Author Topic: RS Mikuni's and GSXR cams (Read 6550 times)

2005B12S · « **on:** May 25, 2006, 12:11:24 AM »

Finally got the GSXR750 cams installed. Decided to do the RS carbs at the same time. I usually would only do one engine mod at a time, but this was very easy.

Cams were a straight swap, used the stock sprockets along with an APE manual tensioner.

The RS Smoothbores were plug and play. Came set up right out of the box. The only adjustment was to set the idle at 1200 rpm.

I could not be happier to get rid of the restrictive airbox.

Took it out for a 30 mile run to wash the assembly lube thru the oil, she still pulls good below 6000 rpm but the real fun begins at 6500. She absolutely comes on the cams at 6500 and pulls clean thru 10,000rpm.

The RS carbs take finesse as they do not use vacuum to open the slides. They rattle at idle also, throttle effort is not much different from stock.

Both are mods I would recommend. Full suspension treatment is next for me. Also note the 1100XX Helibars, very nice mod that allows a small drop in the triples and will work with the S bodywork.

I will get more photos up when I get it all back together.

Ride On, Ed.
2005 GSF1200SZ
1992 900SS
1983 GS750ED

Dragbike · « **Reply #1 on:** May 25, 2006, 02:11:33 AM »

Good deal! As I have said before......... (the pic in my avitar to the left) is a 1988 600 katana with a 90 (rocker arm) 1127 Katana motor I do 9.4 at 143 in the ¼ mile......Really pisses the busa folks off when I play with them at the drag strip and goose it just before the stripe, and with a blast of torque ...beat them.
I know Suzuki wanted more mid range for the Bandit... (Or just placate the lawyers and EPA) But the GSXR setup is really fun!
What size of carbs? I think you said it on another thread in this forum just don't remember...I think you said 36 or 38. I think you might try slotted cams sprockets and degree the cams, might help too in the future. Not to race, just have better tune ability and cleaner smoother engine.
Ok not trying to open up a can of worms here, just curious on your decision on the manual cam chain tensioner. On my low9 high 8 sec motors I still run a stock tensioner. I have not found any problems with the stock one at all,, no chain slap on deceleration what so ever. Just seems to me like more things to adjust and take care of on a street bike. But maybe you can help me with your reasoning on why you did it.
Oh and yes the chatter of the carbs at idle is quite noisy tatatatatattatt or more of a click..click./chatter..chatter
But they do have a nice response and smoothness to them!
But think about it….. if your motor was not breathing very well…….. it would not beckon you for more!
Thanks for the photos! I always like to see pictures of projects.
Brent
Oh! Did you go to Bull Shoals, AR last Sept. on the ride that Craig setup?

2005B12S · « **Reply #2 on:** May 25, 2006, 10:09:09 AM »

Thanks, that has got to be some sleeper you have. I am not a big Busa fan, must be fun to beat them at the only thing they are good at.

On my B12, I went with the RS36's as I thought they would be better on a stock displacement street bike than the RS38's.

If I ever go with full .380 lift aftermarket cams they would be degreed in, I just did not think the time involved was worth the gain on the moderate lift GSXR cams.

The tensioner is cheap insurance, I had one fail on my hot rod 16v GS750 back in the late '80's and have been paranoid ever since

I must say the B12 tensioner is much better constructed than the 750 unit, and would probably not give any trouble with the GSXR cams. Adjusting the aftermarket unit is easy and can be done without removing the carbs.

I am having small alloy side covers made, I will post more photos when they are done.

Ride On, Ed.
2005 GSF1200SZ
1992 900SS
1983 GS750ED

2005B12S · « **Reply #3 on:** May 25, 2006, 02:44:27 PM »

Left sidecover is done, waiting on the right. Honda 1100XX Helibars work great. Tobin seat should arrive next week.

She sure looks good all back together.

Ride On, Ed.
2005 GSF1200SZ
1992 900SS
1983 GS750ED

Kickstart · « **Reply #4 on:** May 25, 2006, 08:22:16 PM »

Hi

I have some 40mm flat slides on mine. Throttle is definatly a lot heavier (and a longer travel).

I have just fitted a heavily chopped down airbox onto the bike to carry the chrome covers on the side and disguise the carbs a bit.

All the best

Keith

2005B12S · « **Reply #5 on:** May 26, 2006, 12:48:48 AM »

I must be getting used to the throttle on the FCR41 carbed 900SS.

Are you running the RS40's with stock displacement/compression?

Ride On, Ed.

2005 GSF1200SZ
1992 900SS
1983 GS750ED

Kickstart · « **Reply #6 on:** May 26, 2006, 07:08:11 AM »

Hi

Nope, it is a 1216 engine with a skimmed and ported head, reprofiled cams and a Akrapovic exhaust to go with it. Around 150hp before fitting the carbs (last run before fitting the carbs was 144hp, but with the C&S on their last legs).

On the dyno the carbs seem to have added about 10% to the power. Only worry is whether the lack of airbox will cause problems at high speed (target for this weekend is 170mph genuine).

All the best

Keith

Kickstart · « **Reply #7 on:** May 30, 2006, 01:20:54 PM »

Hi

Oh well, keep trying.

I had the gearing up one tooth on the front and down one on the back. This was a touch high, so I went back to standard on the back.

Best top speed I managed was 167.1mph (unfaired bike). Want to get it to a genuine 170mph before I resort to a small fly screen or the like.

Managed 171mph on my Bimota YB10 (25% less power than the Bandit, shows you the effects of a fairing to hide behind).

All the best

Keith