jetting

[Mightyzod]

I don't believe it. I started my 1974 GT750 today. I have some questions regarding jetting and setting. I have the K and N individual filters on the bike, and I am currently running a 115 main jet, a 50 pilot jet, and have the jet needle clip set on the third groove from the top. I was trying to set the bike up for an Omar's 3 into one, but after 35 days of frustration, gave up and put the stock pipes on. I haven't put too many miles on it (OK only 0ne) and I am being very gentle with it. I just wanted to hear what the experts think.

Thanks.
MZ

[tz375]

main jets sound too small and pilots sound too larege, but we don't have any idea of how it ran at different throttle openings/revs.

What is working and what isn't?

[Mightyzod]

This was truly a first run on it. Very boggy(?) below 4 thousand rpm, starts picking up at five. New pistons and rings, so I am trying to keep the rpm low for a bit, anyway. I installed the 115 main and 50 pilot at the suggestion of the guy that was supposed to be providing the pipe (Omar's.) The pilot is one step up from stock. How large should I go on the main, how small on the pilot? With the pod filters, it isn't too much of a bear to get the carbs out and away, but it is a bit of a challenge to get them back in the boots.
Thanks for the help. Sorry I took so long to respond, but I thought I had things set up to let me know when I received a response. Obviously technology is not my strong point, either.
MZ

[tz375]

Ah so. I figured that 35 days of frustration was after changing a million jet settings and still nothing. That's different.

We're talking 74 (L) with CV carbs which are not as easy to jet. And yes changing jets is a PIA getting the carbs on and off the boots. Mine has new soft boots and it's hard enough on that.

Let's start with what you have in there at the moment. How is the idle and starting? where are the"Fuel" screws set? remember on those carbs, out=rich and In=Lean. Opposite of VM mikunis.

Try adjusting the fuel screws first and see if that cleans things up any at idle and just off idle.

How well are the carbs slides synched? Did you check the butterflies to be sure they are all at the same angle? It's an easy task. Remove carbs (again) look into the outlet side and see how many bypass holes are uncovered. The Suzuki Carb book says One hole should be clear, so make sure all are the same.

While the carbs are off, stick a finger in the filter side and lift each slide and let it drop back down. All 3 should have some resistance in rising and all should fall smoothly at more or less the same speed. One that goes up and down too easily indicates a diaphragm leak or diaphragm that isn't sealed at the top.

Once you are sure about that, leave the filters off and fire the bike up. Blip the throttle and check that all 3 slides rise and fall at the same rate (nor or less). If one or more slides are not rising, that will be a problem.

That brings up a question I should have asked earlier, how was the bike running in the stock pipes before the change and how is it running now?

[Mightyzod]

I will try to address things in the order asked:

The bike does not idle, but starts very easily. I hold the rpm with the throttle; I let off, the bike dies.
I believe that my fuel screws are set at one and a half or one and three quarters out. I will check them again to make sure.
Carbs should be synched. Slides are smooth and move with equal resistance. Diaphragms look great.
I am on my way out to the shop to check on the things mentioned above. Once I have verified that things are in good working order, what main and pilot jet sizes seem to work best on this model running individual filters?
Sadly, the bike did not run at all when I got it, so every minute it does run is new territory. I have had several GTs, but it was a long time ago and they were solid runners when purchased.
Again, thanks for the help.
MZ

[Mightyzod]

Well, crap. Decided I would just go back to stock jets and settings, just to know where I was at. Put the carbs on, they flooded, then nothing. Time for a beer and a rethink.

That which does not kill me is probably not a GT.

MZ

[tz375]

Flooding is a total PIA and fortunately it's easy to fix. It's probably dirty or work needle and seat but could also be a bent or sunk float.

Easy starting = Good but may indicate rich mixture.

Not idling could be:
Idle screw set too low
Partially blocked slow jet or air jet passage (it's a tiny drilling and 1.0mm pressed in jet)
Worn or oversized pilot jet/s
Or any of the usual things like seals timing points etc.

You're getting close now. I always say that when a project is 95% complete, you have done half of the work In other words, it's all about the fine tuning and problem solving even replacing parts that have already been replaced if they turn out to be defective. It's frustrating to be so close, but you are getting there.

[Mightyzod]

As the band Anthrax sang, "Two steps forward, a hundred steps back.' I am truly going the wrong way. Last time I put the carbs together, I screwed up the threads for the pilot jet, so now everything is on hold until I get a replacement. Hello, Ebay.
I will share, as soon as I get going (again.)
Thanks.
MZ