Stock '90/91 GSXR1100 cam profiles measured

[Gavin]

Hi all,

Not sure if this will help anyone but currently building an engine for my soon to be drag bike and trying to compare the myriad of cams out there but could never find any solid numbers for the stock cam specs so I decided to measure them!

I used a Mitutoyo digital DTI with their SPC digital out protocol and a stepper motor hooked to the ever infamous Arduino so I could get accurate and automated results.  Plotted them up in excel and attached the graph here.

As I say, I could never find this data in the wild!

Regards

Gavin

[DAZ]

Hello and welcome, an excellent and informative first post sir ! 

Edit: Just looked at Kent cams suz7  profile 

245° inlet & exhaust @ 1mm lift and 9.27mm valve lift so a small increase over the GSXR profiles as they become harder to find in good condition after 30+ years  

Edited November 21, 2023 by DAZ

[Gixer1460]

For clarity - measurements at cam or lifter? I don't know what the rocker ratio is on these but makes a mess of the calc if its wrong. Good info nonetheless 

[Gavin]

Hi Daz,

Thanks for the welcome! Yeah, those SUZ7's seem like the closest match for a nice drop in for the bandit.

 

Hi Gixer1460

That's a very valid point, and I should have made it clear in the post!  The measurement was actual valve lift with the DTI mounted against the valve face.  This was with stock valve clearance and DTI mounted as best as possible to avoid any cosine error in the measurement.

[coombehouse]

The lift figures match those in the Suzuki manual for gsxr1100k which is reassuring.