The RD Curse

Today I finished up in the garage and started prepping the RD for a test run of the new carb jetting, until my wife came out to the garage. She was heading out and refused to let me test ride the bike if she was not at home. Confidence inspiring it's not, but in reality my wife's attitude is a reaction to a long string of crashes, wipe-outs, break-downs, and even a dry fuel tank. When I head out on the RD things happen and my wife has taken note.

In the not so distant past I have really pushed on the RD. I also accomplished 1 "I can see my house from up here" high-side, 2 low-sides, and 1 wipe-out that I still don't know what happen, "bringing the bike upright, wacked the throttle WFO and then next thing I remember was sliding on my back on the side of the road". The RD is fun to push...... Its light, its tiny, its got a brutal power-curve when it comes onto the pipe.... Just can't resist.

Need to chill on the RD, or else I'm going to get hurt again.

Jet Test 2 - "Baseline"

• Way too rich - loading up until 6,000 - 6,500 rpm
• Sluggish
• Cyclic thumping in chambers at idle
• Never really comes onto the pipe
• Knew this would be too rich, but I thought it would be at least a tad closer!

• Main - 170
• Slow / Pilot - 48
• Needle - CEL
• Clip Position - #3 (middle)
• Float Height - 19mm

Pre-Work / Testing

• Pulled heads to visually inspect top-end
• New head gaskets
• New reed-block gaskets
• Case Leak Test completed - 6lbs for 6 min.

Next Test

• Double check ignition timing (dial indicator)
• Check plugs & wires 
• Main - 170
• Slow / Pilot - 48
• Needle - CEL
• Clip Position - #1 (top)
• Float Height - 19mm

Tuning,Tweeking & Confusion

I am still perplexed by the lack of performance from the RD!

I have experimented with several different carb setting on the Keihin carbs, but the overall performance of the motor is nowhere near what I know it should be. I have swapped jets, main jet & idle jet, testing a wide variety of options. I have also tested several carb needle combinations. My jetting is correct and power delivery is smoother with less of a "flat spot", but power just isn't what I want it to be.

The engine starts and runs fine, but the bike does not come smoothly "on to the pipe". When the RD does hits it's powerband it's VERY noticeable, but not nearly as powerful as I remember it being "back in the day". Maybe I have become jaded by the powerband of my Gixxer, but I remember the RD as having WAY MORE power than this (but it's been 30+ years)!

Time for a change in plans......

First.... I tried swapping the Keihin PWK33's for the freshly rebuilt Mikuni VM28's.... No dice! The Mikuni's are just too clapped out, so I trash this plan.

Second.... If changing the jetting is not working, maybe I have an air leak? I am in the process of building a "home-brew" leak-down tester and should have it ready for a test in the next two days. 6 psi for 10 minutes is the benchmark.

Third.... Return to a "baseline" jetting on the Kiehin PWK's ; CEL needles on clip #3, Main Jet of  170, Slow Jet of 48. Most of my sluggish throttle response is from 1/4 to 3/4 throttle, so the needle should be my focus. I know the Main Jet is rich, but I like to start rich and work my way leaner. I'll be burning VP C12 fuel mixed with Amsoil Dominator 50:1.

Stay tuned for test results.......

Do I have an air leak?
Burned or holed piston?
Too much carb to even expect a mid-range?