650 Katana cam heights

[Guest]

Hi Guys,

Still cleaning and evaluating components for my rebuild, and I'm short of a piece of information. I've had a good search through the records on this site (and all over the internet) but can't find the info I'm looking for.
I am currently looking at my camshafts, but I can't find the specs for the cam heights anywhere. I have the standard 650 G/GL/GT etc sizes, but I understand the katana cams are slightly different. When I measure them they seem have about 0.7-0.8 mm more lift than the standard cams.
Does anybody have the actual specs and limits?

Thanks,

Ian

[Nessism]

650M camshafts are the same part number as the regular 650 camshafts. Specs are in the service manual. Free download from basscliff's website. http://members.dslextreme.com/users/bikecliff/

[IanW]

650M camshafts are the same part number as the regular 650 camshafts. Specs are in the service manual. Free download from basscliff's website. http://members.dslextreme.com/users/bikecliff/

Thanks for the quick reply - but now I'm confused.

I based my question on the following two quotes:

Note: the GS650GX & GZ Katana engines used different cam shaft profiles to that used in the GS650GT / GL & GS650E. The Katana has a peakier power curve and is several kilowatts up in overall engine performance, the down side to this is that the Kat gets a little bogged down in the lower rev range. (Chris Arthur's 650 Katana page)
and...
The 650 is seen in roadster and custom guise with the GS650E and GS650L. The sports role is played by the Katana which receives a specific oil cooler as well as special cams that amount to a 73bhp @ 9.500 rpm against 65bhp to the GS650E. (Suzuki Katana – the story of a unique style)

This seems to be confirmed by my measurements which indicate a greater valve lift.

I wonder did the specs vary by geographical area?

Regards,

Ian

[60ratrod]

Since the model info on the main page is down, what's different from a gs650g and gs650m?

[GregT]

The little info I have on the 650's suggests that the early G and chain drive models,'80 and '81 - which would include the kat - have 8.0mm lift inlet and 7.5mm ex.
The later E's and G's - '82 and '83 - have 7.2/7.0.
I'd be surprised to find a Kat with anything other than 8.0/7.5. There may possibly be a different part no for cam sprockets too which would mean different timing. This is quite common across the 8V range.

[IanW]

Since the model info on the main page is down, what's different from a gs650g and gs650m?

With all the searching around I've been doing lately I'm pretty sure I read that the 650 Katana was designated 650M in the American market to tie it in with the 550M katana, which had already established a presence. They apparently didn't want to confuse matters by using a different suffix. In the rest of the world it was called a 650G. Whether there were other differences I don't know, but I believe the Japanese home market models had no oil cooler, and had a slightly shorter seat as per the 550 kat.
Sorry if there are any mistakes here, this is all from memory.

Ian

[60ratrod]

I didn't even know there was a 650 kat in 81/82. I just thought it was the 550