Different Lean Condition

[BlgsRX-1mtn]

Instead of being lean on top like JonnyRocket, I have a lean condition on idle (16-20:1 A/F ratio). I'm running a Stage 1 SC in low boost pulley configuration with 127.5 mains, 25 pilots with screw 2 1/2 turns out. I'm running just above 13 in the mid range and low 12's at WFO.

While idling it seems the sled isn't getting firing on the right cylinder (chain case side). We pulled the coil wires and there was no noticable difference in idle like there was when doing the same on the other three. Switched coils from other cylinder and still the same. Plug was dry when we pulled it so we figure no fuel to the cylinder to make fire. Also figure this is contributing to the lean idle condition.

I pulled the rack and checked all four pilots and pilot screws and found nothing. Re-checked the float levels (14.5 mm on all). how do I check the pilot circuit between the screw and pilot jet for a blockage? Also if there is a blockage; how the heck to I get in there to get rid of it?

Thanks, Jim

 

[ptt]

what air/fuel gauge are you running?
Is it a wideband or narrowband?

 

[BlgsRX-1mtn]

I'm running a WMS wideband A/F gauge with a Bosch O2 sensor placed in the front side of the exhaust can. I just called MPI and Mac said he doesn't believe the reading due to the open can (Whiteknuckle QC-1) and recomends I place it closer to the engine. I guess I'll try placing it closer to the exhaust manifold and see what happens.

I wonder how the rear mount turbos get accurate readings. The instructions for the install on the O2 sensor said for after the turbo on a turbo'd engine so I figured at the rear would be the easiest for my SC .

Jim

 

[ptt]

I think the sensor is in the right place.
Can you adjust the response time. the sensor reads a/f?
Also, can you specify output voltage during warmup?
PM allen ulmer as I think we ran one of those gauges last yr on a SC

 

[BlgsRX-1mtn]

I think the sensor is in the right place.
Can you adjust the response time. the sensor reads a/f?
Also, can you specify output voltage during warmup?
PM allen ulmer as I think we ran one of those gauges last yr on a SC

I don't know if I can adjust the response time. I am assuming it is A/F readings. I don't have any idea what the voltage output of the sensor is.


This pic was b4 going to 127.5 mains (135 mains stock pilot settings for a mountain sled) and adjusting my screws to 2 1/2 turns out. Now I just shut the sled down if I'm sitting rather than let it idle until I get this figured out.

Jim

 

[bjniceguy]

I have same gauge. Allen was using it last year. I do not think there are any basic adjustments. I think auto calibrating. My sensor is in the pipe just in front of the stock exhaust. So far it has been consistant, but only have a few miles & a lot of idling. Besure you are using only unleaded fuel as lead will take out sensor almost imediately. If you need info on gauge you would be better off call or e-mailing the guys at WMS. I know the gauge will data log if you could figure out how to tie your lap top to the sled. The info is gone the second you turn it off. Not real handy in a snow bank. WMS is supposed to be coming with a data store device, but they said that back in June & still not ready. It was built for cars & has 5 or 6 wires we do not use. The gauge is very hard to see in daylight also.
Doug

 

[Thomas800]

On the topic of the right cylinder not making any difference when the plug wire is pulled, have you checked your carb sync yet. Just a thought
Good Luck Tom

 

[BlgsRX-1mtn]

On the topic of the right cylinder not making any difference when the plug wire is pulled, have you checked your carb sync yet. Just a thought
Good Luck Tom

Tom, you were right. I re-checked the carbs yesterday and the #4 carb (right side) was way off. I then remembered how it may have gotten that way. I used a screw driver to pry up on the throttle linkage so I could remove the cable and used that carb adjustment as the spot I pryed up at.

Anyhow; I saynched the carbs and now have the sled idling good and the cylinder is definately getting fuel now. My idle A/F ratio is still slightly lean but it is in the range (low to mid 13s).

Thanks, Jim