Author Topic: Help with cb500f starting  (Read 1321 times)

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Offline snowcap

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Help with cb500f starting
« on: June 08, 2010, 09:46:41 AM »
Hi , I am new to all of this and need help if anyone can. I bought a 71 cb500f in feb. , it was not running and was a one owner w/6500 miles. I stripped to the frame and painted it myself , took the motor down to the crankcase and put on new gaskets , new plug caps and plugs , took the carbs apart and soaked in cleaner then put new gaskets on those. New battery , cleaned out tank and fuel lines.Well the big day came to start and nothing , first I should tell you that the starter motor doesn't work at this time so I was kick starting. I have spark , fuel is getting to the carbs , the battery is fully charged and I used starting fluid but nothing happened but a lot of kicking    help please!!!! 

Offline jessezm

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Re: Help with cb500f starting
« Reply #1 on: June 08, 2010, 10:34:03 AM »
Just some questions to help trouble-shoot:

--You know that fuel is getting to the carbs, but are you sure it is getting through them (i.e., are the plugs wet with gas?)?

--You have spark on all 4 plugs for sure?  is it a nice fat blue spark?

--Have you checked compression yet?  When you rebuilt the top end, did you install new rings?  what was the condition of the pistons?

--why no starter?  It shouldn't be dead after only 6500 miles I don't think.

--Does it even want to start?  Any soft popping or turning over?  You may need to kick it hard for a while, even if at first it doesn't sound like it wants to start.  Use a little choke at first but try not to flood it.  It may not need any choke at all.

--have you done your static timing and bench synched your carbs?

--Have you adjusted your valves since the top end, and made sure you installed your cam correctly (not 90 degrees off like I did...)?




Offline snowcap

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Re: Help with cb500f starting
« Reply #2 on: June 08, 2010, 11:44:16 AM »
Thanks for the tips I will check the spark plugs to see if they are wet , I thought I put the cam shaft in the right way , my brother-in law helped so we had 2 sets of eyes on it and it turns over by hand without any trouble. I don't know how to bench sync the carbs . And no there isn't even the slightest pop,even with starter fluid being sprayed while   kicking. Thanks.

Offline jessezm

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Re: Help with cb500f starting
« Reply #3 on: June 08, 2010, 11:52:13 AM »
Sounds like there are still several possibilities, although with a lot of the things listed, the bike should still give you some indication of wanting to start.  Your kill switch is in the right position right? 

you need to do a search of the forum on bench synchronization.  It is really easy, and helps get the carbs in range before doing a vacuum synch.

the cam will move freely if it's out of position, it just opens the valves at the wrong time.  If you were able to successfully able to adjust your valves, then your cam should be in the right place.   Did you do the valve adjustment after buttoning up your top end? 

Again, you said you had spark, but did you test it on all 4 plugs?

Offline snowcap

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Re: Help with cb500f starting
« Reply #4 on: June 08, 2010, 01:32:10 PM »
Embarrassed to say that I have never done any motor work of any kind so I am learning on the go. I did not adjust the valves at all , I assumed that that was ok but will look at my clymers book and do that. Also I  have not tried to check spark from any other plug but no. 1 , so I will do that also . Again thanks for the suggestions.