GS650E Jetting, stock airbix with V&H 4into1

[Vintageman]

Hello,

I acquired a 1982 GS650E, It has 6100 miles, and was stored in warm garage by original owner. Last road it in 1999, but did not run right. What I also saw was few years earlier he bought a V&H 4 into 1 (sadly he did not keep stock exhaust). He had a Suzuki dealer install it along with a K&N air filter to replace the stock one. Also they removed the air box cover, which he did not get from them.

I believe this became the reason the bike was parked. It never ran right. He stated it ran too lean. He wished he did not change to K&N. He did not have stock air filter either. Before he lost interest, he created a custom stock cover out of flat plastic stock with a small 1" by 3" window toward carb. He also handed me some one size too hot plugs which were soot black. As part of the paper work he had the V&H sheet which stated to change main jets to 115, pilot to 45 and remove air box cover. It did not say to change stock air filter.

I got the bike home and what I found was 130 main, stock pilot @42.5, but the fixed fuel screws on the carb top side near engine had the caps remove (I am thinking they were OEM sealed?) and were out 3.5 turns. I am sure they are not OEM setting nor is this published. My plan to solve this issue was simply to follow V&H recommendations of course?. easy?


I proceeded to clean carbs, replaced all intake boots for one separated and others were showing signs of fatigue. I installed the 115 main and 45 pilot recommended by V&H and returned the fuel screw to 3.5 turns out (thinking at the time that was factory). I also purchased a new OEM air filter and it came oiled. Air Cover off as recommended by V&H.

When I drove the bike it ran poorly as I accelerated. I removed the air filter completely (hard for me to tell if too rich or lean) and the bike ran much worse. Too lean! I still had the home made cover and put that on. The bike ran 90% perfect. But the plugs are black for now too much fuel.

So I found a cover on eBay (GS550, but looks same from fiche pic? awaiting its delivery now). I want to return the air box, back to OEM specifications. If I had stock exhaust I would put all jets back to original sizes. What would you do for all OEM but the V&H 4 into 1?


How?s this for a start. First is all EOM and the second is where I think for the V&H change only, and last was V&H recommendations that were too lean)

Anyone know what Suzuki set the Fuel screw turn from factory on a 82 650E??

Main Jet Pilot Jet Fuel Screw turns
97.5 42.5 ???? (OEM? Anyone know what the turns were to be?)


102.5 42.5 2.5 (all stock, but V&H 4 into 1, What do you think??)


115 45 ???? (What V&H recommended with no air box cover only. Too lean)

 

[tom203]

Isn't it fun to explore others attempts to improve things? So you're trying to use an OEM filter in an custom made box? Pictures would be helpful. Did you find a complete setup off ebay- airbox,air filter box, cover? My L version has air filter cover on right side- I think on the E, the cover faced up.Only 6100 miles- this bike deserves a rebirth!

 

[Vintageman]

Sorry if I was not clear. The only thing missing on the stock air box was no cover. Since V&H said to remove the dealer who installed the exhaust system and rejettied initially remove the cover and it got lost.

The previous owner tried to recreate the cover, but did not get the OEM cover (not sold seperately it looks like). Also no ebay back theniether to fiund used. Also he had a K&N filter in the stock air box without its cover. V&H said nothing about how to jet for that. K&N is much freer flowing than OEM filter

So I am going back to complete stock air box stuff, with it OEM cover (from a GS550 should be the same I hope and the stock air filter not K&N.

So all should be like OEM here again.

But I will syill have the V&H four into one not stock exhaust.

I am trying to figure out what I should use for jetting (Up 2 stepps on main for 4 into o1 only?). What the low speed Fuel Screw. What turns should it be for OEM given published info say "Fixed" It was at 3.5 out but I bet this was turned out some at dealer for he did not up the pilot from 42.5 to 45 as V&H advised. Is it 2 turns all stock with 42.5 Pilot jet?


I hope this clarifies and I wish I could get to the point quicker.

 

[Vintageman]

So it is all stock but the V&H 4 into 1. Yes got OEM air box cover off ebay comming. Looks just like fiche pic for my 650E

So I need to know what I should use for main jet (EOM was 97.5) with 4-1 exhau st and what the infamous Fuel Mixture screw turns out should be for stock Pilot jet if we can every know since not published by freekin Suzuki

Thanks for your help!

 

[Steve]

Two sizes on the mains might not be quite enough, might take three or four.

For the mixture screws, start with them out three full turns. Warm up the bike (go for a short ride), then turn the screws in slowly, listening for highest idle speed.
You might end up with them in the 2 to 2.5 range, but it will run OK at three turns to warm it up.

