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Old 01-23-2010, 10:51 PM   #1
allthrottle
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Carb jet kit Q's

My bike's been running pretty bad lately so I've had to leave it parked on the patio. I'm taking advantage of this downtime to do some overdue maintenance, repairs, clean the carbs and install this jet kit I've had sitting for awhile.

I have the carbs apart today, cleaned, and am starting to get to the jet kit in. After reading the install walkthrough and the sheets that came with the kit, it seems like the factory main jets are supposed to be no bigger than 138, and have a non-adjustable needles. However, now that I have it all apart, I notice the main jets on cylinders 1 & 4 have "140k" stamped, 2 & 3 have "142k" on them, and the needles look identical(adjustable) to the ones in my Factory Pro kit.

I'm just trying to figure out if these were re-jetted previously so I don't waste a brand new kit. Any insight?

Thanks
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Old 01-24-2010, 12:02 AM   #2
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Sounds like it has been jetted. Your bike is 11yrs old and unless you have had it since new there is no telling what has been done.
My advice, FWIW, put the new jet kit in following the instructions provided and then have your carbs syncronized. That way you know what you have to work with.
If it runs good ( and it will ) then no problem. If it doesn't, then you know it's not because of some oddball carb kit.
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Old 01-24-2010, 01:12 AM   #3
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Thanks for the response

I'm still planning on swapping everything from the kit into the carbs now, but what I'm confused about now is what the factory main jet sizes are. I assumed at first that these were stock and went up to 142 on 1 & 4 and 145 on 2 & 3, but if stock's 138, I'll just swap in the factory pro jets of the same size, just to be sure I have quality(and new) parts in there. It was running great before it seemed to go dead on a cylinder, so I don't see a reason to change a thing.
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Old 02-02-2010, 09:07 PM   #4
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Just a little update, and a few more questions.

Got the bike back together using 142 main jets on all 4 carbs and replaced the springs and needles with the Factory Pro stuff. I decided to stick with 142's because it already had a K&N and a yoshi muffler, and I found out it was a Yoshimura full system(header back). Got it running a couple of days ago and spent the last few days after work attempting to tune them. I don't think it's going to get any better with carb mixture tuning alone though. The engine just doesn't sound healthy.

I adjusted the mixture of each carb; first turned the mixture screw all the way in, and worked it out until it smoothed out... revving the engine a couple grand to make sure it was smooth and wouldn't backfire. I'd turn the screw out until it felt too rich, would run rough, or would bog with throttle, than turn the screw in until I felt it was idling and revving the smoothest. I repeated this for each carb. It no longer sounds like a 3 cylinder, holds a steady idle and will hold steady at whatever rpm I rev it to, but something definitely doesn't sound right.

I know that's not alot to go off of, but any suggestions would be appreciated. I've been throwing parts at it for the last two months, my paycheck can't keep up with it!
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Old 02-02-2010, 10:01 PM   #5
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Something....as in a knock/tick in the motor, or the exhaust tone?

New or old fuel? Fuel pump sound strong with power?

Glad to hear you used the kit. The jets for motorcycles do not have a uniform number system. Factory pro jets are different from Honda and from Dynojet.

What was your float height?
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Old 02-03-2010, 12:22 AM   #6
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Exhaust tone.. The engine itself sounds internally normal.. Or at least, no knocks, ticks, rattling etc.. I pulled the plugs and checked spark out of each wire. They all seem to have healthy, consistent spark. I emptied out the tank two weeks ago and put two gallons of fresh shell 93 octane in it.

The fuel pump is a newer(still used) pump I bought to replace the original pump that went out on me a month or two ago. I don't necessarily hear it so much as feel it when I grab it. Seems alright I guess, doesn't have the whine I'm used to from car fuel pumps. I ran it without a pump for two weeks and it ran perfect(up to 7k rpm). One day I started it up leaving work, started to take off and it sounded and felt almost like a cylinder went dead. No smoke, no metal clanging around. I figured a plug wire came loose, but it wouldn't stay running on its own the next day without some throttle.

