Dyno'd today with the DJ #136 main jet

Bike setup:
MCM
Stock header + DG-R
DJ stage 2 but with a DJ#136 main jet.
Lid Off

Dyno Run specifics :
SAE corrected HP & TRQ
3 Roll-On runs in 4TH Gear.
I could not get him to start the runs below 4k or extend them out past 9k - I know from previous runs the TRQ comes on strong starting about 3.5k and reaches nearly peak by about 4k.. I think the HP holds very well all the way to ignition cutoff.

Obviously not the results I expected or hope'd for. When I asked how the hell the AFR was still too lean, my dyno tuner started a lecture about metering circuits and RPM's they control... I stopped him and asked how the hell idle/pilot circuits and the needle play much of any role in a snap to WOT... He looked at me and said - It's a CVK, there is no snapping to WOT.. All the circuitry comes in to play all the time... Don't you hate finding out your an idiot on something you don't think your an idiot at/on....

None the less, the top end ( when the #136 comes in to play ) did go pretty nicely toward a good AFR for power. This benefited the top end power and TRQ - but chart only shows very small increases before he chopped the throttle. Somehow, the #136, or something else, got rid of the "lean outs" on the way to max RPM's - So the HP and TRQ curves are smoother than they ever have been. Compared to previous runs - both curves are enhanced by being extended before dimishing - He was impressed with that super broad TRQ curve and corresponding HP curve.. They are very impressive in how long they hold 90% of max..

The decel popping I'm getting will require me to richen the Pilot circuitry - hopefully just with the fuel screw - as well as double check my header to exhaust port seal..

BTW, uncorrected max HP was 19.79.

Edit: After more research, I have learned why/how the #136 stopped the "lean outs" of the AFR - We all need to memorize this article CV Carb Tuning Procedures

 

How about the butt dyno? How'd it feel?

 

Butt dyno says there is big power available everywhere in the RPM band - you gas it and the power builds until you get a speeding ticket..

 

And that's with the larger main and leaner clip position? I've been a die hard two stroke fan for many years and am pretty good at jetting them, and am known to stop on the side of the trail to change jetting just to experiment, but to be honest, having a rough time correctly diagnosing between rich and lean on the thumpers.

 

First of all, thanks for doing these tests! It's rare to find good dyno testing info.

Also, since you are in same region as me and have done a lot of experimentation... what jetting would you recommend for aftermarket pipe? I can do any lid on/off/KDX snorkel config. I'm doing like 90% offroad.

Are you saying you like this #136 on the main the best so far? What's the rest of the jetting config like?

Thanks!

 

Yep, Waco is bout an hour away from my ranch.. Let's see if this helps ya - The DJ kit at standard stage 2 but using the 132 main jet instead of the 128 with the lid off works very well. It is quick and easy - just follow the directions - and your bike will run great. Going to 4th notch down on the needle seems to increase the mid to upper range power some. Note: DJ says their needles do not affect AFR below 3k RPM regardless of clip position.

A 136 main jet is only $2.00 and seems to broaden the curves by enriching only the upper RPM range at WOT. This could be ideal for economy and power..?

DJ wants you to install stage 2 as per instructions with lid on and snorkel removed. They are adamant that lid on is necessary. But they used a stock bike with stock exhaust to develop the kit.

The other option is to go with Keihin jets and the N1C needle - for this option you'll have to research this forum for the best setup at our elevations. There is a wealth of data in here for this option.

Yes I like the 136 very much. The rest of the carb is set up standard stage 2 as per instructions. No other carb mods at all.

 

Awesome!

The previous owner of my bike did some sort of jetting changes to it but I haven't opened up the carb yet to know what.

I wonder if I'll be able to tell what needles are in there by comparing them to the ones in my DJ kit I just got in the mail.

I took the bike for first ride with new 300 header/exhaust (w/ no "buttplug") today, and KDX snorkel attached. Previously, I was running stock exhaust with lid on (but no snorkel) and that seemed to be a decent combo but I figured it might be too lean to leave it like that with uncorked 300 exhaust.

It ran really well and seemed responsive! Front wheel actually tried to (barely) lift off the ground a bit in 1st gear. I still plan on taking out carb and cleaning it and checking and/or changing needles soon-ish, though.

Thanks for the good info!