'81 GS550-T starter & trans problems: two possible solutions?

Catbird

Catbird

DT250 epidemic - Patient Zero
I just purchased what is technically my first bike, a 1981 Suzuki GS550T in rough shape. No electrical problems, frame and forks in good shape, a few idiosyncratic flaws and some cosmetic difficulties. The roughness of the bike excites me in terrible ways.

However, part of the reason that the bike only cost $200 with a title is that second gear tends to slip when I really get on it, and the starter has a bit of difficulty.

I plan to try to sync the carbs in the next couple of days, which *may* affect how hard the starter has to work to fire the engine up, however, the fact still remains that a proper cafe-racer project should really have all gears working properly.

The options I see are these:
1. Attempt to rebuild the transmission and possibly the starter, as the rest of the engine appears relatively solid, but MAY not be.
2. Purchase a new engine for the going rate of $275ish on sleazebay. The total cost of the bike would then *still* be below $500, and I wouldn't have to worry about mucking up what would be my first trans rebuild.

So then, my questions to you guys:
Can I really save myself the time and money by buying the case-splitting tools and rebuilding the trans myself? Is it terribly difficult to do for someone with experience with antique cars but no experience working on motorcycles?
I don't know how much of a parallel to draw. I also don't know if the general consensus would be that it would save me a tremendous amount of time just to buy the new motor, or if the trans rebuild is a lot easier and simpler than I realize.
 
You don't need any special tools to split cases.
You may need a generator puller to get to starter clutch (probably needs new Allen bolts, relatively common)
You can remove lower case without even taking the head off (make sure you drain the oil first)
You have to remove all the outer covers, gearchange shaft (behind clutch)
If you think you can get an engine for $275, you really don' have much to lose by taking it apart for a looksee
You have to be a bit careful lining cam chain tensioner up putting case back together but it's pretty easy
 
I can certainly appreciate the logic there. :D

Alright, I'll see about doing that once I've gotten around my current run of general safety repairs.
 
I've been digging around for parts, and it kinda seems like it'll cost almost as much to find replacement parts for the transmission, which I'm totally feeling like I'm going to muck-up, as it would be to buy a whole engine/trans rebuilt and in working order.

Obviously, I won't know whether it's a worn dog or bad clutches until I split the case open, but I'm terrified I'll go in to remove the appendix and discover terminal colon cancer.
 
There is a risk that when you open it up you might find a problem, but better now that half way down the road.

Starter could be bad electrical connections, worn brushes, bad battery or something wrong in the starter clutch. Those are all easy to fix.

I'm not 100% sure I understood the definition of that second gear problem. Is it jumping back out of gear when you apply power, or jumping out and sliding back in or something else?

If it's spitting out of gear, in all probability two gears will need to be replaced or repaired and the shift fork for that gear is probably damaged or worn.

Why not pull the motor out and pull the lower case off and have a look. If it's really nasty in there, you use that motor as spares and buy a complete motor to drop in. When it's running sweet as a nut, you have the time to either rebuild the original motor into a 100% spot on hot rod or keep it under the bench just in case you ever need an parts off it.

You could take the side covers off and polish them for example and then swap them over to the motor in the bike. The possibilities are endless.
 
I'd love to... You're a man after my own heart. Unfortunately, we've already got six cars and three other bikes, plus a stockpile of parts and large tools for auto work... I was lucky enough to get them to let me warehouse my 400CID V8 and 250CID OHC6 Pontiac motors in the garage... The shed is too decrepit to put an engine in for any length of time though.

THe upside to living at home:
Having access to stuff I wouldn't otherwise.
THe downside:

Space is *not* one of those things.
EDIT:

It slips, like I'm applying the clutch if I get on it in 2nd. Dollars to dimes, it's bad clutch packs or a worn dog, because shifting's fine.
The other gears are unaffected.
I'm just worried that I'll totally screw it up and be out an engine *and* the cost of the parts, *and* have to buy a new engine on top of that.

Big '60's auto engines have a lot more room for error.
 
What Pontiac you got with a 400?
I got a 76' Firebird 'Formula' 400 I'm slowly acquiring parts for
It's damn expensive compared to bikes (you need to multiply everything by 8 ??? )

You can go completely nuts on a GS550 motor and have something that will run with the latest 600's.
I built one that was stupidly fast about 30 yrs ago.
Forget if it was 670cc or 720cc? (I didn't do the boring :o )
Race cams, race exhaust, 12 hrs getting the first intake port right (and another 12 hrs for the other 3 intakes ::) )
Forget how much time I spent on exhaust ports.
It was worth it though as it would 'run away and hide' from Honda VF750S (the original one)
That would only do about 143mph ;D
 
The 400 was in my '65 Tempest for about eight months. I took the 326 out to do a rebuild, fell in love with the pure, unadultered automotive violence that is a 6.6L HO with a Barry Grant 625 stuck on top.

This was when I was turning 18... I'd done a sloppy rebuild that ran great for about 12K (and I mean *great*), then I cracked a piston ring on the way home from work one night. Put my original 326 in, with an ArmaSteel crank, 272-H cam by Comp (I think that's the cam, it came out of the 400), forged pistons, a set of stock-type 350 heads ported and set with hardened valve seats as a gift by Paul Kinnippen (I always spell that guy's name wrong) for my father for computerizing his business, and in exchange for some tail-light bezels, I think it was. The 326 might not have the raw, chest-beating feral fury that the 400 did, but with the right exhaust on there and a very well balanced ratio of exhaust to intake, it's getting 26MPG and still fast enought to show-up most of the tuner kids around here. It's a very well-rounded engine... Though if I could afford to drive at 9MPG you can bet I'd have that 400 back in.

