GT550 Starter clutch and excessive smoke

[losclarkos]

Hello all.

Finally, after 2 years in pieces I finally got my '76 550 back together. Full crank rebuild, new pistons and rings and mucho dinero. But I have a couple of problems. This bike has seen a lot of neglect and lots of corrosion which has taken me many months to sort and tidy up. I think water has been in the engine at some point with some rust staining on some parts. The starter clutch is of the later Borg-Warner type and I've read on here that they do not normally give problems but mine certainly is. When it's cold, it will either spin the engine a couple of times then spin out or simply not pick up the engine at all. I read the Suzuki service bulletin of the time so I took it all apart and cleaned the starter clutch with solvent. On the bench it seemed to be doing exactly what it should do. Gripping in one direction but not on the other. I put it back on the bike and it seemed a bit better but not much. Anyway, after finally getting the bike going yesterday I took it out for a short spin and once it was warm, the starter clutch worked a treat. Can anyone give me a clue as to how I can improve cold operation?
Second question. After my short ride yesterday I went back to it today to do some more tweeking. Once I'd started the bike, I noticed that the left cylinder was smoking much, much more than the the other two. To the point where it looked like the other two weren't smoking at all. Bearing in mind the fully rebuilt crank and new seals everywhere, I can only think that the Left cylinder is burning more 2 stroke oil than the others. But why? Could it be that the non return valves at the end of the octopus on that cylinder are "weak" and allowing all or most of the oil being pumped to go mainly to that cylinder? If that's possible, how do I fix it?
Oh, and is it possible to only be able to select the first 5 gears in a 6 speed gear box? I keep thinking (hoping?)that I've just lost count.
Oh, and how can I get the gear position indicator to work. It just shows 6th. (although neutral light works ok)
Oh, ............... Nah, that's enough for now

[jabcb]

The GT550 only has 5 gears. The display is capable of showing 6th because the GT380 has 6.

Are you carbs synced. Being out of sync can cause the "weak" cylinder to smoke more.
If you haven't ridden it much after the rebuild, the excess smoking could just be some residual oil.

[Alan H]

The starter clutch kicks out if the engine fires but does not start.
Could be a bad battery - test the voltage when starting to see how much it drops.That is the favourite - even with a 'new' batery sometimes. I have a Motobatt on my 550 and it's far beter than a standard one. Try a different battery, or even jump leads from a bigger battery when the engine is cold.
Could be timing slightly out. One cylinder fires easier or slightly advanced but the others don't quite catch it.
Could be one carb open a little more than the others so that cylinder fires but the others don't until the engine actuall picks up.
Set the oil pump slightly richer to see if the other cylinders start to smoke and make sure the oil pump is actually pumping oil down all 6 oil lines.
Many Suzy triples smoke more on one cylinder for varied reasons.

[Cliff]

Starter clutch problems, what oil are you using? Mine will freewheel when cold if I use anything heavier than 50 weight. 15W40 Rotella seems to work not too bad.
Smoking cylinder is the weak cylinder. Carb. or timing adjustment or both? Double check your timing and do a cylinder balance test. Short out one set of points at a time a watch the RPM drop each time. The RPM drop should be about the same for each cylinder. If not, balance the carbs..
The 550 only has 5 gears. Replace the gear position indicator? After I've pressure washed my bike, I've had the gear position indicator read 6, 8, and even 9! Check the bullet connectors for dirt, corrosion etc., and check that you have a good ground.

[pearljam724]

There are close to a dozen reasons why one pipe can smoke more compared to others. All past comments, well made. Timing is one of them. Carbs being another. The most common reason would be crank seals. It's possible that your new seals aren't sealing correctly ? But, before jumping to conclusions. I would triple check timing with a dial gauge, triple check carbs and read your plugs a few times at different rpm's to see if one cylinder is running noticeably leaner than the others. If one is, refer to carbs. If carbs and timing check out fine. Then I would do a compression test. If all those things check out o.k. Run, the bike consistently for a couple weeks and see if it improves. If not, refer to the additional several reasons, lol !

[Suzukidave]

Just to be careful keep a eye on the transmission oil level , if you see the level dropping it may mean the that smoking cylinder is pulling oil from the tranny .

[oldjapanesebikes]

All of the above - plus I'd offer that if the smoke clears once the engine has run for a while, and only smokes heavily when cold after sitting over night then its possible the checkvalve on that injector line is passing. And just to repeat the suggestion about checking the grounds - given this was a full rebuild, if you had the frame powder coated (or painted) make sure you clear off the coating at the gound points so you have good metal to metal contact. A partial ground will affect the starter and the igintion.

[losclarkos]

Thanks for the replies. They've been really useful. God knows where I got the idea that the 550 had 6 gears. Especially as I had one in my yoof (about 40 years ago!!!!!) I can only guess that because the gear position indicator was stuck showing 6 and the wiring diagram shows a wire for 6 gears (OK, now I've checked it, this extra wire doesn't actually connect to anything) I jumped to the conclusion that I must be missing an extra gear. Stupid boy. Also, in my yoof, I had a 380 so maybe I got the two mixed up? That's my excuse and I'm sticking to it.

As regards the rest, all sorted I think. I double checked the timing and sure enough, two cylinders were a tad retarded. Then reset the carbs and the excessive smoking from the LHS has disappeared. I live near Malaga in Spain and it's been a barmy 19c today so did a quick 50km round trip and part from a couple of teething problems (luckily small problems) she is running lovely. And that noise!!!! I'm sure there's a turbo charger hidden in there somewhere.

I fixed the gear indicator. I disconnected the live wire. I'd rather have nothing at all than 6 permanently on display reminding me that I'm a bit of a dork.

The starter clutch hasn't sorted itself out completely. Sometimes it will still spin out without picking up the engine but I can live with it.

I'm sure there'll be more questions before she is set up completely but thanks for the help so far.