Let me know when you want some in-person help. I am within "striking range" and extremely bored on weekends. :-\\\

.

 

[tkent02]

I think I have that cover for you.

 

[waterman]

Give Steve a call, he can get you straightened out. He is right, the mixture screw doesn't have a set position, it is adjusted for best idle.

Nice looking bike. Looks like it was well cared for and has a few extra goodies.

If the exhaust isn't in too bad of condition, I am sure it could be sold to purchase a decent stock exhaust. V & H 4 into 1 that fit a 650 are rare as hens teeth. Decent stocks come around occasionally, but I am not sure the 650 g exhausts will mount up perfectly in rear, should fit fine for head.

 

[Vintageman]

tkent02: If the one coming via ebay is not correct I'll be in touch. Thanks

waterman:
I wish I had the original exhuast for re sale value someday maybe. He held it for a long while then simply threwit in a metal bin (ouch). For riding the V&H is cool. I repacked it and it sounds more mellow than loud.

So far I had to get new batt. Tires, tubes, carb boots and orings, that windshield was cracked (someting fell on it and I found a new old stock ($70 plus shipping), One mirror broke too, so order some out of Thialand via ebay, and had to order the holder braket from suzuki, plug caps (two were open), Full syn 10-40 oil filet, stock air filter, Iridums plugs (why not since I' m tossing money around like water now). 4 new Pilots 45 and four new mains 115 (all per V&H). runs poopy... needs more money... I ramble

Steve:

So I maybe no need to buy 42. 5 pilots, the 45 I just bought are probally OK since I can tweek? What do you think 2.5 more is about 1 turn in? Out is rich and less turn out is leaner correct? Looks like I need to find a real short screw driver. I'll have a fan blow air on the engine while I adjust it for it sounds like it can take a bit.

So you think three or four on mains so that would be 97.5 + 7.5 = 105 or 97.5 +10 = 107.5 I have 115 ( 3 or 4 size over what you adavice ) in it now but no cover, clearly too lean. I am going to wait for the OEM air box cover and try it as is . But 3 or 4 size too much sure sounds like I am going to be way too rich.

I still have the K&N filter. That is much more free flowing than OEM I just bought. If I put that in with stock cover does that require more on the main. I seams if one goes so much on main why is the middle ignore you know Jet Needle and Needle jet... sounds like that would get to lean middle to 3/4 throttle? Maybe better to just bite the bullett leave OEM filter amd back off the size of mains as suggested.

Taking those carbs out was tough (for me) I had a hard time getting intake boots to line up on carb even for if not even the fully on the clamps simply slide back and it pulls boot off carb throat. I'll be a pro at this I am sure.


I'll be in touch eitherway


Thanks guys!

 

[Guest]

What do you think 2.5 more is about 1 turn in? Out is rich and less turn out is leaner correct? Looks like I need to find a real short screw driver. I'll have a fan blow air on the engine while I adjust it for it sounds like it can take a bit.

Turn each mixture screw in until it "lightly" seats (no gorilla force here), then unscrew it back out counting one full rotation as one turn. Set each as needed to achieve the highest idle, then note how many turns each carb (cylinder) needed.

Turning the screws out richens the mixture, in leans it out.

Very necessary to use a fan blowing on a running engine while playing...

I still have the K&N filter. That is much more free flowing than OEM I just bought. If I put that in with stock cover does that require more on the main.

I use K&N replacement filters all the time - I don't think it affects the jetting at all however, you DO need a well sealed airbox or these bikes will not run right - air (vacuum) leaks are killers.

I seams if one goes so much on main why is the middle ignore you know Jet Needle and Needle jet... sounds like that would get to lean middle to 3/4 throttle?

Lots of us here raise the needles about .040"-.050" using small washers (unlelss your needles have an adjustable clip). Really helps eliminate that stumble at mid-range.

Taking those carbs out was tough (for me) I had a hard time getting intake boots to line up on carb even for if not even the fully on the clamps simply slide back and it pulls boot off carb throat. I'll be a pro at this I am sure.

Everyone has their own method for doing this - they can be a real PITA as you know. Some bikes are easier than others too. I spray some silicone on the inside of the carb boots to help them slide on.

I also leave the clamps loose on the engine side, so I can rotate each boot to put it in the best position on each carb inlet - the boots have a slight angle to them and you can see when they fit the best as you rotate each one slightly.




Good luck, your bike looks very nice - if you are lucky enough to have Steve come visit you, you'll seee why he's one of the gurus here...

