Help your bike won?t start!!

[MisterCinders]

With so many threads about non-starting bikes, a basic checklist would clear up recurring issues and get better, faster help from GSR.

Oh Gawd! Bike won?t start!!

First, check the idiot things.

• Kill switch off?
• Ignition key on?
• Battery not dead?
• Any safety kills (kickstand, clutch, etc.) still on?

If so, then elaborate (to yourself, quietly) what ?not starting? means.

Does the engine turnover but not catch?

If the engine won?t turn over at all (silence, or click click), then you have fundamental power problems on the battery end. Check your battery charge, connections to the starter motor, etc. If everything checks out and still nothing, check out the Electrical/Ignition forum. Do a search for threads on non-starting bikes. If that doesn?t help, launch a post there.

If the engine turns but won?t start, you have different possible culprits. Let?s review some basics

OK - every bike needs 3 things to start/run.

1. Air/Fuel Mixture;
2. Compression;
3. Spark.

If you have all 3, your bike will start. Even if you have a weak piece of this Trinity, your bike will start, but may struggle and/or idle badly.

How do I know what?s missing?

First, check the plugs.

Are they wet with fuel? If so, no spark.
Are they dry? If so, no fuel.
Compression is a different creature. We?ll get back to that.

Spark/Wet Plugs - If you aren?t getting spark, that means (a) no spark; (b) weak spark; or (c) missed spark. Mr. Matchless (c/o BassCliff) poops out how to root out your spark problems.

Basic test, remove spark plugs. Fit them to the plug HT leads and ground them to the engine. Turn engine with starter and see if plugs spark. If any one spark plug does not spark swap it out. If the spark seems good on all 4 plugs, the ignition system is very likely in order. If spark is not present or very weak proceed with the following tests.

If the spark is weak but present, inspect the HT leads and plug caps. Suspect coil wires and spark plug caps, or voltage at the coils and thus the battery condition. It could also be due to coils with partially shorted windings, but do not jump on this cause immediately, and they may get hot.

If there is a spark, but the engine will not fire, it could be due to ignition timing, valve timing or fuel problems. Ignition timing and valve timing problems are more likely on a bike that has not run yet after being disassembled and more unlikely to be the cause if the bike was not taken apart and was running before.

A quick test with a few drops of fuel directly into the cylinders before replacing the spark plugs and then trying to start will prove it to either the fuel system or ignition system.

If the engine then starts and runs for a few RPM's the ignition is correct and you need to look at the fuel and carburettor side.

If you have spark but no fire, check timing. Matchless again:

Then finally the ignition timing must be set properly. At less than 1500 RPM connect a timing light to #2 or # 3 spark plug and check that the timing marks line up for 2-3 on F, then move to #1 or #4 spark plug and check that marks line up for 1-4 on F. Check the advance by pushing revs up to 2350 RPM and the timing marks should both line up on the 45 mark behind the signal generator mounting plate through the sight hole at the top. The three mounting screws can be loosened and the mounting plate can be moved slightly in the elongated holes to meet this.

You can only test the Forward timing (can't get 2,350 RPM). But a bike with poor advance timing will start, even if it won't run well.


Air/Fuel

This part of the Trinity is two-fold, because you need fuel and air. Unless the bike is in a lake, there is air for it. But listen closely:

IS YOUR AIR FILTER (BOX or PODS) ON THE BIKE?? PUT IT ON TO START IT.

or at least cover the intakes with a shop rag. You can't start a bike on raw air. If it does start, it will run way too hot.

Otherwise, check your fuel supply.

• Gas in the tank?
• Does it flow on PRI?
• Does it flow in ON/RES when you suck on the vacuum tube (don?t drink gas)?
• Fuel in the float bowls?

If not, root out the petcock or float level/float valve problem to get fuel flowing. Check out the Carb/Fuel/Exhaust forum. Do a search for threads on non-starting bikes. If that doesn?t help, launch a post there.

Compression

If fuel and spark check out, then you have a compression problem. I left this for last because a bike with bad compression usually will start

If it starts but is rough,

CHECK AND ADJUST YOUR VALVE CLEARANCES.

