Hello from Illinois

Posts: 5
Joined: Sat Sep 08, 2018 5:44 am
Real Name: Eric
Sex: Male
Years Riding: 1
My Motorcycle: 1980 Honda CM400A Hondamatic

Hello from Illinois

#1 Unread post by ejseibert »

Hello All,

I am truly a new rider. I just purchased my first motorcycle at an estate auction a couple of months back. It is an old barn find, a 1980 Honda CM400A Hondamatic that sat in a barn for the last 12-15 years. It was purchased by the original owner and ridden little then put in storage. Then the owner's son got it out and got it running again 12-15 years ago, stored it and it sat ever since. It has only 1,200 miles on it! And I picked it up for $450 at auction. When I went to the auction, I kicked it over to see if the motor was free. It was, and I decided to have a go of it.

So far I have:
Rebuilt carbs
Cleaned and red-coated the gas tank
Replaced petcock and fuel lines
Replaced tires and tubes
Cleaned out master cylinder, break line, and Caliper for front breaks

After this it started right up, the oil still looked good, but I figured there may be sludge. I decided I wanted to put a few miles on it to loosen things up in the engine before I changed the oil. So I put about 30 miles on it and then did an engine flush, replaced spark plugs and oil filter. So far so good.

The more I run the bike the better it seems to be. But it still seems to run rough at idle, acceleration can be problematic, the exhaust pops a second or two after the engine is turned off, and it seems to be running quite hot (though I have nothing to compare it to.) After about 30 more miles I pulled the new plugs to try and read them and there is no build up on the plugs except around the outside edge which I think may be from the oil I used to lubricate the plugs before installing them. So in my estimation it seems to be running a bit lean.

Next I plan on pulling the carbs again and verifying the operation of the accelerator pump, replacing the stock pilot screw with new ones, because the old ones have a limiter to prevent adjustments. I will give them another good cleaning and verify all ports and pathways are indeed open. Then if necessary I may re-jet the carbs.

I will probably have some questions on re-jetting the carbs but I will save those for another area of the forums.

But so far I am loving the bike and having a loads of fun fixing it and riding it.

Blessings to All!

User avatar
Posts: 57
Joined: Tue May 01, 2012 6:31 am
Real Name: Carrie
Sex: Female
Years Riding: 25
My Motorcycle: 2014 CTX 1300,2012 Ninja 650

Re: Hello from Illinois

#2 Unread post by Rubiadiabla »

Hello Eric and welcome to the TMW Forums :) New rider or not, sounds like you sure know your way around engines. Those old Honda's run forever and don't demand much, and 1980 was a real good year if I do say so myself ;) Amazing that it sat for so long and runs the way it does now with a little love. I'm sure one of the boys will be around to help you with your jets when you're ready, in the meantime welcome and we'd love to see some pics of your new ride and hear about your adventures.
Keep it shiny side up
- Rubia
'Well behaved women seldom make history.' -Laurel Thatcher Ulrich

Post Reply