Motorcycle Repair: 1993 GSXR 750 engine problems, car parts stores, air leaks

Question
I have a 93 gsxr 750 with about 23,000 miles on it that has had some recent shortcomings I was hoping you could help me out with. I recently had a valve adjustment in which my #1 and #3 were torqued down really tight. once they were brought back into spec, they had no compression. So I had them adjust it back to where I could ride it home. They told me that I would not be able to rebuild it myself because the engine was nic sealed. which brings me to my first question. What is nic sealed and can I rebuild the engine myself? By the way my compression was #1 25psi, #2 125psi, #3 75psi and #4 175psi. What could be the possible causes for the loss of compression? I also noticed that when I throttle down, my rpm's stick between 4000 to 3000 rpm and then eventually go down to around 800 rpm and a rough idle at that. The carbs were also cleaned when I had the valve adjustment done. What could be causing the sticking? I also changed the plugs and gave it an oil change, just for the info. I appreciate your time and any advice you can give me.

Thanks,
Mike

Answer
Hi Mike,

Q:  What is nic sealed and can I rebuild the engine myself?

A:  "www.nicproducts.com/index.shtml"


Q:  By the way my compression was #1 25psi, #2 125psi, #3 75psi and #4 175psi. What could be the possible causes for the loss of compression?

A:  Dished or cupped valve faces and seats.


Q:  I also noticed that when I throttle down, my rpm's stick between 4000 to 3000 rpm and then eventually go down to around 800 rpm and a rough idle at that. The carbs were also cleaned when I had the valve adjustment done. What could be causing the sticking?

A:  Intake air leaks, varnished carb parts, improper carburetor synchronization, and cylinder compression out of service limits, and more.

A cylinder leak-down test will determine the source of the leaky cylinders. You can rent or borrow a leak-down tester at most car parts stores. Depending upon the spark plug size, you may need an adaptor for the hose.

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Respectfully,
Mark Shively