Keihn jets vs. Dyno jets... ?

[660r2a400ex]

i have an hmf full system, hmf claims to run a 180 main from keihn but i bought a dyno kit and i was wondering what would be equavalent to the keihns 180, so what jet would i run from dyno, lower, the same (180) or higher ?

[cals400ex]

some people agree and others disagree. i am a firm believer that their jetting specs are wrong. if you put in a 180, your upper gear performance will probably be less than stock if the only mod is a pipe/filter, etc. with just a pipe i usually run around a 152 to 155 keihin jet. in the kits, i believe the biggest jet is a 170. many people run this. i was told that the dynojets run alittle bigger than the keihin jets. so, a 155 keihin is a tad smaller than a 155 dynojet. i have talked to people who tuned their bike quite extensively and he felt a dynojet 150 was about the perfect jet for a piped 400ex. however, this doesn't come in the kit. if it was me, i would be trying the 155 and the next couple sizes smaller. just be careful to not go too lean. i probably wouldn't go lower than a dynojet 148 for sure with an aftermarket pipe. good luck

[redroost85]

660, take it from cal. he hooked me up in this area. I have fully jetted my 400 all with keihin jets and it runs 100 times better now.:)

[ewalker302]

Just for comparison a (DJ) 142 is the same size as a stock Keihin 148. I run a (DJ) 146 main which is one size larger than a Keihin 148.

But yeah, never trust the jetting reccomendations that come with the kit, they are almost always too rich.

Hope this helps.

:bandit:

[660r2a400ex]

alright, i put a 165 in it allready and i have tested it yet, dont have time till probally saterday. I live in virginia and this bike will be getting ran in 85-90 degree weather? do u think a 165 is too big or should i go with a 160 ?

[ewalker302]

Way big imo.

:bandit:

[cals400ex]

when using dynojets, ewalker is the man to talk to. i must have been misinformed about dynojets. i was told the 146dj was the same as the 148 keihin. didn't you find the 150 dj to work best for you ewalker??

[cals400ex]

Originally posted by ewalker302
Just for comparison a (DJ) 142 is the same size as a stock Keihin 148. I run a (DJ) 146 main which is one size larger than a Keihin 148.

But yeah, never trust the jetting reccomendations that come with the kit, they are almost always too rich.

Hope this helps.

:bandit:


i agree with this. the kits recommendations are almost always too rich in my opinion. i hear some people running the 170 DJ with just a pipe. they just tell me the bike runs great. they haven't felt great because they didn't try a smaller jet yet. however, air temp, mods, and elevation do play a big factor.


660r, i would definately go smaller than a 165 DJ.

[ewalker302]

Originally posted by cals400ex
when using dynojets, ewalker is the man to talk to. i must have been misinformed about dynojets. i was told the 146dj was the same as the 148 keihin. didn't you find the 150 dj to work best for you ewalker??

Thanks Cal, Im certainly no expert, but the DJ kit is screwy, and I wouldnt recomend them b/c of the poor selection of jets they include. 134,142,146,155,160,165,170.

Just dosen't make sense when (DJ)146 is 1 bigger than stock--then it jumps up to 155----so it dosen't even have a 150 in the kit.

With the 155 my bike just bogged--no power, it runs good with the 146 but im afraid that w the lid off its a little lean.

I complained (e-mail) to Dynojet about the jets & they sent me a 148, 150, and a new holder for free, I would suggest that anybody with a DJ kid do the same & maybe they will change the jets they put in the kit.
Heres the thread about that (and e-mail addys for DJ) http://www.exriders.com/vbb/showthread.php?s=&postid=878732#post878732

Anyway, I rode in wet conditions all winter so I left the lid on & the 146 in. I ordered some extra discs for my exhaust & a bigger pilot and have been waiting to change both jets at the same time.

My bike is also pretty much stock--- Slip on, Uni, Degree key, & Ground header welds, so if the 148 works better I'll let you know next week when I get my new pilot.