Need jetting help please for GS1000 1979

[nitrogs]

Its good to be back! have suffered repeated health problems but now cross fingered have made a full recovery and looking forward to finally sorting my GS1000. I would like to thank Keith Krause for the wealth of information that was supplied prior to my illness for which I am greatly indebted for setting up my Suzuki GS1000 1980 model. I have frantically been trying to find our previous dialogues. My Suzuki GS1000 has a wiseco 1085cc forged aluminium kit fitted, a vance and hines 4 into 1 system, K & N pod filters, a dyna s ignition, dyna coils and a stage 3 dynojet kit. All the valve clearances are set, carb boots replaced, timing set and carbs synced. Currently running standard pilot jets as suggested for the dynojet kit set, pilot screws 1.5 turns out. The bike does not seem to have crisp pickup from low revs (feels fluffy) and the plugs are very sooty (rich), but pulls strong from 5500 to redline the plug chop on top end plugs are good and tan. Presumably it is the richness on low revs that is causing the lack of crispness. What is my best move.

kindest regards
Dave Welton

[srsupertrap]

Not sure which year you have because you mention both 1979 (US VM26)& 1980 GS1000 (CV)? Here is a thread between KK & Blackstar which will be useful for T/S your rich condition.

BTW if you have VM's what is your needle position?

http://www.thegsresources.com/_forum/showthread.php?t=109982&highlight=gs1000+baseline+jetting

[nitrogs]

Thank you for responding sorry for the confusion, it is the 1979 VM26 carb model. The needle is on the fourth slot my friend.

[hampshirehog]

Dave, are you sure you haven't got VM28s on your bike (29mm diameter on the inlet side)? That would have been UK spec then.

You don't mention the setting on your fuel screws - that could be the source of a rich mixture at the bottom end. If you've got a Colourtune you'll be able to set your idle ciruit in about 5 minutes.

[tkent02]

Turn the fuel screws in a little bit and see how it runs.

[nitrogs]

Thanks for the replies guys. Hampshirehog maybe that could be the case my friend, the fuel screws are set at 1.5 turns out. Does turning the fuel screws in lean off the mixture. Never tried a colourtune to be honest.

[Big T]

Yes, turning in the fuel screws (the ones under the front of the carb) leans out the mixture for low revs.

Since you have all these mods, try setting them at 1 turn out.

What is your air screw set at?

[srsupertrap]

Dave,

I agree with Big T you are rather close in getting it dialed in. When you turn in the fuel screws be it 1 1/4 or 1 turns out, readjust your idle speed by adjusting the air screws using the high idle method. I would then recommend installing a relatively clean set of plugs and see how it runs with out ever exceeding 1/8 turn of the throttle (index your throttle grip). This of course will only test the pilot circuit. I would also throw in some small hills in your test ride: if it bogs your jetting is probably still a little rich. Conversely surging suggests it's lean but that not your reported condition. Put a couple of miles on it under 1/8 turn and do a plug chop and tell us what you see.

[nitrogs]

Thank you for the replies, do you chaps have to drop the carbs to adjust the fuel screws or can they be done in situ please. I was fairly sure the air screws were set about 2 turns out. When I did all the synch etc it was very hard to notice a max rev peak when altering the air screws

[hampshirehog]

The fuel screws are the ones underneath at the front of the carb (ie engine side). They are a bit tricky to get at - either a very stumpy screwdriver or a screwdriver bit is the tool. Be real careful winding them in fully - it's only 'lightly seated' - or the tips will snap off. Then wind them out 1 turn. You can either tweak with the airscrews or the fuel screws to get the right mix.

And be doubly careful if your hands aren't made of asbestos - it gets a wee bit hot down there!

A Colourtune is a really good investment - dead easy to use and takes all the guesswork out of the job.

[nitrogs]

Thank you for that, when testing the needle circuit at 1/3 to 1/2 throttle how long do you need to travel at that speed to get an accurate plug reading please.

[nitrogs]

Here are a couple of pictures of my GS1000 that I am trying to sort, just for interest.

[49er]

Thank you for the replies, do you chaps have to drop the carbs to adjust the fuel screws or can they be done in situ please. I was fairly sure the air screws were set about 2 turns out. When I did all the synch etc it was very hard to notice a max rev peak when altering the air screws

If you don't have a stumpy screwdriver, you can fashion one out of a piece of hacksaw blade. I found that the blade thickness matches the slot size in the fuel screws. Length is quite important. I settled on 1&1/2". Any shorter and its too hard to hold when trying to line up the slots. Any longer and your hands wont clear the crankcase top and associated vent plumbing. I use a mirror to aid finding/aligning the screw slots. It's still a major test of your patience!!
As a guide, I'm running my fuel screws at 3/4 off the seats for 900cc, 4-1 and a stock airbox. Because you've got pods, I would think that you will end up in the 1-1&1/4 area.
That's a fine looking 1000 you've got there.

[nitrogs]

Thank you for the advice 49er, it is much appreciated will do the required adjustments and thank you for the compliments on my GS

[hp1000s]

Nice bike, Nitro...interesting front failring; it looks like an Eddie Lawson Kawi hooked-up with a HD Road-Glide