Suzuki 2 Strokes

Hello all,

I'm here to document my custom GT550 build. I've been lurking on Sundial for a year or so now, all the while collecting parts, wrenching, and restoring my GT stuff.

My build started with a $400 1974 GT550 that I paid about $440 too much for. I've restored and customized a few other bikes, but never anything as old as the GT or a two stroke. The engine was shot. It had been outside for years and unfortunately stored without a spark plug in the left cylinder, so the engine was full of water.

However, a few months later I bought an ebay engine and a few months after that a very nice restorable GT550 came along for $200 from a friend that owns a Suzuki dealership.

My build started as wanting to do a Blue Smoke Devil build or a Honduki build. Buuuut, after starting the build, fixing the 2008 GSXR forks and SV650 swing arm to the GT frame I didn't like how the build was turning out. For one the longer wheel base really rubbed me the wrong way. All of my bikes come out as daily riders that I can commute on then go out and have a fun weekend ride as well. The stretched swingarms really rub me the wrong way, just not my application. Also, the smaller diameter wheels would've added more stress to the frame. While people who've done this same build report no problems with the handling, I suspect bias towards their build and maybe not absolute truthfulness.

So, after needing a new direction, I came across a few H2 builds. One being Qwikasfaki by a fellow named Cabbie, the other being an H2 build in a 1990ish GSXR750 frame from an outfit in California build.

So, I said to myself, I can build one of those! With a little time and some extra hours in class (I'm a machining student) I can build a 1989 GSX-R110 frame to fit the GT550 engine.

Upon trying to fit my GT engine into the GSX-R frame, I found it doesn't fit! The H2 engine is a bit smaller, dimensionally, of course. I'm going to cut the GSXR frame's front engine cradles and machine pieces that will fit inside the aluminum box section to change the dimensions of the space where the engine sits. I'll need to curve them in to pass the expansion chambers and forward about an inch to clear the crank cases.

A bit about me, I'm 24, living in Bellingham, WA. I studied math for awhile, engineering and now I'm studying precision machining. One of my career 'dreams' is to start building modern 2 stroke street bikes. Since we're so limited here in the states, I'll just go around the EPA by retrofitting engines to frames. Anyway, more to come!

Here are some pictures.

1974 GT550- $440



1976 GT550- $200



Quikasfaki and other inspiration



Here's my custom home built budget built GS450 cafe racer

Nice work. I am a little bit older then you but also fairly new to these bikes. While I am more into the stock look, I admire your ingenuity and choice of bikes. Keep us posted with pics as you move along with the build.

Love your work, and humour. Had to name check the white Kawasaki twice - I'm sure it is
Mike

Welcome to the forum. Bellingham, Aren't Ben Gibbard and Chris Walla of DCFC from there?

I'll definitely be keeping you guys updated and asking lots o questions.

Currently I'm compiling pieces to make a leak down tester, will probably do that this weekend or early next week. I'm hoping (isn't everyone on this forum?) not to have to do crank seals, but we'll see.

Next week I'm also hoping to get on the mill and start making a few pieces. Have to make some clamps for a speedometer first, but as soon as that's done I'll be building the pieces that will change the engine cradle.

With the silver bike pictured I plan to use what remains of it after my build to make a cafe racer if I have the time when that day comes. Or, we'll see, maybe I'll move onto a new project by then.

Welcome to the forum! I'll be following your build as my next project is a GT550 motor into a KTM 640 Duke frame..........
The Kwikasfaki bike is a real work of art, very well done. He has used the GSXR400 frame, with the swinger being Aprilia (I think).
You'll find a wealth of knowledge here, a great bunch of guys.

You can squeeze a GT750 engine into a later GSXR frame . Check my avatar

Looking forward to this one!

J54156 wrote:Welcome to the forum! I'll be following your build as my next project is a GT550 motor into a KTM 640 Duke frame..........
The Kwikasfaki bike is a real work of art, very well done. He has used the GSXR400 frame, with the swinger being Aprilia (I think).
You'll find a wealth of knowledge here, a great bunch of guys.

YEah, I've got about 15 more pages in the street index to go before I'm caught up on the articles on here. Been reading them in my spare time when they jump out at me as something I might want to know.

Yeah Aprillia swinger and Ducati wheels and front forks, I do believe. Might be gsxr forks with the duc wheel mated to them.

I wish we could get those little gsxr400s here in the states... I love those little inline 4s... My girlfriend used to have a CB-1, not my favorite bike to ride, but a good concept.

That's going to be awesome the duke frame. Sam, my gf, works at a Suzuki, yamaha, kawasaki, ktm, ducati dealership in the parts dept. and she looooves the dukes. Do you have a build thread started anywhere?

Kwikasfaki is amazing. Have you read his customfighters forum page? His eye for detail on the little things really pull that bike together. I love how he sanded out all of the weld seems so the frame is nice and smooth..

Suzukidave wrote:You can squeeze a GT750 engine into a later GSXR frame . Check my avatar

Nice! I've seen your replies on the forum, but I couldn't tell from the avatar what was what. I do have my eyes open for a 750 engine that's reasonably priced..

So with yours, is the engine set up to be a stressed member with that monocoque frame? Were the GSXR engines stressed members on that bike, or were they mounted with rubber bushings?

Where I'm at right now is finding out how to fit my engine in the GSXR frame. This week/last weekend I've been spending my time drafting up an image with dimensions for the GT engine as it is about an inch longer than the gsxr engine and will need some new mounts layed out and fabbed up.

Today or tomorrow I plan to get a definite plan in mind, layout some cut lines on the GSXR frame, sleep on it, decide if I still like my plan and go from there.

ON another, similar topic, have you ever seen the CR500 streetbike that Rolland Sands built? Awesome little build. I found another guy who was trying to put a CR500 engine in a SV650 frame, but he gave up near the end. Could've been pretty awesome, in my opinion.

So I've grouped together some components for a leak down tester, and I have a few questions.

When you do the actual test, do you plug all 3 cylinders at the same time, or just the cylinder that you're testing? My thinking was that you should just be able to plug off one cylinder and test it while you have the other cylinders open. Is that correct?

Yep .. you test one at a time as as left and center cylinder can leak into each other and right and center can also leak into the gear box .

GTX-R550 wrote: So with yours, is the engine set up to be a stressed member with that monocoque frame? Were the GSXR engines stressed members on that bike, or were they mounted with rubber bushings?

No ..i have the sub frame bolted up solid but the engine is still allowed to move . I think the engine would shake you off the bike if it was mounted up solid so we will see what this does to the handling as the GSXR engine was bolted solid to the frame but they also were solid mounted in the frame you are wanting to use .

Suzukidave wrote:Yep .. you test one at a time as as left and center cylinder can leak into each other and right and center can also leak into the gear box .

Cool, thanks! I was thinking that'd be the way to go, but just wanted to make sure. How do you tell if it's leaking into the transmission? Er I should say, how do you tell the difference between that and a crank seal leak?



On another note a GT750 + a spare engine just came up for sale not too far from me for $1000.. I need a bigger garage haha.

Spray a soapy solution and that will bubble at the seals , also test at the cylinder base . if you listen at the transmission vent right by the injection pump you may hear the hiss from the leaking seals that vent into the transmission .