2008 XB12R Rebuild... Won't Start/Backfire

[Koop]

I purchased a "project" a few months ago... My 2008 XB12R. The guy I bought it from said it just needs the cams re-installed correctly and it's ready to ride. I got it back together according to the factory service manual, excited to see it run for the first time, and to my disappointment, it won't start. It will turn over, but nothing other than a random backfire. I checked/re-checked all of the sensor connections, made sure the fuel system worked properly, checked for spark (yup!), and ran my ECM for DTC's (nothing). I called the dealership and they said it may be a timing issue, not sure...

Another thing I noticed, with the plug out of the engine and when I hit the run switch, I'll get very noticeable spark from the plug. Is this a diagnostic feature from Buell to check if there is spark? The spark is faint when I try to turn it over.

Has anyone had experience with this same or similar problem? I'm stumped and running out of precious riding time in Michigan.

Mods:
- Fueling HP+ lifters
- Blue Performance Plug wires
- NGK Iridium Spark Plugs
- Revolution Performance 1250cc big bore kit
- Beehive HP Springs and Retainers
- New push rods
- Jardine Slip-on
- K&N Filter
- Breather re-route
- Gel battery

Thanks for your help!

I'll post a link to pictures soon.

 

[Theycallmecrash]

Fo you have tunerpro or ecmspy and a tuning cable? Could be the Air fuel value is not set right. Ive playe with my AFV a bunch if i lean it out too much it will just crank and pop.

Assuming you have air, fuel, and spark, then all thats left is mechanical (compression)

 

[Fatty SS]

Could the TPS be out of whack far enough to prevent start up?

 

[Koop]

I have the cable and both software packages, I've also reset the TPS. No luck.

My buddy just pointed out something today... apparently something that the manual did not specify where the cylinders need to be when setting the points of the Cam. He said the rear cylinder is the primary one and this should be seeing to TDC. So... my primary crankshaft gear could be set 180 degrees off. I'm going to pull it back apart this weekend and check it out.

If that's not it, I am back to being lost.

 

[Theycallmecrash]

Installing the cams, should literally be fool proof. All you should need to do is line up the marks. Long as the marks are matched up and the cams in the right spot, cant mess it up. Good luck! Take pictures for us!
Edit: just re read, you said crank gear... Maybe

 

[Koop]

Well I finished rebuilding the engine... again. It seems that there is only one way to install the cams. The service manual shows the timing marks on the cam faces and what I have matches perfectly.

I put everything back together, made all of the electrical connections, refilled the oil, and tried to fire it up but the battery was dead. Threw a charger on there to try and give it a jump and it didn't want to turn over. The battery was toast. ...At least that was what I thought was my problem with starting. Through that whole ordeal, I noticed a couple of things. The relay holder with the 4 relays in it started to get warm, not sure if that is normal? Took two of the relays out and they were pretty hot. Let them cool down a bit and kept the charger on. I went back to put the relays in and fire it back up, but no action.

My starting sequence:
- Turn the key switch to ON.
> Gauge pod cycles gauges
> No lights come on
- Enable the Run switch.
> Fires the ignition coil check
> Enables the fuel pump
> Check engine light comes on, then turns off after checks
> Neutral light is OFF (not sure why, bike is in neutral)
> Oil light is OFF
- Pull in the clutch
- Hit the start button
- Starter relay clicks... nothing else happens.

So now... I think I have an electrical problem somewhere. I did see a puff of smoke come from the triple tree, but we couldn't duplicate it. I don't know why I would have electrical problems now, I put everything back the way it was originally. (also, checked the fuses, replaced relays [2], loose wires, and double checked the connections)

Anyone have any ideas? I can post a video if need be...

 

[Theycallmecrash]

Bad battery?

 

[Koop]

Battery was replaced...

 

[Theycallmecrash]

Check to make sure cable to starter is good, they are tricky to get tight. Next these things have shit grounding. Ive installed 2 redundant grounds on my bike, one from ground to coil, and one from frame to engine via the dog bone mount near the rear isolator, which made a huge difference in my cranking speed.

Or you've seized your engine/trans/stuck in gear, no neutral light, possibly bent smash mis installed your shift drum detent.

Or defective battery?

