-- Steve Rice Racing --

Question:

Steve,

I was given your name from a friend and co-worker in Clearwater Fl. he said you might still have a 1976 BMW R90/6 in your garage. I have a 1975 R90/6 I'm having some problems with the carbs. I rebuilt them a couple of weekends ago because I don't think that they have ever been taken apart, and the bike wouldn't idle it would die every time I stopped at a light or stop sign. After the rebuild the bike still wouldn't idle, I checked the timing and the points, I regapped the points and the timing looked fine although I might retard it a bit since the bike pings a little. I finally got it to idle but only after adjusting the jet on the bottom of the carb and the idle screw. It still doesn't seem to run right though it almost sounds like its only hitting on one cylinder but it smoothes out when you ride it (runs smooth at ~1500 rpm). Any thoughts or suggestions would be greatly appreciated.

Chris

ANSWER:

Hi Chris,

Actually, my street bike is a 77 R100/S, (some asshole stole my R90/6) I just put a new battery in it and had to clean one of the carburetors because of a running condition exactly like what you are describing.

What you describe could be a problem with pilot fuel and /or air circuit being blocked. This would be the pilot jet, low speed mixture screw and passages in the carburetors themselves.

Since there are two of everything carburetors, cables and screws - making the bike run evenly is a challenge that requires good balancing and synchronization between the throttle cables and idle screws. But, it sounds to me like just a good cleaning and synchronization should fix your low throttle position running problem.

You can determine which carburetor it is by pulling the plug cap off of the spark plugs one at a time to see if it will run or not, The cylinder that doesn't run is the one you need to look at.

Hope that helps, if you have any other questions or if I can be of assistance feel free.

Steve Rice

Question:

Steve-

Have a 1991 ZX-11c 12000miles. this bike is now used drag race only (top eliminator once). Going down strip it is fine - on the return road after getting time slip in first & second gear with slow smooth throttle the drive train gets jumpy like skipping a gear or tooth engagement is bouncing in and out. Engine oil is perfectly clean with no metal on the magnetic drain plug. Going down strip it is fine when shifted hard. Any thoughts that might lead me to solution?

Bob

ANSWER:

Hi Robert,

Sounds to me like you have rounded engaging dogs on second and the gear that engages it.

Most likely you will need to replace second, the mating gear, shift forks and drum.

Be sure to use parts from the later ZX1100-D2 or later, they have been updated.

s.r.

Question:

Steve,

Enjoy your web site keep up the great work.

Question: I am run 1973 Kawasaki in Pro Street, It is turbo charged with fuel
injection, the motor is a J model with a Gpz head stock. The problem is the
cam cap bolts stripping out and then you have to heli coil new threads. Well
even the heli coil will strip out at some point. The head goes through so much
fatigue
with hot/cold cycles. What I would like to know is there a better way to
resolve this problem? or are there any steel incerts on the market that can be
drilled over size to use the stock 6mm bolt or do you go to over size bolts and
make new cam cap sleeves to fit the over size bolts?

Thanks Pat

ANSWER:

Hi Pat,

Usually what you run into is the threads failing from the springs running into coil bind, the caps being over torqued, and just the constant in and out of the bolts stressing the aluminum in the cylinder head.

Of course its always better to start with fresh parts, ie. a new head, but that is not always feasible. Plus a used head is seated in well and will hold a valve job longer than a new head will.

If you have damaged Heli-Coils in your head now, your only recourse may be to install a larger diameter bolt, this can get tricky (read expensive) since you don't want to get the caps out of alignment.

When I have ran into this problem I do not use Heli-Coils, I prefer to use Time-Serts they are a one piece steel insert that goes into damaged threads. They usually provide a lasting repair for the damaged part. I use them any place in aluminum where the hardware is taken in and out allot. Clutch cover, inner clutch hub. etc...

But the best way to keep from damaging the threads is not to over torque the bolts which will pull the threads from the head. The 6mm bolts are a special hardened bolt that is adequate for your application. It is important to follow the manufacturers tightening sequence and use the specific torque number (I have 1/4" drive torque wrench that is dedicated to cam caps).

To keep unnecessary stress on the treads and to prevent gawling of the threads in the head to the bolt use a good assembly lube on the threads and under the head of the bolt.

Hope this is helps.

Steve Rice

Question:

Hello Steve :o)

You have a verry good websight. :-)

I am a man from norway and im rideing a old kawa gpz funny bike with a zxr 750 engine in it.

The last jear i have run the zxr 750 engine for funn and learning the game. and my dream is to find a zx12r engine to use in the bike.

But thru the jear i got the desire to se how fast i can get the 750 engine to run with a low budget. With al original engine i run 11.47 on 1/4 at 187 km.h and 6.97 on 1/8 at 167km.h

I have thru the winter started to fit a garret T3 turbo on it. to se wat it can do.

Maby you have som tec tips for me? Methanol, whater injektion maby. My goal is to beat the hell out off the engine to learn and praktice to leather projekts.

I hope to heare from you.

Venlig Hilsen

Stig Stene

SS-R

Web side

www.ssrbike.com

ANSWER:

Hi Venlig,

Thank you for the compliment on my web-site, I looked at yours I think it is much better than mine.

I think with the addition of a turbo charger your 750 will be quite fast.

Are you going to blow through the carburetor that are on the bike now, or are you going to do a draw through?

Blowing through the carburetor will be a bigger challenge to get figured out, however when its done you will have a better running bike than a draw through system.

With methanol you will want to be 60% richer than gasoline or have a A/F ratio of about 6.5:1, gasoline will be near 13 or 14:1:1, if by chance you decide to try ethanol you will be looking for 9:1 A/F ratio.

With the b/t carburetor it maybe hard to get the jetting big enough for methanol, draw through with an S and S wont be a problem.

Ethanol would be easier the get the correct jet sizes, even more so with gasoline.

If you decide to run gas then I would use some kind of methanol or water injection system.

Waste gate selection will be a factor on how well the bike responds also. I have had best luck with a diaphragm type of waste gate, you can find those at several places or I can supply one.

I hope this information helps and if there is more I can do please let me know.

Steve Rice

Question:

Hey there Steve I have a question I have been drag racing a KZ 1000 turbo charged a few years now and have experienced good luck with the motor combo. But recently i have built a new motor the new motor is 1200 cc with the same turbo that i had freshened up buy Turbonetics. My question to you is I have considered running alcohol but the static compression is 8 to 1 and I have no experience with running alcohol I previously ran 118 octane fuel. Do you think there would be an advantage to running alcohol verses race fuel and could I run alcohol with that low of static compression?