Help! My bike won't start after a spark plug change.

[ScottyG]

Hi all,

First off, this site is great. I've learned so much valuable information and I appreciate all the help that the regulars offer.:thumbup:

On to my problem. I changed my spark plugs for the first time the other day and everything seemed to go fine. It was a pain getting to 1 and 2, but I eventually got them. The old plugs were brown and looked worn, but not abnormally worn. The new ones went in fine. I got some of the Iridium plugs that everyone seems to recommend. I reloaded the plug caps and they all seemed to click in as expected. The bike started up with out any problems and sounded great. I let it run for a couple minutes and turned it off. It was pretty late so I couldn't really take it out then, but I was happy everything seemed to work out

The next morning, I got on my bike to go to work and it wouldn't start. The starter was running but the engine wasn't firing up. I tried again with an open throttle and it seemed to come a little closer to starting but it didn't happen. I pulled the plug caps and reseated them, but still no luck. The next step, as I see it, would be to remove all the plugs and check if I cracked any of them. Before going to the trouble of working all the plugs out again, I was wondering if anyone had any suggestions as to what the problem is. I can't think of a reason why my bike would start up immediately after installing the new plugs, but wouldn't start after sitting all night. Has anyone seen a problem like this when changing plugs or does anyone have any suggestions as to what I should do next?

Thanks

 

[wrightme43]

No man that one doesnt make any sense at all.

 

[SidewallPuncture]

low battery would be my guess

 

[Fz6Sa]

Hi all,

First off, this site is great. I've learned so much valuable information and I appreciate all the help that the regulars offer.:thumbup:

On to my problem. I changed my spark plugs for the first time the other day and everything seemed to go fine. It was a pain getting to 1 and 2, but I eventually got them. The old plugs were brown and looked worn, but not abnormally worn. The new ones went in fine. I got some of the Iridium plugs that everyone seems to recommend. I reloaded the plug caps and they all seemed to click in as expected. The bike started up with out any problems and sounded great. I let it run for a couple minutes and turned it off. It was pretty late so I couldn't really take it out then, but I was happy everything seemed to work out

The next morning, I got on my bike to go to work and it wouldn't start. The starter was running but the engine wasn't firing up. I tried again with an open throttle and it seemed to come a little closer to starting but it didn't happen. I pulled the plug caps and reseated them, but still no luck. The next step, as I see it, would be to remove all the plugs and check if I cracked any of them. Before going to the trouble of working all the plugs out again, I was wondering if anyone had any suggestions as to what the problem is. I can't think of a reason why my bike would start up immediately after installing the new plugs, but wouldn't start after sitting all night. Has anyone seen a problem like this when changing plugs or does anyone have any suggestions as to what I should do next?

Thanks

Im guessing you had the tank off?
Could it be a jammed fuelline? ,- that would explain why it ran at first ....

 

[rdsrus]

Any internal combustion engine needs 3 things to work,compression,fuel,spark. You have to determine which you lack.Since the bike started easily after the plug change chances are it is not the plugs to blame.Easy check for spark,pull one cap,take one of the old plugs and put it in the cap,lay the plug near some metal that is grounded on the bike,head stud,etc.,crank engine and see if you have spark.It may be something as simple as dirty contacts on your kill switch,or fuel pump failure.Troubleshooting something like this takes time and applied logic,make sure you write down what you tried to fix the problem so you are not chasing problems in circles.Good luck,these learning experiences can be enlighting if you don't let it frustrate you! Bill

 

[mkjeld76]

If you lifted the tank start there make sure elec connections are tight fuel lines are ok.

 

[racerws]

I know this is gonna sound goofey, but is the handlebar switch in the
on position. I've had people that turned it off and forgot about it.
Bike won't start!

 

[ScottyG]

I'm sure the ignition switch was on, otherwise I wouldn't have heard the starter motor run. I did not remove the fuel tank, but it does sound like it could be a blocked fuel line. I noticed that there are several hoses running in the same area, above the plug lines. Are these fuel lines? I suppose I could have kinked or twisted one of them when I was "arguing" with the plug caps. In addition, I pulled out the #4 plug and checked that it was sparking with the new plug. It was. It's probably also worth mentioning that I could definitely smell fuel in the combustion chamber and on the plug, so it seems that at least #4 is getting fuel. I'll inspect the lines that run in the same area as the plug lines when I get home from work tonight. Hopefully, that's where the problem is.

Thanks for all your help so far,
Scott

 

[ScottyG]

Problem Solved!! I neglected to resize the spark plug gap. I knew it would be something simple. The plugs were right around 0.8 mm, which is apparently enough to keep you from starting. I resized them to right around 0.6 mm and, sure enough, it started up. Sounds great too. I'm kind of surprised that being off by 0.1 mm is enough to keep you from starting. Does that make sense or did I inadvertently fix the problem by pulling all the plugs and reinstalling them?

 

[rdsrus]

Problem Solved!! I neglected to resize the spark plug gap. I knew it would be something simple. The plugs were right around 0.8 mm, which is apparently enough to keep you from starting. I resized them to right around 0.6 mm and, sure enough, it started up. Sounds great too. I'm kind of surprised that being off by 0.1 mm is enough to keep you from starting. Does that make sense or did I inadvertently fix the problem by pulling all the plugs and reinstalling them?

The gap difference shouldn't make that much of a difference unless the battery voltage is low. But the most important thing is you got it up and running again.:thumbup:

 

[snowmannn]

I've read that you should NOT touch the gap on Iridium plugs - it can easily damage them. Does anyone have any additional info on this one?

 

[dark_isz]

..........

 

[Oscar54]

Well I'm glad you got it running again!

However, I am not convinced that the gap was the difference, since it fired up the first time.

Something else was going on, fortunately redoing the plugs and wires cleared it, unfortunately the cause was not discovered and the members won't have the benefit of that information from your experience.

Anyway, you are back-in-the-saddle, and that is all that really matters!