Stuttering/Misfire... UPDATED

[photomike666]

Being that I booked a trackday yesterday, I thought I'd better pull the 6 out of the shed and get it fired up.

Seems in my haste to put everything away after the Christmas trackday, I didn't drain/turn off the fuel.

The bike fired up ok, but then ran into a few issues.

Firstly revs are very fluffy, particularly between 2-3,000rpm. After this is clears up a bit and pulls ok.

Secondly, the bike ran very hot, and got there very quickly. I assume this isn't a fuelling issue, and is a concern considering oil and water and at the right levels (as always).

Thirdly the fan didn't cut in, again strange,

I can be passed by the fan switch easilly enough, but would like to know why it didn't cut in. The Radiator got hot, so the thermostat is opening. The swith has power, around 9V.

I'm expecting fluffy throttle is due to fuel gunk in carby - hopefully I can remove this with carby cleaner. Will I need to remove the carbys, or is there a spray in the inlets type stuff?

The over heating is the real worry. I was running the bike on the stand for a while, but have done this longer before without any issues. My worst case senario is a dry valve from sitting for three months with no attention; best case is either runnning very lean due to gummy carbs or simply old fuel.

I will try new plugs, new fuel and carby cleaner, but any other possibilities or ideas would be appreciated.

And no, I am not in a position of replace my tracky and would rather not put the 10 on the track.

[mike-s]

Troubleshoot the electrics one step at a time, first try connecting the fan direct to the battery to see if they fire up or not. Then check the thermostat cutout to see if it is connected ok and if it cuts in correctly. then its just a matter of getting a multimeter and going nuts.

[Smitty]

Mike you sure the radiator is full..and not just the overflow ? (which is what we normally check)

[oldman]

If the carbs are running lean then your overheating problem is probably that, as a lean mixture runs very hot. This can also cause other problems such as burned exhaust valves and and fried pistons as well as ping, (pre detonation). I would fix this issue before anything else. Pulling the carbs off and doing a complete overhaul is probably the best way. As far as the fan not coming on who knows, logically trouble shoot it. I thing all the over temp sensor does is provides a ground for the fan circuit, but you probably should look at a wiring diagram so you can see for sure. If thats all it does youi can test the fan circuit by grounding the wire that goes into the sensor and the fan should run, if not check the voltage.

[photomike666]

Stage one is done. Ran her for a while, sprayed carb cleaner into the carbs while running. Then swapped the plugs whilst the carbs soaked in carb cleaner. started her up and she ran fine, and didn't go too hot either. I still need to do a test ride and chase down the fan issue, but am happy I have a smooth running motor again.

Thanks for all the help and info. much appreciated

[Gosling1]

Oldman - where is the tip about a brew and a bourbon ?? I always look forward to that ! !

[oldman]

Oldman - where is the tip about a brew and a bourbon ?? I always look forward to that ! !

Sorry,I was too farked up to remember when I posted, Unfortunately I saw God and she was Henrietta Smultz an old High School sweetheart and she still hates my guts. Probably didn't drink enough.

[oldman]

I forgot another thing about the fan sensor. Most fan sensors are in the radiator and the temp gauge sensor is in the engine block. So if you have a stuck thermostat it will give you an overtemp but the fan will not come on because the water is not circulating to the radiator. I really need to have A Jim before I post otherwise I forget shit. Let us know how it turns out.

[photomike666]

I forgot another thing about the fan sensor. Most fan sensors are in the radiator and the temp gauge sensor is in the engine block. So if you have a stuck thermostat it will give you an overtemp but the fan will not come on because the water is not circulating to the radiator. I really need to have A Jim before I post otherwise I forget shit. Let us know how it turns out.

Rad is hot top to bottom, and now I have sorted the running problem the bike is not overheating.

I haven't had time to look into the fan yet. Something to do with the mamouth ride I did in the hills on my 10.

[photomike666]

Bike was running perfectly at the track. Engine temp was good, throttle response was good, and lap times were good (for me). New tyres were doing their thing very well, fuel was new BP Ultimate and the suspension was working exactly as it should...

Until half way through session 5 (out of 7). We were running 20 min sessions, and revs are continuously high at this track (tight, twisty and the whole back section in 3rd revving 8k to 12k). So I go to drive out of the hairpin and it sounds like its missing, then it clears and pulls clean to red line. I notice this 4 or five times in the second half of the session, but everything else is fine. Temp is good etc... As I ride back into the pits it's doing the low rev stutter again, but not too bad, and it sounds a little fluffy again.

In the pits I pull the fairings off and find nothing out of place - oil good, water good, temp good. I don't have time to get the carb cleaner out, and I'm starting to think that is not the issue. It's been running fine and has new fuel. I go out in session 6 and it's lumpy as hell. I do three laps and return to the pits. Riding back to the pit garage was like riding a bucking bronco; it was stuttering and lurching so bad.

So the bike is now in the shed, the tanks and air box is off, and I stand scratching my head wondering where to start. I've just thought of one thing, and I really don't know if this is related but the battery is stuffed. It got cooked on a proper trickle charger/battery minder thing and does not hold any charge. After each session it does not have the power to restart the bike, but it was doing that at EC in December too.

[photomike666]

So my thoughts are this……………

1) Carb has something lodged in it again. They are soaking in cleaner now. The fuel filter was filthy, and probably hasn’t been changed in many thousand Km. New filter will be purchased, carb will get a clean. Carb sync could be out, and I will get this done at a service before the next track day.

2) It could be out of tune because of the pipe mods and is running lean. This could be killing plugs and it takes 1 track day to kill them. Pipe was modded before EC, get home it runs shit. Change plugs and it runs fine, do track day (Broadford) and it runs shit again. I will get jets done with next service, might even get a dynojet stage 2.

3) Stator is stuffed or dead battery is draining so much charge that at low revs there is a weak spark. With good plugs it is fine, but once they get used the spark is too weak. I am considering running a total loss system; no stator, no reg, just battery and essential elecs and a new battery.

4) NFI, AT the service I will get the valve shims done, and hope with the above this is enough to get it running nice.

[Gosling1]

Its just the battery Mike - you need a new one. All those symptoms in the previous post about how the bike was running in the later sessions - are perfect symptoms of a battery that is mightily fucked.

[Strika]

In most bikes the battery act like a capacitor. So the battery gets to such a low level that it struggles to makes a circuit and you lose power. Yours it at the commencement level of the cycle. Last Sunday, mine was at the last stages and failed completely in a far away town, with not a bike shop or battery place for 120k's! I reckon Gos is right, chuck a fresh battery at it and you might find the problem dissapears. Otherwise...trade it in!!

[photomike666]

Thanks guys, I'll try a new battery and see how it goes. I will try and get most of the other work done anyway.

I also have a wet airbox on the carby side, it's not evaporarting off - any ideas?

[Smitty]

Its just the battery Mike - you need a new one. All those symptoms in the previous post about how the bike was running in the later sessions - are perfect symptoms of a battery that is mightily fucked.

+1...with Gos here
the ECU (which controls everything timing EFI etc) likes nice clean constant voltages