Some Advice

[Anonymous]

Ok Boyz, get out your thinkin' caps on this one. 8) I have recently rebuild the carbs, just got it back from getting them sync'd. I have noticed that when choked(starting when she is cold) will bog it down and kill the bike. I also now have to tweke the carbs. I have 1-2 carbs running way to rich. (Black and sooty from running 3 mins - could it be a too rich choke - need more air on the air idle jet???) I have both the pilot and air jet set at 1.5 turns. Where do I start? How do I go about tuning them carbs? Its a '78 GS750. Any info/advice/tips/tricks will be much appreciated.

Thanks

[hoyterb]

Fuel screws-bottom of carb-3/4 to 1 1/2 out to richen in to lean
Air screws-side of carb-2 to 3 1/2 out to lean in to richen
set fuel screws first at 1 turn out
set air screws and adjust for best idle
turn fuel screws out additional 1/8 turn
should be slightly rich

[earlfor]

The settings for my 79 750E are pilot screw 1 1/4 turns out and the airscrew 2 turns out. Stock exhaust and airbox. Mine starts cold with about 1/2 choke and takes a couple minutes to warm up to where you can slowly increase throttle and equally reduce choke amount. Few more minutes and she's running without choke. Spark plug center ceramic burns a medium tan. These settings are a little on the rich side. You will find very low end throttle response to be slightly boggy if opened abruptly, but this is the nature of a slide carb and not resultant of the settings.

Earl

[kz]

Mine starts cold with about 1/2 choke and takes a couple minutes to warm up to where you can slowly increase throttle and equally reduce choke amount. Few more minutes and she's running without choke.
Earl

Earl,

Remember that you live in an area there cold is like warm to me, this very morning 43* F (I commute to the office if possible, meaning no snow on the road, whatever temp.) my GS 1150 starts at an idle speed of 2500rpm and I have to wait about 15 secs. After that I have to increase the engine revs to approx. 5000rpm, with full choke, otherwise the engine stalls.

After the described procedure I can run the bike with half choke and then without choke.

My thoughts are if I should disconnect the oil-cooler, because I never reach more than 70 - 80* C (160- 175*F), 100*C/212 at the most in the summer and at idle speed in traffic jams.

[earlfor]

You're right Karl. I tend to forget that not everyone lives in an oven. :-) On the coldest winter night, the temperature here may drop to 50-55F or so. I see in your picture that you're wearing a coat. I've heard of them, but have never actually seen one. :-)

Considering your temperatures, I dont see any reason why you would need an oil cooler on your bike. You might need a propane heater muff, but not an oil cooler. :-) Just a thought, have you tried putting an electric blanket on the bike so it will start easier in the mornings?

Earl

Earl,

Remember that you live in an area there cold is like warm to me, this very morning 43* F (I commute to the office if possible, meaning no snow on the road, whatever temp.) my GS 1150 starts at an idle speed of 2500rpm and I have to wait about 15 secs. After that I have to increase the engine revs to approx. 5000rpm, with full choke, otherwise the engine stalls.

After the described procedure I can run the bike with half choke and then without choke.

My thoughts are if I should disconnect the oil-cooler, because I never reach more than 70 - 80* C (160- 175*F), 100*C/212 at the most in the summer and at idle speed in traffic jams.

[mcycle-nut]

The settings for my 79 750E are pilot screw 1 1/4 turns out and the airscrew 2 turns out. Stock exhaust and airbox.
Earl

Where the hell did you find a stock exhaust? I saw a bike the other day with ONE good muffler, but I've never seen a stock exhaust system on a two valve in this day and age. :?

[Anonymous]

Any air leaks, or is the filter on + seated properly.

I had the exact same symptoms. I found that the gasket between my filter frame and air box was ripped and it was not seated properly.

[redliner1973]

Mine is stock, and they can be bought at bikebandit.com. expensive as hell, though.....

[earlfor]

Re: Any air leaks, or is the filter on + seated properly.

I had the same thing on my 750. I made a new filter frame to air box gasket from an old mouse pad and contact cemented it to the filter frame. (works great...cost $0.00) :-)

Earl

I had the exact same symptoms. I found that the gasket between my filter frame and air box was ripped and it was not seated properly.