jet question

[bklyn400ex]

i pulled apart the carb today and it looks like the original owner put in a 155 main jet in and the only mod that was done was a K+N filter, now i added a pipe and holes in the airbox, i ordered a 150, but the shop sent me a 145 he told me it was the next step up from stock. do u think it will be better with the 145 than the 155 i mean the plug it was blackkkkkk with the 155 so im thinking the 145 is a good start, then go up from there what do u think

thanx
chris

[JOEX]

Stock is 148:confused: Tell the dealer to shove the 145 and eat some prunes!

Joe

[bklyn400ex]

bro, thats what i told him, then i called another dealer, and he said the same thing that the book gave two size main jets a 140 and a 148. do u think i should even try the 145?? with the 155 the plug looks like i dipped it in a bucket of black soot

[bklyn400ex]

???

[JOEX]

Clean out you PM box...

According to Clymer there are 2 main jet sizes:
148 for upto 5000ft (1500m)
142 for up 3000-8000ft (1000-2500m)

Depending on your elevation the dealer MIGHT be right...i'm guessing you should be ok to stay with th 155 at least to check things out...to see how it runs.

I think i'll stick to my original statement:)

Joe

[bklyn400ex]

did u mean the 145?

[bklyn400ex]

i just read that NY's average sea level is 1,000 above

[JOEX]

Clymer says 148 / 142 double checked...

Joe

[bklyn400ex]

then i should be ok with trying a 145??

[JOEX]

Assuming these are Keihin jets....i'd stickwith the 155. Your plug most likely black because you didn't have enough exhaust flow to compensate for the filter and 155 main by themselves...

A 145 would be too lean for your set up...I have a k&n filter with a WB-E-Series slipon and a 150 or 152 main (i can't remember:eek:) and ran the same plug for over a year.

I am by no means an expert on this...hopefully someone else will back this up.

Joe

[bklyn400ex]

i have a wb r4 holes in airbox, ground out welds and a k+n filter

[JOEX]

I'd stay with the 155...Does yours have a "k" stamped next to the "155"?

Joe

[bklyn400ex]

nah, actually its right in front of me it says 155rd

[JOEX]

HHhhhmmm....I don't know what to tell you...Does the 145 the dealer gave you have a "k" next to it?

Dynojet has a different numbering system...I don't know if that is what you have but it could be...

You may have to wait for someone else with more knowledge to respond....sorry I couldn't be more help...

Joe

[bklyn400ex]

thanx man, yea the 145 has a K

[JOEX]

Like I said, i'm no expert, but I think the 145"k" is way to lean for your set up...It is usually safer to be too rich than lean...motor wise...

Good luck, Joe

[bklyn400ex]

its in now lol, i'll run it for a few minutes, then i'll see how the plug looks, if its lean i'll try a 150 then a 152 how's that sound?

[JOEX]

Are you doing a "plug test"?

I don't remember the details, but it's something like running the quad WOT than shutting it down instantly....

My understanding is this isn't accurate with the additives that are are put in the fuel these days...it will give you a false reading.

Joe

I thought I had replied to this allready, hmmm maybe you have two going :)

Anyhow, the jetting range your talking about (145-158) sounds close to me for what I have heard so far. Now I am talking about the Keihin jets cause I dont even bother with the dyno jets anymore cause I just get myself mixed up and hate swapping back and forth.

have any of the other jets been changed? like the needle or slow/pilot? You may be rich someplace else.

If your trying it, just how are you trying or testing it? It does makes a diff and you cant just go by the plug color alone due to the probs with pump fuel etc.

And though NY may have an average of 1000ft I doubt that Brooklyn does and with the colder temps it should be looking for more fuel.

Dont forget that jetting is trial and error and your machines fuel needs do change with alt and weather etc. so you may as well get some practice.

[bklyn400ex]

actually i ride in pocanoes, and i also changed the pilot to a 42, because i have a hard time starting in the cold, and it pops and backfires for the first 5 minutes after i get it started

[JOEX]

Thanks for chimming in...I forgot to mention the other circuts...i'm running 40 pilot, needle up one notch, 150/152 main...

Joe

[bklyn400ex]

should i try movin the needle clip, i didnt even check it

[JOEX]

Pilot jet= idle to 1/8 throttle position
Needle= 1/8 to 3/4 throttle positon
Main jet = 3/4 to full throttle position

In my opinion the needle jet is the most used and most over looked circuit.

I bought my quad used with main jet already changed...that's why I can never remember what is:p . I changed the pilot and moved the needle and noticed a big difference. It may have been riding conditions/experence but in theory it seems right.

Joe

[bklyn400ex]

what position does the needle come stock?? imma look at it 2morrow mabye the needle is set too rich, is that possible?

[JOEX]

Stock= 3rd groove from the top.

Mine is fourth from top.

Joe

[bklyn400ex]

mabye i should try the 155 then put the clip all the way up top?

[JOEX]

Take your 155 to the shop to have them identify it when you return the 145.
Put the needle in the 3rd or 4th groove FROM the top.

Joe

Whoa slow down there. Save yourself a lot of troubles later and dont go changing everything all at once. It will be crazy later if you dont get that one in a million lucky shot and its right.

First like I told you in the PM you need to put in a Keihin mj and which ever one you currently have and then ride it with a new plug. Warm it up look at what the exh is doing and then take a quick ride and "feel" what the diff is.

Then you can take that info and start doing tests on all the diff circuits, but you need a start point with a main jet style that you can pick up other sizes local.

All the info on what we others are running isnt going to help you dial it in cause of so many things being diff. so get yourself to a starting point where you can adjust from. You will need to know what your engine is doing at 4 basic throttle openings and then you can start making changes.

Good luck and have fun

[northeast400]

I checked my jet and it ends in rd, I got it from honda, but it came from a different manufacture. I say stay with the 155 I run a similar set up and it seems ok

[bklyn400ex]

with the 155 the plug is coming out black

[JOEX]

Is your air filter clean?

[bklyn400ex]

lol its spotless

[JOEX]

I kinda got lost here.....how about we start over....You may even want to start a new thread to get some input from others....they're probably ignoring this thread by now...

What is your current set up and how does it run....I mean today, right now...from what I have read a plug color reading is not an accurate using pump gas due to additives used...other than extremes...overly dark/wet (rich) or white (lean).

It's usually safer to be a bit rich than lean.

Joe