748 is having fits starting...

[hiero]

Ok, I'm still troubleshooting, but figured I'd get the collective mind going a bit on this one.
I crashed my 1999 748 in February and am just starting to get back on getting it on the road again.  It was a <5mph high side on the left side of the bike (I was stopped at a stop sign and turning right onto a surface street, everything was cold and it slipped out).
In any case, I let it sit and pulled the gas tank (placed some BG fuel treatment in the tank) and the body panels for repair.

A couple weeks ago, I put the tank back on and fired her up.  Started fine, no weird sounds or anything.  After about 5 minutes of idle, it turned off on it's own.  I started it back up and it died again.  A couple of more tries and it wouldn't start any longer.  Now it won't start.  It turns over fine, just no start. Nothing interfering.

I changed the oil just to take a look and found a fairly large piece of unidentifiable metal attached to the drain magnet with some flakes that look like rocker surface damage. no good.  I am not certain whether it was just dislodged in the accident as this bike had significant left side case cover damage due to a loose alternator nut that I repaired some time ago (i.e. years ago), but honestly, I doubt that was the case.  I have megacycle resurfaced rockers so I'm hopeful it's not the case that this metal came from a rocker.  (I guess I'll post a picture of the metal when I get home)  I have drained the new oil at least once since and found no other pieces of metal too. 

I have checked the spark using the horizontal wire and a new spark plug on both coils.  I will need to redo that test using the actual wires and spark plugs on the bike though.  After holding the start button for a bit, I can smell fuel from the throttle body area, so it seems to be getting fuel. 

I pulled the timing sensor yesterday and it looks like it's been 'shaved' a little by the alternator/flywheel, but I can't remember if that's from the prior incident with the loose nut.  The resistance of the sensor measures 720 ohms (I believe 680 is what is normal, so not that far off).  Otherwise, it looks fine and remember, the bike ran for a good 5 minutes.  I did pull the left side case cover to make sure I didn't have another loose nut, but everything in that inspection looked fine.  Nothing out of whack.

All electrics/fuses/etc seem to check out ok.

I am going to pull the timing belt covers and see if the belts got loose, and then pull the head covers and see if I can't see any immediate damage at the rockers and check the clearances real quick to see if there's an obvious rocker issue (since I can't see the chromed faces without removing).  And of course, the aforementioned spark check with the actual pieces on the bike. 

Anyone have any idea what I could be looking at?

[hiero]

Ok!  Figured it out and finally got her to start up real quick tonight!!!    I'll have to try again tomorrow if I have time as I didn't get to leave her on in case I wake the neighbors, but she did start! 

Turns out the belts were way loose and honestly, probably out of service limits too.  Will need to replace them, BUT the bike starts and I checked inside the valve covers and found no evidence of metal anywhere either. 

So not totally out of the woods, but in the right direction for sure! 

[ScottRNelson]

I would be looking at the fuel pump, tank venting, fuel filter, and anything else related to fuel delivery.  The behavior you've described sounds similar to what I've experienced with a clogged fuel filter.

[hiero]

I would be looking at the fuel pump, tank venting, fuel filter, and anything else related to fuel delivery.  The behavior you've described sounds similar to what I've experienced with a clogged fuel filter.

thanks! That was def on my list and I did reroute the vents with the thought that one was pinched but no joy.  I do expect the next step to be clogged fuel filter though if this latest fix doesn't solve it and I already have a new filter and oring in anticipation.

btw, good to have advice from one of the longer time members, haven't been too active on the tech board in a while but good to see you scott, thanks!

[devimau]

lift the gas tank and as you hit the starter and the engine cranks apply some carb cleaner to the ports, if it starts and dies right away it's a fuel delivery issue.
if not look into another direction...........but if you took the gas tank apart and ran for 5 min probably you have a fuel leak inside the tank (loose clamp in any of the fuel lines or cracked fuel filter)
keep us posted   

[hiero]

thanks devimau, but I ran the bike today and let it run up to temp, everything sounds good and runs well!  I have some new belts on order with cycleworks and should be good to go  [moto]  well, still have to get the front and side fairings repaired/painted, but I can at least ride her naked for a while (yes I just said that).

short ride test to come tomorrow, but it's looking good.

////

Short ride went well, bike feels great and went ahead and rode into work this morning  [moto]  Now just need to get fairings repaired