Suzuki 2 Strokes

Im am trying to figure out a way to rebuild my GT550 crank...

any pictures, guides, stories, tricks anything that can tell how to do it would be very appreciated! getting it done professionally would cost half of what the bike is worth! and i'm not convinced that it cant be done by myself

or maybe someone that has got a fine, working crank laying around for sale..?

The somewhat glib answer is that if you have to ask, then you probably don't have the experience or equipment to do it.

But everyone had to start off by learning, right? In this case, a 3 cylinder crank is probably not the easiest crank to learn on. Some other cranks are splined so that at least the center part must be correctly aligned and it's only the two end wheels that might be out.

In the case of a Suzuki triple crank the parts are simply pressed into place and it's not as easy to get everything aligned. There is no reason that you could not learn to do it. Read and absorb everything you can on teh web and maybe if you can get access to a press and jigs it might be possible.

ya right...

the only thing im not sure of, is how to make them rotate exactly 3 x 120degr.. I believe this is the only big problem there should be.

i'm thinking of making a very straight profile and put on the crank before taking it apart, and then make a long thin line on all 3 cranks, and then go for that when pressing it back together.??

Does anyone know the tolerances on the big end bearing side play?

And the other tolerances on the crank?

Kawi Triple crank rebuild manual may give an idea: kawtriple.com/mraxl/files/crankrebuild.pdf

Allan k wrote:Does anyone know the tolerances on the big end bearing side play?

And the other tolerances on the crank?

For the GT550, there isn't much in the shop manual - just a brief mention on page 73. See this link:http://oldjapanesebikes.com/mraxl_GT_Re ... 50-73.html

What my crank guy did for years for bikes with no published specs was to measure every measurable dimension before he split the cranks. H also scribed a mark across the flywheels so he could align them when he press it back together

Let's start from the beginning. Why do you need a crank rebuild?

Cliff - 3 broken oil seal, spring gone thru the rubber, 2 damaged oil guide rings, noisy main bearings and too big tolerances on the big end bearings..

The kawa triple guide gave me a few ideas, thanks

Im rebuilding the crank my self. See info on my blog.

http://Www.allansgarage.blogspot.com" onclick="window.open(this.href);return false;

OK Allan, you need a crank rebuild!! I've done a few GT cranks here at home, it's not that bad. BUT you have to have a good press, lots of patience and the parts to put it back together!
Measure everything first and make a drawing. Mark each part so you know where it goes or came from! Find your replacement parts first, if you get all the parts you need, then press it apart. Change the worn parts and press it back together. Don't worry about indexing the three crank pins 120 degrees, if you've marked everything they're go back in the same place. Once you get it apart you'll see why.
The fun part is truing it!! You want it as straight as possible! Try to get under .002" runout measured at the the throws! This is where the patience comes into play.
Set your crank up on two "V" blocks under the main bearings and measure the runout with a dial indicator at the throws. Mark your high spots. Now this is where the fun begins! Take the crank and lay it on a piece of hardwood with the high spots at the top. With a brass or lead hammer or block of wood and a hammer, beat on ONE high spot, set it up on on the "V" blocks and measure it again. And do it again and again until you're down to under .002" runout!!
It sounds like a lot of work, but really it isn't!
Good luck!
Cliff!

Hey cliff. Thanks for the advice. It looks like its not that bad, and it helps to hear that other people has done it.

Thanks

A short update on the crank fix..

I have pulled the crank apart, and found that the 2 centre main bearings had been spinning on the axel and grinded off about 0.5mm.. thank god I have a spare crank that dosent have this dissease...

I only need the spareparts now..

3 big end bearings.
2 oil guide plates
6 main bearings
seals
6 thrust washers for the big end

finished photo of the press tool

Thats cool , i am impressed you took on what most of us wouldnt think of trying .. thats nice you have the proper machines to machine up what you need .

Allan! You certainly have the tools and skills to do the job!! Finding the parts is going to be the hardest part of this job!