GS1000 valve clearance problem

[NitroGS]

Hi Guys,

Just in the process of renovating the prize 79 model Suzuki GS1000. I have been checking the valve clearances as stated in the manual and got the following readings

Exhaust Cylinder 1 .10
2 .10
3 .08
4 .10

Inlet Cylinder 1 .08
2 .05
3 .10
4 .06

What are your thoughts on which ones I should change. Would you beleive the previous owner or garage has fitted the exhaust shims on cylinder 1 and 2 upside down hence there is no size markings, how do I solve that one my friends.

[salty_monk]

Take them out & measure them... The markings could easily have worn off anyway.

Some of them are not always as stated too, I found some small differences between Shims marked the same.
Any with an x are oversized from the factory.

I'd double check them, strange for them to be too big rather than too small, they get smaller as they wear..... Looks like you need EX 1,2 & 4 Plus In 3.

I guess it's not the end of the world if they are big on the exhaust, better than small anyway!

Dan

[KEITH KRAUSE]

Hopefully you checked EXACTLY as the factory procedure says to.
Some owners insist on checking every valve with the lobe pointing straight up. My experience shows this method to give inaccurate/changing reads. The factory method should be used. The factory clearances are .03 to .08 mm.
If you did as the factory says, I'd change the clearances that read .10 mm to the next standard size thicker to give you a .05mm read. If a number wore off, just measure with verniers or micrometer.
I would not change the .08 clearances. I know that the next standard shim could bring it to the minimum .03 but I personally don't like to run right at the minimum. A valve set at the maximum range is better than one set at the minimum range. If you can locate some "X" shims or "fat" shims, that gives you greater flexability. You may be able to swap some existing shims to get correct clearances.
Be sure you add a bit of oil to each shim and crank through a couple cycles and double check the reads after replacement.
A very thin coat of bearing grease will help the new valve cover gasket seal and the gasket comes off much easier the next time.
Be sure to use only Suzuki shims. Some owners thought they could use Kawasaki shims but they are a different outer size diameter.

[NitroGS]

Thank you for that Keith it is much appreciate. Do you measure the clearances in position A or B personally. Will change the .10 ones thank you.

[KEITH KRAUSE]

Thank you for that Keith it is much appreciate. Do you measure the clearances in position A or B personally. Will change the .10 ones thank you.

The correct, factory recommended method...stone cold motor, overnight is best.
Turn crank to bring exhaust cam cyl 1 so it points parallel with top of the head. That is, basically pointing at 9:00. (If you start with exh cam cyl 1 in this position, don't be concerned where the remaining lobes point. They WILL be facing in the correct position as you follow these instructions.) Remember, the top of the head is angled slightly downward and the center of the cam lobe will be pointing at that same slight angle.
In this condition, read the clearance at exh 1 and 2.
After setting those clearances, turn the crank 180 degrees (1/2 rotation), which will bring intake cam cyl 1 to 12:00. Read the clearances at intake 1 and 2 and adjust if necessary.
Turn another 180 degrees which will bring exh cam cyl 4 to 3:00. Read the clearances at exh 3 and 4 and set if necessary.
Rotate crank another 180 degrees which will bring intake cam cyl 4 to 12:00. Read intake 3 and 4 and set if necessary.

The above assumes you have any needed shims available as you go through the procedure. But you would still check existing clearances the same way if you just want to see what you have.
It's true that the factory manual says the cams can be checked in two positions, one of which is pointing up, but I've found that you will get different reads if you insist on checking/adjusting all of them in only the up position. I always trust the EXACT factory method if there's a difference or any doubt.
During my very first valve tappet clearance job, I ended up checking/setting them with the cams all pointing up. I thought it was OK. The bike ran a little weak so I worried and took the bike into the Suzuki dealer. I had bought the bike new and it was less than a year old. They quickly found 3 clearances set too tight (less than .03mm). I was sure I checked and double checked. I told them how I set them and they told me that the "lobes up" method not only requires more cranking, it gives inaccurate results, as I found out. Since then, my valves clearance jobs have gone well following the factory method. I try to let others know because I know the lobes up method is mistakenly used by many owners.
Hopefully I described the correct lobe position well. A pic would make it simple. Because the top of the head surface (where the rubber half moons fit) is not exactly parallel with the ground, you have to make the lobe point parallel with the top head surface.
Be sure you replace those half moons if they are at all old/hardened. They are notorious for leaking soon if not immediately. Don't put them in backwards as some say they've done. Many use a bit of pliable sealer to assist sealing. Just enough to assist, not so much that it oozes into the motor when you torque down.
Another tip...many here say they like the silicone valve cover gaskets made by Realgaskets. Do a search on this or make a new topic requesting opinions if interested.

