[Drbarson]

Hi all.
Wanting to know if anyone has swapped latter model cams (98-99) into (95-97)

I'm not interested in just swapping in latter model mtr as current one (97)is getting a freshen up. Correct me if iam wrong but I believe 98-99 mtr had more compression, different cams, and different carbs and airbox.
Mods so far are full system, ig advancer and removal of charging system.
Bike is raced in a pre modern category and I believe 97 is the cutoff hence why I'm not up for 98 99 swap.
Any info would be muchly appreciated.

 

[RJ2112]

I’m going to wait for RiversZZR, or some of the other long term engine builders to comment. I would expect head work to improve flow would be at least as valuable as different cams.

 

[riverszzr]

G model cams do fit inside an F model engine

 

[mmattockx]

If you're going to fit different cams make sure you get slotted cam sprockets and do a proper job of degreeing them accurately as well.


Mark

 

[Drbarson]

Thanks for the response guys, I'll sort some G model cams and look into the slotted cam sprockets.
Head is undergoing a mild port clean up. I can post some pics once finished.
Any chance Riverszzr are you able to answer- if the compression ratio jumps between the F and G mod, what part/s were different or machined to achieve this. If it's a machining job of barrels or head that's straight forward. But if I'm replacing rods / crank / pistons to achieve it I'll leave it.
Cheers.

 

[riverszzr]

Thanks for the response guys, I'll sort some G model cams and look into the slotted cam sprockets.
Head is undergoing a mild port clean up. I can post some pics once finished.
Any chance Riverszzr are you able to answer- if the compression ratio jumps between the F and G mod, what part/s were different or machined to achieve this. If it's a machining job of barrels or head that's straight forward. But if I'm replacing rods / crank / pistons to achieve it I'll leave it.
Cheers.

While the G model does share some/many engine parts with the F model, ie.....the pistons, the rings, the cylinder assy and the sleeves in the cylinders are all the same between them---as such you can buy aftermarket piston kits that fit both

the head, cams etc are all different as are some of the lower end parts


the compression ratio difference could come from either or both combined but most likely it is in the head assy.......

 

[Drbarson]

While the G model does share some/many engine parts with the F model, ie.....the pistons, the rings, the cylinder assy and the sleeves in the cylinders are all the same between them---as such you can buy aftermarket piston kits that fit both

the head, cams etc are all different as are some of the lower end parts


the compression ratio difference could come from either or both combined but most likely it is in the head assy.......

 

[Drbarson]

Thanks for the response, looks like I need to source a 98 99 head and play spot the difference.

 

[riverszzr]

Thanks for the response, looks like I need to source a 98 99 head and play spot the difference.

Same valves in both.....

So combustion chamber design
port shape/design to some minor extent

I think the intake boots are different (smaller) for the smaller carb bodies........

 

[Drbarson]

Same valves in both.....

So combustion chamber design
port shape/design to some minor extent

I think the intake boots are different (smaller) for the smaller carb bodies........

So the looking I've done shows a different stroke on the models. It's a bit all over the place depending which page you go into regarding the specs but most lean towards (bore & stroke) 66x43 for 95 -97 model and 66x43.8 for the 98 -99 models. Above you mentioned piston, cylinder assembly is the same across each model, do they have the same part numbers?
And this .8mm extra is achieved by rods, crank, piston height or shape?
Thanks.
Dan.

 

[mmattockx]

So the looking I've done shows a different stroke on the models. It's a bit all over the place depending which page you go into regarding the specs

Instead of trusting the interwebz, download the service manuals from this thread and get the correct info straight from Kawasaki:

Master Service Manual Thread

I got tired of having 50 threads stuck to the top of this sub forum, so I've made one master thread which I'll keep updated to the best of my ability. If you have a new manual to add to the list, or if one of the links is broken, then PM me. At the time of this posting all links are valid and...

www.zx6r.com

You can also use various online parts suppliers to see which parts were common between the models.


Mark

 

[riverszzr]

The pistons and rings and cylinders and cylinder liners etc are the same part numbers.........

but sound advice to look up the part numbers yourself and to download and look through both oe service manuals!