It's a better engine than the 455, IMO. Better suited for race application, but still huge enough to generate plenty of torque.

That Sprint engine though, I got for a hundred bucks with all the bits. GUy said it was probably scrap, he forgot to prime the oil pump before starting it.
If it's serviceable, it'll probably be getting a turbocharger and replacing the 326 as a more powerful *and* more economical powerplant.

Any 1968 production car motor that'll do seven grand from the factory is alright in my book.
 
Catbird said:
It slips, like I'm applying the clutch if I get on it in 2nd. Dollars to dimes, it's bad clutch packs or a worn dog, because shifting's fine.
Click to expand...

That's worn clutch plates / springs....or the wrong oil (slippery car type).

As for your starter, what is happening? If it's just struggling to turn over, then you probably need to service the starter motor, or replace the solenoid, or the battery. If it's spinning and "slipping", then it's the starter clutch. Fortunately on the Suzukis, the starter clutch is outside the crankcases and is relatively easy to get to / fix.
 
The starter gets really hot, but I actually think that's just because initially, the bike was really hard to start and would require a tremendous amount of cranking to fire.
Because of that, I may pop the starter out and check the clutch over to make sure it's still fine.

I'll try flushing the case tomorrow with something light like a 5w cycle oil and then draining it and filling it with factory-spec stuff, see if that doesn't help the slip issue any.
I should get a build project up for this damn thing while I'm at it...


EDIT:
The battery is almost certainly knackered. I'm going to try charging it fully tomorrow, but I've just been jump-starting it since I got it home. It fired right up when I started it off my Tempest... Little bike must have been afraid Matilda was going to eat it.
 
I don't think that's the problem... I was able to totally disconnect the battery after jumping it and the thing still ran. I actually took it around the block before I realized how horribly overstretched the chain was, and forgot to connect the battery again... It push-starts easy enough.
 
I saw your shout out about the new battery after the brake fail incident. since it is a wet cell be sure to follow the instructions on slow charging it the first time. Hours at 500mA (1/2 and amp). You can trash a new battery by putting too much to it too fast that first time.
Your trans problem sure sounds to me like clutch plates and springs as mentioned earlier. Should NOT require splitting the cases at all. Check Z-1 for replacements good guys who know their Zooks. http://www.z1enterprises.com/
I am finishing up my GS750... You got a build thread on this yet?
 
The regulator/rectifier is pretty crap on GS550's, (it is on most Suzuki's)
You may well have 'screwed the pooch' by running it without a battery (it's REALLY bad for things)
You fed everything AC voltage, probably trashed reg, even if it was good when you started?
You need to get a new battery, make sure ignition is OFF, connect + lead, use voltmeter on DC volts between ground lead and battery.
You shouldn't get a reading (but up to 0.5V is OK)
Then, swap leads on meter to 10A (and move selector dial) do same test.
If diodes are good, you will get a few milliamps, any more than 500Ma and you need new parts (DON'T connect battery directly, if things are faulty it can burn out stator and wiring harness
I had to do a lot of them in Britain, used to cost 325.00 pounds for parts in 90's(about $500.00at the time)
As I always recommend, ;) I would get a CB/CM 400/450 solid state reg/rect
You should be able to pick one up for less than $25.00 including shipping
If you can't find one, I've got a Kawasaki one, same part number as Honda but different wiring colours (you can have it for above price)
 
PJ, I'm all for solid-state, keeps things simple. I might bug you for that even if this one appears to be functional, because moving parts means failure points.

Tomorrow I have to tear down gutters, but if I've got daylight after that project, I'm printing your instructions, stealing the pack out of my brother's Buell and running through the checks.

I've got a pretty cool fully digital multimeter, and a brand new battery that still needs to be filled. I'm not looking forward to that, but Nitrile gloves and a box of baking soda handy have saved me before while working with sulfuric concentrates in stupid amounts... Tangentially, greenhouses use some crazy stuff.

ANYHOW, instead of connecting the battery directly, I run current through the wiring harness, or direct hot-wire and frame-return? Or am I misreading something?

Also, thank you. I swear some times you're not even a person, but a robot connected to a comprehensive database of motorcycle information and experience. And I mean that as complimentary as possible. :D
 
Hoosier Daddy said:
Crazypj is spot on... heed his advise.
And read this... THE STATOR PAPERS on GSResources
Click to expand...

That's an awesome link.
As I've never owned a GS I'm not a member of GS resource (worked on an awful lot of them though, was workshop manager at Suzuki dealer ;D )
I haven't read all of it yet but everyone with a permanent magnet alternator who wants to do electrical modifications should read it
 
Hey crazypj, here's a challenge for you- I have a fried stock 1983 gs550es regulator/rectifier (pic: http://awes.me/10BduUf ) and so I bought a cb 400 regulator/rectifier to swap in. (Pic: http://awes.me/10Be9Fc ) which, as you can see, has a different set of connectors.

The Suzuki rectifier wires are colored black/white, yellow, white-blue, white-red, and red.
(Only 1 of the three yellow suzuki stator wires is sent to the regulator, the rest just go to the harness, unregulated)

The Honda cb400 rectifier has 3 yellow inputs, and a black green and red output.

So how do I correctly wire up the cb400 rectifier to the gs550 harness?

Any help would be super appreciated. Thanks!
 
3 yellow from Honda R/R go to yellow, white/blue, white/red
Red goes to red
Suzuki black/white to green
 
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