TOPIC:

I have a handful of other updates and questions about things that I need to post here, but due to my work pressuring me to get my bike out of the building, I need help troubleshooting why I can’t get my bike started.  

So it’s pretty much done and ready to ride, but it won’t start. So far I have charged and load-tested the battery, cleaned the carbs, replaced the cam chain tensioner for a manual one, and replaced the main fuel hose, and have not been able to get it to roar to life. 

While trying to start it I have been able to get it to combust randomly, and at one point it sounded like it was firing on a single piston. This morning it backfired. 

I’m stumped. My best guess at this point is that somehow three out of four spark plug died or aren’t firing despite them not having been touched since the last time I had the bike running (January 4th). Either that or the timing is off, even though I followed the manual cam chain tensioner instructions very strictly. 

Open to suggestions and thanks!

Hi Paul, as a rule backfiring is normally a timing issues (combustion is occurring when a valve is open)

1. have the coils been disconnected ? Crossing the wires will Mean the timing is 180 degrees out
2. has the ignition been on for a long period without the engine running ? (Can burn the coils out)
3. is there an earth wire that has been disconnected during the work that is still off ?
4. Is one of the carbs flooding?
5. have you got full battery voltage at the positive side of both coils ?

if all of the above is ok you will need to go back to basics and identify which cylinders aren't firing, once you know this we can look at a diagnosis plan to pin point the problem
 

You might try starter fluid 

wrote:

You might try starter fluid 

I was going to suggest the same thing.  Starting fluid is good for quickly answering the "is my problem fuel or spark?" question.

If it fires with starting fluid, look at the fuel.  If it does pretty much the same thing it's doing now, check the spark.

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wrote:

wrote:

You might try starter fluid 

I was going to suggest the same thing.  Starting fluid is good for quickly answering the "is my problem fuel or spark?" question.

If it fires with starting fluid, look at the fuel.  If it does pretty much the same thing it's doing now, check the spark.
Nicely edited DOHC - I was really confused by the email notification 

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wrote:

Nicely edited DOHC - I was really confused by the email notification
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Proofreading is important!

wrote:

Hi Paul, as a rule backfiring is normally a timing issues (combustion is occurring when a valve is open)

1. have the coils been disconnected ? Crossing the wires will Mean the timing is 180 degrees out
2. has the ignition been on for a long period without the engine running ? (Can burn the coils out)
3. is there an earth wire that has been disconnected during the work that is still off ?
4. Is one of the carbs flooding?
5. have you got full battery voltage at the positive side of both coils ?

if all of the above is ok you will need to go back to basics and identify which cylinders aren't firing, once you know this we can look at a diagnosis plan to pin point the problem


 

Timing issue, so I should check the cam timing first, correct? That’s the thing where you set it to TDC on piston 1 and count links right? I’ve done that before when resetting the old cam chain tensioner. 

1. At no point since owning the bike have I ever disconnected the coils, and a visual inspection shows everything to be connected and no frayed wires or anything. If anyone knows a good tutorial on how to test coils with a multimeter I’d love to see it. I can’t quite understand the FSM instructions regarding that. 

2. Depends how long I guess, but no not really. Would repeated attempts at starting (with no success) ever do that? I’ve definitely wheeled it out to the parking lot, and tried to start it with no luck quite a few times now. 

3. None that I can find. By and large there has not been any electrical work needed done to the bike, caused by the accident. The only electrical parts I had to replace were the front right blinker (now works perfect) and the gauges. For those, I sourced a complete used set off eBay, which had an intact wiring subloom. I swapped in the original speedo and tach from my old gauges. As far as I can tell it all works except for the hi-beam indicator (the hi-beam itself works, it’s just the dash light doesn’t come on). I suppose I could try disconnecting that whole subloom?

4. Maybe? I haven’t tested that yet. 

5. I don’t know, how do you test that? 

Thanks for your help, everyone!

if you have any doubt at all regarding the cam timing you need to sort this before anything else. Once that is ok did you try the "easy-start" if it made no difference I have attached a PDF that I put together to help you check the coils. Once you have done that let me know the results and if necc we can move on to checking the rest of the ignition system (CDI unit etc)
You might find my electrical fault finding guide useful if you aren't 100% confident with electrics (in the FAQ section)

Thanks for that Wookie58. I’ve checked the cam chain timing now and it’s good. Must’ve been a freak backfire. 

Long story, but I don’t have my tools today to check plugs and/or coils. But I was able to make a video, so maybe this will help with sorting out the issue. 

That sounds exactly like you're right in the middle of the "is my problem fuel or spark" dilemma.  

Two quick tests I would start with.  First, pull out one of the outside plugs, plug it in to the wire and lay the threads of the plug on the cylinder head, in a place where you can see the electrode.  Try to start the bike and just look to see if you can see the spark.  Might as well do this with the choke off and the throttle wide-open to minimize the amount of fuel coming out of the plug hole.  I've never had an issue, but safety third right?

If you want something a bit more formal than laying the plug on the head, you could get one of these:  www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6

The second test is the starting fluid.  You could get fancy and pull the air filter, but if you can get to the air inlet for the airbox you can just hose the stuff in there and it'll find a way through.  If it has spark and the cam/ignition timing is good, it should fire right away with starting fluid, but only run for a second or two.  

I'm assuming you've confirmed that the vacuum line is connected to the petcock.  Have you tried it on the PRIME setting?

 

Are the coil wires reversed?
Steve

do you smell a lot of fuel, when cranking it?  if not, are you sure the engine is getting sufficient fuel?

I have a similar issue with my My XS1100, if it's been sitting for a while..
i need to loosen (not remove) the drain plug on each of the fuel bowls, until fuel starts seeping out.
at that point, the bowls are filled, and the bike fires right up.