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Thread: Who can help me out with 79 GS1000E carb sleuthing? VM26SS with Dynojet questions

  1. #1
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    Default Who can help me out with 79 GS1000E carb sleuthing? VM26SS with Dynojet questions

    79 GS1000E. K&N pods and V&H 4/1 - but may try to return to stock(ish). First thing is to try to tune it with what I have. But what do I have?

    The main jets are Dynojet #138 which is the base jet per the 'fact sheet' for kit 3304.001 which is all I can seem to get from Dynojet support. Tech sheetd oesn't get into installation, drilling, etc. It just lists it's a 5/32" drill and there is a screw included, as pictured here in Z1's ad.

    What would be useful but DJ can't seem to find is the installation guide Part# DI0007 that is specifically mentioned by part number in the fact sheet. Ugh.

    OK, so what gets drilled out, the opening under the main jet I assume? And where does that screw go? I see no screw like it anywhere.

    I looked at the needles and washers, and the washers at least look stock, exactly like the ones off my 79 GS850G. Pics below. I fear I may have some mish mash but maybe if it's not been drilled out (and needles are stock) it's a good thing, as I can baseline to stock and start over.

    So, any gurus out there?



    Last edited by oldGSfan; 02-11-2021 at 05:48 PM.
    Tom

  2. #2
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    Ideally you need to put the carbs back to stock.
    Increase the main for the pods and pipe and fit air corrector jets to correct the off idle hesitation.
    That's all that's needed.
    No need for over complicated Dynojet kits with different needles , over large mains and bigger pilots etc that go to elaborate lengths to cure a simple fueling glitch.
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    https://www.ebay.co.uk/itm/254380193...84.m1555.l2649




  3. #3
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    That is exactly what I want to do. I just want to be extra sure I'm understanding what the Dynojet changes were/might have been. I got a 5/32 drill, checked it with micrometer to be sure as my eyes are getting bad.... and it is far too large for the opening under the main jet in the carb body. If that is what is supposed to be drilled out, then it hasn't been done, which is great news to me. And if the needles aren't Dynojet ones either (hard to tell but a hint in those washers perhaps), and no funky sheet metal looking screw has been stuck in 'somewhere', all I need to do is what you say.

    Edit: I see the spec sheet calls it a 'plug drill' so it may be that is for the 'emissions mixture screw', and the sheet metal screw is to block it off once drilled out? Seems very hack-ish, if so. And mine are not drilled out regardless. Hey, I don't know shine-ola about Dynojet kits but I think maybe the needle has no damage done, as the song says, sorta.

    And I could ditch the pods if I can find a stock airbox for a decent price, and slightly mod my nice GS850G pipes to fit the clamp spacing at the head, as they fit fine otherwise.

    Quote Originally Posted by zed1015 View Post
    Ideally you need to put the carbs back to stock.
    Increase the main for the pods and pipe and fit air corrector jets to correct the off idle hesitation.
    That's all that's needed.
    No need for over complicated Dynojet kits with different needles , over large mains and bigger pilots etc that go to elaborate lengths to cure a simple fueling glitch.
    Last edited by oldGSfan; 02-11-2021 at 06:21 PM.
    Tom

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    The GS1000E Dynojet kits include larger main jets , Different needles, metal shims a plug drill and THAT screw.
    The drill bit and screw is used to remove the anti tamper caps on the fuel mixture screws on the far right of your pic which are not present .
    You will need some genuine needles to put it back to stock , smaller mains than those 138's and if keeping pods just fit air correctors which do a nicer job than the Dyno jet.
    Dynojet needles are known to be a bit rough and wear the needle jet.
    Those plastic needle spacers are original and located correctly with the thin one underneath and the thick one on top.
    Mikuni Viton Choke Plunger Seat Renewal.
    VITON Choke plunger seals .KAWASAKI Z1,Z900,Z650,Z1000,Z1R,SUZUKI GS1000,GSXR,RF | eBay

    Air Corrector Jets for Mikuni VM 24, 26 and 28mm carbs .

    https://www.ebay.co.uk/itm/254380193...84.m1555.l2649




  5. #5
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    OK I see, so that screw just is used as a puller to remove the anti-tamper cap then, once the cap has a hole punched in it. That is good to know, I can work with these.

    Needle shows up as same part number from the '79 850G which I have a full set of...

