gs1000g now starts but still running rough at high revs

[80GS850GBob]

A good point, they are not expensive, I'll get a new set of plug caps.

Well, check them....they might be fine. That's also easy to do if you have a meter that'll read out in ohms. If not, then yeah, they're cheap. On my 850g the lowest speck cap was 16 ohms while the other three were in the 20 to 23 ohm range. The give away for me was the PO said she was hard starting and I saw the starter relay posts were discolored looking from over heating...and I needed new wires too....that was fun.

[DaveWatts]

Well, check them....they might be fine. That's also easy to do if you have a meter that'll read out in ohms. If not, then yeah, they're cheap. On my 850g the lowest speck cap was 16 ohms while the other three were in the 20 to 23 ohm range. The give away for me was the PO said she was hard starting and I saw the starter relay posts were discolored looking from over heating...and I needed new wires too....that was fun.

Ok, I checked them, all the 4 original Suzuki ones read about 10 ohm (+-0.3 ohm) and the 4 NGK caps read about 5 ohm (+- 0.2 ohm). One of the Suzuki ones had no continuity, so that could well be the problem for one cylinder. I am guessing that the 10 ohm figure is for spark plugs without an extra resister in them (I can't find any info in the manual about cap resistance), which is the original plugs specified are B8ES (no resistor), I got B8ES spark plugs so I should use the original plug caps, with the NGK caps maybe I would be better off with BR8ES to bring it up to 10 ohms.

Cheers

Dave

[80GS850GBob]

More ohms is more resistance....meaning less spark and harder starting at the plug end. I'd strongly suggest the ngk, or any, cap that has only 5 ohms reading. BRes plugs are fine though if your running a fairing and radio you might get some interference. I think oem plugs ask for resister plugs, but I run yhe es type and its fine.
Now, when you screw on the new caps, cut off roughly a 1/4" of wire end for a fresh connection there....time promotes corrosion there and can add resistance.

[2BRacing]

"Check the mechanical advancer in case it's frozen" is that something that happens often? it would explain things.

The diaphragms were the thin rubberised canvas originals and were installed directly on the slide cylinder, the diaphragms also had the tang for locating in the carb housing, I think they are ok.

I want to check the chain tensioner as well, Are there any good resources out there, the manual pages are a bit confusing?

With checking the value clearances, the lobe should be sticking up perpendicular to the shim face for maximal clearance, right? I've seen some videos where people have the exhaust cam lobe facing forwards and in line with the rocker cover gasket surface, it also says that in the manual, but that doesn't make sense to me, does anyone know why Suzuki specified it like that?

You mention you fitted " a new set of original diaphragms" in the carbs. I was always under the impression that OEM diaphragms were only available complete with the slides. Would you mind sharing your source of these diaphragms (and part number), as the slides are usually OK, so sourcing diaphragms only would be great!

The Factory Service Manual describes the positioning of the cams when checking valve clearances. It is not correct to just have each lobe perpendicular to the shim face. The adjacent lobe will be pressing down on its shim/bucket, and this will "skew" the cam slightly in the journals, resulting in incorrect clearance. There were a number of posts recently on this subject, with replies by members Steve and Nessism, who explained the reasons and procedure much better than I am able to. Do not follow the Clymer manual description.

Go here for resources on checking the cam chain tensioner: http://members.dslextreme.com/users/bikecliff/ and here: http://bwringer.com/gs/camchaintens.html

[salty_monk]

You'll be fine using the NGK plug caps (the Z1 enterprises sell - at least that's where I got mine) with B8ES plugs. Been using that combination for years.

[DaveWatts]

You mention you fitted " a new set of original diaphragms" in the carbs. I was always under the impression that OEM diaphragms were only available complete with the slides. Would you mind sharing your source of these diaphragms (and part number), as the slides are usually OK, so sourcing diaphragms only would be great!

The Factory Service Manual describes the positioning of the cams when checking valve clearances. It is not correct to just have each lobe perpendicular to the shim face. The adjacent lobe will be pressing down on its shim/bucket, and this will "skew" the cam slightly in the journals, resulting in incorrect clearance. There were a number of posts recently on this subject, with replies by members Steve and Nessism, who explained the reasons and procedure much better than I am able to. Do not follow the Clymer manual description.

