750gtA.Engine Overun problem

[Dave Robbo]

I’ve just got the bike all seems ok starting and power ok but each time I change gear the engine overruns as if the throttle is not closing proper but I’m sure it is. Also difficult to hold a steady speed as the engine starts surging. I’m pretty sure it’s a carb problem but wondering if you guys have a quick fix.

[karl pa]

I would look for air leaks on carbs or boots, spray carb cleaner on carbs and boots while running and see if engine speed or tone changes.
Could be a lean mixture setting also. During cold weather riding, I need to adjust my mixture on the richer side.

[GTandcbr]

You can try these from bluesmoke baz
https://m.ebay.co.uk/itm/SUZUKI-GT750-J ... 2f08f32d56" onclick="window.open(this.href);return false;

[karl pa]

If you have surging, (many GT750 have), there are many posts on that subject.
Mine has, and cold weather magnifies the problem.

[Dave Robbo]

ok guys ive no air leaks and rubbers are ok. Ive ordered the anti surge jets off Bluesmoke Baz cheers.

[karl pa]

Just beware, when mine surges, it doesn't act like a hung throttle, it just bucks back and forth at low speeds.
Like Baz says in his ad, they are not a cure all, if other issues exist.
I ended up taking my anti surge jets out, they can help surging issues, but can cause other issues.

[tz375]

http://www.pinkpossum.com/GT750/carb/BS40carbs.htm" onclick="window.open(this.href);return false;

Try the air jets first. They are just Mikuni air jets and different sizes are available. Stock jet is 1.0mm and is too lean under high vacuum. Try 0.9mm first but I suspect you will end up with 0.8s.

Revs not dropping does sound like an air leak though, so check the inlet rubbers and the exhaust for leaks.

If you remove the carbs to tap them for the air jets, try replacing the pilot jets with new CORRECT type jets just in case yours are incorrect or partially clogged. And also clean out all the tiny drillings and blow through them with a can of WD40 or carb cleaner to see all three flow the same. A partially clogged bypass could be an issue.

[Dave Robbo]

Really helpful thanks guys.

[Dave Robbo]

Quick update. I removed and cleaned the carbs but never found anything. Tapped and fitted bazs new pilot jets. Amazing the difference they made. All the bucking has gone now.

[Evans Ward]

The air jets, right? Yes, they made a difference on my A model also. Glad for you it is running smoothly.

[Suzsmokeyallan]

On M,A & B models using the 0.6 air correctors, fitting the L models 45.7 pilots and raising the fuel level in the bowls approx 1.5 to 2mms is going to cure all the surging issues on engines with stock pipes. You will then also turn the mixture screws out to between 3/4 to one full turn from seated. All the other options I have tried over various time frames and none of them can fully cure the surging.