Topic: new hondamatic owner with a change relay question

[cwilli78]

   Hey! I recently bought a 1978 hondamatic cb750 for dirt cheap! I was in the market for a bobber/chopper and came across a hondamatic bobber and got the price down to $160!..of course it didn't start, but after messing around with the solenoid (which its very existence surprised the hell outta me) managed to get it started...it now runs, I just need to get the carbs cleaned and figure how many necessary parts were taken off during the "chop/bob"...like the change relay..which is missing, along with the air box..and speed warning unit..
    I got my hands on a change relay and was going to wire it up like the 76 model..bypassing the speed warning unit altogether..would that work? I don't ride it all right now, just start it for 2 mins a day till I get the carbs cleaned. Now my REAL concern is that the carb cleaning wouldn't solve the acceleration problem I am having, and the change relay is the main culprit...any info would be greatly appreciated! Thank you for letting me join your fine forum..

[raymond10078]

The good news - what you are suggesting will work:  http://forums.sohc4.net/index.php?topic=112231.0

The bad news - restoring the function of the solenoid has nothing to do with your acceleration problem.  The solenoid - and the dashpot/diaphram it controls - only opens the throttles slightly when the bike is in gear - to prevent stalling when the bike is in gear.  Without the solenoid/dashpot/diapgram, the idle speed drops too much when in gear - and will most likely die.  This system controls no other carb functions - it doesn't do anything else but "bump up" the idle.  When the bike is in neutral, the solenoid does nothing.  For the 1977/78 bikes, when the bike is going faster than about 17 MPH, the solenoid is off and again does nothing.  If you have acceleration problems, the issue is not in the solenoid.

In fact, "messing with" the solenoid didn't get the bike to run, that had to have been a coincidence . . . .  Good that you've got it running - that's a start!

Lastly, without the stock air box you will have other carb issues.  Use this sites Search function - put in the word "pods" and you'll find a lot of poor performance stories (with very few success stories thrown in).

[cwilli78]

Thank you! I appreciate the info!