2000 Ry Backfiring Through Throttle Bodies And Fouling Plugs.

[David Offor]

Hello everyone (again).
This is my 3 different post concerning my original problem.
The symptoms are that of wrong mechanical timing but it's right, according to two differnet workshop manuals.
My previous posts mentioned in the title about only running on 3 & 4 cylinders, I'll attach the link when I work out how to do it.
Things I've tried and done, over the last 2 years (on and off):-
Map sensor changed (3 different ones)
Sucked on the vacum pipe to the map sensor, to check that the map is recognising a vacum
Water temp sensor tested and changed
Camshaft sensor, new replacement, tried 2 others
Fitted another wiring loom/harness
2 different sets of coils
New sets of plugs
15 pins counted back from exhaust cam to inlet cam, with crank lined up on TDC mark, with slack on chain at tensioner side
Cam chain removed and measured for wear (slack), chain is in good condition
Leak down test, all cylinders holding good pressure
Compression test, all good
Valve clearances all checked and withing tolerance
All cams in very good condition (just fitted a head from a 16000 mile bike)
Throttle bodies synchronised
Checked for air leaks around throttle body to head rubbers, all good
Vacum from map sensor is 'Teed' between all 4 cylinders
Injectors tested
Changed side stand switch
Changed gear selector sensor
No TRE is fitted
Put into dealer mode to check for codes, none showing
Set TPS during dealer mode, showing -00
Voltage checks and resistance checks carried out on all sensors, as per the book specification

I'm at a bit of a lost tbh, I don't give up and I don't want to give it to a shop, I've eliminated the ECU and wiring loom, so it means the garage will re check all the things I've checked and eliminated, which will cost me a fortune.
The only thing I can think of (because I can't test for a fault) is the crankshaft sensor, could a faulty CKS send a bad signal to the ECU, telling the injectors to inject at the wrong time or the plugs to fire at the wrong time? Also I've read that on start up the busas do something called 'batch firing', is it possible that it is trying to constantly 'batch fire' on all cylinders because of a faulty CKS?
I've got a real problem with this bike, hope some new eyes can suggest something.
Thanks in advance.
Dave.

 

[sixpack577]

I'de try a crank sensor before I brought it to a shop.
Are you positive the 2nd ecu is good? Or did the seller just claim that it was?
Know anyone with a 99/00 Busa that would let you try your ecu's in their bike? As if they are bad, they won't hurt the other bike in any way.
Defiantely sounds electrical to me.

 

[David Offor]

Hi Sixpack
The crank Sensor is integral with the stator, I can pick up the stator/crank sensor for about £84
I've actually tried 2 different ECUs (one a long time ago, when I realised something was wrong with the bike), swapping the ECUs has no change on the running (same with the loom that I fitted today).
I don't know anyone with a gen 1 busa and unfortunately, I'm the one people call, when problems arise lol.
Yes, it does sound electrical now and the CKP is the only thing with a ? over it.
Thanks Sixpack.
I'll update on this thread because the other one got a bit long

 

[GIXERHP]

Hey i just remembered this, gmbusa had a similar problem a few years back, he found the key was damaged under the rotor. Witch was throwing the timing off.
Just something else, to look at.
If some had changed the CKP with a newer one the wires are reversed on the newer bikes too.

 

[David Offor]

Hi Gixerhp
Thanks for that information, interestingly enough, when i bought the bike, riding away from the guy the front brake locked on and threw me off at about 25mph, it fell on the right hand side, i classed it as a low speed drop (compared with most of my spills) the guy then informed me that the bike had been off the road for over a year and hadnt moved, information that wouldve been useful at the time of purchase, i rode it the 150 miles home (sprung an unrelated water leak but thats another story).
Ill take the stator cover off and crank it over, check for staor drum spinning out of true and see about endfloat on the crank, hope i havent got a bent crankshaft, that would be just my luck but theres also the reason for it being off the road for so long, maybe there was a problem already on the bike, that has just got worse and worse.
Think ill just bite the bullet and change the CKP while im in there but will do voltage and resistance checks first.
Thanks, update to follow.

 

[GIXERHP]

It's not the the rotor will spin out of ture, it the fact the Key, could be damaged in the slot from a kickback or something. You cant see it until you remove the rotor and inspect the key.
I know it sounds like bizarre but you have checked everything.
And since you stated that it was dropped on the right side, also i would inspect the spline on the right hand side to insure that the spline is not twisted.
The crank should be fine, but the small Cam gear that slides onto the crankshaft can twist.

 

[David Offor]

Update time:-

Partial success.
The bike is now running very well but unfortunately we did not find a failed item or definete wiring problem.
What was checked yesterday:-
1. Checked resistance at CKP terminals and to earth, as per book spec, checked out ok 235ohms and open circuit to earth.
2. Checked voltage on cranking at CKP, coming up at .2, book says peak should be 3v minimum but we do not have a meter that can measure peak, so thats probably a red hearing.
3. Removed rotor to check GIXERHP suggestion, keyway all good, no endfloat or movement in crank *sigh of relief*.
4.Put rotor in our lathe, spun it up to about 2000rpm and i held the CKP close with some card supplying the air gap (tricky), measured the voltage, now showing around 4v, not a great test but showed consistency and operation of the CKP, so i think we can say its ok.
5.Checked the condition of the sliding splined chain sprocket, all good.
6.We hooked up a pressure gauge to the fuel pump and meassured the pressure on priming and running, it holds a steady book pressure (just over 3bar).

