[No Worries]

My 1990 CBR 1000 accelerates smartly, but at around 5,000 RPM, it really wakes up. I told this to a mechanic and he said that at around 5,000 RPM the needle pulls out of the main, so the bike is mostly running on the main jet. He said that my needle may be lean, to meet emissions, and that I should put in a Dynojet kit, which may wake up the lower RPM.

I've taken apart my carbs many times and have balanced them with my carb stix, so I have no fear of the carbs. Should I just get the kit and install it to see if it wakes the lower RPM?

 

[No Worries]

Larry G: I have stock pipes. I looked at Factory Pro and Dynojet. I liked that Factory Pro included different piston springs, but I also liked that Dynojet made a high altitude kit for my bike. Although the only difference is the main jet and different groove for the needle. All my riding is over 5,000 feet. But I could go with either manufacturer.

Speaking of carb pistons, Honda's are plastic. The get varnish on them which makes them stick. You can spray carb cleaner on the front and back, but they have to come out to clean the sides and top. Usually clears up a stumble.

Shanman: To me, the hardest part of carb work, besides getting the carbs on and off, is removing the dozens of phillips-head screws without stripping the heads. Did you rejet to fix leanness from an exhaust change? Did rejetting make you bike run better?