Actually, if the bike starts and runs great, but you are new to the bike

CHECK AND ADJUST YOUR VALVE CLEARANCES.

Seriously, the other compression problems are a lot of work. Having bad valve clearances leads to those problems. Adjusting to proper clearance gives swift and certain improvement to operation. Also, every time a GS runs on out-of-spec valves, God crushes a puppy. Think of the puppies.

Otherwise, test your compression. It should be even across the cylinders and close to specs in your service manual. As the bike will be cold, your compression numbers will be lower than stated in the manual, so don?t sweat that. So for my bike, the compression should be in the 125-150 psi range, but a cold test might only get 90 psi. That should still be enough to start the bike. If they are ridiculously low (like 30 psi) or zero, there is a bigger problem in the head. Either a bad valve is not closing, or the cam timing is off so the spark and fuel are going into the chamber at the wrong time. Either way, your bike needs serious help, expensive gaskets and an expedition into the top end. If you think you need to explore that, check out the Engine/Drive/Train forum for 4-cylinders or 2-cylinders Do a search for threads on non-starting bikes. If that doesn?t help, launch a post there.

I hope that this thread can sort out some of the recurring questions on these forums. If other folks that know more than I do (i.e., everyone else here ) have other pieces to the puzzle, jump in.

 

[bruin]

This is great info. I know I am fairly new here but can I request that this thread becomes a "sticky"? Thanks for putting the time in to this thread.

P.S. You know this won't actually decrease the number of "My bike won't start" threads right?

 

[Ranger]

I'd like to add something that seems to becoming quite common now, especially with the bikes getting up their in age.

- The contact underneath the starter button can have debries in it, the contact could have came loose (as I helped a neighbor figure out this problem last week on a brand new bike).

Doesn't hurt to pull the assembly apart, especially if it had just been running and you see power being fed to everything.

 

[bonanzadave]

My Bike has been hard starting the last couple days. Fired right off all summer. Couple days ago it wouldnt start on the starter. Had to bump it down the drive way. Ran fine. Yesterday it wouldnt start again. Didnt bump down the dive way either. Put it on the charge. Checked the plugs. Good voltage at the coils (coil mod). Good fresh gas at the petcock. Finally got it running and gave it a good gulp of sea foam. Ran great for 20 miles. This morning it had trouble again. Wouldnt start with the choke but it would with a little throttle ???? The choke seemed to load it up. Same thing after work. Here is a vid when I got home....

 

[bietau85]

I'd like to add something that seems to becoming quite common now, especially with the bikes getting up their in age.

- The contact underneath the starter button can have debries in it, the contact could have came loose (as I helped a neighbor figure out this problem last week on a brand new bike).

Doesn't hurt to pull the assembly apart, especially if it had just been running and you see power being fed to everything.

My bike did that last year. Contacts and spring had nothing but red rust caked all over them. PB Blaster and a wire brush made them good as new.

 

[MisterCinders]

My Bike has been hard starting the last couple days. Fired right off all summer. Couple days ago it wouldnt start on the starter. Had to bump it down the drive way. Ran fine. Yesterday it wouldnt start again. Didnt bump down the dive way either. Put it on the charge. Checked the plugs. Good voltage at the coils (coil mod). Good fresh gas at the petcock. Finally got it running and gave it a good gulp of sea foam. Ran great for 20 miles. This morning it had trouble again. Wouldnt start with the choke but it would with a little throttle ???? The choke seemed to load it up. Same thing after work. Here is a vid when I got home....

Did you adjust the valves? Do that.

 

[bonanzadave]

Did you adjust the valves?

Did that earlier this summer. Actually I think I got some adjustments a bit loose. Rattles a little but its been starting like a champ up until a couple days ago.

 

[MisterCinders]

Starting weaker and weaker? Check your charging system.

 

[bonanzadave]

Starting weaker and weaker? Check your charging system.

Got an on-board voltmeter. Solid 14.5 vdc all the time. I think its something with the enriching circuit in the carbs....maybe....

 

[MisterCinders]

Could be the choke passages are clogged. Watched that video, it doesn't look that terrible. The bike doesn't catch right away, but it starts up pretty good.

 

[bonanzadave]

Watched that video, it doesn't look that terrible.

