FSE 450 2005 idle misfire/stall when hot
 

Okay...i'm out of ideas.
I have a 2005 FSE450, last year rebuild, new crankshaft,piston,cylinder etc.
At one point, this year, in the middle of the forest, bike started to idle rough(misfire) and then stalls. Starts most of the time easy again and runs a little bit but then again, idle/low revs misfire and stalls if not given throttle.
High revs, everything OK. Some backfire when slowing down. Works fine when cold! but about 20-30min riding, engine getting hot, then the issues start.
Can't ride properly because stalls too often when riding slow forest trails. :(
Changed and adjusted TPS, new fuel pump, water temp. sensor, checked air temp sensor, fuel injector tested-good spray pattern, no leaks and flow rate ok.
Can't find any air leaks.
My next step would be change:
1) Ignition coil - i think i can find VW analogue (hell no i'm paying $200 GasGas "original" coil if i can get VW coil with $25)
2) Fuel pressure regulator? - PITA to find in Estonia :/
3) Pick-up coil? - does anyone know what should be the gap between pick-up coil and toothed wheel?

Any ideas?

Okay progress so far.
Managed to replace original ignition coil with 2013 Honda CBR coil.
Got a brand new fuel pump assembly with fuel regulator for testing.
Put 2007 MAP to ECU, made things little bit better.
But still after all of this, when engine gets hot, at low revs and sometimes when taking off it feels like engine starves and then pulls nicely. Higer revs, everything fine.
I start to suspect maybe leaking valve(seat)?
Out of ideas.... :confused:

One more remark....when bike starts to misbehave and i pull over for couple of minutes, let the bike idle, and then start to ride again, it works okay for sometime and then starts to act up again.....so something over heats but what??? :confused:

Have you checked the fuel tank breather??? Might be partially blocked causing a vacuum in the tank!!

No issues with the breather :)

Hello,

I know these Issues actually from my 03 FSE.
Please check the valve clearance.
Ex is fine, even about 40k Kilometers after repair.
Can't measure both In-valves, cold 0, think they won't close when hot.

Valve clearance is in spec. Just week ago had valves and valve seats grinded/cut and seated. Tought the valves might be leaking when hot but no change.

That's fine!
Helps getting closer to the causing part.
The hardware (Motor) is as new,
Software trimmed,
Sensors etc checked,
seems no EFI/fuel/intake problem.
Ignition. Coil is new, so are HV-cable and Plug?
Maybe a brandnew weak spark plug?
Let's think: what else heats up while running: pump relais,
rectifier/regulator,...next step...

only in german:

from GG mounting instruction

Tried different spark plugs, still the same.
If relays would heat up, then the problem would be in whole rev range but my problem is only in the beginning....from idle to 3500-4000 rpm....after that its ok. But slipping clutch and holding revs so high in tricky stuff is pain in the a**.
I will try, at some point, to borrow a second injector....i checked my injector but in the test bench the injector doesn't get so hot...so maybe it's still the injector. Pretty much out of ideas....would like to get it running and then sell the bike :(

almost causing headaches...

Two more Oks.
You've already done a lot of good work, man.
Plenty new Parts, lots more checked,
Another injector-test helps.
Don't know much about injectors... thought, good spray or bad spray. Would be nice to let me know the results.
Still got suspicion on ignition.
Can there be a timing-problem when getting hot?
Thinking about the pick-up, heat issue, resistance to engine rpm.
Theory, too early timing (sparking) when hot causes rough run, but less affects at higher revs. Might it feel so?
Improbable, but there's an Info from GG about the flywheel, bent pin causes offset:
only german. Hope it helps.

I don't think it would be pickup coil....resistance seemd ok cold and hot....usually pickup coil works or not, at least i have fixed some engines with bad pickup coil, on those engines the pickup coil stopped working at all or when they got hot then also stopped but when cooled down started working again....haven't seen pickup coil that works ok on high revs and bad at low revs.
But i will double check.
The original injector got tested in the bench when cold and had very good spray pattern and flow rate was in spec.
It feels like the engine fuel mixture gets too lean when hot...when adjusting the CO trim with guzzidiag, it gets little bit better but the problem is still there.
Are you sure that the pickup coil data on your picture is correct? I have a different pickup coil than on your second picture....
I think they changed that in 2003-2004?
If i'm not wrong then the newer pickup coil resistance should be around 500 ohms. Maybe you can find data for newer pickup coil? It's okay if it's in german...have learned german a little bit in school :D

