Odd problem

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Nicholaskent54
Posts: 23
Joined: Tue Sep 20, 2016 12:49 pm

Odd problem

Postby Nicholaskent54 » Thu Aug 17, 2017 5:57 pm

So I have a 1980 honda cb650. I got this bike not running so it's been rather difficult for me. I got it running for about 30 seconds and it was leaking oil from the head. So I replaced all seals made sure the valves and time correct. Have spark. However she won't start. I am however shooting gas out of the tubes of 5he back of the carbs. Not sure why this is happening any help would be greatly appreciated.
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20170817_175116.jpg
The bottom two tubes is where the gas is shooting out.
20170817_175116.jpg (3.95 MiB) Viewed 201 times

Nicholaskent54
Posts: 23
Joined: Tue Sep 20, 2016 12:49 pm

Re: Odd problem

Postby Nicholaskent54 » Thu Aug 17, 2017 5:58 pm

Sorry top two holes in the picture. It's upside down lol

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GeorgeSweety
Posts: 62
Joined: Tue Aug 08, 2017 11:47 am
Location: UK.

Re: Odd problem

Postby GeorgeSweety » Fri Aug 18, 2017 5:22 am

Hi Nic, is it all of the carbs or just one? If it is blowing when it should be sucking I would suspect inlet valves being open at the wrong time but you say you have set them. I would remove the valve covers just to see if there is anything obvious like a sticking tappet.

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GeorgeSweety
Posts: 62
Joined: Tue Aug 08, 2017 11:47 am
Location: UK.

Re: Odd problem

Postby GeorgeSweety » Fri Aug 18, 2017 6:39 am

I do recall reading on the net (not sure if it was on this site) that a guy had a starting issue and he couldn't find anything wrong with his valves when he took the covers off but the bike just wouldn't start. It turned out that he had forgotten to put the cup shaped washers underneath his valve cover bolts, making the rear screws sit just low enough to interfere with the tappet and hold the valve slightly open. Might be a long shot but worth investigating. :?

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tario
Posts: 165
Joined: Sat Mar 07, 2015 2:26 pm

Re: Odd problem

Postby tario » Sun Aug 20, 2017 12:18 pm

The engine turns over fine by hand? I know my manual has misleading information on setting the valves, there is a little chart that shows the exhaust settings on bottom. When you stand over the bike the exhaust is on top. I've also dealt with the timing being off on the cam shaft. Make sure it's right on 1.4T and the notch is lined up on the front. I've fixed wrong timing twice on one of these(at the cam). Both times it was checked and double checked but... shit happens i guess.
1979 cb650
1980 cb650

Nicholaskent54
Posts: 23
Joined: Tue Sep 20, 2016 12:49 pm

Re: Odd problem

Postby Nicholaskent54 » Sun Aug 27, 2017 1:14 pm

I was afraid it was the cam. I've checked it three time and it all looks correct. The engine turns good by hand. But it won't even try to fire even if I use starting fluid. And I definitely has spark. I'm gonna have to try taking it apart again and check everything one more time

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tario
Posts: 165
Joined: Sat Mar 07, 2015 2:26 pm

Re: Odd problem

Postby tario » Wed Aug 30, 2017 4:41 pm

You do have the air box on the bike when you try to start it, right? The choke won't block enough air on its own. You could try blocking off the intakes with a sheet of something and just letting in a little air to get it to fire. The coils need to be hooked up a certain way too. If they are backwards they won't ignite the fuel. (it won't be compressed when they fire) If they haven't been changed you should be fine. Make sure you are using imperial .003 and .002 for the valves . Obviously .02 or .03 would be a problem as well... if you made that mistake.
1979 cb650
1980 cb650


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