: Mar 2012 Location: south west (uk) Posts: 106	Well after a nice long w/e in Wales we had two days of sun and one day of wind and rain on race day. The long manifold was causing problems in that it was creating this back flow thing and belching out a huge cloud of vapour that was soaking my arm and cleaning/dissolving Chads visor when he was out for the right handers! first thing was to rule out jetting and the new lower altitude in relation to the tank so we ran it with the fuel turned off and let it empty the float bowl. Even when it was starting to pick up revs at tick over due to getting lean on an empty bowl it still pumped out the plume when the throttle was twisted. I used the top half of the manifold which is similar in shape to the old blue silicone tube elbow that was on there before and remounted the carb in it's previous position. The belching cloud was gone and we no longer had a racing tricycle steam train. So I can only imagine that the large volume manifold was storing some higher pressure mixture which then backflowed after the intake valve shut and then back flowed out of the carb picking up a second dose of fuel as it passed the tube. Some research needed me thinks. It was running nice after remounting the carb and quali was looming so we left it be after that. Qualified 3rd which is our best yet and knocked 0.6 sec off our previous best lap time at this circuit with a 58.6 second lap on a 3/4ish mile track. First start went well... up to second then nearing the end of the race laying in 3rd we broke the chair wheel axle and spun off. Second start went well with a similar result but we were on the wrong tyres and dropped back to 4th at the finish. Last race, did not start, we suffered a split chair wheel tyre and only noticed it on the way to the holding area :( The zonger is pulling well against the other more modern engines, think it's still the slowest out there but not by much. Our outfit is the heaviest at 110kgs too but we arent exactly total fatties so we end up in the middle somewhere when you look at combined weight. Going to give her a little run at an indoor track this w/e and may try that other carb. We will then look at what the next step is with the motor for some winter modifications. __________________ Last edited by Jibberwobble; 09-22-2013 at 09:04 PM.
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