Please forgive my ignorance

That may be a sync issue then.

 

I've sprayed carb leaner on the carb boots while idling, nothing. Has a regular petcock so no line goin there

 

You can try a crude bench flow using a vacume cleaner. I did on mine once I drilled the vacume holes in the slide to see the effect before installing.

I've done this in the past with UV dyed alcohol and a black light just for kicks once to see how the fuel atomised. If nothing else it's interesting to watch.

 

saw the vc cleaner thing on youtube. may give it a try

 

next time I have some spare cash to throw around and order dye I'll be glad too, not sure how well it will photo though with a black light, when ever I get around to it I promise it won't be with V4 carbs unless they are off for another reason. Prob gank the carb off the kids dirt bike, have it off in about 5 minutes.

 

F'n Georgia......ok.....had hope that it was a Cailfornis bike and you were closer.

 

Yo, I can't remember if the forward cylinders are 1/3, I think so... But the reason the needles are different is likely because the front cylinders run cooler than the rear ones. On later FI bikes the front bank has diff fuel maps than rear ones due to this.
I am guessing that the rears would run richer to keep them cooler? Using that logic you may be able to deduce whether or not yours have been switched. Just double-check the net for more accurate info, I am not 100% I've got it correct here...

However, this doesn't answer your question about what would happen if they were switched... but I agree with the above earlier post that it shouldn't make enough difference to give you the symptoms you are seeing.

 

Hope this helps...

There are a couple of general rules of thumb to consider when you're having the trouble you're describing.

I don't have the reference in front of me here at the coffee shop but it doesn't matter becasue the rule is uniform: if you have two sizes of main jet the SMALLER size ALWAYS goes in the number 2 and 4 carbs (the forward ones, as sitting on the bike). It has to do with air flow and gravity owing to the fact that the forward two carbs are down-draft and the top two are side-draft. Likewise, the LONGER slide springs ALWAYS go in the 2 and 4.

Plus which, some models have a different slide needle in 1 and 3 than are in 2 and 4. If you remove a needle from its slide and look carefully you'lll see a tiny code stamped in the top of the barrel. If you have different needles, use a micrometer to determine which one's shoulder (the point where the taper begins) is closer to the tip, yielding a sharper angle of taper. This one will correspond with the 1 and 3 carbs.

You can expect major problems if they get mixed up. Essentially the carbs are going to get into a tug-of-war with each other.

Another rule of thumb is that if you're having problems while asking for horsepower (while accelerating) you're running too rich. Conversely, if the the engine stumbles while cruising at constant speed you're lean. IMHO you're way to large on the mains. Lastly, the principal symptoms of out of synch carbs are a slow return to idle and an idle that tends to rise as the bike warms up.

Check me out on ebay--just do a member search for oldschoolcarbs. This is all I do nowadays.

 

Just spent 20 minutes on the phone with factory pro. Very helpfull guys. I think I blew his mind a little with this on tho. He mentioned that even with the factory jets (122) in there that it could have still been rich. He was leaning more toward a non fuel related issue. The only thing that hasn't been checked is ignition timing. But if I understand correctly, it is non adjustable so that should rule out timing unless there is a faulty part. That being said, why just in the mid to upper rpm range? Possibly bad cdi?

 

Dija know the mainjet holders are different front/rear ??

Slightly different heights of lowest holes.

 

Didn't know that. I took them down one at a time and kept everything seperated. B ut the previous owner could have done any number of things

 

Tore into them again today. The springs were in the right spots, but the needles were switched. I put the 122 jets back in after the guy at factory pro reminded me of something I already new, but for some reason I didn't think of. "if the mains are too small, you will have a flat spot but it won't cause a severe bog". Haven't got to try it out yet, because I found something extremely ignorant. Some dumba$$ put a piece of cable tv coax on there for a plug wire. I thought I'd seen it all. Anywho, gonna borrow a plug wire off a buddy's parts bike tomorrow. Crossing fingers.

 

Put it back together today. Cranked easier than it ever has. Took off down the road. Runs a lot better. It is pulling through 7000 now. Gonna order some 130 mains and see if that will clear it the rest of the way up. Also goin to the parts store tomorrow and see about some plug wires. It has a pretty bad miss above 7000 so I figure the cable coax is arcing to ground. Either that or it is trying to pick up re-runs of american chopper.

 

Well, rode her to work today, ran pretty good. A little flat due to the 122 jets but man what a difference. I work next door to Napa so I went there today and got a foot of metallic core spark plug wire. Changed it out and got rid of the high rpm sputter. Now just got to order the new jets. jetsrus.com has aftermarket jets for less than $3 each. Keihin brand are less than $7 each. Any reason not to go aftermarket?