[OBD]

Hey y'all, new to the forum.
Got this 2005 Honda Rancher as a project. First thing needed was a new carb. Got an OEM one, not the cheapo and mounted it.
Bike has fresh fuel to the carb., has good spark, and has some compression. (I haven't gauged it, but thumb over plug hole) Neutral light is on.
Engine cranks over but that is all. Occasionally will backfire really loud. Starter fluid does not help.

 

[alloutdoors]

I would do a compression test

 

[retro]

Going by your explanation, I'd guess that its either losing clean hot spark under pressure (bad spark plug, weak or shorting coil or bad plug wire) or the camshaft is out of time. Put a new NGK spark plug in it and try starting it again. Then yank the valve cover and check the valve lash. While you are in there you can check that the valves are not sticking, spring not broke etc. Let us know what you find.

Welcome to the forums!

 

[Jeepwm69]

Welcome to the forum. Follow Retro's instructions.

Sounds to me like it's jumped time, but his instructions will cover and easy stuff that could cause it.

I tend to think worst case scenario anytime something isn't working. LOL

 

[OBD]

Thanks.
I'll do the compression test this weekend. I did have the valve cover off, everything seemed to be fine. I don't know what valve lash is, though. I will try a fresh plug, and get the compression reading and get back to you.

 

[retro]

Valve lash should be .006" on both valves cold. Use a feeler gauge to measure them. See the instructions in the attachment...

The reasons for verifying those valve clearances are firstly, each valve must completely closed for the cylinder & piston to generate enough compression to fire off. Setting the valve lash properly insure that they each may shut completely. And secondly, while the valve cover is off you can look for reasons why the motor backfires... overly tight valve lash holding a valve open, a bent or sticking valve, broken valve guide or spring, loosened up adjuster on a rocker arm, etc. AND you can verify whether the camshaft is in time or not by watching the "T" mark on the flywheel and slowly turning the motor over in its normal rotational direction.

When the "T" mark lines up on the compression stroke both valves should be closed. Adjust both valves right there. Turn the crankshaft one more revolution and stop on the "T" mark again... you should see the exhaust valve closing while the intake valve is beginning to open. In other words both valves are slightly open and in motion... continue rotating one more revolution and stop on the "T" mark again. Verify with your feeler gauge that both valves are still clearanced properly.

These are diagnostic steps... let us know what you found and where you are at, before putting it back together.

 

[OBD]

OK, I watched a video about valve adjustment, and it seems like something I could do, but there is a problem. The guy that had this bike before me tried to make it sink-proof. He has plugged all the holes and the bike doesn't have a pull start anymore. Do I need to fix that first, or is there another way to turn the engine slowly?

 

[Jeepwm69]

OK, I watched a video about valve adjustment, and it seems like something I could do, but there is a problem. The guy that had this bike before me tried to make it sink-proof. He has plugged all the holes and the bike doesn't have a pull start anymore. Do I need to fix that first, or is there another way to turn the engine slowly?

You'll have to take the pull start off, or whatever is in place of the pull start, and use the 17MM bolt on the back of the motor to turn it over. Put a socket and ratchet on it to turn it slowly.

 

[OBD]

New spark plug didn't help. Will have to get a 12mm adapter for my compression gauge before I can check compression.

 

[dimitrge]

Did you change the fuel line from the tank to the carb? When I got mine there was sludge from the inside of the tank to the old carb. I replaced it all to make sure I was getting all the fuel to carb

 

[OBD]

No, I didn't change the fuel line, but I did disconnect from the carb. and turned it on and fuel flowed well. I also managed to get the pull start housing off. I'm not sure I will be able to get it back on. Will adjust the valve lash when I get a chance.

 

[dimitrge]

It’s a pain getting the bolts out but easy enough. Take your time. Also check the kill switch in the controls make sure it’s in middle

 

[OBD]

There wouldn't be spark at the plug if the kill switch was off, right?

 

[_Wilson_]

the kill switch in the controls make sure it’s in middle

Yes your correct.

 

[OBD]

on another subject. Is there a good tool that will remove rounded lug nuts? The bike has aftermarket wheels that have only enough clearance for a socket wrench.

 

[_Wilson_]

Can you post a pic of the wheel and rounded lug nut ?

 

[jeraldberald]

about the starting problem, i had the exact same thing on mine, and what fixed it was just setting the valves. they are .006.

 

[OBD]

I checked and set the valves to .006. Checked the compression and it barely registered on the gauge. It might have been 10 psi. Kinda explains things.

 

[OBD]

Here's the pic of the lug nut.

 

[retro]

You said the motor backfires sometimes, so the next step is to check whether the cam chain has jumped time or not.