EDIT: One more thing, that could eliminate the pickup coil....when standing still and let it idle....it usually idles good. When trying to give throttle then theres 40:60 chance that it will rev okay or will sputter/die. So basically the sputter is really bad when there is load...so i would think theres something wrong with the fuel mixture (or timing). But why did that problem start just randomly in the middle of one ride.... :/

Hi mate, all the work you have done sounds reasonable. Just foraleft Reid view point, I am having a similar issue with mine. I was told to check coil etc. but tonight looking at the service report the mechanic has put an extra 400ml of oil in the sump for me. 1.6l instead of 1.2. You mentioned a rebuild, have you had a look to see that the oil isn't the cause?

Have made many oil changes after rebuild (i usually change oil after 10 hours).
Different oils, different amounts....

Okay, changed the pickup coil as some recommended. But still no change...about one hour of riding and starts to act up as always.
So at the moment I can think of only two things left:
1) Try some other injector (chinese injector was crap)
2) ECU (something shitty going on there maybe? Visually didn't see any cold solders...)

Hellllloooo....it's meeee agaaaain.
Okay...got used but working Ducati injector and things got little bit better.
First ride alone i had only few hickups but otherwise everything worked okay...i was happy at that point.
So today i went for a ride with friends and after few whoooops it started again....like misfire at low revsm slipping the clutch. At one point i just had to stop, it stalled. Started it again, fired up, little touch of throttle and stall again...and this continued many times, as soon i touched the throttle, it stalled.
So i started the bike WOT and got moving again. Worked decent for a while.
At some point it stalled again but not tooooo bad. So i rode the whole ride like this....somepoint works good, then again f**s my nerves.
Someone got matches? :)

Was looking at the ignition map and at 6000 rpm is the last value, is it running ok between 4 and 6000 rpm

EC 250 2001, FSE 450 2004

Bike runs great above idle...if i can hold the throttle up at least 3500-4000 rpm, then everything seems to run great. But riding tight forest trails and considering i don't have balls to ride with open throttle then the problems start. So rev range about 2000-3500.
Slipping the clutch a lot but even then i struggle....get the revs up,slip the clutch, clutch engages, revs drop a little bit too low and it starts to skip beats.
It's not like stalling because of the low revs...that's little bit different.

Anyone have any more suggestions?
Let's brainstorm.... :o
What are the chances that ECU is bad? (then it wouldn't work at hig revs also...?!)
Too tight valve clearence? At the moment they are in spec (closer to the min. value) but maybe loosen them a little bit?
Crankshaft/connecting rod bearing f***d again? Symtoms are similar before i replaced the crankshaft/cylinder/piston but started suddenly and appear only when hot.
Decompressor spring too weak, so it starts to open exhaust valves at low revs? What are the chances of that happening? Decopressor looks working when moving it with finger but MAYBE somehow at low revs engages. How to check that?
Anyting else....? :confused:

Does it matter what map you run?

EC 250 2001, FSE 450 2004

Very slight difference when running 2005 or 2007. With 2005 map the trouble starts a little bit quicker....gets hot quicker? But i'll have a try with 2006 map soon...

Check the charging coil, heat it up and see if it has affect on the resistance. My bike started to misbehave when one of the wire broke loose from the center of the coil.

EC 250 2001, FSE 450 2004

Just came from a ride and measured stator resistance and everything was ok.
Rode today with 2006 MAP and changed CO-trim while riding up/down from default value and not much difference.
I'll check tomorrow one thing that i think might misbehave...i'll let you know how it goes :)

So...little bit soon to cheer, i think, but i might have fixed my bike. I'll try to test one more time on wednesday, but yesterday the bike rode fantastic!
As you remember, then i have changed most of the parts already. One day i was out of ideas and took the original TPS apart.(not really meant to be opened.... ) Cleaned the tracks with alcohol and glued it back together. Put it in place and adjusted TPS.... And....i think that helped.
I dont know why bike didn't like the replacement TPS...measured with multimeter and all the values seemed more or less the same....
So yeah, it was nice to ride on forest trails and not worry about the bike....had forgotten already how the bike felt when all is working okay.
Will let you know if it really is fixed now :)

Yeah, seems that cleaning the TPS worked. Yesterday was also fun to ride without bike acting up :)

Congrats

Sent from my LG-D855 using Tapatalk

Please explain to the dummy - what is TPS? Are you talking about Throttle Position Sensor ?
I own GG EC 450, 2005 for a few month - when I've tested it before buying, everything went well...however, after few ridings it has started to misbehave - it is hard to start it, when hot. So maybe the problem is similar.

