Lean condition 79 GS1085

[79moneypit]

Thanks for your help on the thread "1 long story". I listened to everyones suggestions and increased my main jet size to 130 with 17.5 pilots I rode about 5 miles today between 4-8000 rpm. I am running cheaper pods, 4 into one with no baffles, dyna ignition, 1 turn out on the pilot fuel screw and 1 3/4 turns out on the pilot air screw fifth (fattest) position on the jet needle. Can I richen the mixture enough by backing out the fuel screw?? Any suggestions??

[Nessism]

Fuel screw is for low speed. What are you trying to do?

[srsupertrap]

Thanks for your help on the thread "1 long story". I listened to everyones suggestions and increased my main jet size to 130 with 17.5 pilots I rode about 5 miles today between 4-8000 rpm. I am running cheaper pods, 4 into one with no baffles, dyna ignition, 1 turn out on the pilot fuel screw and 1 3/4 turns out on the pilot air screw fifth (fattest) position on the jet needle. Can I richen the mixture enough by backing out the fuel screw?? Any suggestions??

I have one of these GS1000 Wiseco 1085cc and I take it your running VM26SS carbs based on your description. The pilot fuel mixture can be richened by backing out the fuel screw which so we don't confuse screws is located underneath the float bowls. There a lots of good threads out there already, use the Search but I will borrow some information posted by KeithKrause & Blackstar etc. The pilot fuel screw s/b set at 1.5 turns out and work out from there. I haven't run the VM26SS for a long time but I got interested in rebuilding my original set and found the "untampered" pilot fuel screw setting was 2.5 full turns out.

A lean condition would be exaceberated by those cheap Emgo Air Filters. If you oiled them they will actually choke the motor. Most would agree to go with K&N's. Nessism always seems to find the best deals on stuff in general. I think a new K&N set can be had for about $100

Second the stock position of the GS1000 5DL36 Jet Needle is Position #3. Raising the needle up will make it richer and lowering it will lean the mixture. It sounds like you have lowered the Needle all the way because you mentioned the fattest portion which would make it very lean. KeithKrause has stated you should be at Jet Needle clip position #4.

That should help but again use the Search since this Topic has been well documented.

[79moneypit]

I mis spoke on the jet needle position, I meant "fattest" as in rich, if you were looking at the needle as it would sit in the carb the clip is in the lowest position which to my understanding is richest and raises the needle up allowing more fuel. I am use to messing around with 2-stroke snowmobiles and I know what happens when those lean out, looks like a four stroke is very different to tune, I will do a search on this topic, I would just hate to damage the motor, I have already spent enough money on this bike and listened to too many local people who charge too much and don't know what the heck they are doing.

[Paul Kelly]

in sympathy

Hey bud, I know how frustrating this crap is. I just bought a real nice gs1000gl with a 1083 big bore kit in it but I have bs34 mikuni's on it and am having a tough time getting the mix right. In my case I'm way too rich even with 105s in for main jets. Hope you get it solved before summer. I'm about to give up and pay large for expert help.

[terbang]

This is the method that I have used to great success when setting up my 1100's. It takes a while and you do need to be patient. What I do is tackle it a step at a time over one day, sleep on it and make any further adjustments the next day.
Make sure everything else is OK (intakes/valve clearances/ignition/timing...) and don't do this at the top of mount Everest either. Set the bike into the configuration you want (exhaust/Inlet filter) and follow the steps.
Have fun..

Step 1.Top end (full throttle / 7.5k to redline) -Main Jet.
To get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the hardest pull at high rpm.
If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges. If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small. In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use! Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end /cruise later - after step 2.

Step 2. Midrange (full throttle /5k-7k)-Clip position
Step 1 (Best Main Jet) must be selected before starting step 2!
Select best needle clip position. To get the best power at full throttle / 5k-7k rpm, adjust the needle height, after you have already selected the best main jet. If the engine pulls better or is smoother at full throttle/5k-7k in a full throttle roll-on starting at <3k when cool but soft and/or rough when at full operating temperature, it is too rich in the midrange and the needle should be lowered. If the engine pulls better when fully warmed up but still not great between 5k-7k, try raising the needle to richen 5k-7k. If the engine pulls equally well between 5k-7k when cooler as compared to fully warmed up, the needle height is probably properly set. Do not pay too much attention to the low-end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets (Step 1) that produce the best power at high rpm. You will deal with the low-end / cruise next.

Step 3. Low end (full throttle / 2k-3k)- Float Height
Step 1 (Best Main Jet) and Step 2 (needle height) must be selected before starting step 3! To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 2.5k to 3k rpm at minimum. RESET float level to the Suzuki specification as the base line, test the engine and make adjustments from there. If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner. If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level by resetting the float level 1mm lesser (if the original was 13mm - go to 12mm).
REMEMBER, since the main jet WILL also have some affect on low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before adjusting the final float setting. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm.
NOTE: A bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm.
Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!

Step 4. Idle and low rpm cruise-Pilot Fuel Screw setting/Pilot Jet change
There is usually a machined brass or aluminium cap over the fuel screws. This will need to be removed. Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation.
Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation. If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets can be obtained if required. Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem. NOTE: A rich problem gets worse as the engine heats up. If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture. NOTE: A lean problem gets better as the engine heats up. If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!

[79moneypit]

Thanks for the elaborate, thorough explanation of setting up carbs. I worked on it today and the bike is running excellent now, still just a little rich when cruising in the 3k-4k range, I a going to turn the fuel screw in from 2 turns to 1.5. I really appreciate everyones help and advice. This is a great website.

[BassCliff]

Sources?

I think someone should have given credit to The Factory Pro website. :-D



Thank you for your indulgence,

BassCliff

[terbang]

I think someone should have given credit to The Factory Pro website. :-D



Thank you for your indulgence,

BassCliff

Yes, that'll be the one I guess. Its an article that I cut and pasted from somewhere, (thought it was a site on SV's) and kept on my computer.

[BassCliff]

Yes, that'll be the one I guess. Its an article that I cut and pasted from somewhere, (thought it was a site on SV's) and kept on my computer.

Yep, it's a very handy reference. I have it bookmarked and have read it several times myself.


Thank you for your indulgence,

BassCliff

[Go Mifune]

Good to see you got your bike running better moneypit, now if you could, would you please post some good sized pics of this moneypit bike. It looks very interesting in the small pic of your posts.
Thanks