GS 850 wont start

[Jinks]

I have just done a top end rebuild & it wont start, have spark, petrol & valve gap. It may be 360 out, how do I rectify?

[Nessism]

If the cams are out of phase, 180 degrees, remove them and set them right.

[rphillips]

Jinks, kind'f wish I hadn't brought this up, it's been so long I can't be positive of what we did... Back in "81" or "82" I'd had a GS1100 eng. apart, replacing a crankshaft, got it all back together, and like yours it wouldn't hit a lick. A buddy of mine had the idea the timing was the problem. Best I can remember we removed the ign. cover, removed the center bolt, then slid out and turned the "governor assy. advance" (spark advancer) 180 degrees then tightened it back up and all was good, fired right up... Hopefully somebody else will chime in.

[Nessism]

Jinks, kind'f wish I hadn't brought this up, it's been so long I can't be positive of what we did... Back in "81" or "82" I'd had a GS1100 eng. apart, replacing a crankshaft, got it all back together, and like yours it wouldn't hit a lick. A buddy of mine had the idea the timing was the problem. Best I can remember we removed the ign. cover, removed the center bolt, then slid out and turned the "governor assy. advance" (spark advancer) 180 degrees then tightened it back up and all was good, fired right up... Hopefully somebody else will chime in.

I think the same thing can be accomplished by swapping the signal wire at the coils. That doesn't solve the problem properly, though.

[KiwiAlfa156]

Jinks, kind'f wish I hadn't brought this up, it's been so long I can't be positive of what we did... Back in "81" or "82" I'd had a GS1100 eng. apart, replacing a crankshaft, got it all back together, and like yours it wouldn't hit a lick. A buddy of mine had the idea the timing was the problem. Best I can remember we removed the ign. cover, removed the center bolt, then slid out and turned the "governor assy. advance" (spark advancer) 180 degrees then tightened it back up and all was good, fired right up... Hopefully somebody else will chime in.

The ATU has a locating slot that mates to a pin in the end of the crank, so this might be difficult without removing the pin...

[KiwiAlfa156]

Do you get a firing/misfiring at all?

[Rob S.]

On my only V8 engine swap, I put the distributor in 180 degrees off. Stuff happens.

[rphillips]

I dun'no, it's been over 40 yrs., but remember all we did was rotate something in there 180 degrees and couldn't believe there wasn't something there to keep it from being assembled wrong.... I just looked on ebay, at a 1980 GS1000 spark advancer. It looks like the part with the actual "pick up" sticking out the side, is a tube that slides down over the main part of the advancer shaft, not shown as a separate part on Suzuki parts diagram. That tube may be what we turned 180 degrees.... Thinking if that part is in backwards, the ign. is firing when piston is at bottom instead of at top.... Also what Ed said, if you put the cam gears 180 degrees out won't work. Simple to check, With cam timing marks, 1, 2, & 3 in proper locations, little square slots on end of each cam shaft should be pointing directly at each other, opposite of each other, cams are 180 out.

[Jinks]

KiwiAlfa156 not even with aerostart, nothing, how can I tell that it is 360deg out? I don't think I did full rotation on assembly, I am baffled!

[KiwiAlfa156]

KiwiAlfa156 not even with aerostart, nothing, how can I tell that it is 360deg out? I don't think I did full rotation on assembly, I am baffled!

The only way is to inspect. I would take off the ignition cover and cam cover and re-check that the T (1.4) mark aligns with the pointer and that the cam end cut out slots/cam sprocket arrows are in the correct alignment as per the manual. If you look you'll have peace of mind and eliminate a potential cause. Do two full clockwise rotations of the crank using the large nut on the ATU and check that everything gets back to the same point (cams of course rotate at 1/2 crank revs). Did you remove the sprockets from the camshafts? it is possible to bolt these on 180° out.... and potentially bolt an inlet sprocket on to an exhaust cam (and vice versa). Which is why both the slots and the arrows (and the IN. EX. stamping/casting on the camshafts) have to concur. Although you'd probably have bent valves and catastrophic damage if this was the case.

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If this is all by the book, I'd be looking at the ignition system as if it doesn't even cough on starter spray, (and valve timing is right) then there's likely to be no spark. Even when you get the coils connected the wrong way (1 and 4 coil sparking 2 and 3 -and vice versa) you get a pop and a backfire from mistimed combustion.

[Nessism]

Pull 1 or 4 spark plug, and make sure it's at TDC during the cam timing process also.

[Jinks]

IT GOES, rookie mistake timed the cams to 2-3, retimed it & it fired up. Had me concerned agout 360 out, what a relief, now to put some miles on it over summer!

[Jinks]

Oh & thanks for everyone's help!

[rphillips]

Sorry Jinks, I mis spoke in that other thread, possibly 180 out, not 360. And yes, you were 180 out, your plugs were firing with pistons at the bottom, 180 degrees from at the top, where they should be firing... Glad it's worked out and going... Congrats

[Jinks]

When I first got the gs 850 going it went ok, then I did the rebuild & at the same time I found out that you need some weather seal on the air filter holder, it went better, then I remembered I'd put some tape on the drain holes of the air box, I took them off & it's like I'd put a turbo on it, the 14/1 ? Air /fuel ratio had been achieved. Thank you gs resources for saving another gs850. I've just heard of another gs850 for sale, cheap, hmmmm