Weak sparks , poor running

As per the July4th thread, I still haven't sorted my Blade out. Thought I had made a breakthrough this morning when I changed the pulsar unit on the end of the crankshaft and got good sparks. Put it all back together and sure enough it's no better Basically when I shut the throttle for a tight corner and then try to power out of it, the bike bogs down, slows and then slowly accelerates? It also hunts at steady speeds with a steady throttle?
One other thing is that the timing had been slightly advanced(on purpose) with the old pulsar unit and crankshaft rotor. I thought I had put the timing back to standard by putting the rotor back one tooth (anticlockwise), but the engine feels quite harsh now and the popping on overun is a lot more. I suppose I could have advaced it even more somehow, but I doubt it ??? DAVE!!!!

 

shud have just persuaded helrazzer to part with his carbs for a few gold coins...seems your bike was happiest with those carbs on...

 

Hmm, I'm with Hoppie

Assuming that the fuel and air are doing everything that they should be all the way through the range, which I'm guessing is the case as they were set up recently and he didn't offer any suggestions. That only leaves the electrics, quite rightly.

How is the bike on launch? Pulling away from a standstill and nailing it, does it act the same as mid corner?
Would confirm if you're having a weak ignition only after open throttle (and theoretically higher ampage) or all the time at low rpm.

Popping on overrun is unburnt fuel, partially expected on overrun - mine sounds like firecracker, but if it's a change then it's relevent and poor ignition would cause more fuel in the exahust of course.

My first thoughts would be why was the timing advanced, when did you change it back and does it tie in with any of the symptoms?
I'll have to have an investigate on the timing adjustment, it may be that anticlockwise advances not retards the timing.
If you're not sure it's back to standard, that would be a good thing to confirm in the first instance.

 

Havnt you already parted with some of yer hard earned for this to be sorted professionally? If so hope you got a refund or at least take it back as that havnt seemed to have solved the problem..

 

The ignition advance is a red herring Dave. It was done after the initial problems started after I handed Helrazzers carbs back. It is a standard Fireblade mod consisting of turning the rotor one notch to over advance the timing and then modding the position of the pulsar coil to bring it back to about 4 degrees advance over standard , which often works and didn't in my case. As I changed the pulsar coil I had to change the rotor position.
I did ask Helrazzer if I could buy his carbs, but NO was the answer. Hoping I can have another look at them to check the differences.
It seems good on launch ,with the throttle pinned open and blipping up through the gears, but anything more than a slow wind up of the throttle afterwards and it bogs down, coughs and accelerates slowly.
Yes Kev, I paid a lot of money to have the carbs sorted and the Dyno readout confirmed that they were. The bike performance is slightly better than unrideable, but it was enough to get me to Belgium. Once I have sorted the ignition problems, I will be having a word with HMR, but I can't afford another £240 !!!

 

Right, let me see if I get this correctly;

HR's carbs on - bike runs great.
HR's carbs off - bike runs wank.
Ignition fiddled with - bike runs wank.
Carbs set up - bike runs better.
Ignition fiddled with - no change.

Is that the correct, condensed sequence of events?
If so, Occam's razor tells us that the cause is the advance fiddling is to blame. Either that while the carbs were at fault it went unnoticed or that now the carbs have been set for that ignition timing, retarding it has pushed your spark / crank positions out too far for effective burn.

You did set the advance from TDC and not just twist it a bit, didn't you? Might sound a ridiculous question but if you haven't (being in a hurry etc) the timing could be miles out.

 

My 4d's worth would point to a intermittent electrical problem(s) ...... corroded/ bad connection(s), broken wire(s), poor earth, coil breakdown, HT lead crack, ECU?.
IMHO I think the whole carb issue is a red herring and its the disturbance and removal/refitting of tank/carbs/seat etc that disturbs said electrical fault. In Belguim... running well .... then running on 3... fiddled and fitted new plug.. running on four.... later fault reoccurs running back on 2/3 because the spark is not strong enough to burn fuel and fouls the plug/s.

 

Ahh right so it was running fine briefly?
Cheers Rob! It's definitely pointing at electrical, as the carbs are ay least 90% spot on and as its doing it on all cylinders it has to be north of the leads (chances of all leads going bad at once is pretty slim).
If the symptoms vanished between fiddles briefly then I'd agree its pointing to something isn't attached / making good contact.

As I said on the other thread, the most thorough (if slower) solution is to start at the battery and follow the conections forwards until you find a break / bad connection.
Swapping known working parts can help but you have to ensure the connections to those parts are good.