Mike

 

[Vintageman]

Update,

I put the stock air cover and stock air filter in the air box, 105 on the mains. 45 on the pilot (too cheap to put new 42.5 back in). Started with mixture screws at 2 turns out since I was 2.5 large than stock on pilot. New plug caps and iridiums in it. The bike runs very well. Accept occasionally while cruising easy it acts like it bogs or not responsive. Open it up an pulls to redline and beyond no problem. Idles well.

Man I wish I could tell the difference between too lean and too rich just by driving feel. My first conscious call was too rich due to idle jet larger than stock pilot. I set mixture screw to 1.5 out only. Seamed better, but it did it again.

Well I am not at idle maybe 1/8 throttle so maybe it is the needle and I am too lean?

Well I suppose when it is doing it I should just hold it there, then quickly turn it off and look at a plug.

I am just not sure if too lean or too rich by feel.

I am thinking of raising the needle washer trick.

Would that hurt?

Is it simply a good idea?

Can make that change without taking carbs off?

So I am 95% there. Sometimes (not always) while cruise light throttle it bogs like it?s too rich? Or too lean? I open it up and then return to cruise it is OK

Must be adjustment or needle Can't be mains at that throttle position???

If I am 2.5 larger on pilot can the mixture screw compensate? like less turns out

Thanks

 

[Guest]

Read my previous post about setting the idle mixture screws - take your time doing that & it should help smooth out the transition from idle to pilot circuit. 2 turns out seems a bit lean to me.

IMO, raising the needles is a necessary thing to eliminate mid-range stumble. The washers are hard to find, but Radio Shack sells them in an "assorted washer" bag - you want the #4 washers out of that bag. The kid at the counter doesn't know jack - go through the drawers and locate the flat washers yourself.

No, you don't have to remove the carbs to shim the needles - just remove the carb tops to get at the needles & slides.

Have you done a carb sync yet? That should bring it all together...

Just curious, where are you located? I spend at lot of time between St. J & Derby VT.

good luck

 

[Vintageman]

Hikermikem,
I went back a read your initial reply.
I am not sure I understand. So here I go.
I think you are you saying to start at 1 turn out on all four carbs. Then I can see three ways of doing this
1) Adjust one carb only for fastest idle my choice (one of the two ends since can reach it). Then count the turns and then set the other three to be the same?
2) Adjust each one time individually while looking for max idle speed each time
3) I initially thought I would adjust all four at once 1/4, restart and check idle.
Can I use my tach or are we talking small changes and need RPM instrument?
Carb synced, when I had them off I checked the butterfly gaps at Idle and the opening gap was the same as best as I could measure so sync should be close.
One question I ask, but now answer. I am using 54 for pilot not 42.5. I was thinking OK since I can adjust screw. Am I wrong! Is 2.5 (about 6% more than stock) more on the pilot more than say a turn in? When I was at 2 turns out it seems like I was going to foul plugs (skipping until I revved it up a few time to clean it out like a two stroke ) so I went 1.5 turns out on all 4.
1.5 may appear lean but again I have 45 not 42.5 pilots. Maybe 2.5 more is trivial maybe not. Wish I wasn?t so cheap, I have a guilty conscious and not sure how much issue 2.5 is. I wish Suzuki published turns on this bike and not bloody fixed
I am on the same side as you but south a bit more in-between Lebanon NH and Charlestown NH

 

[Guest]

You want your option #2 - adjust each carb using the "highest idle" method. I use my tach & my ear for this. Set one carb, then bring the idle back to 1k or so, then move on to the next carb & repeat the process.

No, I didn't mean to imply that you should start each carb at 1 turn out - that's too lean. I would start at 2.5 - 3.0 turns & go from there.

I don't think the pilot jets & the idle mix screws really interact that much with each other - they are two different circuits. The idle circuit is active when there's no throttle, the pilot circuit is active at 1/4 throttle. However, I don't think the 45 pilot's you have will be an issue.

Once you have the carb mix screws set, then a good carb sync is in order. The bench sync will get you going, but it still needs to be done with vacuum gage.

Good luck

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. Vintageman,

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Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Rebuild Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[Vintageman]

hikermikem


I did not know the Pilot Jet and idle Mixture screw were seprate circuits. I have experience with the VM Mikunis where the idle screw is really the air adjusting screw feeding the pilot jet for atomization of the fuel throught it.

So in these CV Mic Carbs the air feeding the Pilot screw is a fixed passage somewhere (Any theory on these carbs I can read).

The Idle Mixture screw is adjusted at idle but influences up to 1/4 throttle. By george that is the one that must be out. Also sinc eI am at 1.5 turns out chances are I am too lean

One more questions, When you do this adjusting, do you have the gas tank off out of hte way or lifted up on one end.