As there was no difference with the new loom, i decided to re connect the bike back up to the original equipment (less confusing).
I found corrosion in the large yellow block connector next to the fuse box, cleaned that up.
Got the bike ready to start, fires up but back to running on 3&4 (doh), changed a plug in No.2, now 1&2 burst into life (go figure aye), so, now its running good on all 4 cylinders, i synced the throttle bodies, all running even, bed time, im sure the neighbours are happy lol.

Today rode it, it pulls much better but still hesitation when accelerating, from approx 1500rpm, backfiring a little when reved up to around 5000 and then backed off on the throttle quick, bike still feels rich, on tickover, different MAP sensors tried, no change.
Engine is so much quieter and smooth now, fan cuts in at half on the gauge, instead of 3/4 up the gauge and runs consistentely well, compressions are all aound 160psi (not great but good enough), plugs are now dry when removed and all 4 are a good coulor (not fouling anymore).

So the things ive found are:-
1. Worn valve guides.
2. Clatter when started, when i originally did the headgasket, probably did damage to the valves, causing bad readings on the leakdown test.
3. Slight corrosion in yellow block connector.
4. 1 faulty plug but i had changed the plugs twice.
5. Had to adjust throttle bodies during sync, probably out because id synced it to a head with leaking valves.
6. On changing the headgasket ( COMETIC headgasket this time instead of a suzuki one) bike is not seeming to get too hot anymore.

Wish we had found something obvious and i dont know what to do about this hesitation from low reves?
Dave

 

[David Offor]

Im thinking to get the injectors tested, ill probably run some injector cleaner mixed with the fuel today before paying to have them checked.
I disconnected the paired system on the bike and have the No 1 throttle body vacum to valve blanked off because ive done the mod to the air box, removing the flap and removed the vacum pipe from the airbox to the valve cluster inside the engine bay, maybe one of those valves ive disconnect from the No 1 throttle body is causing an issue?

 

[David Offor]

I'll check and reconnect and vacuum hoses that Ive removed back up and see if there is any difference.

 

[David Offor]

How the bike is now running, hope it's dry tomorrow for a proper test on the road, fingers crossed.
As I finished my final adjustments the alarm decided to pack up, wow, what's next?
Think this bike hates me lol.

 

[David Offor]

Bike is fixed, runs like a dream.
Thank you for everyone's patience and suggestions, learnt a lot from this bike, invaluable experience I feel but glad its finally resolved.
Dave.

 

[sixpack577]

So what exactly was wrong?

 

[David Offor]

Ok, this is what I think was wrong.
1. Valves not seating, on 3 cylinders, leak down test proved that and badly worn valve guides.
2. Partial head gasket leakage, I was always finding a little milky residue in the oil filler cap, starter cover and rocker cover, since doing the head gasket, no residue and bike temp stays at half way on the gauge, instead of 3/4 up the gauge.
3. throttle bodies needed resyncing because I had synced them to a head with leaking valves.
4. Fitting the restrictors back in my open exhausts cured the backfiring, could've been that the bike was leaning off too much, instead of being too rich, maybe I'd taken away backpressure, that was needed on the exhaust side, to balance the running.
5. Reconnected the left hand throttle body vacuum to the VCSV SOLINOID and VC collector.

So, I'd say it was head and head gasket damage, was the cause, that made me make wrong adjustments, compensating for unknown faults and also my lack of knowelege about the VCSC vacuum side of things and wanting a loud exhaust note and not thinking about the gasses coming out of the bike and how it could affect the running of the bike.
I think that's a conclusion

 

[sixpack577]

Glad you got it figured out.

 

[David Offor]

Thanks sixpack.
Im so happy, to have finally fixed it.
Having input from yourself, gixerhp and a few others was so helpful, from a moral boosting angle, the bike shops my way either didnt want to help or just couldnt offer any suggestions and im the only person i know, that knows about any complicated technical bike mechanics, so having hayabusa.org was invaluable and suggestions, that i wouldnt have thought off, i know how hard it is to diagnos faults, when you dont have the vehicle in front of you and especially when the customer has been medling and modifing it, most of my problems were my own poor workmanship because it was my first performance engine overhall but getting the timing out to clout valves was a first year mechanic error and im 29 years in the trade, ohhh well, live and learn .
Thanks again.
Dave

 

[K-Man]

Still running good?

This thread should be stickied considering how many that have similar problems!
I hope not all of them have bad cylinder heads. Maybe even renaming this thread with SOLUTION
as the hundred other threads don't have one.

Based on your conclusion my problems should disappear when I turbo my bike. A new head gasket will be fitted and vacuum things will be simplified and sorted. Probably only used to control the fuel pump regulator.

 

[K-Man]

Can you specify how your vcsv Vacuum Control Solenoid Valve was hooked up before and after? What you think might have caused a problem

 

[David Offor]

Hi Karl.
I'm just going over my old posts.
As you know, I've recently found that my fuel pump, was probably the underlying issue with my bike.
We had thought that we had ruled out the fuel pump, as being a possible problem, earlier on in my fault finding, we were testing the pump outside of the bike, so we were getting inaccurate readings (you live and learn).

 

[Bugixxer]

Bike is fixed, runs like a dream.
Thank you for everyone's patience and suggestions, learnt a lot from this bike, invaluable experience I feel but glad its finally resolved.
Dave.

Having the same issues with my 06 is the any one or 2 things you think may have been the cause ?? Getting really frustrated also what octane gas are you running

 

[Bumblebee]

Having the same issues with my 06 is the any one or 2 things you think may have been the cause ?? Getting really frustrated also what octane gas are you running

The thread you are replying to is from 2016 and the person you quoted hasn't been active since 2020..

If you are having issues with your bike, you would be better served to start your own thread and fill us in on some information on your bike so we can help.