[diesel4wd]

I have recently added a HMF Utility pipe to my 500 foreman. Installed 165 jet and around 2.5 turns out on the a/f, also a new plug which wasn't gapped correctly(my fault). Seemed to run flat on the top end couldn't tell much power difference than stock. This was my first time tinkering with a carb i didn't want my bike running lean. I took it to a local motorcycle shop to let them professionally jet my bike. Now i live at 2000 ft and temp has been around 30-40degrees. So i got my 4wheeler back today. they took the 165 jet and put the stock (162) jet back in. and also installed a new properly gapped plug. didn't touch the air fuel. The bike seems to pull much better than before threw the gears. But shouldn't my main jet be larger? like a 165 or 170? i don't have a snorkel just a uni filter and hmf. I pulled the plug today after riding the bike for 5-10 miles. Ran it wide open till the top of 4th and killed it. The porcelain on the plug was white. L shaped electrode had a gray tint to it. The bottom of the plug where the threads are was black. Now this shop i took my bike to they build racing dirt bikes and work on anything with a motor in it. I have trust in them. but running my stock jet doesn't seem correct. Does anybody have any advice or tips for me? anything would be greatly appreciated!
thanks!
-sam

 

[Robb]

thats interesting. Every bike is different, my buddies Rubicon with the same mods ran best with a stock jet too, as long as the plug looks good, and its not getting to hot and running smooth, then you should be good.

 

[eric]

according to your plug description your jetting is correct; if anything a hair rich...................leave it alone and start thrashing on it

 

[diesel4wd]

well it sounds like time to give her ****! i think my a/f might need a little adjustment. can i just let it idle, check my plug, and adjust my a/f it its rich or lean? also dumb question.....when installing spark plug how tight should it be?

 

[eric]

You'll feel the compression washer collapse and then give it a little more. I always put a little never-seize on threads before installation. Why do you think a/f screw is not right.

 

[diesel4wd]

well i had messed with the a/f when u gave me that technique to go by and i adjusted it so many times im not sure if its dialed in. also on the tailpipe of the hmf its black like its running rich possibly?

 

[eric]

well if it starts good and idles good and seems responsive than I would leave it