lean condition?
Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan
-
- To the on ramp
- Posts: 280
- Joined: Fri Oct 19, 2012 9:57 am
- Country: U.S.
- Suzuki 2-Strokes: 1974 gt750, 1963 superhawk
lean condition?
well I changed the plugs (1974 gt750) and the right side (from sitting on the bike) always seems to be leaner or hotter than the left and middle? the left and middle plugs are a nice tan color and the right side plug is just slightly tan and looks like its running hotter?, I forgot is it the right side crank seal that can go bad and it sucks air in or is it the left side? I thought it was the right side?
-
- Expert racer
- Posts: 1485
- Joined: Tue May 18, 2010 5:38 pm
- Country: USA
- Suzuki 2-Strokes: Suz, Yam, Honda, Kaw.
- Location: New Hampshire
Re: lean condition?
When you checked the plugs what type of driving style did you just complete?
For example were you just cruising streets easy with small throttle or did you just do a long WOT run . I'll take a guess its the former.
For small throttle you want to make sure the carbs are synced for one, After, you want to make sure the pilot fuel screw is set equal to start. You can dynamically tune it too, but if equal and all is well should be close Even before all this you want to make sure you pilot jet, jet needle, needle jet are in pristine condition and float heights set
I would start by verifying that carb is synced with the others for it may not be contributing enough where its being pulled along by the other two cylinders making it leaner.
In neutral feel the exhaust pulse strengths versus to other cylinders
For example were you just cruising streets easy with small throttle or did you just do a long WOT run . I'll take a guess its the former.
For small throttle you want to make sure the carbs are synced for one, After, you want to make sure the pilot fuel screw is set equal to start. You can dynamically tune it too, but if equal and all is well should be close Even before all this you want to make sure you pilot jet, jet needle, needle jet are in pristine condition and float heights set

I would start by verifying that carb is synced with the others for it may not be contributing enough where its being pulled along by the other two cylinders making it leaner.
In neutral feel the exhaust pulse strengths versus to other cylinders
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
-
- To the on ramp
- Posts: 280
- Joined: Fri Oct 19, 2012 9:57 am
- Country: U.S.
- Suzuki 2-Strokes: 1974 gt750, 1963 superhawk
Re: lean condition?
well mostly cruising around, although I did go on the highway for about an hour and a half at 75mph or 80 mph, then back to the city at city speeds. I have always had this problem ever since I got the bike, I have adjusted floats, checked timing, cleaned carbs and nothing seems to help it, so then I started looking at possible crank seals? im not going to tear it apart , going to ride her till she cant go anymore but I would like to know what else it might be , or at least figure it out before I do rebuild her in the future and hopefully not have the same problem after I rebuild her....also I synced carbs when I put the newtronics kit on,, did it just like the book says,,
- Coyote
- Moto GP
- Posts: 3404
- Joined: Tue Oct 21, 2008 2:41 pm
- Country: USA
- Suzuki 2-Strokes: GT550x2, GT750, GS1000
- Location: Tulsa, Oklahoma
Re: lean condition?
Have you pulled the baffles and re-packed them?. That one could be oil soaked. I would pull the baffles out and tear down the highway again and see if she still smokes when you get back.
I was born with nothing and still have most of it left.
.
1978 GS1000C
1976 GT550 ongoing money pit.
.
1978 GS1000C
1976 GT550 ongoing money pit.
-
- Road race school
- Posts: 841
- Joined: Tue Feb 19, 2013 2:45 am
- Country: Australia
- Suzuki 2-Strokes: Suzuki GT750A 1976
- Location: Sydney New South Wales
Re: lean condition?
Hi,I'm dealing with poor running at the moment...just pulled all the pipes off the 750,removed baffles all o.k.with them,but pipes need a major clean..
the left cylinder pipe is so badly choked with sludge & carbon,that it may not respond to hot tub industrial bath
Might be looking for another pipe
Cheers,
Roger



Cheers,
Roger
GT750Battleship.
-
- To the on ramp
- Posts: 280
- Joined: Fri Oct 19, 2012 9:57 am
- Country: U.S.
- Suzuki 2-Strokes: 1974 gt750, 1963 superhawk
Re: lean condition?
well, I decarbonized the baffles (blow torch) a while back, but I never re-packed them, im at 4,000 feet elevation and with the baffles clean and no packing all the cylinders look good except the right one which is lean. I rebuilt the carbs a few times and I cant remember which re-build kit I used but I think it was keyster, maybe I need to adjust the float more on that side?, I measured and adjusted all of them the same , and my left one will weep some fuel from the over flow once in a while (very little) but the plug looks fine and then the right one is lean? what a pain in the butt.....well its been like this for some time now (around 800 miles) so I guess its not to bad...