Newbie Intro

[PHPaul]

Howdy.

I'm Paul, an old retired fart from Downeast Maine.

Started riding in the late 60's and really enjoyed the heyday of the 70's. Had a long break from the mid-80's to the early 2000's as adulthood, family and job got in the way.

Really got back into it 5 years ago when I finally nabbed a Yamaha XS650. I had a new one in '74 and its one of a very few bikes I truly regret letting go.

I've got it about 99% the way I want it and ride it a lot in the summer.

But, ol' man Winter is coming quick here in Maine and I need something for a winter project to keep the cabin fever away.

Looking at a '74 GT550. 2 stroke street bikes are another icon of the 70's and I've been half-way looking for something for a while now. This one seems like a good lead, hoping to go see it and give it a good once-over Sunday. Doesn't appear to need much beyond perhaps some charging circuit tweaking/repair.

Hope to learn a lot here, and I'll help out when I can.

[GTandcbr]

Hi and welcome to the forum! Great choice of scoot the 550 in my view but then I am biased.... If you buy why not put some pictures up for us to see.
Have a look here http://www.oldjapanesebikes.com/mraxl_G ... /index.php" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Will give you some info re what is genuine or not!
Good luck

[PHPaul]

Here's the picture the guy on Craigslist sent me.

Supposed to go and put the Mark I Eyeball on it Sunday. Says it ran until the battery went flat.

I'll be taking some tools and a hot battery with me. Hope to get it started, if not at least pull the plugs and check the cylinders with a bore scope.

Tin looks pretty good, doesn't seem to have a lot of rust.

If he's willing to negotiate a bit, I'll likely bring it home.

[GTandcbr]

Seems to look okay as you say the tinwork is good. Hope it starts okay . There is plenty of help on here many experienced 550 owners too! Good luck

[Alan H]

Welcome from another old fart (retiring next month - woohoo!!)
Good luck with the 550, I've got a few and love them. Charging problems can be a pain but are usually easily(!) fixable.
Plenty of advice on here.

[PHPaul]

Thanks, folks!

I'm a reasonably experienced mechanic on the old bikes. As long as they're pre-computer and pre-fuel injection, I'm good to go.

Also, I was an Electronics Technician in the Navy and worked in industrial maintenance on electrical/electro-mechanical, programmable logic controllers and computers in my post Navy career right up until a couple of years before I retired for good, so I'm comfy around the wiring and electrical end of them as well.

Last winter I had the XS engine in the basement and torn ALL the way down for all new seals, gaskets and o-rings as well as a valve job, cylinder hone and fresh rings.

As long as parts are available (and not staggeringly expensive) I'm confident I can fix pretty much anything on this one as well.

Can anybody give me a quick nickel tour of the charging system and ignition on the GT? The '79 XS 650 has a brush-type externally excited three wire alternator, external solid-state rectifier and a mechanical regulator. It was points ignition, I converted it with a readily available electronic unit from PAMCO. WAY more dependable and requires essentially no maintenance. Alternator just needed new brushes and a quick buffing of the slip rings on the rotor.

Might I expect a similar situation on the GT?

[GTandcbr]

How about this
http://www.3cyl.com/mraxl/gt/manuals/gt ... 550-49.htm" onclick="window.open(this.href);return false;

[GTandcbr]

And if it helps
http://www.3cyl.com/mraxl/gt/manuals/gt ... 550-82.htm" onclick="window.open(this.href);return false;

[PHPaul]

Lovely, thanks!

Inspection date has been moved up to tomorrow evening. Assuming I close the deal, I'll be ordering a manual ASAP.

Any preferences as to Clymer/Haynes/Other? My experience over many bikes and ATVs is that neither Clymer nor Haynes is The Bible and both contain minor differences/errors.

[Alan H]

Get a parts catalogue. Very handy and shows all parts and 'exploded' diagrams of EVERYTHING on the bike.
http://www.ebay.co.uk/itm/SUZUKI-GT550- ... SwYHxWLnXs" onclick="window.open(this.href);return false;
Although this is a UK auction, they are available in the US too.
Make sure it covers your model, but the later the better so it covers later updates.
If you want a copy of an early service data book, pm me your email address and I'll send one FOC.
Some parts are still relevant for the later models with linked carbs like yours.

[PHPaul]

Excellent tip, Alan.

If I close the deal tomorrow, that'll be at the top of my to-do list.

[Craig380]

A good battery will enable you to test the "it ran until the battery went flat" theory.

Providing you use the kickstarter to fire her up, you should get at least 90 minutes running out of a good, freshly charged battery (lights off) even if the charging system isn't working.

Don't forget to turn the gas tap to 'prime' for a few seconds to fill the floatbowls before kicking ... the vacuum tap can catch people out if they are not used to them. And check there's some 2-stroke oil in the oil tank

[Alan H]

Points work just fine. These engines peak at 8000rpm, usually go no higher than 7k, so points are plenty good enough.
If an electronic system faults, it all faults.
With 3 sets of points, if one set goes out, the bike still runs on 2 pots.
If you get a charging problem, it's fairly easy for someone with a decent knowledge of electrics to sort.
3 phase alternator into a 6 diode rectifier, with a wound rotor controlled by the regulator.
Plenty of info on here and elsewhere, and plenty of advice similar.

[PHPaul]

Well, I bought it.

Not as nice as the picture would lead you to believe, but not bad.

It'll need to be completely re-wired, some previous owner or another has buggered it all up, toggle switch for the ignition, wires hanging loose, melted insulation...pretty much every sort of abuse you can heap on a wiring harness.

Did get it to start and run briefly so I'm pretty confident the engine is more-or-less sound.

Way more surface rust on the chrome than shows in the picture and part of the air cleaner box and one filter element are missing.

Motor cases are oxidized quite badly on the right side as well.

Plan is to strip it to the bare frame and repair and polish each bit as necessary as I re-assemble it. Won't know until tomorrow if I can repair the existing wiring harness or will be shopping for a new one.

Quick question: How well does this bike tolerate pod-type air cleaners? Major carb tuning/re-jetting required? I know the Mikuni BS38 CV's on my 650 don't do well at all with pods.

I'll start a build thread on the main 2 stroke street bike page.

[Alan H]

Wiring harnesses are sometimes available, but new ones are very expensive unless you are lucky.
Standard air filter parts are available new, or can be made. Don't use furniture foam, it's too dense.
You will be surprised how well Suzuki chrome polishes.
The alloy side casings come up very well too.
Have a look at the before and afters HERE if you've got half an hour spare.
THAT rebuild has stalled recently due to my finger trouble - I chopped the end off my left 'bird' finger a few weeks ago, and been a bit short handed since. It's back working now, but brings a tear when stubbed. Yes I know the jokes are dire, but there all I have!