Dropping cyl at idle and 1/4

[SRX7]

check here
http://www.mikuni.com/fs-tuning_guide.html

 

[daman]

I know, I appreciate the help.

Just the whole point of the post was to find out if running outside the jetting specs is what's causing the two symptoms I described. The post is basically asking two questions.

1. Is it more likely I have a dirty carb, or am I just fouling cause the pilot is too rich?

2. Can a rich condition cause a backfire?

No offense intended daman.

none taken....

see that's what we need to find out,,,you need to test in the temperature
the sled is going to be ridden in,you can't tune in 32deg weather,we/you
don't know what you need till you test in the right temp!!!!

then you can properly watch color and wash

make any sense??

 

[YamerDown]

Exact same test as before. Sled on stand, 1/8th throttle for 5 min. Temps this time were 4*F. Still looks really rich eh?

 

[YamerDown]

Forgot 2 things. Yes I know you can't jet on a stand, but it was an idle test anyway so I'm not sure it makes a diff.

Also, after one good pull it did still hickup (not quite a backfire, but headed that way). Another couple of times after a long hard pull and a quick stop the idle would hang? Thought that happened when it was lean? Anyone??

 

[extreman1]

Now before I get 20 replies telling me to clean the carbs let me say that they were cleaned when we did the jetting for the pipes. Yes we took the jets out and sprayed carb cleaner through each, etc... Could there still be dirt in there? Yes of couse and I will probley clean them again anyway, but I've got a questions I want answered regardless.

-- rant over, down to business --

Like the title says. Only riding I've really had a chance to do so far has been on warm days. Sled is jetted for 0-20F and both times I've had the problems it's been approx 32F. I think it drops the PTO cyl which run the richest due to lower compression and the fact the pipes run close to the other two. Seems to be worst from idle to 1/4 throttle. If I put it to the bar it takes off on all three and climbs right to peak RPM. Anyway, I think the pilot is so rich it's fouling the plug? Once you crack it open it clean it's self off and starts firing again.

One more thing to add here. When it starts running bad (i.e. one cyl not firing), if you let it idle it will backfire lightly now and them (mostly after a long WOT pull). Is that just cause the plug finally decided to fire and there was a tone of fuel to burn?

Help....

Check your idle adjustment your torrs switch might activating, thats what mine was doing

 

[extreman1]

Forgot 2 things. Yes I know you can't jet on a stand, but it was an idle test anyway so I'm not sure it makes a diff.

Also, after one good pull it did still hickup (not quite a backfire, but headed that way). Another couple of times after a long hard pull and a quick stop the idle would hang? Thought that happened when it was lean? Anyone??

your right mine hangs about 4000 rpms might need to lift needles