07-06-2002, 04:04 PM
I had posted asking for help before, thanks to those that replied.
link to my original post here, http://209.120.142.52/showthread.php?s=&threadid=20153
I am wondering if anyone out there has ever needed more than a 170 main?? right now I have a 38pj, 170mj, needle on 4th notch down.
Below is a recap of the results I have had so far.
The carb is stock. I have an alum airbox w/ no lid, UNI high flow multistage foam filter, and ground out the welds on the headpipe and gutted the spark arrestor. I have 87 octane gas, should I use 93? The weather is like 95 outside with 40% humidity.
First I raised the needle one notch and I can tell a big difference, it starts and idles easy when cold with no choke. Even on a hot summer day if the engine was cold id have to choke it a bit to get it running smooth.
So I figured if it started easy I’d remove the choke assy. and put in the 160, I ran 2 passes WOT, killed it and rolled to a stop. I pulled the plug and the porcelain is white which is too lean right?
I had forgot that I had 1 step hotter plug in so I put the stock plug in (DPR8Z) and changed from a 160 to a 165 and it is still white after a WOT run.
170 and plugs still white but mid throttle and idle the plug shows tan-chocolate brown. I went and rode it hard for a few minutes and the only thing is after I ran it WOT thru the gears up to 4th and let off the gas it popped thru the exhaust a little. The quad doesn’t seem to have any bogs or flat spots at all, if it wasn’t for the plug being white it’d be hard to tell anything is wrong.......except that one pop out the exhaust when I let off. I did a search for backfire and saw people describe the same thing and everyone responded that it was lean.....
I have ridden it and it certainly runs better. My cousin has a Raptor with Trailtech speedo and I seem to be running aprox 70 MPH, I have no idea how fast I was before the jetting…. also he doesn’t walk off and leave me in a race anymore.
link to my original post here, http://209.120.142.52/showthread.php?s=&threadid=20153
I am wondering if anyone out there has ever needed more than a 170 main?? right now I have a 38pj, 170mj, needle on 4th notch down.
Below is a recap of the results I have had so far.
The carb is stock. I have an alum airbox w/ no lid, UNI high flow multistage foam filter, and ground out the welds on the headpipe and gutted the spark arrestor. I have 87 octane gas, should I use 93? The weather is like 95 outside with 40% humidity.
First I raised the needle one notch and I can tell a big difference, it starts and idles easy when cold with no choke. Even on a hot summer day if the engine was cold id have to choke it a bit to get it running smooth.
So I figured if it started easy I’d remove the choke assy. and put in the 160, I ran 2 passes WOT, killed it and rolled to a stop. I pulled the plug and the porcelain is white which is too lean right?
I had forgot that I had 1 step hotter plug in so I put the stock plug in (DPR8Z) and changed from a 160 to a 165 and it is still white after a WOT run.
170 and plugs still white but mid throttle and idle the plug shows tan-chocolate brown. I went and rode it hard for a few minutes and the only thing is after I ran it WOT thru the gears up to 4th and let off the gas it popped thru the exhaust a little. The quad doesn’t seem to have any bogs or flat spots at all, if it wasn’t for the plug being white it’d be hard to tell anything is wrong.......except that one pop out the exhaust when I let off. I did a search for backfire and saw people describe the same thing and everyone responded that it was lean.....
I have ridden it and it certainly runs better. My cousin has a Raptor with Trailtech speedo and I seem to be running aprox 70 MPH, I have no idea how fast I was before the jetting…. also he doesn’t walk off and leave me in a race anymore.