I mean how do you access the inner two adjustment screws for they are hard to access with tank on.

You have been very helpful and I plan to give this a go this weekend.

Also guys thanks for the welcome,

 

[Vintageman]

OK I just did two reply in a row.

I still would like to know how you guys adjust the Pilot mixture screw while running. That is how you get access to Pilot screws due to Gas Tank in the way. Please let me know.


Some Low speed carb theory (as I see it first review) ->

From the welcome packet, I did see the Low speed carb theory in the 650E service manual. There is a relationship between Pilot Jet size, Pilot air jet size (at carb throat), and Pilot Mixture screw.

From figure in manual, there appears to be 3 low speed passages, 2 are exposed when butterfly closed (idle). One of these is fixed (controlled by Pilot air jet and Pilot jet size and the other is controlled not only by the Pilot Air jet and Pilot Jet size, but the Pilot mixture screw following. The third passage kicks in when you start to open the Butterfly (off Idle) and its contribution is fixed determined by Pilot Air jet and Pilot jet size (which I increased).

I also found two interesting posts explaining this tuning with respect to pilot jet size versus Pilot Screw setting, etc. The first implies if you up the Pilot size one step you have to back off Pilot Mixture Screw by about 1.5 turns. The latter post tells you how to know if Pilot Jet too small or too Large. If too large turning Pilot Screw All the way in won?t cause Idle to stumble since the one remaining passage is supply enough fuel. This is easy to know if a single cylinder engine though

http://www.gixxer.com/forums/showthread.php?t=13944
http://www.exriders.com/archive/topic/229923-1.html

It may be wise I change the pilot jet size back to 42.5 stock versus the 45 it has. They also say in manual the factory jets are extremely accurate. No offense to EBC, but there Pilot jets I have in there (here I go again being cheep. Actually in this case I wanted true Mikuni, but supplier gave me EBC and I should have waited and got Mikunis).


Now I am thinking my issue is when the third low speed passage kicks in. Maybe it is too rich as first thought? why it is not consisted If I rev out and return since not loaded up anymore, but comes back after a while with sustained cruising. Also explains why two turns out versus 1.5 was better for this issue. If when stock it should have been 2.5 turns out, per the first web link it should no be at one turn out If you believe the 1.5x rule.


So I?ll see if I can tune it via pilot screw. Or I may just get four 42.5 Mikuni Pilots, take off carbs again.

I am getting good at taking of carbs. The hard part is the airbox boots to carbs alignment and staying on carb throat.

Well I f I do it again I can check to see if the boots are turned properly. My thought in hindsight they rotated and I did not check. Also don?t over tighten clamps. I can see from other post here this is pain for others too.


Stock is best. Those engineers spent a lot of time getting it right!

 

[BassCliff]

I still would like to know how you guys adjust the Pilot mixture screw while running. That is how you get access to Pilot screws due to Gas Tank in the way. Please let me know.

Hi,

You'll need a temporary tank. Some folks buy a manufactured auxiliary tank, others use a washer fluid tank from a car, still others use a lawn mower tank or similar. I went really low-tech and used a gear oil bottle, a length of fuel hose, and a barbed connector.

You'll find lots of information on my little website that may help you. Feel free to stop by. There's a link in my signature file.

Thank you for your indulgence,

BassCliff

 

[Vintageman]

BassCliff.

That is simple and perfectt! I have an empty gear oil jug just like that, some hose, and couplings. I don't have the I-V stand, but will rig something up. I'll give it a go tomorrow.

Thanks everyone!

 

[Vintageman]

Conclusion,

I did the adjustment. I lifted the back side of gas tank about 6 inches and allowed me access to the screws with a short driver just fine. The first one carb I did I found that I had it at the best spot to start. However, two of the others were too lean.

The method I used-> I turned 1/2 turn at a time. When I went in-lean direction, there was a definite drop off point in the idle. On the rich extreme it took quite a few turns to have the Idle drop and was not as pronounced. So, I used the drop off point lean then backed off until the RPMs maxed and add 1/4 turn out. My settings are between 1.5 and 2 turns. so there is variation between carbs. Also since it drops of on both end the 45 pilots look OK, but probably why I am about 1 turn lean then others using 42.5.

Took the bike out for about 30 miles runs well no stumbles.

Thanks everyone for your help

 

[BassCliff]

Hi,

Nice work.

When you get around to performing a vacuum sync on the carbs you will have to remove the tank. That's where a temporary tank comes in handy. You'll find lots of pictures of the procedure in the carb synchronization guide (PDF file) on my little website. There's another guide on Mr. bwringer's site HERE.

Thank you for your indulgence,

BassCliff