I didn't check the float height. I read it was non-adjustable, and I don't have anything it check it with.
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Old 02-03-2010, 12:33 AM   #7
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Take it to Pat at Motorcycles Unlimited........
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Old 02-03-2010, 01:33 AM   #8
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Last edited by DrAwkwArD; 02-03-2010 at 01:36 AM.
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Old 02-03-2010, 10:55 AM   #9
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+1 on the sync....

DrAwkward, I borrowed a sync tool from my neighbor, but my kawi doesn't have the to hook the tubes up. I'd like to see the home-made one you setup if you had a picture of it.
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Old 02-03-2010, 11:56 AM   #10
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Old 02-03-2010, 01:07 PM   #11
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Quote:
Originally Posted by DrAwkwArD View Post
If you need a sync tool I have a homemade one or I can tell you how to make one. Very inexpensive and they work.
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Old 02-03-2010, 04:15 PM   #12
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Take it to Pat at Motorcycles Unlimited........
Was planning on it when the bike trouble started, but it got so bad that I didn't feel safe riding it up there, then it got worse and wasn't able to get up there under it's own power. I don't know much about bikes, but I've been working on cars for 14 years. I've been able to perform any labor on it without a problem so far, but lack of ability to diagnose issues with bikes and proper tools has made it difficult to get it all done myself. I've still been thinking about taking it to him, but I haven't had spare cash laying around to pay someone else to fix it for a few weeks, or a way to get it to them.

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Before you take it anywhere and waste your money (no offense Patrick, I think you know from some of my previous posts I'm a do-it-yourselfer), it seems like you are mechanically inclined...

Have you synced the carbs yet? No amount of tinkering with fuel mixtures will cure your problem if your carbs aren't sync'd. If you need a sync tool I have a homemade one or I can tell you how to make one. Very inexpensive and they work.

EDIT: Your mixture screws are for IDLE adjustments. They don't necessarily matter under normal open throttle conditions. It's a different circuit.
Haven't sync'd them, the thought never even crossed my mind. What exactly do I need to put that together?

And if this mixture screw is really only for idle, I guess I don't need to mess with it much more. It seems to idle fine, just sounds a little off.

Thanks for the help guys!
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Old 02-03-2010, 04:39 PM   #13
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PORTS, yes vaccuum ports, to hook up to on my kawi.....sorry lol.

Very neat setup!
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Old 02-03-2010, 05:14 PM   #14
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Sync'ing the carbs can make a world of difference. You will likely find that as you sneak up on getting the sync just right that the idle RPM will start to climb.
By the time they are fully sync'd it is not unusual to have adjusted the idle waay back down from where it was.

Again it is hard to diagnose thse kinda things from just reading, but it sounds rich to me. My advice would be to, after sync, do the test where you take the bike on the road. Get up to about 50mph, hold it for about a minute and then turn it off.
Just flip the kill switch without changing throttle position. Then pull over and whip out your trusty plug wrench and see what they look like. Of course this is gonna require some pre planning to find the right location.
That is the best way to get an accurate idea of what is happening, under load at higher RPM, in each cylinder. I know it may not be possible to do this to all cylinders on the side of the road, but do the best you can.

Hope that helps.
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Old 02-03-2010, 06:46 PM   #15
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Old 02-03-2010, 07:37 PM   #16
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Quote:
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...then do what Bumblebee said...

Please report back.
FYI...
You should ALWAYS do what Bumblebee says.

And please do let us know what happens.
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Old 02-06-2010, 10:12 PM   #17
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Just another update... It finally runs halfway decent spent yesterday night and this morning fiddling with the mixtures screws a little more, then decided to mess with the middle "sync" screw, just to see if it would make a noticeable difference. As I adjusted it a little, I noticed the exhaust tone and throttle start to smooth out. This gave me hope, so I made a trip to cycle gear(I know, I know, they're 5 minutes from me though!) And picked up some plugs. Put them in when I got back, fired it up, and the engine was instantly noticeably smoother, and sounded how it did when I first got the bike.

Haven't had a chance to get it synced, but after today I'm pretty sure it'll help improve throttle response even more. One weird thing I did notice was a burnt up wire harness connector and a wire severed from it. I traced it to wires going into an engine cover(stator I believe, not 100% positive). I chopped one at a time and soldered them all back together, which if they were from the stator, will help with the charging issue.
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