Up and running....help me read my plug please

[YFZRob]

Okay, I've been through 3 heat cycles now and decided to ride it and perform part throttle plug chops. First of all, the combo is the same (ESR 310 w/ TRX-7 porting, TRX5 pipe, Keihin A/S 38, CR reed cage and boot, Uni filter, stock airbox-no lid, stock ignition, stock gearing, BR9ES gapped at .018") except for DDJ needle over the DGH (on 4th clip), 18cc dome in ESR head over the 21cc pump gas dome, and 110 leaded Sunoco vs. 93 pump, and lastly a PWR radiator over the stocker.

Right off the bat I noticed the much improved bottom end power having the race gas dome. The bottom was very soggy before with the pump gas dome. I rode it around very lightly letting it warm up. I was expecting it to warm up past 175 or so where it used to run on the stock radiator. This PWR made a WORLD of difference. The highest it got was 160!! I'm VERY impressed with this upgrade!

Anyway, I stayed out of the main jet and just rode 1/4-3/4 throttle. The power delivery felt great, but I did notice a miss around 1/4-1/3rd throttle that cleaned up with more revs.....probably a rich condition from the DDJ needle.

So, I consistantly kept the throttle between 1/4 and 3/4, doing one final 3rd gear blast at 1/2 throttle before killing the motor and pulling the plug. Here are the results.

http://www.looseboltsmotorsports.com/images/atv/NGK0001.JPG
http://www.looseboltsmotorsports.com/images/atv/NGK0003.JPG
http://www.looseboltsmotorsports.com/images/atv/NGK0005.JPG
http://www.looseboltsmotorsports.com/images/atv/NGK0006.JPG

The bottom ring at the base of the porcelain looks fairly dark, almost black. Based on how it looks in these photos, would you say it's rich enough?!?!? I am NOT going to let this thing seize again. Also, regarding that, a noise that I always debated about that sounded a little like detonation is now gone. I am HOPING that it was detonation on the previous two top ends, and now the race gas has fixed my problems!

Thanks guys!

[SnowRacerX]

looks good to me, i wouldn't lean it out at all.

[JTRtrx250r]

I'd say it looks ok(hard for me to tell from pics, if in any doubt...run it fatter, better safe than sorry!)

Whats your compression (both cold and warm?)I always check both... then again after break-in

Hoping you all the luck w/ this 1 bro!!
;)

[powerslider]

From the plug pics it looks fat but I'd leave it that way till you get more time on it and it's broke in then drop the needle one position. If you have needle shims try one when you drop the needle and do another plug chop. Paper bag brown is what you want at the porcelain base.

You need to keep in mind the ambient temperatures as the jetting has to change with temperature changes.

Any thoughts of running an EGT? They are a good reference to monitor your settings and an early warning to prevent the problems you've had with burndowns.


This was/is the infamous quad that Scott had...right? I have an 88 from him also....

[YFZRob]

Thanks for the info guys. Powerslider, yes this is one of scott's Rs.....seems like he's had a lot of them!! Not sure how infamous it really is though. It didn't have the stock slug as Scott stated, plus needed a few things here and there. I spent about 3 weeks of cleaning and updating worn parts, and it's finally the way I want it. I've replaced the bent stock bars, worn grips, Z400 stock tires, cables, swing arm and rear linkage parts that were worn, bearing carrier, chain, sprockets, and touched up some rust spots on the frame. The one thing that keeps me so impressed is the originallity of the quad, plus the frame is completely crack free! The few things that Scott did (I'm assuming) that was nice are new OE decals and powder coated front and rear OE bumpers.

I'm going to keep putting some easy hours on it. It appears to be a given that the part throttle jetting is safe. I'll try and get a good solid hour or so of riding by the weekend, in the meantime keep doing some heat cycles as well as plug chops.

Compression tested again today when warm, again not with the right adapter (for equal depth, because it wont FIT), is 175 psi. I haven't done a cold test yet. I'm going to shop around for a compression tester that doesn't have such a long section on the long reach adapter so it will fit without removing the tank.

I've considered an EGT gauge, but have no clue on info about it. How do you power the gauge? Where can you mount it to monitor while riding? Installing the probe is the easy part, just the other stuff I am unsure on. I really don't want to get involved with touching the factory wiring. Other than the top end of this motor, tires, a-arms, and front shocks, I am trying to leave this quad all original. The one thing I DO NOT like about the parts I have added is the fitment of the ESR pipe. It fits like sh*t! Even with Ultra-Copper RTV at the connection point (which just oozes out with the flange from heat and the oil residue, even after properly drying), the pipe isn't completely leak free. On top of that, it hits the frame and front fender support bracket. No matter how much tweaking I do, one part gets worse. If the pipe is adjusted to clear the frame (up front just after the connection between the two pipes), the flange doesn't sit flush, and the leak gets worse. I want to ditch it for a Sparks MX, but they are 5 weeks out for a chome plated pipe. May just order it and wait.

Anyway, thanks again for the assistance.

[JTRtrx250r]

I have a couple Digitrons, both have EGT and RPM's, They are powered by a 9V battery, they just attach to the plug wire w/ a nice clip, and the probe lead goes to the exhaust header about 6 or so inches away from the flange. They sit on a couple diffrent kinds of brackets(guess it depends on which unit) but are all pretty easy to fit to the quad, most are easy to monitor while riding but get crushed if the quad flips(guess it just depends where its mounted also) Mine have saved me many times, but choose not to run them on my R

The more $$ invested in the motor... the more reason for 1 is how I see it. they are a nice investment but you gotta be sure the probe attachment is in the right place and that the mount(a nut) was welded up good w/o leaks, the other down fall is drilling into a new pipe(unless its a POS)

Could be something to consider