    Stock main is a Mikuni #95 on the 1000 but the 850G is bigger at #102.5. Interesting, I wonder if trying that combo plus the 'air correctors' makes sense? I have them in hand except the corrector, where can I source those? Oh wait I see you have on eBay.... future sale coming :-)

    Thanks for your help, learning a lot.
    Tom

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    salty_monk's Avatar
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    That does look like a Dynojet. You can see when they are stock, the Dynojet is quite a lot sharper and stock is usually a goldish color like a yellow passivate.... Do you have an airbox for it? I might have the set of stock needles and jets mine came with somewhere along with the DJ box & instructions.

    I've personally had no issues with the Dynojet stage 3 with K&N pods & 4:1.

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    No I don't have a stock airbox, wish I did. Let me know if you can scrounge those bits up, thanks!


    Quote Originally Posted by salty_monk View Post
    That does look like a Dynojet. You can see when they are stock, the Dynojet is quite a lot sharper and stock is usually a goldish color like a yellow passivate.... Do you have an airbox for it? I might have the set of stock needles and jets mine came with somewhere along with the DJ box & instructions.

    I've personally had no issues with the Dynojet stage 3 with K&N pods & 4:1.
    Tom

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    Quote Originally Posted by oldGSfan View Post
    OK I see, so that screw just is used as a puller to remove the anti-tamper cap then, once the cap has a hole punched in it. That is good to know, I can work with these.

    Needle shows up as same part number from the '79 850G which I have a full set of...

    Stock main is a Mikuni #95 on the 1000 but the 850G is bigger at #102.5. Interesting, I wonder if trying that combo plus the 'air correctors' makes sense? I have them in hand except the corrector, where can I source those? Oh wait I see you have on eBay.... future sale coming :-)

    Thanks for your help, learning a lot.
    Good news with having the original needles.
    With the air correctors you should end up around 117.5 on the main jet.
    Once fitted you should put all carb settings to stock, this includes needle clip position and just increase the main.
    Make sure you use good quality free flowing pods such as K&N, S&B, APE and not the cheap Emgos etc as these are often more restrictive than the airbox which will result in rich running and strangled top end power.
    Mikuni Viton Choke Plunger Seat Renewal.
    VITON Choke plunger seals .KAWASAKI Z1,Z900,Z650,Z1000,Z1R,SUZUKI GS1000,GSXR,RF | eBay

    Air Corrector Jets for Mikuni VM 24, 26 and 28mm carbs .