[NitroGS]

As usual Keith, your responses are absolutely first class and I am indebted many thanks. I hope you can stick with me. I have read alot of your previous posts and I am starting to tackle all the tuning and setup jobs in the order you suggest. My GS is running a Harris 4 into 1 and bellmouth carbs with a Wiseco 1085cc high compression kit. Once I have checked and adjusted the valve clearances, I shall be fitting a Dyna S ignition system, Dyna Coils and Dyna leads and splitfire plugs. Then I shall be moving onto the VM carbs which I am looking forward to having the benefits of your vast experience. I have 4 sets of carb repair kits and o ring sets, I remember you saying stick with your original jets if they are in good condition, so shall be checking that. I haven,t bench synched or vacuum synched carbs before so it will be a new experience. I have read numerous threads on the subject just to improve my understanding. I look forward to further communications in the coming weeks. Again thanks alot

[NitroGS]

Many thanks Salty for the reply and information. This forum really is a community to behold. Long live the GS's, I have had mine 24 years now.

[salty_monk]

Hope you're not flooded out!! Not much riding weather there at the moment!

Dry down my end (originally from South East London).

Your bike looks great by the way, never seen a fairing, mudguard or scoop like that on a GS before. Did you make them yourself??

Dan

[NitroGS]

Hi Dan,

No luckily, we are fine in this part of the woods, but it is not biking conditions. Gives me time to sort the old GS out.

[NitroGS]

Thank you for all your help guys, mission accomplished on the valve clearances. Now onto fitting the Dyna Coils, DynateK ignition tomorrow. Then on Tuesday its the carb cleaning bench synching, enjoying every minute.

[KEITH KRAUSE]

As usual Keith, your responses are absolutely first class and I am indebted many thanks. I hope you can stick with me. I have read alot of your previous posts and I am starting to tackle all the tuning and setup jobs in the order you suggest. My GS is running a Harris 4 into 1 and bellmouth carbs with a Wiseco 1085cc high compression kit. Once I have checked and adjusted the valve clearances, I shall be fitting a Dyna S ignition system, Dyna Coils and Dyna leads and splitfire plugs. Then I shall be moving onto the VM carbs which I am looking forward to having the benefits of your vast experience. I have 4 sets of carb repair kits and o ring sets, I remember you saying stick with your original jets if they are in good condition, so shall be checking that. I haven,t bench synched or vacuum synched carbs before so it will be a new experience. I have read numerous threads on the subject just to improve my understanding. I look forward to further communications in the coming weeks. Again thanks alot

Back from vacation. How's it going?
By the way...you sure you want to run without air filtration?

[NitroGS]

Hello Keith,
First of all I hope you have had a good vacation my friend, it is very reassuring to have you back.
Quite alot has happened since we last spoke. In line with your suggestions I have ensured the engine is in
top tune prior to finally syncing the carbs (still to do, carbtune snychroniser on its way more later). I have fitted the Dyna S ignition,Dyna coils, Dyna leads and new plugs. The ignition timing is set spot on and checked cam timing which is also spot on. The valve clearances are now set to specification (edging on the .07 to .08 side). New carb boots should be with me anyday and will be fitted. I have opted for the Kawasaki boot version with adaptors (quicker for synch connection), slightly different mounting hole spacing but not a problem. The Vance & Hines 4 into 1 exhaust has just arrived on the doorstep this morning and things were looking rosy.
I removed the bank of VM carbs with a view of giving them a thorough cleaning, finishing in a bench synch and then the final vacuum synch. But on removal and inspection of the carbs I noticed that 2 of the pilot fuel crews were sheared in their respective seats. My first thought was panick, then I pulled myself together over a coffee and asked our GS Resource experts. I was pointed to an excellent thread on pilot fuel screw removal. Met with some sucess, removed one of the tips. But the other tip will not come out, I have tried everything. So I slashed the mattress broke the childs "Piggy Banks" and purchased a bank of Suzuki GS1000 VM's off ebay (just awaiting their arival). The setup on the Suzuki GS1000 at present is it has a 1085 Wiseco Piston kit, velocity stacks (I take your point about the stacks but I am going to have to run with them for a while until funds recover) and a Harris 4 into 1 exhaust which will be replaced with the Vance and Hines 4 into 1 in the next 2 days. What are your thoughts on the setup Keith.
ps When the carbs arrive I am going to be so nervous about seating the pilot fuel screws

[NitroGS]

Hi Guys

Struggling to find a Stage 3 Dynojet kit for the Suzuki GS1000 1979 model (slide carbs) in the UK, do any of you guys live near a supplier?

