GSXR Cams in 1170 Kat

[Guest]

Hi Chaps, I have a 83model katana, with an Arias 1170 kit, EFE cams , HV epoxy ported head(Standard Valves), and RS36 Carbs.

Just picked up a set of Cams from a 1988 GSXR750 , and was wondering if I had to use both or could just install the inlet cam for more bottom end.

Only just fitted the Ported head and dialled the cams in to 110IN, 110EX a month or so ago,goes great!,but itching to give these GSXR cams a run.

Also any indication what to dial them in to, I think original was 105IN,105EX , but with the HV head I have been told if you spread the lobes 110-112 , you get more effect from the porting.


cheers,

Spot

[chef1366]

Rapidray knows what do do. He'll fill you in on the details.

[jimb12]

Stock GSXR cams don't have the double-wide bearing surface cut for the inner cam caps of a GS motor so they're not right for your engine. Another thing to consider if you do find some bigger cams that are made for a GS engine is, do you have aftermarket HD valve springs installed in that cylinder head? If not, then the 1150 cams you already have are as big as you should go in my opinion.

[stetracer]

Stock GSXR cams don't have the double-wide bearing surface cut for the inner cam caps of a GS motor so they're not right for your engine. Another thing to consider if you do find some bigger cams that are made for a GS engine is, do you have aftermarket HD valve springs installed in that cylinder head? If not, then the 1150 cams you already have are as big as you should go in my opinion.

Yep what he said
But I will add that Cam-Motion did make some GSXR cams on GS blanks so there are some cams out there that will work on both motors. Also I would set the cams you have now at 108 intake and 110 exhaust I run the cams on my 85 GS1150 at 110 intake and 113 exhaust


.

[rapidray]

There is a small area that the GSXR cam needs to be ground to work in the GS head. I've done them, they work. The 88-89 GSXR 750 intake cam is the biggest at .350 lift. Lay the GSXR cam in a GS head & you will see where it needs to be ground. There is PLENTY of the cam in the journal that if you grind it SLIGHTLY undersize, in that area, it WON'T be an issue. If this is a street motor, not a drag bike, set the cams up at 106 on the intake & 108 on the exhaust. This will give you decent bottom end, good top end & VERY strong midrange. Bigger numbers than those will sacrifice bottom end streetability. Ray.

[Spot1000Kat]

Thanks Ray, i put some rockers out of my other head in , which had the oil bump ground down, the cams fitted in great ,only take up half the centre journals but got heapa of oil up top with 750 pump gears.dialled in to 105 in 107.5ex yesterday and turned over with good clearance. Hopefully fire the beast up this afternoon. Will keep ya posted how it goes

[Spot1000Kat]

Took the ol'e girl for a blat today, goes like a rocket, will have to take her for a good ride to sus out how the jetting etc is looking, thanks for the help,

cheers,

Spot

[rapidray]

Glad to hear & happy to help! Knew a girl in Townsville a long time ago. She was fun!! Ray.