    https://www.ebay.co.uk/itm/254380193...84.m1555.l2649




  9. #9
    KEITH KRAUSE's Avatar
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    The drill bit and screw have been addressed. They don't apply in your case. Your jet needle pictured is from DJ. DJ needles in your kit have 6 e-clip grooves. Factory jet needles have only 5.
    As for properly jetting with the stage 3 DJ kit, with a quality pipe like V&H or Kerker, and quality pods like K&N...Use the 138 DJ mains, place the jet needle e-clip in the 3rd groove from the top, if this results in a little too lean then place the e-clip in the 4th groove from the top and then place the DJ provided jetting spacer directly on top of the e-clip. The thicker spacer (ring) goes on top the e-clip or jetting spacer if used and the thinner spacer goes under the e-clip. That adjustment is equal to "position 3 1/2". I seriously doubt you would need to go richer. Set the float height to .95 which is in the middle of the factory setting range of .90 to .98". Be very careful adjusting them. Be sure all of the float needle valves are in good condition and DO NOT mix the valves with valve seats as the valve and seat wear as a unit. Mixing will result in fuel leaking through. Also be sure to replace the fiber gasket for the seats. The stock pilot jets (15) are fine as is. Initially set the side air screws at 2 turns out from lightly seated. Initially set the pilot fuel screws underneath to 1 1/2 turns out from lightly seated. REMOVE the 2 float bowl vent lines to allow the bowls to vent better. Do not cap the vents. Leaving the vent lines on will result in various levels of fuel starvation, especially on windy/crosswind conditions. Carefully bench synch the throttle valves. Unless you're extremely lucky, the bench synch must be followed by a vacuum tool synch with a quality gauge such as a CarbTune. Synch at 1,600 to 2,000 rpm's by setting the idle adjuster knob. Once synched properly, fine tune the side air screws using the "highest rpm method". Place the bike on the center stand is best. With the air screws initially set at 2 turns out, be sure, as with the synch, to warm the motor fully, place a fan or two to cool the motor, set the idle with the idle adjustment knob underneath to ideally 1,000 rpm's. Start at carb #1. Slowly adjust the air screw in or out and listen for the highest/best idle. Once you find the sweet spot, stop. Re-set the idle to 1,000 rpm's by using the idle adjuster knob if necessary. Repeat to each carbs. ALL basic tuning must be done before synching the carbs. Valve clearances, ignition timing, no intake leaks, proper 5/16" fuel line, proper spark plugs and gapped properly, everything must be right before tuning the carbs and re-jetting.
    Be very careful to not over-oil the K&N's. If you follow the directions on the K&N spray can you can easily over-oil them. "Spray each pleat" results in too much oil and the motor will bog when you open her up. Spray about "3 pleats at a time from 4-6" away with a fairly quick sweep of the can.
    The real benefit of the stage 3 kit is in the more sharply tapered jet needles. You spend the most time riding at the throttle positions of 1/5 to 3/4 throttle. The jet needle controls fuel flow at those throttle positions with a small overlap from the pilot circuits and main jet. Besides the looks and sound of a quality 4 into 1 pipe and K&N pods, the HP gain is obvious compared to stock, but only at higher rpm's. At about 7,000 rpm's a properly jetted bike will pull away from a stock bike. If you don't really care about that higher rpm performance, then maybe going back to stock is best?
    Keep in mind the stage 3 settings I suggest may require fine tuning of the pilot fuel screws and as I mentioned, changing the jet needle position. If you need to adjust the jet needles, you must always re-synch the throttle valves.
    If you use the stage 3 mains but you use the factory jet needles, you'll most likely have to place the e-clips in the bottom groove (factory position is #3). The factory jet needles DO NOT mix as well as the DJ needles and often give poor results with intake/exhaust mod's, but not always.
    If you go back to stock, the factory mains are #95. Jet needle position is #3 groove from the top on factory needles. Pilot fuel screws setting are impossible to re-set without emissions equipment. Try 3/4 to 1 turn out from lightly seated. Side air screws are as I said earlier. Put the float bowl vent lines on and route them to the sides and near the top of the stock air box. They need to be factory length or close to it. I forget now but about 18" long?
    Any short cuts, such as not checking/replacing the intake manifold o-rings, not replacing the o-rings in the carbs, not doing the other tuning, will make a re-jetting inaccurate and frustrating.
    Also, I have had bad luck with buying the genuine factory bowl gaskets lately. They are often harder than they should be due to sitting on a shelf too long? They can easily allow leaking. I tried the bowl gaskets from Z1 Enterprises and found that they are softer and seal better against leaks, at least for me. One other note, if you replace the manifold o-rings, replace the stock Phillips screws too. Use Allen screws instead. You can then torque them to about 9 ft/lb. First apply a light coat of high-temp grease to the o-rings to help them last. Be sure the manifolds are in good condition, inside and out.
    I have never needed to change any other part of the jetting for basic intake/exhaust mod's, including larger pistons. The "air correctors" are not needed. Only with more extreme mod's would you maybe need to make changes to the air jets or throttle valve cut-away, etc.
    Good luck!
    Last edited by KEITH KRAUSE; 02-20-2021 at 10:34 PM.
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  10. #10
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    Wow, thank you very much Keith. I couldn't have asked for more.

    I have new carb and intake O-rings but hadn't thought to go with Allen screws, that's an easy update. I still have my Motion Pro carb stix with mercury that has travelled around the world 3x since I got them in the 80's. Latest use was on my '73 Honda CB750, and I've got that bike running great.

    I will read and re-read your advice as it seems spot-on and what I need. I am good at following directions and have been meticulous in cleaning and keeping each carb's bits with the right one (but who knows what secrets the past holds).