[KEITH KRAUSE]

Too bad about the pilot fuel screw tips. Hoomgar, a member here, made a good thread about removal, so I'm a little surprised you couldn't get the one out. I hope your new set of carbs will be good. I used to rebuild carbs for extra spending money and you really have to ask lots of questions to try to avoid receiving carbs with more problems.
I'm against running the stacks but I'll try to suggest jetting that will work. It's very possible that your re-jet will have to be done again if you decide on some K&N's later. That means not only main jet changes and possible pilot jet changes, but possible jet needle adjustments that mean taking the slides out again. And every time you disturb the jet needles on VM carbs, you must re-bench synch and then re-synch with a vacuum tool. Personally, I wouldn't use my time and possibly re-jet/re-test twice. If at all possible, I'd get the K&N ovals (P/N- RC2454).
This brings up another $ issue...a jet kit. If you've read any of my past posts on re-jetting for 1085/V&H/pods, you'll see that the stock jet needles SOMETIMES just don't allow enough richness. That's why I come right out and suggest the DJ jet kit. I'll make suggestions for your stacks and stock needles but at least you've been warned that your efforts may not work. The stacks make it more likely the stock needles won't work, but what helps a little is the typical higher humidity you have there. I'm no expert at your actual weather, just things I've heard about it.
I suggest a look at the VM carb series clean up/rebuild section here. If you don't have the factory manual, this section is helpful.
When re-jetting, I always follow a strict list of things to do to make the re-jet easier. One of those things is to replace ALL inner o-rings. Robert Barr, a member here, sells a very good o-ring kit for the VM carbs. I recommend it. Don't re-use older, hardened/brittle o-rings.
Be very thorough when cleaning. Verify every tiny hole and passage is clean. I use high pressure air after soaking/cleaning and I verify that air passes in and out of every passage.
Don't mix the carb parts. Keep each carbs parts with that carb, especially the float needle valve and its seat and the jet needle and needle jet combo.
Set your float levels right in the middle of the factory recommended range of .90" to .98", that means .94". You may have to slightly tweak the floats a bit to be sure both sides are even with each other.
Be very careful that every part goes back in the right side up and in correct factory order. The thin brass plate that sits under the throttle arm base (between the base and inside of slide) is sometimes installed upside down if you didn't pay attention. Note the little raised dimple on it. When making jet needle e-clip adjustments/re-assembly, be sure the two plastic jet needle spacers go back in correct order...thicker directly on top the e-clip/thinner under the e-clip.
Don't over-torque small hardware. 3.5 ft/lb for the throttle arm-to- throttle shaft bolts. 3.5 ft/lb for the holder nuts that hold the synching screw on top of the slides.
You say the valve clearances, ignition timing, manifolds are good.
Be sure of clear gas tank venting, correct 5/16" fuel line and good vacuum hose condition. Be sure the petcock is clean.
Be sure the plugs are NGK B8ES, gapped at approx' .027/.028" and all leads are in supple condition. Coil lead to plug cap connections must be verified solid and tight and clean. Spark should be a good bluish/white color.
As a side note, inspect/clean all electrical connections. The wires from the stator are often over-heated due to the poor design of the stock reg/rec. The rubber boot that holds a wire bundle right by/above the battery, often has burned connections in it. Check your electrical system. Read the Stator Papers here to understand why you may want to install a superior R/R, if you see any problems. Pay extra attention to good grounding of the system. Install the extra grounds, etc.
A bit of work, but if all the above is done first, then any performance problems will be jetting related and that makes things easier to adjust.
I'll get back with the jetting in a bit. Got to eat supper!

