Lets beat the dead horse... again

[65fury]

Nahh, you think you were told wrong. Think of the carbs w/Vboost as a big 4bbl carb with vacuum secondaries. The reason why Vboost makes the power is the introduction of more fuel. Same with turbo's, Superchargers, Nitrous. The addition of more fuel with the proper amount of air (nitrous is the oxidizer when it's used) creates a bigger combustion that equals more power.

If you are already running too rich (or lean) with the carbs, once Vboost opens up another rich or lean carb enters the picture on that cyl. Thats going to make things worse.

You said you've already tried the choke test and you didn't feel anything, makes me think your on the rich side of the street. Have you pulled your plugs to have a look? If you can, pull your plugs and post a picture of them. You can get alot of info on the way they look

The main thing is, shit happens and we'll get you through this and riding in no time. unk:

Okay good, i was thinking vboost made it richer too but then was told it made it leaner:ummm: but i believe/know your right about the making it richer

So some new info... i put some DJ needle in(they have 5 clip positions i believe) i set the needles at the LEANEST setting(clips at the end of the needles) started the bike up and found that i could even go WOT in neutral with out it cutting out, and then with vboost open it would actually kill the bike if i held it at WOT...

So i know my 170 mains are way to big, im thinking of putting some 145s in(i dont have any 147.5s) but ive run 150s and found my top end to be lacking in power...

Also the ignition box issue was brought up.... any thoughts? could the vaccum advance be bad in mymmidrange??

Ill pull a plug and report back

jason

 

[65fury]

Okay quick update, so i pulled the faux tank cover and removed the "Y" on the air box since my bike wouldnt even free rev without stumbling or dieing with the vboost open. and it really didnt want to free rev without the "Y", so i decided to put my hand in the filter entrance to block air and see if that helped... and IT DID!!!! come to find if i block off the intake about 3/4s of the way with my hand itll free rev quickly and crisply! but with the "Y" on it wont... it stumbkle and almost dies... so ive come to the conclusion that my midrange is too lean, it has to be, cause if i dont allow the motor to get much air it runs better, so tomarrow im going to test my theory a little better and richen my needles and probably pull the 177.5 PAJ2s out and put my 170s back in. I got a wedding party thing tonight so i cant play with my carbs anymore. Any thoughts or suggestions are welcomeunk:
Jason

 

[KJShover]

:thumbs up:

 

[Rusty McNeil]

If putting the choke on doesn't chnage anything then something is seriously wrong. It should go rich as hell and get really "soggy"............. putting the choke on on my bike at cruise or on the throttle sends the A/F from a nice 13.5-15.5 to down off the scale i.e. richer than 10:1

I agree, maybe you need some dyno with an a/f sniffer just to troubleshoot?

 

[65fury]

Okay another update, so i pulled the 170mains and put my 165s back in(i know they are big... but thats what the bike had when i bought it and it was an animal!) besides my top end pulls great with them. So i pulled the 177.5 PAJ2s and put the 170s back in. i adjusted my needles to the third clip from the top to richen it, and installed shorter springs and synced the carbs. Free revving still has a stumble if i go WOT, but can actually stumble thru it. I went for a ride and it still stumbles thru the mids but not as bad. So as i richen my mids its runs better.

So i tried my free rev test again and put a shirt on my air box with the bike idling and found that it revs great no stumbling if my shirt is covering both ends of the "Y", so i know im still too lean in the mids, so ill be richening the needle even more and hopefully ill find the sweet spot.


Jason

 

[65fury]

And another update, i changed clip positions on the needles again, and im down to the 4th clip position from the top of the needle, i only have one more clip position to try(these are stage 7 needles btw) im still getting a stumble in my free rev(altho its slowly getting better) and my mids are still stumbling to, so i did something really okie.... i put duct tape over both "Y" intake holes and covered each one up about 3/4s of the way.... went to get gas and NO stumble in my mids, it pulled hard( i didnt really test it out and go for a long ride, it started raining)

So my question is.... why is my midrange SO lean?? I put in the stage seven springs to help the needle get outa the main jet fast to help richen it up, but it still doesnt seem like enough, what else can i change?? after moving the needle to the last clip position and adding a shim im outa ways to richen up my mids???

I thought adding the kerker 4-2-1 would help richen thing up a little bit... but maybe not??

Any thought and suggestions please:biglaugh:


Jason

 

[gamorg02]

esp with a stock airbox, i'm baffled now, i just assumed you had individual filters. i wonder if you may need air correctors?

 

[one2dmax]

That's what I am wondering? If you look at virtually every dyno you'll see the midrange is rich which is normal to some extent. Not sure why yours would be so lean? Maybe sucking air in somewhere we aren't thinking about. You could maybe try larger pilot fuel jets? I haven't tried this before but not sure why it wouldn't work at least temporarily.

