GT250 Cafe project

[Damian_74]

Had a mid life crisis. The first bike I owned was a GT250 and was born in 1974 so w hen I saw a 1974 GT250L for sale I had to have it. The bloke that I bought it off has a home resto/ repair business for old Jap bikes and but this bike together from bits and pieces. It is overall a nice bike but as it was done to a price it has it shortcomings. I originally had intentions of taking the angle grinder to the 74L but it was too nice a bike to hack up. After I finish this project I might attack it and do a proper job.



So in the mean time I went and bought this!!!!!!!!!!!!1976 GT250B
What the hell was I thinking??????



It needs everything.


Not entirely which way this project will end up - definitely leaning to the Cafe style but not committed as yet.

[Damian_74]

Going to start with the engine until I decide what I'm doing with the rest of it - it was locked up and originally suspected the crank - got a surprise when I split the case. The bike had been sitting in the weather with no gearbox filler cap and it had partially filled with water - definitely didn't expect that.







There isn't too much to salvage in the gearbox bit the crankshaft is in fairly good condition (obviously needs a rebuild but turns freely).
Supplied with the bike were a set of barrels and a head that had been Vapour-blasted. The bores were 0.5mm over-size - and almost usable and was seriously considering just throwing a set of pistons in them - more on that later.

The cases were as expected for a 40 year old 2 stroke - hours spent with de-greaser, phosphoric acid and a petrol powered pressure cleaner and I found the cases.

[titan performance]

Admirable. You clearly don't mind some hard work. I would have just fired all those bits to the local vapour blaster !
Good luck with your project....following with interest. I owned a 250M in the mid 70s, and it was a great little bike.

[Damian_74]

Thought that I was on a winner.....found a 74RAM engine in Tassie that had had had been overhauled and partially assembeled. Advertiser (who turned out to be a Mate of a Mate) had "rebuilt" the crank, New OEM 1.0mm OS pistons gasket set, all casings vapour blasted. $1000 delivered to Brisbane - how could I go wrong!



Well..................I had asked specifically about the crank rebuild when we were negotiating the deal and specifically asked about the crank seals but something was lost in the phone call.

WHY WOULD YOU GO THE THE TROUBLE OF REPLACING THE MAIN BEARINGS, CONRODS AND PINS AND NOT REPLACE THE SEALS!!!!!



The seller didn't intentionally miss-lead me, was going off poor advice from others. Emailed the bloke and he agreed to refund $300 towards the crank rebuild.

Now what to do - re-build the 74 engine or use the parts in the 76 (correct for the frame)?

[sportston]

Clean out the crappy casings and put the good parts in the right casing for the bike, but with new seals? Seems like a good idea if it is matching numbers. What kinda twit doesn't bother replacing the cheapest part of the crankshaft assembly? That really was a bonehead thing to do. It might be worth getting the crankshaft balanced while you are getting it rebuilt...again.

[karl pa]

Now what to do - re-build the 74 engine or use the parts in the 76 (correct for the frame)?

Just beware that 76 & 77 had a new crankshaft design with 4 main bearings instead of the older design with 3. Some parts can interchange, but I don't know how many, center and right crank seals for 76-77 are obsolete.

[Damian_74]

Now what to do - re-build the 74 engine or use the parts in the 76 (correct for the frame)?

Just beware that 76 & 77 had a new crankshaft design with 4 main bearings instead of the older design with 3. Some parts can interchange, but I don't know how many, center and right crank seals for 76-77 are obsolete.

Thanks Karl, Yes I am well aware of the different cranks. My biggest unknown was the gearbox and clutch.

When they went to the 4 bearing crank the gearing was also slightly changed

K,L,M 1st 2.333, 2nd 1.50, 3rd 1.105, 4th 0.905, 5th 0.782 and 6th 0.708:1.
A,B,C 1st 2.333, 2nd 1.32, 3rd 1.050, 4th 0.905, 5th 0.782 and 6th 0.708:1.

Had a fit up of all the gearbox and clutch internals of the 74L to the 77B's cases, it all appears to fit - so it is the 77 engine it will be!

As you pointed out the bearings for the 77 are now obsolete. There are NOS on eBay for silly prices, and then there is the concern of how well the bearings have been stored for the last 30 years and how long an ancient rubber seal will last????

The other option is the eBay seller "cruzinimage". Complete crank and bearing seal kits for under $200 AUD shipped to Australia and about the same for the rod kit. Obviously Chinese pattern parts.....quality unknown!

Has anyone had any dealings with cruzinimage?

[dollydog]

Has anyone had any dealings with cruzinimage?
yes mate, plenty, and always been pleased with their service and products.

obviously chinese pattern parts.
no, i don't think so. if they are, they are good quality, but most stuff made in japan

cheers, dd.

[Damian_74]

Has anyone had any dealings with cruzinimage?
yes mate, plenty, and always been pleased with their service and products.

obviously chinese pattern parts.
no, i don't think so. if they are, they are good quality, but most stuff made in japan

cheers, dd.

Thanks DD, it is always and unknown with 3rd party suppliers!

[Damian_74]

Just got the cases back from the Vapour Blaster - they look like they just came out of the die! Couldn't be happier!

[sportston]

Looks triffic. A pity to get the engine dirty with road grime and oil when they look that good.

[Damian_74]

I didn't expect the hurdles to jump up at this early stage. I work away month at a time hence ordered the crankshaft parts so that they would be sitting ready for when I get home - thought it was all sorted..........

Ordered form Cruzinimage via eBay.

It appears that they have sent me the parts for a GT250 X7.......not really the same engine!
Different mains (they completely failed to send any seals) and different length big end pins (need 57mm pins rather than the 50mm).

At least they are talking to me on eBay and trying to sort the problem.....see how this works out!


From what I have researched.........can anyone in the know please confirm that these are the correct crank parts for a GT250A (4 bearing) crank.

2 pc. Suzuki # 09262-25009, Koyo # 83197-9, Size 25x65 x17
2 pc. Suzuki # 09269-25005, Koyo # 83190-9TC3 NR, Size 25x65x17/14

1 pc. Suzuki # 09283-25019 crankshaft oil seal 25x65 x12
2 pc. Suzuki # 09289-33006 crankshaft oil seal 32.3x65x10

[dollydog]

all sound right to me mate. i checked on alpha sports page https://alpha-sports.com/suzuki_parts.htm" onclick="window.open(this.href);return false; and apart from one typo which read '55' instead of '65' they are all ok conrods and one of the main bearings are the same as the 250m, as is the big end bearing, and probably a few other bits and bobs if you cross reference the part numbers. very useful tool is alpha sports at times like this
cheers, dd.

[Damian_74]

Cheers DD,

Most of the part numbers I'm using are off the Partzilla site (they have the same misprint with the bearing OD at 55mm).

Still waiting for Cruzinimage to get back to me - they have gone uncomfortably silent!

[Damian_74]

It seems that my engine overhaul has stalled for a bit till I sort the bearing and seal issue - so in an effort to push the project along I have started on all the components. Hadn't intended to strip the rest of the bike at this stage but with all the delays I wanted to at least feel like I was making some progress.

Have a selection of different cutting and polishing wheels and started with the side cases and wheel hubs.
WHAT A PIG OF A JOB but at least the effort pays off.








But makes a hell of a mess.