TOPIC:

I sleazed out and threw the carbs back on this spring with a cheesey ruler float height setting.....because I didn't want to take the carbs apart. Now I'm paying for it and I have reformed. I will do the wet service fuel check the proper way this time because I want this thing to run the way that I know it can. Currently I am experiencing erratic firing/bogging, to the point were the bike dies when I dial on the gas too quickly. This appears between 1500-3500 rpm or so. After 4000 rpm the bike clears, sits up and runs like a cat. I had some erraticly bad plug wires so I am changing them out. Two done today with two more splicers coming in tommorow. Last year I had in my Mikuni 24SS carbs (stock rebuild kits installed) 17.5 pilots and 102.5 mains, needles middle clip, timing on the nose. With stock air box and MAC 4 into 1. The bike ran really well all season until the fall when it was getting ratty between 0-2500 rpm, but it was also going out of tune. I took the 17.5 pilots out and installed factory 15's over the winter. Now it really runs like crap until 4000 rpm. I'm wondering if I should (1.) put the 17.5 pilots back in. Or,(2.) leave the 15 pilots in as per factory setting, and lower the needle clip setting one notch to 4th down from the top? I WILL set the float height properly this time.

Sorry I cant help regarding jet sizes gas. I have found that a really good carb cleaning at the start of the year works a treat. This year before I fired up the bike for the first time I dumped all the gas in the tank into the minivan and filled the bike with fresh. Based on the way she started up and has been running the past few weeks I think I'll make this procedure an annual habit.
Made me wonder if part of your problem is running with last winters old gas + stabil
Probably a long shot. Good luck.

Actually buddy, I removed the carbs last fall at shut down, sprayed them inside and out with carb cleaner, and they looked pretty good, I totaly dismantled them the winter before and I use an inline fuel filter. I feel intuitively that I should keep the 15 pilots and drop the needles one notch. I'm trying to get it right this time because doing this multiple times is a pain in the fart release mechanism.

Well you provide lots of information but none that would help with your problems... what altitude are you operating the bike and are you running OEM intake and exhaust or have they been modified? Do you air screws or pilot fuel mixture screws?

Altitude: zero.
Stock air box/filter and Mac 4 into 1.
Pilot screw type.

Currently: 15 pilots and 102.5 mains, needles middle clip, or, third down from top. Pilots screws 1.5 turns out from seated. Timing is on the nose, but I need a carb synch and proper float level adjust.

I had the same as above last year, but with 17.5 pilots and it was quite rich.

I'm hoping that a good float level job (wet) and dropping the needles down to the fourth from the top clip position, will straighten out the dying/bogging up to 3500-4000 rpm.

Post edited by: gas, at: 2006/04/19 13:12

gas wrote:

I feel intuitively that I should keep the 15 pilots and drop the needles one notch.

I think the stock needle position is 4 (that's what stated in my Clymer manual which also states that you count grooves from the top to get this number). So stock is one groove LOWER (needle one notch higher) than you have now. Lowering the needle will make it run even leaner. It sounds like you need to richen it. Also, I think the stock pilot is 12.5.

bemoore wrote:

gas wrote:

I feel intuitively that I should keep the 15 pilots and drop the needles one notch.

I think the stock needle position is 4 (that's what stated in my Clymer manual which also states that you count grooves from the top to get this number). So stock is one groove LOWER (needle one notch higher) than you have now. Lowering the needle will make it run even leaner. It sounds like you need to richen it. Also, I think the stock pilot is 12.5.

I see what you're saying, I mispoke/wasn't thinking/don't know. I come in from being outside all day and I'm very tired. No time to pull plugs right now for an eyeball. Maybe I should consider all of these factors after a good rest. I don't consider carbs a particularly facinating study/topic, actually quite the opposite. I just try to set them up for decent performance then I forget them.

Post edited by: gas, at: 2006/04/19 17:10

I just recliped the needles to the 4th position, counting from top to bottom. A wet float level adjustment and carb synch. will be done in the next couple of days. I am now sitting with 15 pilots, 102.5 mains. I want to test this set up before trying 17.5 pilots, if need be. I'm wondering what pilots you 650 owners are running, and were your needles are clipped, if you have a similar set up to me. I have a stock air box/filter and a Mac 4 into 1.

gas,
I have a 78 650 with the stock airbox , UNI filter and stock exhaust. My pilot jets are 15, mains at 102.5, needle clipped in 4th slot. The bike pulls strong from low to high, no misses. With that 4-1 pipe you have you might need to go up 1 or 2 sizes on the main jet. But first you should get the float level set proper, and probably check the valve clearances before diving deeper into the carbs. Write back.

Kent

Thanks Kent. I just wanted to know how other 650 owners were set up, with similar hardware to mine. As I said in the previous post, a wet float level and carb synch are next on the list, so I can see how this set up performs. The valve clearances are all fine, I reshimed last winter when I replaced the cam chain. I'm sure glad that I put anti-seize on all my carb bolts, particularly those tiny throttle valve screws. Everything came apart and went back together again, as smooth as a babies bum.

Yahoooooooooooooo, I've got my old war pony back! I adjusted the floats with the wet method. It was a bit of a pain in the butt, but not too bad, threw them back on and vrooooooom. It runs clean from bottom to top. There is a tiny hickup around 2000-2500 or somewere in there, that I noticed when the bike was colder. After it was warm it ran like a cat. I still have to synch. the carbs and maybe play with the pilot screws (or maybe not), I'm not playing with it if it runs on the nose! B.T.W. I had my floats set at 24-25 mm with the ruler method and this is what I found when I did them wet: Carb #1 slightly higher than the recommended upper level, #2 slightly higher than the recommended upper level, #3 Way, way high (this is why I had a gassy plug last fall in the 3rd cylinder when I was putting the bike away for winter), #4 Borderline higher than upper recommended level. So, I'll never do that upside down ruler/float adjusting malarky again. It might half assed kind of work, but it's a poor crap shoot by the looks of things.
Oh ya I forgot about this. I bought 4 of the NGK cable splicers and cut off the old coil wires about 4 inches from the coils, then installed them. I also grabbed some generic (practicly free,77 cents a foot) black coil wire from NAPA. Put it all together with the NGK plug caps that I got last year, and it all runs GREAT!

Post edited by: gas, at: 2006/04/21 17:39

GReat going! These 650's are a BLAST aren't they?