Hey guys. I finally got a chance to ride the 686 in some tight woods out at our club grounds. I've got some jetting problems. When really lugging the machine in any gear the carb loads up and the motor starts missing. I would assume it would be the pilot jet because its at low throttle, but its almost like the floats? Here is what I am currently running. Thanks!

160/165 Mains Dynojet
22.5 Pilots, Air Screws 3.5/3.125 out

 

I had similar problems when I first changed my motor over, maybe just a coincidence but after all kinds of jetting changes to track it down it seemed to be a float level problem, currently running 148/150 mains (ride at 7000'+ altitude), 25 pilots and my air fuel at 2.5 out (lean it out for the altitude), I am using a k&n, and my airbox is 75% cut out

 

ZRwhat and Vraptor- where did you get your kits. Trinity shipped a 180 and a 187.5 with mine. I am having it installed tommorow. I had the larger intake valve done. That head work looked to good to cover up!

 

Thanks vraptor. It runs perfect wide open, but if I lug it in the woods or up inclines it seems to foul the plug. I will check the floats first. I am also running the K&N no lid, but bumped it up from 155/160 this last time I had it apart because in installed a Nology plug wire which they told me I could go up one jet size because of the added spark. It definitely runs good, can't wait to get some drag racing in.

 

14mins: I built mine with the help of "Raptor720"(Thanks!). I'm not sure why they would have you run the stock jets and not the Dynojet kit? Dynojet mains go in increments of 5 after 150(155,160,165, etc.) What did they tell you to run for the pilot? I have been told to stay with the stocker, but have the 25 and 27.5 waiting just in case. I know most on this forum run the 25's or the 27.5's with just a pipe and air filter. Who knows?

 

ZRwhat- i did not look close at the jets, they might be dyno's. They are big. Raptor720 had alot to do with mine also. Can't wait to get the dino on dirt. I will call trinity when the time comes to dial it in. I was impressed with the parts, service and the care they used in shipping the parts back! Where did you get the nology plug wire, and what plug are you running? Thanks

 

did mine myself with some help from the local yam dealer (bore and polish and port), based the parts on the trinity/ct racing engines

 

14mins: Well I know they aren't Dynojet jets, because they don't offer jets in that size. On the Nology, just jump on their website and give them a call. The sales guy that I talked to was pretty cool, he knew exactly what I was looking for. You just need a 4" 90deg boot. They say 300 times the spark of the stock plug wire, because of the capacitor that they use. This will allow you to bump up one jet size higher due to the added spark energy and the ability to burn that much more fuel.

 

WTF? more spark energy = more fuel burning capacity??

I don't claim to know it all, but that sounds like a load of horse poop if you ask me..

to make more spark = more fuel you'd have to have the other key ingredent.. AIR

remember.. lean is MEAN.. (IE more power), but it's also HOTTER and has the potential to do more damage than being rich..

More fuel does NOT equal more power.. end of story..
The perfect mix of air and fuel detenated at the perfect point makes the most power.. add fuel to that mixture without adding extra air and you do nothing but lose performace, I don't care how hot your spark is..

Just my $.02
Brad

 

Ok, so if you added more fuel you are rich. But if you add more fuel with a hotter spark and are able to burn the added fuel(hotter spark will more completely burn the fuel) you will make more power.

Here is Nology's explanation. Nology Performance