rich condition?

[Eddie]

Hi all, I haven't been on here for a pretty long time now, but I have a question , I always notice that my left cylinder seems to smoke more than the others at start up, and it smokes a little while warm (74 gt750) . I did a compression test and the left cylinder is 110 and the far right one is 110, I did not check the middle one yet but in the past it was about the same, anyways I noticed that the left cylinder which smokes more, looks like the float level may be a little high, I noticed that the rack that holds all the carbs on has a small amount of fuel on it, very slight amount, so the question is can I remove the float bowl without removing all the carbs? I have always just taken all the carbs off to work on them, I have never tried to just remove one float bowl. I had the carbs off and on a lot on the past trying to get them right so im not new to taking them off, just wondering if anybody has taken just the float bowl off while the carbs are on? its the far left one so its in a good spot, also if it was rich im assuming that that should cause it to smoke more? also when I check the plug it is wet around the edge of the plug and the others are dry and sooty light tan color, the left one is dry and tan on the center but wet around the edge, so im not sure if its rich and its wet because of fuel or if its burning oil (bad crank seal) im hoping its just to rich, sorry for the long story I just posted but any help is appreciated!!!

[tz375]

It sounds like too much oil in that one which suggests a leaky check valve.

[GT750Battleship]

Hi,we had this question in the past about pipes & their smoking habits...I've had my "A" model for 13years now,& I think I've seen the lot !!
Smoked more from the top left for months...then switched to top right ! I've done some big trips recently....& now the only real smoke is on start up from cold,then she smokes on all 4 !
The check valves can leak & the SRIS can have issues as well...or maybe she needs a nice long trip at some decent speeds ?

Cheers,
Roger.

[Eddie]

We'll I have cleaned the siris valves in the past but not recently , just wondering what does a spark plug look like that has a bad crank seal? I would think oil fouled and not tan on the electrode? It's weird on my left cylinder the plug has oil around the outer edge but the electrode is tan, kinda almost lean looking, and the other plugs are just dry sooty looking, next time I will take a picture and post it. The motor has never been rebuilt, although everything else has been replaced , she has 15,500 miles on her now. I replaced the coils and put the newtronics kit on it, and so far so good, the compression is slightly low I think at 110 psi, thanks for the help and suggestions , I will check the sris system next..

[pearljam724]

Like, Battleship said. You can drive yourself nuts worrying about one pipe smoking more than the other on 2 strokes. I have not been around these bikes for a long time. But, I have 3 of them now. They all process this behavior at times and sometimes not. Watch a lot of videos of 2 strokes on Youtube at start up. They nearly all seem to me, to smoke more out of one pipe. I would however bet, on your float level being affected by either the adjustment or the needle valve, seat. If you have fuel leaking onto the rack somewhere. Not saying someone out there couldn't remove a float while the carbs are still attached to the bike. But, that person would have to be darn good at what he does. I wouldn't try it. Knowing it's a lot easier to just remove the carbs. Adjusting the float level, maybe. But, the problem may be you needle or seat with the fuel being found. You can't get to that, unless the float and pin is removed and reinstalled. could be your gasket. That could be easily changed with carbs attached to the bike. I'd suggest posting a good video and pictures of plugs related to which cylinders. Likely, to be what Richard said. Try a used set of oil lines off of Ebay. Hoping to win the lottery.

[Alan H]

Just remember the bike is 40+ years old. It will never be perfect so enjoy it as it is.
I would suggest sorting the fuel leak though for the sake of your health!

[Coyote]

You can probably get the bowl off while in place, but then what? You won't be able to do much and gravity will be your enemy - especially when it comes to installing the float needle. You definitely won't be able to adjust the float level in this condition.
Feel fortunate though. At least with the BS carbs you can take the tops off and adjust needle clip position with the carbs in place. Us poor guys with the post 73 550's cant do anyrhing with the carbs in place. Bummer. Changing the needle clip position on those rack mounted VM's is about a 4 hour job. Over and over. I had my carbs off so many times, I wished they were velcro mounted, 0r some kind ring like an SLR lens mount..
If the oil lines are weeping into the crankcase, she will smoke like a big dog - especially on the cylinder that has the leaky valve. Blast down the highway for an hour. Then check your plugs and report back!

[Eddie]

thanks guys! I was thinking of just taking the float bowl off the one carb and bend the tang slightly on the float and reinstall, I had measured every float multiple times before and all were the same, the left one though seems to be a little high, maybe the needle is slightly different than the others or something , not sure but my plan was just to bend the tab on the float just a little so it will shut off earlier, the other carbs are fine, just didn't know how hard it would be to remove the bowl (getting to the 2 screws that are on the side next to the middle carb) I have adjusted floats on old Hondas this way but never tried it on the gt750, I always just take the rack off...I will take her for a ride and post some pics...thanks...

