The story so far:
Before I started doing anything at all, the GS1000 ran well. No pops, no excessive buildup on plugs etc. Nice linear power curve at least up to 9,000 rpm.
Then it stopped. I found that one of the points had broken off the rocker, and replaced both points and condensers. Adjusted gaps, but not timing. Ran excellent after this, which was why I skipped adjusting timing.
Next, I developed an oil leak, which turned out to be from the cylinder base. Off with everything down to the block. Spent a couple of days cleaning off old gasket, and while waiting for new gaskets I decided to clean the carbs.
I disassembled everything EXCEPT the pilot jet and air screw, which both the Haynes and the Suzuki manuals said not to touch. Everything else was in atoms, and got a run in an ultrasonic cleaner. I did not have new orings for the carbs, and reused the old ones. They all felt fresh and fit well.
Next, ressembly of the engine: All new gaskets from the cylinder base up. Went well, afaik.
Now here is the snag:
I had to fit a different exhaust than the V&H 4-1 that was on there, because the "DMV" did not accept the V&H. I got hold of original pipes, stamped GS1000 and all, and mounted these, hoping they'd work as far as the DMV and back without re-jetting. They almost did. At least the bike got the OK from the DMV and I now have the license plate.
So, after getting the use of the 4-2 Suzuki pipes that I needed, I put the V&H 4-1 back on. This was the exhaust that was on there before all this started, so the jets should be the correct ones for that. This is why I did not make any changes to jetting. It worked before.
The air box? Hm. The air filter box holds a pod style cone shaped KP filter, which again was part of the system that worked well before all this. The connections are good between the carbs and the box, and between the two boxes. They both have designed holes and openings, what do you mean by "sealed"?
I had a very incomplete set of shims, so I decided to check the valves, but without changing any shims. The thinnest feeler in the kit I had was 0.04, and it slid under all but two of the rockers. Thus I have no idea about two of them, other than that they are tighter than 0.04.
Assuming that they are tighter than the specified minimum (0.03mm), could this cause my problems?
Checked points gaps again, and fired up. Sounded just right, so I went home for the night, charging the battery overnight. In the morning I started the bike, and it fired up immediately and sounded good.
Drove off, but at about 3,500 rpm in second she started failing. It sounded (and felt) like not all cylinders were firing consistently, and massive popping suggested lots of unburned fuel found its way to the pipes. A few seconds of this, and it stopped again. Plugs are blackened and covered with carbon.
I will check timing with a light today, make absolutely sure the ignition timing and gaps are spot on.
What else could I do?
I hope this clears up the 4-1 misunderstanding. I am trying to get the bike to work with parts (exhaust, jets, air filter) that worked perfectly before. Not fitting a V&H without rejetting. All this worked well three weeks ago.
Any thoughts, guys? Thanks for your time.
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