Cylinder replacement GT550

[TheFinland]

Do the differing years matter when replacing the cylinders? Can I use a 1972 cylinder on a 1975 bike? I know the heads are different cause of the style of ram air duct that's on em.

As always, help is massively appreciated.

[tz375]

Some markets had nicasil type plated (SECM IIRC) bores with split transfer ports on later cylinders but i believe that the US market only had the one design as it relates to porting and materials.

What did change was the fins above the inlet ports. Early cylinders had individual carbs and the fins extended towards the rear. Later bikes used a gang of carbs with a linkage and the fins were shorter above the inlets to allow for the linkages on top of the bank of carbs.

All cylinders with iron liners are interchangeable but late cylinders on an early motor might look a little strange to anyone looking too closely. For a daily driver or race bike it makes no difference, but if you ant it to look stock, you may prefer to get a matching cylinder.

[Alan H]

I ain't writing all this again!
https://www.kettleclinic.co.uk/kcforum/ ... ilit=Heads
Joining the Kettle Clinic is easy and free if you wish to contribute.
It's for all Suzy 2 strokes despite the name, and we have a world wide membership and spares availability/rebuild help/advice etc..
Follow the subsequent links for barrel and other info, and if you do a search, lots of 'stuff' about electrics, charging, alternators, rectifiers etc. etc.......
And yes, I do post there (and elsewhere) too.
Just traded my GT750B for a GT550B as well, so I daresay there will be 'upgrade' info soon.

[jabcb]

...
What did change was the fins above the inlet ports. Early cylinders had individual carbs and the fins extended towards the rear. Later bikes used a gang of carbs with a linkage and the fins were shorter above the inlets to allow for the linkages on top of the bank of carbs.
...

The early heads & ram air covers were also extended towards the rear.

Later bikes also have the petcock moved forward. The early & late gas tanks are different.