Issues Starting the Engine

If it's broken or just needs tweaked

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ccoulon
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Joined: Fri Aug 06, 2010 7:33 pm

Re: Issues Starting the Engine

Postby ccoulon » Wed Aug 25, 2010 12:05 pm

Today I went out to work on the bike and it started up normally (weird) and if anything was running better than it used to cold. I took it out for a spin and it was responding very well (possibly just do to the fact that I let it warm for a while before riding it). At one point while riding I got it up to roughly 7000 rpms (in first gear) to see if it was getting adequate fuel/air ratio, sounded good then switched into second gear and back to about 4000 rpms where it suffered the same problem as before, I shifted back to 1st and it seemed as though only half the pistons were firing again as it was very un-smooth and jerky. I turned the bike off and started to push, reached a hill, waited a few minutes and for fun tried to start the bike again, it again started normally and rode it back home.

I am not sure if it would be related at all but there may be a chance it is running better in the lower gears and this occurs as I rev up high and shift to higher gears. (?)

I no longer am thinking it is a ruptured seal as compression still seams to be good when it is running normally. And as for the fuel flow, also seems adequate as it was riding fine for a while, then cut out then ran again.

Now my guess is that it is an electrical issue and that only one pair of the pistons are cutting out. The main culprit that I can think of is the Spark Unit (a.k.a. ignition control module) seems to be oozing a black tar-like substance. I have not been able to find any in-depth description of the workings of this device, however some have recommended using epoxy to refill the oozed out sections and thereby re-seal it.

I do have an in-line filter and had just changed the oil and oil filter the day before the bike broke down the first time.

Thanks.

Rocky
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Re: Issues Starting the Engine

Postby Rocky » Wed Aug 25, 2010 1:26 pm

Could be the Ignition Coils. how do the plugs look after you take it for a short ride?

The way you are describing the problem, I would suspect the ignition system.

Spark units if they look melted then fill them back in and seems to usually work for everybody else.

ccoulon
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Re: Issues Starting the Engine

Postby ccoulon » Thu Aug 26, 2010 1:40 am

Thanks Rocky,

As for the Spark unit, should I try to get some of the melting tar-like substance back in? And if so how? (seems like heating it up might make is less viscous to the point of re-filling the unit. Or should I cut off what has already come out and partially refill the unit with epoxy?

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Volker_P
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Re: Issues Starting the Engine

Postby Volker_P » Thu Aug 26, 2010 6:08 am

Right, once soft, that stuff won't get hard again. I just did put it back (as it probably has the required thermal and electrical properties) and then covered it with epoxy to keep it inside. Often the spark units survive melting of the stuff, but possibly one of your spark units already got damaged.
If you can identify the not working cylinders (header temperature?), you may try to swap the spark units between 1+4 and 2+3 to see if also the bogging cylinders will swap.
Another idea: next time starts bogging, close the petcock and stop the bike (in that order), then try at the carb bowl release screws if you have fuel in all four carbs now.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

chuter
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Re: Issues Starting the Engine

Postby chuter » Thu Aug 26, 2010 8:49 am

My spark unit podding compound melted out. A good Honda wrench buddy suggested I replace it with a very common epoxy product called "JB Weld". It's available at auto parts or many home repair stores. It works great and doesn't cost much.

cb650
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Re: Issues Starting the Engine

Postby cb650 » Thu Aug 26, 2010 7:27 pm

So you used it?
Did you clean the tank out?!?!?!?!

ccoulon
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Re: Issues Starting the Engine

Postby ccoulon » Mon Aug 30, 2010 10:45 am

Thanks for all the advice! I ended up pushing/remolding what was left of the compound back into the spark unit and using epoxy to hold it in. However, the problem seems to still persist. After riding it more it seems like it will shut down when I am trying to accelerate too fast. The last two times that it has died I have waited about 5 minutes and the bike will start back up again like normal. I am still under the impression that it is the ignition system, so next on the list to test is the ignition coil. Does anyone know a good site with information on testing the coil? Thanks again.

Chris

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Volker_P
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Re: Issues Starting the Engine

Postby Volker_P » Mon Aug 30, 2010 12:49 pm

Try out closing the petcock and check fuel in bowls as written above. Possibly your inline filter is too restrictive or you have something similar like e.g. a kinked fuel line. If only one ignition circuit was affected, there will be a considerable power loss, but a CB650 runs not that bad on three and should run and roll on two somehow (maybe up to 55mph), too.
For the spark units it seems rather they just work or not, modern CDI's are more often tricky on temperature.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

cb650
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Re: Issues Starting the Engine

Postby cb650 » Mon Aug 30, 2010 6:09 pm

I had a pickup go out on my last year and it will go 40 on 2 cyl. Would run fine untill it got hot then run on 2.
Did you clean the tank out?!?!?!?!

chuter
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Re: Issues Starting the Engine

Postby chuter » Tue Aug 31, 2010 8:05 am

CB: yes, I used the JB weld. I pulled the spark units so they would lay flat, mixed the JB and using a small puddy knife, re-podded the units. JB does not conduct electricity and is not as reactive (it doesn't melt) to higher temps like podding compound.

cb650
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Re: Issues Starting the Engine

Postby cb650 » Tue Aug 31, 2010 6:14 pm

Cool Adam needs to do this to his ignitors. Wanted to make sure it worked.
Did you clean the tank out?!?!?!?!

chuter
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Re: Issues Starting the Engine

Postby chuter » Wed Sep 01, 2010 2:36 pm

CB: Here's the ignighters with the JB weld.
Attachments
Igniters for web.JPG
Igniters for web.JPG (23.36 KiB) Viewed 4465 times

my79650
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Re: Issues Starting the Engine

Postby my79650 » Wed Sep 01, 2010 5:13 pm

great idea as mine have been leaking goo out of them for quite awhile; definitely will give it a try also.

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Volker_P
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Re: Issues Starting the Engine

Postby Volker_P » Thu Sep 02, 2010 1:25 am

Looks good. One should do this with leaking ignitors as soon as possible. If the inner components don't have thermal contact to anything any more, they may overheat and fail. I'd try to have the original stuff at least between components and the bottom side with the cooling fins as this stuff probably offers the required thermal conductivity.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

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Rocket Man
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Re: Issues Starting the Engine

Postby Rocket Man » Fri Oct 04, 2013 8:36 pm

I used high temperature silicon before reading this. I imagine JB weld would have better thermal conduction. So far so good.


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