Relays getting warm, suggest bad connection, bet if you hold the crank button long enough pops a fuse. To demonstrate this disconnect the ground cable from your car/truck hold it against the terminal have someone crank, bet it gets hot fast

 

[Koop]

Thanks for the info guys. I had a buddy of mine come out to take a look at it. He's an electrical engineer, so I was sure we could get to the right solution. Turns out that the tie bar from at the top of the engine was not grounded properly so that's why everything "stayed alive" and why my relays were getting so hot.

... corrected the grounding issue and tried to fire it up and I still have the same problem. It will crank over, but will not run. I checked codes, nothing on the radar. My ECMspy shows that the crank position sensor is on 5 and RED, but I'm just getting into the programming side and don't know if that is an issue. I've done a TPS reset and that did not solve the issue. Regardless, I know the bike is put together correctly, so that leaves a bad sensor, or timing issue within the ECU. I'm going to dig through the manual more to see if there is anything else I have missed.

Any other suggestions would help. Thanks guys!

 

[Fatty SS]

I'm leaning towards the cams being out of phase. I've seen this on other forums (sv650 and Ninja 650) where people put their cam(s) back in using the marks, only to find they're 360* off. Are you absolutely certain, beyond a shadow of a doubt, that you had the correct cylinder at tdc when you aligned the cam?

 

[Theycallmecrash]

Aligning the cams is fool proof. Long as the marks match up they are good. You cant install them 360 off thats just silly. Cam phase? It doesnt have cam sensors or variable valve timing.

Assuming you absolutely have fuel entering the engine, even with timing out, youd get ignition eventually a pop a smoke a fire or a bang. Leads me to believe you either dont have fuel like you think so or you dont have spark like you think you do.

Pour some fuel down the intake give it a crank? Whats happens? Still nothing? Inspect for spark near top dead center.
(Put bike on stand in fifth gear, plugs out, power everything on, spin tire watch for spark, if sparks, check that piston is near TDC)

Im hoping youve checked the obvious stuff. Compression would be the last thing to test for. Fuel pump primes? Everything is plugged in? Its easy to mis something IE: the main ground from frame to engine ontop

 

[Fatty SS]

Hmm, well is there something special about the Buell motor that the cam can't possibly be installed incorrectly? On every other twin I've seen, there are two ways to install the cam while lining it up with the marks. With the front at tdc, and the rear at tdc. If you use the wrong cylinder, it absolutely will not run because the valves will be open at the wrong times in each cylinder's stroke. That's what I'm talking about with cams being out of phase. Does this not apply to the Buell twin?

 

[Theycallmecrash]

You can install them wrong. But yoyd have to do it on purpose. The crank only has one mark, you match that mark up on the cam, its literally connect the dots. As long as the dots line up they are in the correct location.

 

[Fock347]

stupid question but did you install the cam timing sensor and did you plug it in . Or its burnt out

 

[Theycallmecrash]

stupid question but did you install the cam timing sensor and did you plug it in . Or its burnt out

I feel like a troll today, just dead at work.

But the bike is a 2008, they did away with the ignition module, had a crank sensor instead

 

[Fock347]

oh my bad, but the crank sensor could be your problem , ive had issues like that with cars same symptoms , im pretty sure you can use a volt meter to check the crank sensor while your cranking over the motor , to see if it has a pulse. sometimes those wont throw code even if they are bad.

 

[Koop]

I checked the cps against the owners manual test specs... They seem to check out ok. I also checked the ecm and reflashed a stock program. Still the same outcome.

I broke down and took the bike to the dealership to get taken for $100.00, that was a waste. My local harley dealership apparently no longer supports Buell aside from anything mechanical. I wanted them to check if there are issues with the ECM.... Wish they could have told me that before I forked over $100.

The bike is now back in my garage, it its exactly the same as the last time i posted. I'll try and take a video of the bike cranking when i'm able to get to it.

Anyone in the metro Detroit area have experience in working on these and want to give me a hand?

Thanks again guys

 

[ich]

try setting afv to max value.
plugs, wet or dry?
ht leads?
compression?
iac position?
record a log with ecmspy v2, post a link.

 

[Koop]

Could my wideband O2 system be causing a no start problem if it's not sending proper readings?