Crank cases GT-T500

[GT500Andy]

I’ve tried looking in the search section but could not find what I need to know. I see in the part catalogue that there are different part nr. With M-1975 and GT 1976. For the casings. And the oil modification was done after 73. Are there any further significant changes to the casings? Andy

[Rustygt550]

It could be that the T500M cases have a different gearbox breather than the earlier models, the t500M has the same breather as the gt500

[Rustygt550]

Or it could be that the Gt500 has electronic ignition & the cases are different to mount the electronics

[gyrocfi]

Yep the GT500 has different machining for the ignition. Check with Stu, Bikegeezer, he has remachined a T500 case to work on a GT. Dofin

[GT500Andy]

I have a set of casings which are not a pair the bottom half has of cause the engine nr. 5***** so it’s a 73 ‘er. With steel crank inserts. The top half has inserts from messing (Bronze) so therefore they are not a pair. But has the large gearbox breather I think it’s an earlier one may be about 71. From these casing I want to build a T500 engine with contact points so this shouldn’t be a problem?
Andy

[Suzsmokeyallan]

Its important you get matched halves for any engine thats split horizontally. The machining for all the shaft holes is done on a jig and so its only understandable the 'set points' for holding the cases during machining can shift ever so slightly when boring lots of cases as in mass production.
This basically means that either half of the shaft holes will not be 100% equal to the other side unless they are matched/bored sets.
So putting two mismatched case halves together can therefore relate to an ellipitically bored set of cases.

[tz375]

I believe Allan is right that case halves are machined as a set.

Unlike old British bikes which varied from one to another, my experience with Japanese parts is that top and bottom halves can usually be interchanged with no adverse side effects.

In fact Honda sell the case halves separately and so do yamaha. I think Suzuki do also, but I'm too lazy - I mean busy- to check. If Suzuki list uppers and lowers with their own part numbers, there is an extremely high probability you can mix and match.

[Suzsmokeyallan]

To lazy to check Richard??? thats not like you at all,,, ok go look at the side of your buffalo cases just behind the drive sprocket on the case joint. You will see what appears to be some marks like a chisel was laid across the halves and hit to emboss some lines there.
This is a way Suzuki used to make sure the machined case halves stay matched with a quick visual check.
To make sure the marks did not line up on all cases, the places they hit the lines and how many they put, how deep they are, plus an angle to them if possible easily verifies the halves match on only one set.
Honda are very anal today about what they refer to "select size matching" of parts so you get as close to a blue printed assembly as possible.
For the older bikes it wasnt so important back then but sometimes the manufacturers do surprise you now and then.

[Buffalo-guy]

Allan.
Welcome back from the GREAT WHITE NORTH. Nice visit. We'll do it again.
Grand Poobah of the Loyal Order Of Water Buffalos
Fred

[Suzsmokeyallan]

Fred it is always a pleasure visiting you and your family, and thanks for having me around to your place again.
I definately need one of those new WB hats you showed me, so let me know when you have some more stock for sale.
That morning i left you, it was so cold that the bottle of water i had in the centre console of the car had frozen solid.
The layer of ice on the windscreen meant i had to wait for some blower heat to warm the glass before the wipers would move it.
It was only minus 26c so thankfully it cleared quickly, as it was a clear night i'm surprised it wasnt colder.
I cant wait for summer to get there in Calgary and im sure you feel the same by now.

[Frank]

Allan, just curious - do you know if Suzuki did the case marking on other models also (ex. T500)?

p.s. if you ever get up to Maine you'll be welcome to crash at our place; same goes for anyone else on the forum

[Suzsmokeyallan]

Frank thanks for your generous offer, its most appreciated.
The marking of crankcases seems to be the norm for Suzuki as my 69 T500 cases also have one just behind the drive sprocket on the joint. You can see its been placed there when they were together, so for most if not all the horizontally split cases it would be a common feature.
To answer a statement Richard posed earlier, i checked the cases on a 1993 CBR900RR for comparison and they are only sold as a set.
One part number means you get both the upper and lower crankcases, therefore you cannot buy one half only.
Most parts books place the item number in a square block on the image diagram if that item is only sold as an assembly.

[tz375]

In the case of the GT750, Suzuki sold them as complete set of upper and lower and also color coded a couple of gears to match.

Just for idle curiosity I did a quick mix and match and the pairs I mixed up were fine. There was no discernable gaps, steps or misalignments.

Your results my vary.

Simple answer is try the two halves and see how well they fit. If you get lucky, that's great and if not, need to find another half case.

We're not talking rocket science here. These things don't make 180HP with super thin wall castings. They are bricks. If they fit, they fit. If they don't they don't. You just grab another one.

[Zook-e]

FWIW I have also mixed case halves with no discernable effects.

[GT500Andy]

I've just taken a look at the casings on the drive sprocket side. By the kick start shaft and your right there are markings and they don't match! But I’m going to see if they will match. The other casings which I have are too badly damaged to be repaired. I will try just the transmission first, if that fits in first and then the crank.
Andy