Try blocking off the inlet with maybe tape where the air correctors go and pop a pin hole through the tape. I've not tried this before so not sure if it will work??

Sean

 

[gamorg02]

maybe he should check is manifold boots and such. a big rip there or something could cause a lot of leanness.

run the bike and spray carb cleaner/starter fluid on all the connections and listen for idle changes.

 

[65fury]

Yup kinda weird...... I can't figure out why my mids are so lean......?? But all my boots have been checked thoroughly, almost everytime i remove my carbs i spray around the boots after reinstalling them again. I've never had a leak yet either. My fuel pilot jets are 40s my paj1s are 90s. Maybe drop my paj2s?? try 160 or 165s?? even my plugs show that important running lean in the mids. Or smaller paj1s?? Am i suppose to have air correctors in the holes next to my paj1s??

Jason

 

[Rand-5107]

I loaned Jason some stage 7 stuff to try. I suggested that he might have a vacuum leak. He told me all his boots are in good shape and that spraying starter fluid hadn't shown anything. I was wondering about the vacuum advance unit. There must be a diaphragm in it. Would a ruptured diaphragm leak enough vacuum to cause this lean condition? If it is indeed lean.

 

[Rand-5107]

If you've got a vacuum pump, pull a vacuum on the advance line and see if it holds.

 

[gamorg02]

Yup kinda weird...... I can't figure out why my mids are so lean......?? But all my boots have been checked thoroughly, almost everytime i remove my carbs i spray around the boots after reinstalling them again. I've never had a leak yet either. My fuel pilot jets are 40s my paj1s are 90s. Maybe drop my paj2s?? try 160 or 165s?? even my plugs show that important running lean in the mids. Or smaller paj1s?? Am i suppose to have air correctors in the holes next to my paj1s??

Jason

what is stock for fuel pilots and paj1s?

 

[65fury]

what is stock for fuel pilots and paj1s?

Stock pilot fuel jets are 37.5 and stock PAJ1S are 90(although I've read some years actually had 95s)

Hey Randy, thanks again for letting me test things with your parts! And i don't have a vacuum pump to test that vacuum line, but even if that was leaking id know, cause if just one cylinder has one of those manifold nipples open it idles bad and doesn't run well. And im running pretty lean i think, cause i had to tape off 3/4 of my airbox intake for it to run right.


Jason


.

 

[Rand-5107]

Stock
P.A.J.1 #90
P.A.J.2. #170
P.J. #37.5
Main cyl. 1&3 #152.5 cyl. 2&4 #150
main air jet 2.0
Jet needle 5EZ43
Needle jet Y-O
Carb. I.D. Mark 1FK00. VMX12NC: 1JH00
Ref. 1988 shop manual

 

[Rand-5107]

Well you can always suck on it, cover it with your tongue tip and see if it holds. Wow that sounds bad, but it should work. Might run with a ruptured dia. But not with vacuum plug off also. I have a pump if you want use it.

 

[65fury]

Well you can always suck on it, cover it with your tongue tip and see if it holds. Wow that sounds bad, but it should work. Might run with a ruptured dia. But not with vacuum plug off also. I have a pump if you want use it.

hey wheres your mind at Randy!:rofl_200: well i actually did try that and it worked pretty good, it kept suction for a while....... im sure if someone walked in on me and my bike at that moment it may have been awkward:biglaugh: well i went for a run with the tape still covering the intake holes and it worked pretty good up till about 5k and stumbled at WOT so i pulled over and moved the tape to allow a little more air.... and it still stumbled at WOT but cleared up much faster.... so i get home and decide to remove all the tape... but it started raining as i was riding out and i only got to hammer it once... BUT it ran even better! so without really getting to test it and run WOT in different gears and such im finally making progress!!!!unk:unk:

Although im a bit confused that its running better now without the tape than before when it ran like dookie without the tape...

Jason

 

[[email protected]]

Well you can always suck on it, cover it with your tongue tip and see if it holds. Wow that sounds bad, but it should work. Might run with a ruptured dia. But not with vacuum plug off also. I have a pump if you want use it.

You could use a mityvac brake bleeder to test

 

[65fury]

and another update.... i finally got to go for a real test ride.. but nothing has really changed:bang head:... i cant go WOT in any gear but 3rd and it still stumbles hard in my mids. Infact at idle i cant rapp the throttle fast or to hard cause itll stumble then regain itself and rev.. but same thing, if i put a rag over both intake holes and rap the throttle it revs quickly and smooth.

Ive got the stage seven needles at the richest setting and i even put 160 PAJ2s in to richen my mixture.... nothing helped tho. :confused2:

Even my spark plugs show im running lean still:damn angry:


Jason

 

[wood1]

Wholly hell man, you must be ready to strip a gear. Have you considered borrowing a set of carbs from someone with similar mods? Just reading this makes me want to ship you mine!