Suzuki 2 Strokes

Hey guys, so I'm getting ready to start moving forward with a barn find 1974 GT550 that I picked up a few weeks ago. To date I have just been stripping it down and cleaning what I can, I also rebuilt the carbs but thinking back on it now I need to check the float levels on all 3.
I am going to be posting here because this is my first 2-stroke and I will need some help from all you knowledgable smokers out there . I have followed a few threads on this site and it has been a great resource so far. Thank you to everyone for your help along the way, feel free to comment, add suggestions or tell me I'm being a goon if you see me doing something stupid..
At this point I am just trying to get the bike running and back on the road, eventually I would like to turn is bike into a cafe racer style build, but I am quite a ways off from that right now limited by funds and room in my garage!


I am in the process of swapping out the crank on my cb750, as well as helping a friend build up his xs650 and between those, the GT, and keeping my everyday ride running correctly (oh yeah, and WORK!) I am pretty stretched thin. Anyway, thought I'd share my trials and tribulations, joys and sorrows here in case anyone finds my build entertaining enough to observe. So... Guess I'll get started then.

I picked the bike up from a guy just outside Santa Barbara where it had been covered (albeit under a tarp..) outside for nearly a year and a half. The po had the intention to restore it when he picked it up, but apparently it sat right where he left it the day he picked it up and didn't move until I came around. Anyway, his loss is my gain as I have become very excited about these early 2-strokes. A day trip to SB and one uhaul van rental later it now lives in my garage for me to chip away at it on nights and weekends. (There goes all my friends )
I guess I'll start with the SRIS, I need to replace these hoses because they were very brittle and and one is now broken. Does anyone know if these are still available from suzuki? Or if there is an acceptable replacement hose I could buy at the hardware store?

This is how she sits now, brains all exploded trying to figure out the wiring, I got a great color diagram off one of the threads here that someone translated from German .

Oh yeah, I have both the Nippon denso & Kokusan alternator assemblies, currently I believe the Kokusan rotor is attached to the crank, I think I've heard the Nippon denso puts out more. Is there any advantage to switching it out? I'd rather not deal with finding a rotor puller if it's not going to be anything noticeable. One day I'd like to get an electronic ignition kit on this and my CB.

You are correct, the Nippon Denso alternator has more output.
See page 18 of: http://www.ozebook.com/compendium/suzi/suzidata1.htm

The Kokusan is ok with stock electrical load.
You should switch alternators if you might someday add much more load, like heated clothing or driving lights.

You should take a close look at the alternator brushes, as they can wear out or crack.

Newtronics is a good choice for electronic ignition. They recently added a kit specifically for the GT550 (kit # SU6B).
They occasionally list products on eBay. Since its a "one day" item, it will be easiest to get it that way.

Two other good electrical upgrades are modern rectifier & voltage regulator. Oregon Motorcycle Parts is a good choice for both.

For more info about available electrical parts see: viewtopic.php?f=29&t=4824

Have fun with the project.

Cragdog wrote:Hey guys, so I'm getting ready to start moving forward with a barn find 1974 GT550 that I picked up a few weeks ago. To date I have just been stripping it down and cleaning what I can, I also rebuilt the carbs but thinking back on it now I need to check the float levels on all 3.
I am going to be posting here because this is my first 2-stroke and I will need some help from all you knowledgable smokers out there . I have followed a few threads on this site and it has been a great resource so far. Thank you to everyone for your help along the way, feel free to comment, add suggestions or tell me I'm being a goon if you see me doing something stupid..
At this point I am just trying to get the bike running and back on the road, eventually I would like to turn is bike into a cafe racer style build, but I am quite a ways off from that right now limited by funds and room in my garage!


I am in the process of swapping out the crank on my cb750, as well as helping a friend build up his xs650 and between those, the GT, and keeping my everyday ride running correctly (oh yeah, and WORK!) I am pretty stretched thin. Anyway, thought I'd share my trials and tribulations, joys and sorrows here in case anyone finds my build entertaining enough to observe. So... Guess I'll get started then.

