38 miles no fouled plug... but plug reads little lean...

I went for my ride today, we went 38 miles mainly slow speeds tight woods. some burst but not many..

My jetting was dvp4# 48 pilot 3/4 turns out, 178 main.. yz timing no baffle no air lid.. the bike seemed to run very well. Idle was a little rough but not bad good throtle response... maybe turn screw out to 1 or

1 1/4 this might richen jetting a little..

the plug is more towards white than tan...

what do you think...

fred thet is unbelievable. you've just gotta be having us on. i would have bet you chewed up 6 plugs in them there 38 miles.

tell me, how quick can you change a plug coz it takes me 14 minutes & 6 seconds. that's my record. i always cross thread the bolt that goes into the radiator. the left hand radiator is the worst because i'm right handed.



This is great news! Glad to hear it. A good fall back point if things go wrong again. :)

Why would the idle be rough? Try 1 turn out on the pilot screw and reevaluate. Don't go to 1 1/4 yet.

Do you think the accelerator pump is set in a good position? You had adjusted it and I never heard if you were able to measure the delay/gap as being .6mm. As long as it doesn't hesitate it's probably OK.


well Taffy

before on this same trail it was taking two plugs to get around it...

and for the plug changing, I can do that in 5 min, 13 seconds my best time..

and if I'm pissed I can down 2 beers in this 5 min, 13 seconds...



I glad to hear you got to ride your bike without having to change a plug--this is vary good news. You now have a baseline setup from which to work but only work on one thing at a time.

First try the fuel screw out at 1/4 turn increments and see if it is any better. I would not go out more than 1 3/4 turns with the 48PJ.

If not go back to 3/4 on the fuel screw and then go to #5 on the DVP needle (this is what I use when I run the DVP). Give this a try and if you feel it still is a little lean then go with the 1/4 turn more on the fuel screw as before.

One thing at a time and remember you baseline.

Good luck


thanks guys

the bike is running very well...

third gear crack the throttle a little front wheel right in the air..

no delay on the bottom...

I was hoping the plug reading would of been better, but at least now I'm getting somewhere..

YZ timing rippppppsssssss

Gotta love that..

The leaves are all on the ground here in western Pa and I think the 739 is not the tire of choice for these conditions....


I'm moving up your way soon, near York. I've already checked out Tower City and we are going to join. My 14 yr old rides as well. I also liked the fact that you get MX and trails in one deal.

The 739 is not the best or the worst. But if you have the stock seat and tank. The biggest change you can make is putting on a YZ style seat and tank. This will allow you to move further forward on the bike and weight the front wheel. I wished I would have done this first before any other mods.

There has been a lot of debate on what to change first and the top two are seat and tank, also installing a dampner.

Check it out!



86TT225, 98CR80, 99WR, WR timing, throttle stop trimmed, air box lid removed, White Bros head pipe, silencer and air filter. Odometer and headlight removed. Moose hand and mud guards. YZ stock tank and IMS seat. Renthal Jimmy Button "highs" and Renthal Soft half waffle grips. AMA, SETRA.

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