Hey Mr. C, Sorry for the intrusion into your tutorial about starting issues. I probably shoulda started my own thread. I do appreciate the follow up comments from you. Im gonna go shoot another vid. Its 49 degrees this morning so normally I would give her about 1/2 choke, turn the key, hit the start and it catches. Stand by.........

 

[MisterCinders]

No problem on the "thread-jack." If this thread becomes a clearing house for starting problems, that would be cool.

That is a lot of wear on the starter/battery in the video. Have you tried fiddling with the idle screw? If you are getting it to catch with a blip of the throttle, then your idle setting may be too low for good starting.

That backfire is probably from cycling the engine over and over without catching, loading the cylinder with fuel.

When it chugs and chugs without starting, pull the plugs to see what they show. If your spark and voltage is good, I would guess fuel starvation. If the plugs are dry after chugging, try putting a couple drops of fuel in the cylinders to see if that starts her up.

Since the cold weather coincides with the starting problem, you might have dirty/clogged "choke" passages in the carbs. Basically, you could be getting too little enrichment from the choke system. When it was warm, that had less impact, but now that it's cooler, your bike needs that extra fuel that the choke is not giving you.

HTH

 

[bradleymaynar]

Hey Dave, just curious if your starting issues coincided with a change in the temps. That landphoon we had earlier this week wreaked havoc on our temps here. But I know that my 1100 always likes a bit of priming on chilly start ups. My choke is non functional currently so I will give a couple of puffs of air into the carb vent tubes. Always does the trick.

Brad bk

 

[bonanzadave]

I will give a couple of puffs of air into the carb vent tubes. Always does the trick. Brad bk

Thanks guys. Still No joy. I just tried to blow into the vent tubes. I had to blow hard and then I could hear air blowing into the tank then gas started dripping out the airbox drain hose. ????

EDIT: Heres something new. The plugs are wet. Its getting gas. I pulled #4 - stuck it back in the plug cap and laid it on the valve cover. It ONLY sparks when I RELEASE the start button. Did the same thing to #3. Same results. Just as I let go of the button it sparks once and then starts.
??????

EDIT II: After getting some tips from Mr.Steve I started probing around the coils and coil relay mod. All of the sudden 3 & 4 started sparking while cranking. Nothing seemed loose...strange but it seems to be back to normal now.

 

[Buffalo Bill]

Crimp Connectors?

Crimp Connectors?

EDIT II: After getting some tips from Mr.Steve I started probing around the coils and coil relay mod. All of the sudden 3 & 4 started sparking while cranking. Nothing seemed loose...strange but it seems to be back to normal now.

I was going to say, the floats may have worked themselves up over time, so now they're too high and flooding over.
But the fiddling around with your coil mod, makes me think you used crimp connectors that are, sometimes making a good contact, sometimes not.
Crimps suck, all electrical connects must be soldered.
About the coil mod: did not work well for my bike. Could be yours is malfunctioning in some way.
Just some of my own discoveries.
Bill

 

[bonanzadave]

Thanks for the feedback Bill

Crimps suck, all electrical connects must be soldered.

If you use a cheap plastic terminal or splice and a $2 plyer style crimper then yes. But Im using good PDIG (nylon) terminals and an aircraft grade crimp tool. All my connections are pretty solid. I like solder but remember that solder is brittle and offers little flexibility.

About the coil mod: did not work well for my bike. Could be yours is malfunctioning in some way.

I believe your right. When the starter loads the battery I think the latching voltage at the coil relay is too low to keep it latched. When I let off the button it un loads the battery, the relay latches, and I get one spark. Could be my ground point for the relay. Thanks, Ill look at that.

 

[zaipai]

Great post..

 

[Guest]

i know this thread was from last year but i just thought of something.

the ignition triggers the relay to send good solid power to the coils. if the batt voltage drops low enough the coil doesnt have the proper voltage to keep the relay triggered.

you could use a relay with a 5v coil and a 7805 voltage regulator to keep the 5v coil happy. the battery would never get this low when starting the bike so the relay would never cut the power to the coils.

i actually did this yesterday to a little kids 24v razor scooter. 12v relay with a 7812 voltage relay cause the original 24v relays were burned out.

Brian