Dynojet YFZ 450 HELP!

[Z-135]

I have a CHM slip on pipe, pro design K&N air filter no lid. I have a dyno Jet kit. The kit said to run a 48 pilot jet 160 main jet needle on the 5th from top spot 1.5 turns on the air screw. It ran like crap! So I put a 150 main in and it was a lot better. But now if you hold it 1/4 throttle (when riding) it will cut out. Any help? Would that be the pilot jet? The dyno jet are a different size! Thanks!

[Quad18star]

Yeah I would think that the Pilot is too big . Also you're running a 150 with a slip on ?? Usually you go up on the main when you add stuff .... I took my baffle out and removed the airbox lid and I'm running a 168 or 170 main(can't remember) with a 45 pilot . Check your plug and see if it's lean at all ....

I'm sure someone with better knowledge than me can help you ... but I'd get rid of that 150 main thats for sure .

[Z-135]

It is a 150 dynojet they are sized different!

[seven]

My advice is get rid of the dynojunk kit and use regular khehin jets and a NCVQ needle

[daddio]

Originally posted by seven
My advice is get rid of the dynojunk kit and use regular khehin jets and a NCVQ needle

I agree......... I tried 3 times on 3 different peoples bikes and could not get them to work.

[seven]

What is your elevation??

[rc3]

just tried dyno jet, could not get it dialed in, but i never switched from a 160 main, i went to 4th clip on needle, and it ran a little better but not good enough yet, so I put GYTR Kit back in for now!

[SRH]

i made th e mistake of buying a dyno jet kit, it sucked no pilot jets came either this season i just went to dealer and bought 168-175 main jets and 45-48 pilot and the nvcq needle...better and cheaper

[440EXR]

I am at sea level with a Dr. D slip on KN proflow with no lid I was running a 170 Kiehen main with needle on 6 and I was still lean. I just had a dyno done and they ageed the main had to go to 180 for now 185 in summer the needle was only slightly lean so we left that and the stock pilot was fine the fuel mixtuer screw was also enriched . I have also tried the dyna jet stuff on my stolen 440 it was a lot of trouble so I went to the quicksilver carb If it backfires on deceleration its usually lean if it bogs on accelleration its to rich Try some plug runs after you rejet

[Z-135]

About 350' above sea level.

[Z-135]

For your info dynojet has a new kit for the yfz450 the # is Q421.002. You have to call them and they will send you the new parts (new needle, a pilot jet and some new main jets). I have the kit but I am still having some trouble!

[seven]

I would try a 45 pilot,175 main and a NCVQ needle in the fourth position with the fuel screw at 2 turns out to start off. This would be with all kheihin jets not Dyno stuff.

[SRH]

Originally posted by 440EXR
I am at sea level with a Dr. D slip on KN proflow with no lid I was running a 170 Kiehen main with needle on 6 and I was still lean. I just had a dyno done and they ageed the main had to go to 180 for now 185 in summer the needle was only slightly lean so we left that and the stock pilot was fine the fuel mixtuer screw was also enriched . I have also tried the dyna jet stuff on my stolen 440 it was a lot of trouble so I went to the quicksilver carb If it backfires on deceleration its usually lean if it bogs on accelleration its to rich Try some plug runs after you rejet

why would you jet up in the summer? thats bass ackwerds:eek2:

im running a dr d with fmf powerbomb sx header , cam mod, lid on uni filter...what do you guys recomend for jetting, i was thinking a 170 with 45 pilot nvcq needle on 4th clip

[Z-135]

Ok I got rid of the dyon junk! I put the stock needle back in on 6th clip, 48 pilot, 180 main. K&N prodesign filter with the lid off. The mid rang is still missing it cutting out only when you are ridding it. When you are sitting still it will pop and shot flames. Any HELP!

[SRH]

180 is really big

if its like 60 degrees and your around 1000-1500 above sea level id guesstimate you should be running a 172 or somewhere in th at neighbor hood, everyone over jets yfzs...

[daddio]

Just a thought........make sure you didn't over oil your k&n. I've seen many people have simular jetting problems, just because they oiled their K&N too much. Look at the inside of the intake boot, with the filter off, and see if it's wet with oil.