P500 15 p500 will not start

[Hazen91]

Hi I bought a non running pioneer 500 from a auction. When I got it home I went over itand changed the gas and spark plug. it has fuel spraying out of the injector and spark according to an inline spark tester. When I’m turning it over it sounds like it’s so close to starting but didn’t. Every now and then it will almost backfire but that’s it. I’m at a loss any help would be appreciated thanks

 

[Admin]

 

[Remington]

Hi I bought a non running pioneer 500 from a auction. When I got it home I went over itand changed the gas and spark plug. it has fuel spraying out of the injector and spark according to an inline spark tester. When I’m turning it over it sounds like it’s so close to starting but didn’t. Every now and then it will almost backfire but that’s it. I’m at a loss any help would be appreciated thanks

You might be still pulling some nasty gas that was in the fuel system. How is the air filter? Was it swamped? spark arrester clean? Easy stuff to check off the list.

What year, milage?

BTW Welcome from Michigan. We like pics For proof. Pics Or It Didn't Happen!

 

[Hazen91]

It a 2015 with 326miles. I unhooked the fuel line at the injector and ran the pump until new fuel came out everything looks fine as far as the air box, filters and throttle body are clean.

 

[Hazen91]

Any idea on what the compression should be? Seems like quite a bit of blow by coming out of the case vent when cranking

 

[Dave75]

At this point remove the spark plug and see if there is fuel on it. Do a compression test. Someone here will know what it should be. I would be looking for a minimum 100 psi.

Good luck.
Need to post photos.

 

[Hazen91]

Ok just did a compression test and it’s at 55psi. How tuff is a top end rebuild on these? Any tricks? Can it be done in the bike?

 

[906UP]

Ok just did a compression test and it’s at 55psi. How tuff is a top end rebuild on these? Any tricks? Can it be done in the bike?

No tricks, the Honda Service manual is available on the site for contributing members, probably cheaper than buying a manual from Honda or Ebay.
Keep in mind, these things have an automatic decompression gadget on the cam, a compression test can be misleading. Have you tried spraying some carb clean down the throttle body and see if it will start?

 

[Keebler]

Before doing a top end job I would check the valve adjustment. At 326 miles I wouldn't expect a problem but who knows! If you don't want to check the valve adjustment you could first squirt some oil in the spark plug hole and redo the compression test, if the compression does not increase then a value adjustment would be the next step, then the compression rechecked.

 

[Hazen91]

No tricks, the Honda Service manual is available on the site for contributing members, probably cheaper than buying a manual from Honda or Ebay.
Keep in mind, these things have an automatic decompression gadget on the cam, a compression test can be misleading. Have you tried spraying some carb clean down the throttle body and see if it will start?

I have heard about the automatic decompression thing but I couldn’t find a whole lot of info on it. I have sprayed some carb clean and it didn’t start

 

[Hazen91]

Before doing a top end job I would check the valve adjustment. At 326 miles I wouldn't expect a problem but who knows! If you don't want to check the valve adjustment you could first squirt some oil in the spark plug hole and redo the compression test, if the compression does not increase then a value adjustment would be the next step, then the compression rechecked.

I didn’t think about the oil in the cylinder that’s a good idea.

 

[906UP]

I have heard about the automatic decompression thing but I couldn’t find a whole lot of info on it. I have sprayed some carb clean and it didn’t start

Pic from the service manual, at slow, cranking rpm it holds the exhaust valve open a little longer so the starter can spin the engine, once the engine fires centrifugal force overcomes the decompression lobe so it doesn't contact the valve. This is why a compression test will always show low. At the mileage you stated I would look elsewhere, I doubt it needs a top end.

 

[906UP]

Many years ago my step dad had a Foreman that wouldn't start, backfire occasionally. It ended up being the voltage regulator, it was shorted internally and not creating good spark. Easy to check, unplug the voltage regulator and see if it will start. Make sure you have a good, charged battery.

 

[Jerryg]

It won't run on 55psi.

 

[Dave75]

You need to find why the compression is so low.
Jerryg is right, it will not run at 55psi.
Did you change oil? Was there any metal in the old oil?

 

[Keebler]

When you did the compression test did you spin the engine for 4 or 5 compression strokes? I think I remember that on motorcycles you do a compression test over 4 or 5 strokes with the throttle wide open.

 

[Buggyman]

Hi I bought a non running pioneer 500 from a auction. When I got it home I went over itand changed the gas and spark plug. it has fuel spraying out of the injector and spark according to an inline spark tester. When I’m turning it over it sounds like it’s so close to starting but didn’t. Every now and then it will almost backfire but that’s it. I’m at a loss any help would be appreciated thanks

welcome from Ohio

 

[Kwb]

Hi bought 2017 non runner would start some times but if gave starting fluid it would start traced problem to ground bolt on engine block wires felt tight but used wrench and bolt was stripped put longer one in darts great now