first yamaha plz help!

[oldskool153]

Ok so i just bought my first yamaha 2 weeks ago and it would run great at idle and on the highway BUT at random intervals when i would come to a stop and go to take off it would sputter and bog so badly that i culd have the throttle wide open and it would be running at 1500rpm and puffing black smoke for a good 3 mintues than it evens out and runs great again..I took the tank off and noticed that it was the orignal filter from 94! so i changed it and put fresh gas in with some carb cleaner and it seems to be getting better but I still randomly get bogging down and loss of power when i go to leave from a stop. I have noticed that almost everytime if I pull the clutch in and start giving it throttle b4 I take off is when it starts to bogg and flood...BUT if i let the clutch out until it starts moving and than I give it gas its fine every time...Thats how i have been riding but something is obviously wrong because I shouldnt have to let the clutch engage to be able to give it throttle without it bogging down.. so my question is...carbs,plugs,clutch adjustment,exup valve??? I can hear my exup valve rattle at idle than when it hits around 2000rpm the rattle goes away, culd that valve being out of adjustment be to blame?

[ragedigital]

so my question is...carbs,plugs,clutch adjustment,exup valve???

YES.

It could very well be all or most of those. Anytime you buy a new bike, your best bet is to go through every fluid change and adjustment available on the bike.

I suggest tearing down the carbs and cleaning them really well. Don't modify them in any way, just clean them really well.

Change the plugs - gap them correctly.

Pull the EXUP valve and clean all internal parts.

Adjust your clutch as per the manual.

[yamaha_george]

so my question is...carbs,plugs,clutch adjustment,exup valve???

YES.

It could very well be all or most of those. Anytime you buy a new bike, your best bet is to go through every fluid change and adjustment available on the bike.

I suggest tearing down the carbs and cleaning them really well. Don't modify them in any way, just clean them really well.

Change the plugs - gap them correctly.

Pull the EXUP valve and clean all internal parts.

Adjust your clutch as per the manual.

+4 on that it would have been a +5 but yer forget the worst bit about FZR's the Voltage regulator !!!!!!!!!!!!!!!

Take a look on the left side (sitting) under the seat side panel, the VR sits there if it has fins on it great if it is a tin can full of rubber compound for GOD's sake change it can destroy your electrics on the bike and NO I do not over emphasize

[ragedigital]

George - I wasn't sure what VR the 1ks have. Do they have the same poorly designed ones?

[sweekster]

The EXUP 1000's have alternators and no external vr. They have a hydraulic clutch-no adjustments other than rebleeding (ask me how I know ). From what I can tell this bike just needs a good going over. I'd put in new plugs (that is an ordeal in itself and they require an 18mm socket),replace the fuel filter, run a bit of carb cleaner and/or Seafoam through it and pull out the exup valve and regrease everything along with adjusting the exup cables. I'd synch the carbs as well. After doing all that you should be fine.

[mossy1200]

+5 exup valves.Could be stuck open.Remove the exup valve cover and the rotating plate should do a reset cycle when ignition turned on.
After this there is a slot edge at bike front of the plate that should line up with a hole is the casting behind.When you rev the bike the plate will rotate then return when bike idles.If you turn the servo fully open by hand before you turn on ignition the plate will rotate back to its normal position.

[DonTZ125]

This sent me off on a bit of digging. It would seem the big FZRs (and FJs) use internal VRs, inside the alternator housing, vs the external VRs used on the vast majority of bikes. Ron Ayers sells one for US$261, should yours lose its magic smoke.

Sweekster - just being pedantic here, but all of our bikes have alternators. The little bikes have the simple permanent magnet version with a 'dump the excess' VR; looking at the parts fiches, I'd be willing to bet a beer or two the big bikes in question are using automotive-style alternators, where the VR is controls the voltage output by actually varying the strength of the (powered) electromagnetic field by modulating the current flow through the exciter coils. This VR is more robust than the type on the smaller bikes, but the advantage of the PM alternator is it can be bump-started with an absolutely flat battery. With no battery power to excite the VR coils, the powered alternator has no mag field, thus no juice. Of course, not many people are going to be bump-starting a fully-loaded Fj1200 touring barge...

[sweekster]

Sweekster - just being pedantic here, but all of our bikes have alternators. The little bikes have the simple permanent magnet version with a 'dump the excess' VR; looking at the parts fiches, I'd be willing to bet a beer or two the big bikes in question are using automotive-style alternators, where the VR is controls the voltage output by actually varying the strength of the (powered) electromagnetic field by modulating the current flow through the exciter coils. This VR is more robust than the type on the smaller bikes, but the advantage of the PM alternator is it can be bump-started with an absolutely flat battery. With no battery power to excite the VR coils, the powered alternator has no mag field, thus no juice. Of course, not many people are going to be bump-starting a fully-loaded Fj1200 touring barge...

Well yeah that's why I said external VR. And it's an automotive style alternator like you said...

[oldskool153]

so i should do what 1st? fuel filter has already been changed..now what?

[sweekster]

so i should do what 1st? fuel filter has already been changed..now what?

I'd do the exup valve, change the sparks

[oldskool153]

thanks, i called my local yamaha dealer and they are telling me to leave it open...something seems fishy about that to me

[DonTZ125]

Pinning / wiring the EXUP open should solve your bottom end, but you'll lose serious top end. A fellow here recently had a stuck (down) EXUP on his FZR250R; it wouldn't rev past 10k - on a bike with an 18,500 rpm redline!

http://www.cartestsoftware.com/fz1/exupmaintenance.html - one of the best EXUP pages around.