QuestionMy name is peter, and I own a 1983 Honda nighthawk 650. DOHC 16 valve inline 4 etc...
I have had a somewhat conplicated problem, and I will do my best to explain it clearly.
When I bought the bike, it had a stock air filter, but the pipe tips were drilled out a little. The pipes must not have affected the mixture however, since the plugs were a nice brown color.
The filter was old and dirty, and i was going to buy a new one. I asked various sources if a replacement UNI filter would be likely to lean out the mixture since it is a higher flow filter. I was told that since the bike was ok with a stock filter, it should be fine with a UNI.
So i bought a UNI, and installed it properly, and went for a 40 minute ride. When i returned i checked the spark plugs and found they were quite white.
I was afraid i would damage the engine if i ran it too lean, and i found out how to shim the main jet needles with #4 washers. I shimmed it with one washer per needle, cleaned the plugs, and took it for a ride to test it.
After riding a little over a few days time, i checked the plugs and they were somewhat brownish, and definately not the bright white they had been.
However I had noticed while riding, that the bike lacked the top end power. It wasn't bad in lower rpm range, but power did not really increase at high rpms like it should.
I was told by someone that i should change the main jet size up one, but I'm so confused about what the problem is and how to treat it and I need some reliable advice.
If you can give me any advice at all that would be great.
I would like to fix it myself if i can, seeing that my budget is limited.
Thanks so much!
AnswerHi Peter,
Great narrative description of the problem. I'll need your email address as requested. I'll return repair information files via email. I will explain possible cures in the email.
Send to me here: mshively1@woh.rr.com
You may contact me as needed for assistance.
Respectfully,
Mark Shively