Thanks!

Hi,

Yes, TPS is Throttle Postition Sensor :)
Have you checked the valve clearance also?

Hi,

Thank you!!! No, I did not check yet. The bike started to act like I've said suddenly, so I firtsly think that the prolem can be of electrical nature. Also, after some reading in this forum I've found out, that many things can cause problems with starting, thus, I want to check what I can do by myself (check connections, etc.). BTW, could you possibly now: I've changed the spark plug to the new one (NGK CR8E) and after ~ 5 hour of riding I've foud out, that it is black. May this be a situation causing problems with starting? Should I install the new spark plug, like CR9E. As the manual says:

"To find the correct heat grade spark plug is being used, take it out
and examine the insulation around the electrode. If the ceramic is
light brown, the spark plug is correctly matched to engine temperature.
If the ceramic is white, the plug should be replaced with the next
coldest plug. If the ceramic is black, the plug should be replaced
with the next hottest plug."

Have you ridden the bike "good"....i mean, little bit more gas than idle :D
The plug gets black pretty easy when riding at idle speeds.
If you have used the throttle more then i would start checking other things...seems like running too rich.
TPS could be the issue BUT the injector can be also the problem!
I think my problem was caused by two things....worn/dirty TPS and injector.

Hi,

Thank you for reply. Well, I took the bike to the forest lately :D And when it is running, it "wants to go up on wheelie" on the 3rd gear. However, if for any reason engine shuts down, it is very difficult to start it again - it doesnt not start, later it fires, and if I open full throttle during starting process, it seems like starter stops its work (to be short: opening full throttle kills starting).
If I wait for a ~ minute, in mostly cases I can start the engine. Maybe it is normal for GG?
I remember having Yamaha XT660R - I could start it again after engine shutting down immediately during riding, even when I am still on the bike :)

Yeah, the hard starting sounds familiar :)
If you try to start, are you touching the throttle? If yes then DON'T!
There's two ways to start GG:
1) ignition ON, wait until the fuelpump primes and then hit the start button.
2) If after 2-3 tries no luck then: ignition on, fuel pump primes and then turn the throttle fully open and then hit the start button.
Moving the throttle during starting is NO-NO :)
Is your starter okay? I had also some problem when starter clutch was slipping....
But yeah, injector and TPS could be also issue :)

Thank you!

So, throttle should be opened beforing pushing starting button, if the bike failed to start in 2-3 times?

Yep, hold full throttle and then push the start button. Worked for me :)

Thank you again!!!

BTW, yesterday I've done compression test, and the reading was 0.5 Mpa (~ 72.5 psi or 5 bar). Do you know, whether is OK? I cannot find info about it.....

And I've found the info (in workshop manual):
The correct compression of a cylinder indicates that
the internal conditions are good. The decision to
inspect a cylinder is based on the results that we
obtain when measuring the cylinder compression.
Compression verification should be included in
concessionaire inspections.
DATA Compression:
Standard: 1000 Kpa (10.0 Kgf/cm2).

So the journey to find out the problem (valve clearance, pisto, rings, etc.) begins....

Did you measure the compression correctly? I mean cranked the engine until the pressure didn't rise anymore? Usually it helps to hold throttle fully open.
5bar is too low.

Yes, I did measurement with throttle fully open. And there may be two things:
1. My measurement instrumet is too old/faulty, or
2. Compression is too low, which is very possible, as I have problems with starting.
I've found somebody that repais GG in Lithuania, so, I'll take the bike to them to do the valve clearance checking.

If you need any parts then contact with Antonio at Motocrosscenter. If i remember correctly then you can get piston from W?ssner but other parts are hard to find. I got good deal from Antonio...original piston/cylinder etc.
Let's hope you need only piston change :)

Try and squirt some engine oil in from spark plug hole. If the reading then jumps up to normal or even more, then you have a worn engine. Also, you can test your pressure gauge against some other manometer (tire for ex).

Hi,

Thank you for the advice, I'll try things you've suggested :)