I just bought the bike. Former owner told me the bike runs rough when the outside air temp is below 65 degrees. I should say the bike runs rough till it gets warmed up , but it takes a long time to warm up. I live in Michigan the ridding season is short and temps are cool for a large part of the season. Is there anything I can do to change this…different spark plugs or do I need to be patient and let it warm up for 10-15 min when it is cool out.
Do you know where I can find an owners manual and repair book for this bike.
Your web site is Great
Lots of air cooled bikes tend to be cold blooded. In my experience the Honda CM motors aren’t particularly prone to this. I would guess that your bike just needs a nice little tune up. When was the last time the valves were adjusted and the carburetors synched? Both of those can cause hunting idle and sputtering, particularly when cold.
I believe I have a manual for this bike. Let me check and I’ll repost with it shortl
Note from Reader:
I just bought an ’82 Honda CB450 Nighthawk. The owner told me all sorts of lies about the bike. Needless to say she is a basket case. Good thing is I was able to get her started (one cylinder only) but she did idel well and sound ok (no wierd knocks or anything). I am also looking for information on this bike. I would rather get my info for free while working on this bike. I do have a copy of the repair manual for a Honda VTX 1300 ’05 on email if you could use it also one on 2009 Kawasaki Ninja 650r. Also looking for parts on this bike. The bike fixed up is not worth much but every time I see parts for sale they are asking more for the parts than the bike is worth. Makes no damn since to me. Need info on rebuilding carbs most of all. Thanks for your help.
Unless your carbs are truly trashed then there is no reason to buy replacement parts for them. Start out with what you have and give them a good cleaning and reconditioning.
You can just follow my carb cleaning article here: How to Clean a Motorcycle Carburetor
What parts specifically are you in need of? Tanks, seats, and plastics will always be expensive for any old bike.
Also – Sure, I’d happily accept those manuals from you and put them up on my site for download.