Go here for resources on checking the cam chain tensioner: http://members.dslextreme.com/users/bikecliff/ and here: http://bwringer.com/gs/camchaintens.html

I got them from a guy in Australia off ebay for a reasonable price, they came with the slides (1350049200). But you can always get them at cms (eu) or partzilla (usa) but they are expensive. https://www.cmsnl.com/suzuki-gs1000g...1.html#results I think the originals are better since they are rubberised canvas. The pattern parts are often just rubber and seem stiffer which cant be good for the action.

[DaveWatts]

More ohms is more resistance....meaning less spark and harder starting at the plug end. I'd strongly suggest the ngk, or any, cap that has only 5 ohms reading. BRes plugs are fine though if your running a fairing and radio you might get some interference. I think oem plugs ask for resister plugs, but I run yhe es type and its fine.
Now, when you screw on the new caps, cut off roughly a 1/4" of wire end for a fresh connection there....time promotes corrosion there and can add resistance.

Any ideas why the original caps all seem to be 10 ohm, do you think that is what Suzuki intended? It would be interesting to know if it is just my plug caps or if others also found theirs at 10 ohm.

[salty_monk]

No idea. Quite possibly something they did on the early model with ignition electronics. On the older models with points there is nothing to interfere with anyway....

I ran 3 ohm Dyna coils on my 1000G with a Dyna S pickup (to get ride of the faulty ignitor box) with B8ES plugs and no suppression in any of it....

[DaveWatts]

A good call to check the valves clearance, they were mostly way too small. Many of the ones with no clearance had a broken off bit of feeler gauge underneath, what a bodge! I swapped a few about and things are a bit better, but then the sun started getting low so I quit for the afternoon. I think that the previous owner also may have got the timing wrong, but I'll need the book to check for that properly, I'll check that once all the shims are sorted.

[DaveWatts]

Set all the valves between the limits and changed the coil and plug caps and now the bike now revs up cleanly (after a bit of sputtering). The cam timing was good and the ignition advance as well. Now that's done I will investigate why the clutch seems to be stuck.

[80GS850GBob]

Set all the valves between the limits and changed the coil and plug caps and now the bike now revs up cleanly (after a bit of sputtering). The cam timing was good and the ignition advance as well. Now that's done I will investigate why the clutch seems to be stuck.

As things wear, valve clearance wise, the gap tightens up and can even close. It's best set to the high side as you can...this will give you more time, so to speak, till the next needed adjustment.
"Clutch is stuck"...whats the problem?...hard to pull, slips...?

[DaveWatts]

They are mostly set a 0.05 mm a couple are at 0.07mm, there are none that are so close to 0.03. I can't anyway easily get the in between shim sizes so I will leave it for a year or so. The clutch plates are stuck together so that even when the clutch is pulled in turning the wheel turns the gears & motor. I am leaving the clutch lever pulled in a few days to see if that helps, if its still the same then I will change the oil and wash the plates (& maybe get a new set depending on condition).

[80GS850GBob]

If they're stuck together now, I'd say drain the oil and check it out. Look at the steels and the fibers..mic the thickness of the fibers to see if they're still in spec. I've seen steels that were blue from slippage. Check the drum for tangs for any groves from the clutch tabs. The springs should be checked too.

[2BRacing]

........ The clutch plates are stuck together so that even when the clutch is pulled in turning the wheel turns the gears & motor. I am leaving the clutch lever pulled in a few days to see if that helps, if its still the same then I will change the oil and wash the plates (& maybe get a new set depending on condition).

I have not read all your earlier posts, so I may have missed something - my apologies.

Have you been able to ride the bike recently, or has it been standing for a long time? This will cause the clutch plates to stick together. Before opening the clutch up, try the following:

Make sure that when you pull in the clutch lever, you can see the release lever above the clutch casing moving. Do not switch the ignition on. Sit on the bike. Select a high gear -- 3rd or higher. Pull in the clutch lever and get a friend or two to push the bike forward and rearward (just a brisk rocking motion should be enough). Repeat until the bike will roll without turning over the engine. You will probably hear a slight "bang" when the clutch plates free up.

If this does not work, you will have to open up the clutch. Keep the plates in the same order and orientation when you remove/replace them.

Good luck!

[DaveWatts]

Good advice, I'll try that later. I did rocking just with the wheel but it could be that it is not quite enough. Yep the bike has been standing a while