i THOUGHT my engine for sure had to be on the lean side.... mainly because of the few backfires through the carb, and for how hot it was getting.... (my fan even kicked on a few times in like 20 degree riding...)

i pulled my plugs to find they are quite black.....

i hate to lean it out more, if its already getting hot. Do black plugs ALWAYS mean rich? i figured they did, but is there anything else that could cause that besides too much fuel?

i was thinking id go one step leaner on the needle, and possibly switching down main jets... (running 175 right now)

The only thing that would make me think it is running rich, is that on the startup there is considerable BLACK smoke (def not anywhere near a blue-ish tint...so im assuming im not burning any oil at all) that, along with a nice build up of soot on my White brothers discs....

is it possible im rich on say, the bottom end? then ok on the top? (whatever i end up doing ill do one step at a time...[im not gonna change main/pilot and needle all at once...] )

let me know what you guys think is going on...

Thanks

 

Warm the motor up then put in a fresh set of plugs, run it wide open on the top end for at least 5 seconds in high gear, click the ignition, pull in the clutch and leave the throttle pinned. Pull the outside plug, if its chalky white then your lean on top.



Horsepower Research

 

At idle if the idle is rich, in less than a minute it will blacken the plug.

 

ok, im assuming im rich on idle, and lean in the upper 3/4....


so once its nice and warm, pop in both new plugs, then take it out WOT in 5th, Keep throttle pinned, Hit kill switch, and pull clutch in....


hopefully im able to do this.... its a little wet outside from the rain we have been getting.....

the field i ahve to work with is only about 1/4 mile long.... so ill have to get it up in 4th/5th along the side, then make a big turn and then hammer it.... (because on one end, is a large pond, on the other is a big road, and then a river...so i would rather not slide into either.... [img]i/expressions/face-icon-small-smile.gif[/img] )

ill let you guys know what happens!

Thanks for the help so far [img]i/expressions/face-icon-small-smile.gif[/img]

 

Check my page for a general pictures of the tuning guide. (Give the mods time to approve.)

What kind of riding were you doing when the fan went on? Take a look at the charts and depending on where you are in your throttle position should tell you which circuit to adjust.

Try leaning out your pilot or air/fuel screw a bunch. You aren't going to hurt anything if you are a little lean on the bottom 1/4 of your throttle. Are you on the middle needle clip? I think a 165 sounds a little closer with that pipe. But, someone else with the pipe should be able to fiill in.

 

Why do a plug chop in 5th gear, and not 1st? The carburetor can't tell what gear you are in, so 7000 RPMs should be about the same in 1st, or 5th right? I've heard people talk about doing it one way or the other, but I've never seen anything compelling either way.

 

Probably because in 1st you don't have enough time to get good color on the plug. I assume the longer you run it at WOT the more accurate the color will be. IMO

 

The load on the engine in 5th gear wide open is more than 1st gear wide open, so yes there is a difference. It may not be noticible but there is a difference. I do the same thing Mr Hp describes with my race car all the time to balance out each cylinder and to get the right jets for the rpms and engine load that I race at. I dont know if the outside air temp makes a whole lot of difference on quads, but its the difference between night and day with race cars, so might take that in to consideration also.