There's a, lots of things you can d.i.y and save money.. so get out the Mother's billet polish.. ( don't tell anyone, but it works good on chrome too) i cut up all my kids old tee-shirts for rags,, ( don't buy them) and for rusty nuts and bolts.. i use , a patio cleaner/deck cleaner (asid type don't breathe the fumes in when working ) then rinse off in water. and spray wd40 on to stop rusting.. or spray can in siver of black.. A wire wheel on a 8" bentch grider, works wonders.. did you say ... cb750? well look at my friends one.. a baeuty... keep the photo's coming... http://s888.photobucket.com/user/brownb ... sort=3&o=6" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

SRIS hoses and retainer clips are still available from Suzuki. The part number for the hose is 09532-20503-600. You need 3 of that part number. The retainer clips are part number 09401-04401. You need 6 of those.

Kokusan alternators are just fine. My 550 cafe sports one and everything works including the charging system.

Okay, good info. I guess I will stick with the Kokusan for now since that rotor is already attached, just need to get some bolts to mount the alternator to the case.

Coyote wrote:SRIS hoses and retainer clips are still available from Suzuki. The part number for the hose is 09532-20503-600. You need 3 of that part number. The retainer clips are part number 09401-04401. You need 6 of those.

Thanks Coyote, is there any benefit going the OEM route over just buying some small hoses and clips from the hardware store?

kettle kid wrote:did you say ... cb750? well look at my friends one.. a baeuty... keep the photo's coming... http://s888.photobucket.com/user/brownb ... sort=3&o=6" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Wow, that sure is a fine example of a clean restore. Great looking bike.

jabcb wrote:You should take a close look at the alternator brushes, as they can wear out or crack.

Two other good electrical upgrades are modern rectifier & voltage regulator. Oregon Motorcycle Parts is a good choice for both.

For more info about available electrical parts see: viewtopic.php?f=29&t=4824

Have fun with the project.

Thank you! Are the brushes those two black pins that contact the rotor surface in the above picture of my alternator?? If so I think they looked pretty good, but I will need to double check now that you've mentioned it.

God I just love the stance of these motors:


My contact points just arrived in the mail yesterday, I'm getting really close to trying to start this thing for the first time! Just need to figure out those SRIS hoses first.

If you PM me your email address, I'll send you a copy of the 550 service manual.
The cost?
You must swear undying love for three cylinder Suzuki two strokes!
Cheap at twice the price!!!

Haha thanks Alan,
You helped me out with the engine numbers a few weeks back and suggested I buy the service manual. I have now both the Clymer guide and parts catalog, but if you have another helpful manual I'm all eyes.

The hoses are metric. 2mm to be exact. Not even the best of hardware stores will have it. You might get by with 3/32 hose but the clips are another issue entirely. Never seen anything like them. anywhere. Essentially they are a very thin walled split sleeve. You slip them on the hose before pushing the hose over the barb. Then the clip slides over that.
This is a budget build right? There is another method that is used widely. Just omit the whole damned mess. Just remove the SRIS valves from the crankcase and replace them with bolts and new crush washers. On the cylinder end, just install some tight fighting vacuum caps on them. You're good to go.
The SRIS was invented by Suzuki. It's only purpose was to prevent excessive smoke while waiting at stop lights or in heavy traffic. The bike will run no differently with the SRIS omitted and the cost is nearly zilch.

You should have mail Cragdog.
Another handy book is HERE (clicky) and goes into much more detail than either the Clymer or Haynes books. I have one of the original ones that I bought in 1972 and it's VERY well thumbed. Before you buy one, ask the seller which year models it covers so you get the correct one. Later the better.
A parts manual is also handy, if you get a late one it does for all models and you can see when parts changed, and also full exploded diagrams of ALL parts are handy when putting it back together.

Just re-read your post and note that you have one - D'ohhh!!

Yes. brushes are parts # 7 & 8 in this diagram:
http://www.powersportspro.com/pages/Oem ... 6021160022

Ouch, at about $124 for a pair those Kokusan brushes are expensive!

If the brushes are bad, then I'd switch to the Nippon Denso alternator. Those brushes are only about $12 for a pair.

Hose clips similar to THESE will work, but they are available much cheaper if you search.