[KEITH KRAUSE]

As always, I try to suggest what has the best chance to work, hopefully the first try but that's not easy. Your stacks and climate make it a little more difficult. Again, it's likely that the stock jet needles won't supply enough fuel but you can try.
This is for the stock jet needles and buying separate GENUINE Mikuni jets.
DJ and Mikuni have different ways to determine flow/jet size, so don't let the numbers confuse you.
I think your bike will have no problem running 135 mains. The 135 Mikuni mains are only a little larger than 142 Dynojet mains, which are the larger of the two main jet choices supplied in the DJ jet kit designed for use with your pipe and K&N pods. Your stacks figure to require just a little more fuel so I suggest the 135 mains. It's also possible a little larger may be necessary (137.5 or even 140?) but only full throttle tests will tell. The thing is, while operating on the mains from approx' 3/4 to full throttle, the stacks have greater high rpm effect than at lesser rpm's. They're for racing, not for general street manners. You may find that at 3/4 to full throttle/higher rpm's the bike screams but you may have a bog when rolling on the throttle at lower rpm's. It's just hard to guess what will happen.
Only chance the stock jet needles have is to place the e-clip at the bottom position. You CAN reverse the two factory plastic spacers and this will allow the jet needle to raise up even more but I haven't actually done this. I always go with a jet kit if the stock needles don't work. I only mention the spacer swap because in theory, it could work and you mention $ as a limiting factor here. HOWEVER, keep in mind the factory determined the top spacer (actually called a ring) should be thicker than the spacer under the e-clip, probably for shock/vibration/strength issues. Test the jet needles and get plug/performance reads at solid 1/3 throttle.
For the pilot jet, I'd try 17.5. Check yours and order the correct length, since there are two lengths for your carbs.
Decel' popping is a common problem with freer flowing exhaust/intakes. (Be sure the header gaskets are new by the way.) Sometimes trying to eliminate the popping can cause worse problems. A little is acceptable in my opinion. I'd probably set the pilot fuel screws (underneath) to 1 1/4 turns out from lightly seated initially. Adjustments/fine tuning will most likely be needed. Set the side air screws to 1 3/4 turns out initially. All pilot circuit tests should be done at a minimal throttle position, under 1/5 throttle.
REMOVE the two floatbowl vent lines to avoid fuel starvation when running pods or stacks. Leave the vent ports open. This is mentioned in stage 3 jet kit info.
After the carbs are bench synched for both the fully closed and fully open positions, they will need to be synched with a vacuum gauge.
Be sure throttle cable slack is adjusted correctly. About 2 to 3mm on the pulling cable, and zero on the return cable.
If the bench synch was set correctly, the bike should start up. Warm it up completely.
Adjust the side air screws using the highest rpm method. With the bike fully warmed up and idling at 1,000 rpm's and on the centerstand, start at any carb. Turn a screw slowly in either direction until you achieve highest rpm. The sweet spot is generally between 1 1/2 to 2 turns out. Fine tune. Now re-set the idle to 1,000 rpm's if necessary by using the idle adjuster knob. Repeat to the other carbs.
Now you can hook up the vacuum tool and synch the levels so that the difference from the highest to lowest level is about 3/4" or less, if you can do that without taking too much time and over-heating the motor. I synch at approx' 3,000 rpm's. Some here have different opinions. The higher the rpm's, the quicker the heat builds. Use two good fans. The closer the levels the better, but trying to make them perfect isn't necessary. If within 3/4" as above, I see no significant performance gains by trying to get them perfect. I've found that after viewing the initial levels produced by your best bench synch, you should LOWER any higher level(s) you see to reasonably match the lower levels you see. Be careful and make small adjustments. The levels will move a bit as you tighten the synch screw holder nuts if you allow the synch screw to move. This method helps to avoid the condition where the bike will begin to idle too high, despite the fact that the idle adjuster knob tip is no longer contacting the throttle pulley. This is caused by the slides being adjusted until they rise too much and an adjustment at one carb can actually change the adjustment at another carb. If you reach this point, it's best to stop and re-bench synch and start over with the vacuum tool synch. Some of us have to aquire a feel for synching. It can take some tinkering. Just don't over-heat the motor. If you take too long, turn it off and let it cool down. Keep in mind that with mercury gauges, upon re-start, you may see condensation mixed in with the mercury in each cylinder line. This can, depending on the amount and size of the gaps, create problems in trying to adjust the levels accurately. You can sometimes remove some or all of the condensation gaps by quickly pulling off the gauge hose connected at the manifold and quickly re-installing it. Condensation can take a long time to remove itself from the gauge reservoir. Experienced synchers have little trouble with condensation and I hope you won't either. The Morgan synch tool uses metal rods that obviously stop this problem. It does cost quite a bit more than a typical Motion Pro mercury gauge. Also, be careful to not back off the throttle too quickly or mercury can suck up into the motor.
Check performance and do throttle chop plug read tests at the appropriate throttle positions for each jetting circuit.
Let us know how it goes.
If you decide to buy the DJ kit, I can help you with that too, but keep in mind the largest jet they supply may not be large enough for the stacks and you may need to buy separate DJ mains too.