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Sean Warnick

Old Thumper won't start.

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I'm on the verge of giving up... I have a 1982 Honda XL500R that refuses to start.  Clean carb, new sparkplug with plenty of spark. When I do get her to start she runs very rich. She did run fine at one point startin on the first kick.  I don't know what has changed.

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9 minutes ago, Sean Warnick said:

I'm on the verge of giving up... I have a 1982 Honda XL500R that refuses to start.  Clean carb, new sparkplug with plenty of spark. When I do get her to start she runs very rich. She did run fine at one point startin on the first kick.  I don't know what has changed.

Need more info to help.    Is your fuel fresh? Air cleaner element dirty?  Is the fuel overflowing?  Did you take the carb out? I lost my Ouija board so you will have to fill me in.

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Drained and added fresh fuel, added a brand new cone filter, (back when it was starting first kick it was running without a filter, cone filter has very little air resistance) took the carb out multiple times and cleaned with carb cleaner and compressed air.  (There are no air leaks) Compression is solid. Bike has a auto decompression cable that has been set correctly.  I don't know what else to tell you please ask away.  After kicking for a while spark plug is wet. Like I said, new sparkplug with nice blue spark,  I'm thinking either overfueling somehow or maybe spark timing is out somehow...

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Other than carb, what has been altered since it was running ok? 

If nothing, then its fairly likely its carb settings. 

Simply winding the idle up a bit, and not touching the throttle can often result in success.

Once its going again, then the problem(s) should be easier to diagnose.

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1 hour ago, Muzz67 said:

Other than carb, what has been altered since it was running ok? 

If nothing, then its fairly likely its carb settings. 

Simply winding the idle up a bit, and not touching the throttle can often result in success.

Once its going again, then the problem(s) should be easier to diagnose.

Only the carb has been fiddled with. Basically took it off for a cleaning and that's where it all started. When you say winding it up, do you mean open the slide? How much?

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3 hours ago, Muzz67 said:

 Enough to idle at 2-2.5k rpm. It just takes away a variable so choke amount can be concentrated on.

Are you getting any firing at all? Smell of burnt or unburnt fuel from exhaust?

Yeah problem is I don't know where that is at all. Maybe two or three turns in of the idle dial once engaged? The only firing I'm getting is a back fire every now and then when I have the choke and throttle open to clear out a flooded engine.

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On 9/10/2019 at 10:41 PM, 00boob said:

Need more info to help.    Is your fuel fresh? Air cleaner element dirty?  Is the fuel overflowing?  Did you take the carb out? I lost my Ouija board so you will have to fill me in.

Any new thoughts?

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have you verified spark plug getting wet with fuel?

Has Spark plug been gas fouled, it might be getting blown out under cranking compression?

Shut off fuel, drain carb bowl, SEE if engine will fire off using starting fluid or flammable brake cleaner only sprayed in air box?

You are sure of fuel quality, sample it in clear jar.

You might have contaminated fuel. I have worked on many a vehicle that got Diesel contaminated in gas or gas contaminated diesel. Verify fuel totally evaporates in open container/drain pan & NO oily residue left behind.

Are you sure needle is staying in place on the slide?

Otherwise with correct valve timing/compression, good quality fuel, and proper ignition timing she should be a runnr'.  As you know those are the 3 requirements.  

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12 hours ago, AMSinator said:

have you verified spark plug getting wet with fuel?

Has Spark plug been gas fouled, it might be getting blown out under cranking compression?

Shut off fuel, drain carb bowl, SEE if engine will fire off using starting fluid or flammable brake cleaner only sprayed in air box?

You are sure of fuel quality, sample it in clear jar.

You might have contaminated fuel. I have worked on many a vehicle that got Diesel contaminated in gas or gas contaminated diesel. Verify fuel totally evaporates in open container/drain pan & NO oily residue left behind.

Are you sure needle is staying in place on the slide?

Otherwise with correct valve timing/compression, good quality fuel, and proper ignition timing she should be a runnr'.  As you know those are the 3 requirements.  

This is random but avout the oily residue wouldnt u have some if u did this using mixed gas for a 2 stroke(kx250)

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7 hours ago, Funny Man Jr said:

This is random but avout the oily residue wouldnt u have some if u did this using mixed gas for a 2 stroke(kx250)

If you are adding oil to your fuel you will have oily fuel. I'm not a scientist though..

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20 hours ago, AMSinator said:

have you verified spark plug getting wet with fuel?

Has Spark plug been gas fouled, it might be getting blown out under cranking compression?

Shut off fuel, drain carb bowl, SEE if engine will fire off using starting fluid or flammable brake cleaner only sprayed in air box?

You are sure of fuel quality, sample it in clear jar.

You might have contaminated fuel. I have worked on many a vehicle that got Diesel contaminated in gas or gas contaminated diesel. Verify fuel totally evaporates in open container/drain pan & NO oily residue left behind.

Are you sure needle is staying in place on the slide?

Otherwise with correct valve timing/compression, good quality fuel, and proper ignition timing she should be a runnr'.  As you know those are the 3 requirements.  

Fuel is good. Compression is high. Is faulty ignition timing possible with a cdi box?   Also, my plug gap should be 0.6 - 0.7m.  What difference does is make? Short strong and quick but with little exposure or long and weak but with larger exposure?

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1) When carb was taken off, did you disconnect any individual wiring for harness (I ASS-u-me) the connectors are individual single plug like on my older XR/XLs.

Verify by a correct model & year wiring diagram the proper color connections.

Same color wires do not always go together, reason for proper wiring diagram.

I left a ground wire loose on my 85' XR-200R 2V conversion that ran me in circles, until I was finally reverified wiring connections to find loose ground connection.

KISS = "Keep it Simple Sam/Samantha" (or in my case, :banghead:"Stupid") diagnostics help. YOU must eliminate the tests methodically, like a check list, but DO not Assume...

2) I Ass-u-me the needle is locked in slide and not moving up out of slide getting hung up out of main jet = >>richer condition. 

3) Plug gap is dictated by manufacturer & coil output ignition system design.  IF, the gap is too wide, when installed into the combustion chamber the cranking compression can make the firing voltage search for a easier ground, thus not jump the gap. Electricity is LAZY and looks for the easiest ground in which to discharge by. A new spark plug can be gas fouled look like it fires out side chamber fine and misfire/ground spark anywhere but where it needs to go, across gap. :prof::blah:,  thus called fouled. 

4) You say plug was wet, has the engine been kicked over with plug out, to see if excessive fuel mist can be seen. If engine is severely flooded you may have to let cylinder air out or blow compressed air through spark plug hole WITH exhaust valve open. You might squirt one shot of starting fluid in hole to see if it hits. BE CAREFUL REMEMBER, THESE CHEMICALS ARE EXTREMEMLY FLAMMABLE!!!🚭

Install known working spark plug before attempt starting. 

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16 hours ago, Sean Warnick said:

If you are adding oil to your fuel you will have oily fuel. I'm not a scientist though..

I was meaning since u use mixed fuel with 2 strokes then you couldnt use that method to verify if your original gas was contaminated

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On ‎9‎/‎11‎/‎2019 at 6:28 AM, Sean Warnick said:

I don't know about valve specs

 Tight valves cause hard starting, if your XL has the removable covers on the valve cover to check valve clearance like my XRs' did, I'd get on that to remove another variable... it's fairly easy to do

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