    Quote Originally Posted by KEITH KRAUSE View Post
    The drill bit and screw have been addressed. They don't apply in your case. Your jet needle pictured is from DJ. DJ needles in your kit have 6 e-clip grooves. Factory jet needles have only 5.
    As for properly jetting with the stage 3 DJ kit, with a quality pipe like V&H or Kerker, and quality pods like K&N...Use the 138 DJ mains, place the jet needle e-clip in the 3rd groove from the top, if this results in a little too lean then place the e-clip in the 4th groove from the top and then place the DJ provided jetting spacer directly on top of the e-clip. The thicker spacer (ring) goes on top the e-clip or jetting spacer if used and the thinner spacer goes under the e-clip. That adjustment is equal to "position 3 1/2". I seriously doubt you would need to go richer. Set the float height to .95 which is in the middle of the factory setting range of .90 to .98". Be very careful adjusting them. Be sure all of the float needle valves are in good condition and DO NOT mix the valves with valve seats as the valve and seat wear as a unit. Mixing will result in fuel leaking through. Also be sure to replace the fiber gasket for the seats. The stock pilot jets (15) are fine as is. Initially set the side air screws at 2 turns out from lightly seated. Initially set the pilot fuel screws underneath to 1 1/2 turns out from lightly seated. REMOVE the 2 float bowl vent lines to allow the bowls to vent better. Do not cap the vents. Leaving the vent lines on will result in various levels of fuel starvation, especially on windy/crosswind conditions. Carefully bench synch the throttle valves. Unless you're extremely lucky, the bench synch must be followed by a vacuum tool synch with a quality gauge such as a CarbTune. Synch at 1,600 to 2,000 rpm's by setting the idle adjuster knob. Once synched properly, fine tune the side air screws using the "highest rpm method". Place the bike on the center stand is best. With the air screws initially set at 2 turns out, be sure, as with the synch, to warm the motor fully, place a fan or two to cool the motor, set the idle with the idle adjustment knob underneath to ideally 1,000 rpm's. Start at carb #1. Slowly adjust the air screw in or out and listen for the highest/best idle. Once you find the sweet spot, stop. Re-set the idle to 1,000 rpm's by using the idle adjuster knob if necessary. Repeat to each carbs. ALL basic tuning must be done before synching the carbs. Valve clearances, ignition timing, no intake leaks, proper 5/16" fuel line, proper spark plugs and gapped properly, everything must be right before tuning the carbs and re-jetting.
    Be very careful to not over-oil the K&N's. If you follow the directions on the K&N spray can you can easily over-oil them. "Spray each pleat" results in too much oil and the motor will bog when you open her up. Spray about "3 pleats at a time from 4-6" away with a fairly quick sweep of the can.
    The real benefit of the stage 3 kit is in the more sharply tapered jet needles. You spend the most time riding at the throttle positions of 1/5 to 3/4 throttle. The jet needle controls fuel flow at those throttle positions with a small overlap from the pilot circuits and main jet. Besides the looks and sound of a quality 4 into 1 pipe and K&N pods, the HP gain is obvious compared to stock, but only at higher rpm's. At about 7,000 rpm's a properly jetted bike will pull away from a stock bike. If you don't really care about that higher rpm performance, then maybe going back to stock is best?
    Keep in mind the stage 3 settings I suggest may require fine tuning of the pilot fuel screws and as I mentioned, changing the jet needle position. If you need to adjust the jet needles, you must always re-synch the throttle valves.
    If you use the stage 3 mains but you use the factory jet needles, you'll most likely have to place the e-clips in the bottom groove (factory position is #3). The factory jet needles DO NOT mix as well as the DJ needles and often give poor results with intake/exhaust mod's, but not always.
    If you go back to stock, the factory mains are #95. Jet needle position is #3 groove from the top on factory needles. Pilot fuel screws setting are impossible to re-set without emissions equipment. Try 3/4 to 1 turn out from lightly seated. Side air screws are as I said earlier. Put the float bowl vent lines on and route them to the sides and near the top of the stock air box. They need to be factory length or close to it. I forget now but about 18" long?
    Any short cuts, such as not checking/replacing the intake manifold o-rings, not replacing the o-rings in the carbs, not doing the other tuning, will make a re-jetting inaccurate and frustrating.
    Also, I have had bad luck with buying the genuine factory bowl gaskets lately. They are often harder than they should be due to sitting on a shelf too long? They can easily allow leaking. I tried the bowl gaskets from Z1 Enterprises and found that they are softer and seal better against leaks, at least for me. One other note, if you replace the manifold o-rings, replace the stock Phillips screws too. Use Allen screws instead. You can then torque them to about 9 ft/lb. First apply a light coat of high-temp grease to the o-rings to help them last. Be sure the manifolds are in good condition, inside and out.
    I have never needed to change any other part of the jetting for basic intake/exhaust mod's, including larger pistons. The "air correctors" are not needed. Only with more extreme mod's would you maybe need to make changes to the air jets or throttle valve cut-away, etc.
    Good luck!
    Tom

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