[pearljam724]

thanks guys! I was thinking of just taking the float bowl off the one carb and bend the tang slightly on the float and reinstall, I had measured every float multiple times before and all were the same, the left one though seems to be a little high, maybe the needle is slightly different than the others or something , not sure but my plan was just to bend the tab on the float just a little so it will shut off earlier, the other carbs are fine, just didn't know how hard it would be to remove the bowl (getting to the 2 screws that are on the side next to the middle carb) I have adjusted floats on old Hondas this way but never tried it on the gt750, I always just take the rack off...I will take her for a ride and post some pics...thanks...

Eddie, the next time you have the carbs off. Compare the spring action on all 3 needle valves. They should pop up very quickly, after you push them down and let go. If not, they need replaced. When, I was rebuilding my 750, I had a very similar problem as you described above. What I found, was the aftermarket needle valves I bought. Stopped a millimeter or 2 short of the base. Where the oem needles were flush. I had to readjust all of my float levels according to the difference. Once, I did that. All was good. If you'd like, I'll offer you my help. If you'd like to mail me your carbs. I can look them over for you. Hell, I'll even properly clean them. I'd mail them back immediately. I absolutely don't mind helping you with that. Make sure, none of your floats have gas in them either. It's common for floats to have microscopic cracks. Those cracks allow gas inside. That could prevent your needles from being shut. Stick them in very warm water and if they bubble, you have cracks. Is your tank, rust free ?

[Eddie]

Thanks pearljam I appreciate the offer, I had rebuilt the carbs a while back and all was replaced with new parts, I recall the springs were the same, but not sure about now? I can take them off and check its just time consuming and I have been working a lot right now, thanks for the offer but I will probably just do it when I get time, that's why I thought about just taking the bowl off the one carb and slightly bending the tang to make it shut off earlier. I had sealed the tank with caswell and it looks awesome, no rust , I also run a filter and check it all the time, if I don't get time I may take you up on your offer, but for now ill try to do it, but I really appreciate the offer! also not sure if you guys have used caswell tank sealer but so far that stuff has really worked for me ! I have used kreem in the past and it worked ok on one tank but then I had two bad experiences with it, then I tried the caswell stuff and I think it is way better than kreem, just my 2 cents....

[pearljam724]

I agree with you on Kreem. I have an RZ 350 and the previous owner used it. Did the job, but don't like how durable it looks compared to POR -15. I used POR - 15 just recently on my 550 even though it only had mild specs of rust inside. Which is enough reason to seal it. The POR 15, turned out fantastic. Very shiny metallic silver, thick and smooth looking. Made the tank look as if it's somewhat the original bare metal. I had some adhere itself to the expansion plug I used for the gas tank filler hole. I tried chipping away at the POR -15 that was on the plug to see how durable it really is. It's hard as steel. I couldn't chip away at it or even scratch it with a flat blade screw driver.

[Eddie]

I have never used por 15 but it looks nice! the caswell is clear so you can see the actual metal on the tank, its pretty cool, I think either the center and far left plugs are wet with fuel or oil, but I cant tell, I know it sounds weird but I cant tell yet, im having trouble trying to download pics,,,,,the top plug is the far right one, it looks good , the bottom is the center plug, both the center and far left look the same, not sure if its wet with fuel or oil?, I cant tell by the smell either?

[pearljam724]

They appear slightly rich. No big deal to me. I prefer my plugs to be slightly rich looking. The one does seem to be too rich. That's related to the issue with you finding fuel under the carbs. If that carbs fuel height is slightly too high, that cylinder will run richer. You have to look at the floats and make sure the arms are not tweeked also. It's very common that one can side of the float can be tweeked ever so slightly. That will throw off any float measurement. Sometimes you can't visually see the tweek. That's why you have to measure the float height on all 6 float lobes. To be sure of that. I measure all 6 lobes, twice. It's better to be sure of things before sticking the carbs back on and finding out otherwise. I found with the late model carbs you have about 2 millimeters of cushion max to the height being correct. You have to be very careful, where ever you set that height. The lobes don't touch the ceiling of the float chamber. That's where that cushion come into play. Depending on the tongue angle or an arm being tweeked. A lobe can touch the ceiling. The tongues may not completely depress a needle. Causing too much fuel. You also have to consider, the higher you set the float level. Will be a shorter measurement.

[GT750Battleship]

Hi,yes a little rich,but better than lean ! What plugs are you using NGK 8ES ?
What sort of use is the bike getting ? Around town..lots of low speed ?
Would like to see photos of plugs after a bit of high speed use ?
Cheers,
Roger.

[pearljam724]

Eddie, like Battleship was referring to. You have to give these bikes the beans often enough. Try a throttle chop test. That's the best way to read your plugs accurately. Install new plugs. Immediately, after you install them. Hold, the throttle wide open in 2nd or 3rd gear. Never letting off the throttle. Once you hit full throttle for roughly several seconds hit the kill switch. Pull in the clutch lever and let the bike coast to a stop along the side of a road. Then immediately take the plugs out and read them. There's too much low speed riding mixed in over long periods of a plugs life to get a very accurate reading. Regardless, that one plug looks a little too wet. Not a big deal, unless it effects having to clean it constantly in order to get that cylinder to fire.