'86 Interstate suddenly not running - help!

[RobH]

Hi, All. I'm at a loss here, and am hoping some of you with far more knowledge than me can point me in the right direction. Thanks! Here's the story: last week we had a bit of warm weather, so I took my bike out for a spin. Rode around about an hour - no problems. Went to ride it this week, followed the usual starting procedure (ignition, choke, kill switch, start button - off and running!), and it wouldn't start. Wouldn't even sound like it was trying to start. Since I've had the bike, as soon as the start button is pushed with the choke engage, the engine would start immediately. Now it just turns over, as if it's not getting any spark. I pulled a plug to check for spark, hit the start button, saw good spark on the plug and the engine started! ??? I put the spark plug back in, hit the start button - nothing. It turns over, but acts like it has no spark. Like I said, I'm at a loss as to why it would start with one plug out, but not even cough with the plug back in. The only other thing I can add to this is that it's starting to have a "clunk" when the starter's engaged.

Any help and guidance you can offer would be muchly appreciated! Thanks, and stay safe. Rob

[neoracer]

possible dirty engine stop switch,2nd try starting by putting 12v (backprobe) to the yellow/red wire at the starter solenoid connector,after that try wiring bypass around the engine stop switch

[1060dsl]

possible dirty engine stop switch,2nd try starting by putting 12v (backprobe) to the yellow/red wire at the starter solenoid connector,after that try wiring bypass around the engine stop switch

But Neo, he says he is getting spark - Id be looking to a fuel delivery problem - did you try to either, or take the plugs out and see if it spits any gas or spray some either into the air breather? How is the gas maybe water in it or a plugged fuel filter, did you try a line to a clean gas source?

[neoracer]

sounds kinda like one time he has spark then again when he puts everything back together he doesn't

[RobH]

Thanks for the responses! I also forgot to mention that I did try spraying starter fluid into the air breather - something else that has immediately given life in the past - nothing. It's just so weird that it ran fine, then a week later went dead, then started with a plug out, then dead again with the plug in.... days like these....

[sparky65]

If you have a spare set of plugs use them to test the spark then you won't have to take the plugs out, it can be a pain trying to get them back in if the engine is warm...but then yours is'nt starting anyway. Check for spark with both plug wires not just one because each plug is on its own coil. Also make sure the plugs are ok because I've seen plugs that spark when out for testing but when put into the hole won't fire because of the compression environment and this engine is a bit higher compression than some other engines.I always check the simple things first.

[RobH]

thanks for the guidance! I'll check this when I get home - er - after I find a spare set of plugs. I appreciate it! Rob

[neoracer]

If you have a spare set of plugs use them to test the spark then you won't have to take the plugs out, it can be a pain trying to get them back in if the engine is warm...but then yours is'nt starting anyway. Check for spark with both plug wires not just one because each plug is on its own coil. Also make sure the plugs are ok because I've seen plugs that spark when out for testing but when put into the hole won't fire because of the compression environment and this engine is a bit higher compression than some other engines.I always check the simple things first.

1 and 3 is on left coil
2 and 4 on right coil

[bs175dths]

Remember, these are old bikes…….
There is a possibility the spark plugs are shorting to ground if there is debris in and around the spark plug holes.
Honda put in some drainage and if these drainage holes are plugged, the spark plug holes will fill with stuff which may cause the plugs to be grounded.
With the spark plugs installed, clean out these drainage holes.

Another possibility is there is an open in one of more of the spark plug wires not allowing the plug to arc. By moving the wire to test the plug for spark, the open is now closed and you see a spark.
Putting things back together after seeing spark allows the wires to work until their near 30 year memory causes the wires to move back to where they cause an open again.
Replacing the spark plug wires with fresh will solve this problem.
Also, when the bike is warmed up and idling nice, see if there is any arcing going on at the coils, the spark plug wires or at the spark plug boots.
This is best accomplished in the dark. BUT NOT IN AN ENCLOSED AREA, DO THIS TEST OUTSIDE AFTER THE SUN HAS SET.

When the bike is running, is it running on all four cylinders or does it sound like it is missing?
Also make sure your battery if fully charged. Don’t just test for 12.65V at the battery when the engine is off and cold, also measure the specific gravity of each cell to see the strength of each cell.
You may have 12.65V at the posts, but if one or two cells are less than 50%, your battery may need replacement.

[RobH]

this is why I love this site - so much information from people who know so much more than I do! Thank you all - I truly appreciate it! It will probably take me awhile, but I'll post when I finally get it fixed. Stay safe all, and Happy New Year! Rob

[RobH]

Hey, All. Okay, I'm going to look like a total freakin' idiot, but simple is as simple does.... I figured out the problem - the battery wasn't charged sufficiently to turn the engine over fast enough to fire. DUH! That would explain why I had spark - and it started - with the plug out: less compression, faster turn over. Plug back in - hard work again, no start. I charged the battery fully, hit the starter button, and it fired up right away as usual. Sorry for being such a dolt, but thanks again to all who offered information!

[bs175dths]

no worries

I have made a suggestion to folks who have a hard time starting the bike when hot....
open the throttle all the way, THEN hit the starter button.

Opening the throttle reduces how much effort the starter motor needs to spin the engine fast enough for it to catch.

This is just a work-around and the fix still needs to be performed, whether it is a started brush issue or a battery issue.

Ain't learning fun?