Apollo DB-36 with Nibbi PE30 installed...jetting issues....

[Madeaupollo]

I have the OHC motor on my DB-36 deluxe and finally got the Nibbi PE30 installed. Used a piece of silicone rubber turbo tubing 2" to 1.75", cut a stainless exhaust connector down, and attached a K&N to it. I removed the air box and routed the filter behind the shock. Had to cut the idle screw and spring down and re-grind the head on it because it was hitting the frame. It still is, but it doesn't get in the way so much that it causes the carb to be pushed aside, as it was.


I read some posts from various users here who have installed the PE30 on their hawks and installed a 125 main in it to begin with, assuming I'd step down. A 125 main jet with my setup is dangerously lean wide open.....if this was a two stroke, I would have rode wheelies up and down the road before it died and then found a gaping hole the in the piston(been there, done that).

...So, I moved up, and up and up and up...and it got better and better and better....now I'm at a 140 main(biggest i have), 38 pilot, and it will go WOT now without cutting out, but it doesn't pull hard at WOT...it flats out and then surges when I release the throttle slightly. I assume it is rich as can be through the range but still too lean wide open. I've done plug chops and it's mainly white/clean if I can do a WOT run but I don't have the best spot for doing it. When I check it after a 20 minute ride, it is white on top and black as night around the outside, but it runs well. (I think these iridium plugs would burn just about anything). It NEVER pops on deceleration now. I have checked for air leaks at idle, in which I have found none. Not sure how to do it at speed or under load. The only other thing I can think that may cause me to be using such a large jet is the tube/K&N filter(doesn't make a lot of sense to me). I assume a foam filter probably flows as well, if not better. I can't imagine a filter/tube and/or OHC is making that much of a difference, but maybe it is. I assumed I could use the hawk info as a base, but maybe it isn't the best idea. Also, if my fuel filter or petcock wasn't allowing enough fuel to enter the bowl, I think it would act completely different than it does. I did adjust the floats slightly to allow the bowl to fill up more because it was running out of fuel to begin with. Also, battery terminal was corroded. I cleaned that off and greased it.



I use 93 octane and NGK Iridium plug 2022. Needle clip is 3rd slot(intend to move once I get WOT jetting done). The Cadillac converter , stock air box, and spark arrestor have been removed and battery moved to opposite side of bike. Let me know if I missed anything relevant. I'll add links for the other items I'm using below.


K&N Filter - https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Intake Manifold - https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Filter Tube - https://www.ebay.com/itm/1-75-to-2-45-Degree-Silicone-Reducer-Elbow-Bend-Turbo-Intercooler-Black-51mm-6/182049295447?ssPageName=STRK%3AMEBIDX%3AIT&_trksid =p2057872.m2749.l2649
15t Sprocket - https://www.ebay.com/itm/520-530-20MM-12T-13T-14T-15T-FRONT-ENGINE-SPROCKET-ATV-HONDA-YAMAHA-DIRT-BIKE/163449456913?ssPageName=STRK%3AMEBIDX%3AIT&var=462 790939741&_trksid=p2057872.m2749.l2649

All that said, should I just keep moving up in jet sizes and then move the needle down to to lean the mixture mid range or should I stop and figure out exactly where the extra air is coming from?? I'll try to post some pics if I get a chance.