Suzuki 2 Strokes

allow me to introduce the reason I am frequenting your rather excellent forum - project XR11/73. This is being built in response to a challenge on another 2-stroke forum here in the UK, the rules of which are fairly simple - build a project bike using an engine and frame combo that aren't made for each other. My entry into this challenge is a GT750-powered, GSXR400 (GK73A)-framed track day bike which will have visual connections to the early TR750 racers - namely the blue/white paint scheme, gold wheels, TR seat unit, forward-facing calipers etc.
With the acquisition of a GK73A frame today, I now have a near-complete rolling chassis to complement the GT750J motor I bought while back.Shame they aren't compatible..........
So first job is to get the behemoth of a motor to snuggle into the lovely alloy beam frame. The rear mounts on the Kettle motor measure 16.5mm across (with the rubbers in place) - the cast-in frame lugs are 14mm apart. So thats the first (of many) obstacles I will have to overcome.
Pictures to follow.....................

Sounds interesting Garry....looking forward to some pictures. I have thought about a similar mission myself, using a T500 engine. I have access to a Honda NC30 which would make a good looking donor.

Do it !
one of the other "build-off" competition bikes is a T500 motor in a RGV250 (VJ21) frame.
would like to see a T500 motor in a NC30 chassis

Garry - I was looking at your thread on the KC. So you plan to run no lights on your build ? Or just a total loss battery system ? Given the modified points cover, I'm assuming you will switch over the ignition to the alternator side hence the question.

Hi Ian

going to run a self-generating ignition system with a small lithium-ion battery for the electric water pump and temp gauge as well as the horn that is required for the bike to get a "daytime use only" certificate - that way I can run it on the street legally without lights.
Ignition will stay on the left side like the TR750's - I am removing the starter clutch and all the gears from that side (hence the need for an electric water pump).

garry55 wrote:...going to run a self-generating ignition system with a small lithium-ion battery for the electric water pump and temp gauge as well as the horn that is required for the bike to get a "daytime use only" certificate ....

That's what I'd guessed - we don't have that same use category over here where I'm located, although I suppose it may be legal south of here in some areas of the States. Across Canada you always have to have the headlamp on so a battery only, total loss system could make for very short rides.

You are a bolder man that I as the one thing I would not want to take a chance on is the water pump ! There really isn't much weight to the pump, and if I recall correctly that cut down left side cover plate doesn't prevent you from having the gear train. Your call of course.

Hi Ian
electric water pump + lithium battery weigh 0.7kgs. I will weigh the starter clutch / water pump / drive shaft / gears when removed - sure they will be heavier.
I also read that the early water pumps should be swapped-out for a later one anyway - is this correct?
I hope to lose approx 3 inches from the width on each side of the engine - we shall see!

More mod bike being talked about here viewtopic.php?f=2&t=9614" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; A big problem you will have to figure out is the length of the engine as the GT is at least 2~3" longer than the GSXR engines .

garry55 wrote:I also read that the early water pumps should be swapped-out for a later one anyway - is this correct?

Yep - no problem. Impellers differ, but can be made to fit just fine.

Suzukidave wrote:More mod bike being talked about here viewtopic.php?f=2&t=9614" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; A big problem you will have to figure out is the length of the engine as the GT is at least 2~3" longer than the GSXR engines .

I am following that build thread too.
There appear to be many reasons why the GT motor doesn't want to fit the GSXR frame - the block is too wide to fit between the upper mounting brackets, the crankcases are too long, the motor mounts are too wide and the GSXR frame I am using doesn't have an engine cradle. I am part-way through addressing #3 which, when complete, will allow me to hang the motor from the frame and then attempt to resolve the other problems.

Suzukidave wrote:A big problem you will have to figure out is the length of the engine as the GT is at least 2~3" longer than the GSXR engines .

The most I can move the motor back in the frame is 1.5" and that involves major surgery (removing all existing motor mounts and fabbing / attaching replacements). I will have to wait until I can hang the motor in the frame to see if the front wheel will clear the headers.
Time to fire-up the angle-grinder................

Garry, Garry, Garry,

That's so old school thinking. Think modern engineering solutions such as stacked gearbox shafts. Check out a GSXR and maybe you could cut the back end off the GT and stick on the box from a GSXR. That will save you 4-6 inches for only a small amount of machining and welding and machining etc.

I have a GSXR trans chopped off its crankcases here that I keep threatening to weld on the back of a GT but my head hurts each time I look at it.......

If you have access to CNC machining, it might be feasible and as an added bonus if you order right now, you will get one extra gear for the price of 5. That's right. 6 gears for teh price of 5. We have operators standing by for your call.

garry55 wrote:

Suzukidave wrote:A big problem you will have to figure out is the length of the engine as the GT is at least 2~3" longer than the GSXR engines .

The most I can move the motor back in the frame is 1.5" and that involves major surgery (removing all existing motor mounts and fabbing / attaching replacements). I will have to wait until I can hang the motor in the frame to see if the front wheel will clear the headers.
Time to fire-up the angle-grinder................

I guess you read thats what i had to do to my 99 GSXR750 frame engine mounts , the engine was tipped up in the rear to direct the exhaust ports more down in the front so i could make the bend in the pipes but tuck them in close . This allowed me to use the stock frame lower rear engine mount to attach the subframe to , the top rear stock mount had to be removed and a custom bolt on one made .

tz375 wrote:Garry, Garry, Garry,

That's so old school thinking. Think modern engineering solutions such as stacked gearbox shafts. Check out a GSXR and maybe you could cut the back end off the GT and stick on the box from a GSXR. That will save you 4-6 inches for only a small amount of machining and welding and machining etc.

I have a GSXR trans chopped off its crankcases here that I keep threatening to weld on the back of a GT but my head hurts each time I look at it.......

If you have access to CNC machining, it might be feasible and as an added bonus if you order right now, you will get one extra gear for the price of 5. That's right. 6 gears for teh price of 5. We have operators standing by for your call.

You dont need all that special equiptment Richard ... just look at that builder that makes all those V8 bikes useing a hack saw and JB weld

Suzukidave wrote:

garry55 wrote:

Suzukidave wrote:A big problem you will have to figure out is the length of the engine as the GT is at least 2~3" longer than the GSXR engines .

The most I can move the motor back in the frame is 1.5" and that involves major surgery (removing all existing motor mounts and fabbing / attaching replacements). I will have to wait until I can hang the motor in the frame to see if the front wheel will clear the headers.
Time to fire-up the angle-grinder................

I guess you read thats what i had to do to my 99 GSXR750 frame engine mounts , the engine was tipped up in the rear to direct the exhaust ports more down in the front so i could make the bend in the pipes but tuck them in close . This allowed me to use the stock frame lower rear engine mount to attach the subframe to , the top rear stock mount had to be removed and a custom bolt on one made .

I haven't read your build thread yet - but I will when I get stuck!