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lorenzo
Joined: 20 Aug 2018 Posts: 35
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Posted: Mon Aug 20, 2018 11:23 am Post subject: SB6R, question |
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guys good morning to everybody.
my name is lorenzo, writing from Italy.
sorry for my bad english..i'm italian, driving on the ...wrong side!!
anyway i have three motorbike BMW K 1200GT, RGV 250 gamma, and....bimota SB6R.
the bike is old 1998, but only 1493 km are on the cockpit !
now in general motorbike is ok the only problem is the following:
- i clean all bike, changed oil, oil filter....and air filter
- i bought a new filter apparently a good one, double side (one is with big structure and the second is much more fine)
- and now i'll explain you the problem.
installing the new filter the engine is not rising well, at 3000 rpm i'll get an huge hole ...
but if i'm putting a small piece of cotton (tshirt) on the foam's filter the engine is perfect.
it is clear that probably the filter is to much ...open !!
my question is ...the engine is really so sensible at air filter ?
i can change the filter ...but before to do that i would like to get your comments.
thank you to welcome me in this forum !!!
th |
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Jonny B Bad
Joined: 05 Dec 2009 Posts: 555 Location: NE London
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Posted: Mon Aug 20, 2018 12:20 pm Post subject: SB6R |
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Lorenzo welcome.
First thing, is the new foam filter oiled? If it is dry, it may be flowing too much air.
However, more likely is that the bike is not getting enough fuel, rather than too much air. The most likely cause of this is the fuel pump in the air box, if it has not been removed by a previous owner. If it is still there, you should remove it, as the bike works perfectly well on gravity.
With so few kilometers, the bike has clearly stood for long periods of time - this could have resulted in dirty carburettors. If it has had ethanol blend petrol in, this could have resulted in degradation of the lining of the fuel tank, which will have resulted in a grey paste blocking some of the jettings downstream of the throttle butterfly.
I would start with removing the fuel pump and then take the carbs off for a look/clean.
Good luck & let us know how you get on. _________________ What, Jonny's gone! |
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Jonny B Bad
Joined: 05 Dec 2009 Posts: 555 Location: NE London
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Posted: Mon Aug 20, 2018 12:24 pm Post subject: SB6R |
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Sorry, should have said that the fuel pump is usually guilty of providing too much fuel rather than too little, but if it has stopped working altogether (works off engine vacuum) it will be impeding flow of fuel. _________________ What, Jonny's gone! |
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lorenzo
Joined: 20 Aug 2018 Posts: 35
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Posted: Mon Aug 20, 2018 1:32 pm Post subject: |
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hi Johnny !!!
wow interesting proposal
concerning the carburettors...when i bought the bike there was red gasoline in side (lucky me) and the carburettors were clean
in any case i took out them and cleaned it very well looking at all specifications reported in the maintenance manual.
i'll follow your recommendation taking out the vacuum pump.
btw the filter was oiled before installation
i'll keep you posted |
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lorenzo
Joined: 20 Aug 2018 Posts: 35
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Posted: Mon Aug 20, 2018 1:54 pm Post subject: |
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ciao again
in case i need to clean again carburettors ...which is the best solvent to do the job ?
or only mechanical cleaning ?
th |
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Jonny B Bad
Joined: 05 Dec 2009 Posts: 555 Location: NE London
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Posted: Mon Aug 20, 2018 2:35 pm Post subject: SB6R |
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You can buy contact cleaner, but really the answer is to have them ultrasonically cleaned. However, if the bike has a good steady idle, they probably don't need cleaning, as the idle jet is the smallest and if that isn't blocked, the rest are probably ok. _________________ What, Jonny's gone! |
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SuziEngine2
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Joined: 24 Jul 2018 Posts: 15
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Posted: Mon Aug 20, 2018 4:07 pm Post subject: Re: SB6R |
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Jonny B Bad wrote: |
You can buy contact cleaner, but really the answer is to have them ultrasonically cleaned. However, if the bike has a good steady idle, they probably don't need cleaning, as the idle jet is the smallest and if that isn't blocked, the rest are probably ok. |
When I had to get my carbs cleaned it would idle fine but respond to throttle very badly between idle and 6000 rpm. Twisting the throttle killed the engine when still cold, warm it would cough and splutter all the way up to 6000rpm and then go like a rocket.
I keep reading about that vacuum powered pump. The one on my SB6R is electric. It runs for a second or so when the ignition is switched on and I assume it is running when/after the engine is started. AFAIK the electric pump is standard factory. Maybe the vacuum one is SB6?
The fuel cock is vacuum driven, but that's a different component.
Unfortunately, the workshop manual shows both the pump and the cock (Fig. 01-9), but does not discuss the pump anywhere. It discusses the fuel cock briefly and then switches to the carburettors. _________________ 1998 Bimota SB6R
1982 Suzuki GS1100SZ Katana |
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Jonny B Bad
Joined: 05 Dec 2009 Posts: 555 Location: NE London
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Posted: Mon Aug 20, 2018 4:58 pm Post subject: SB6R |
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I've seen quite a few 6Rs and they all started life with a vacuum pump and an electric fuel cock. I guess some 6R owners will have replaced the original iffy vacuum pump with an electric one. _________________ What, Jonny's gone! |
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Jonny B Bad
Joined: 05 Dec 2009 Posts: 555 Location: NE London
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Posted: Mon Aug 20, 2018 4:58 pm Post subject: SB6R |
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I've seen quite a few 6Rs and they all started life with a vacuum pump and an electric fuel cock. I guess some 6R owners will have replaced the original iffy vacuum pump with an electric one. _________________ What, Jonny's gone! |
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brian
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Joined: 22 Aug 2011 Posts: 3770 Location: Australia
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Posted: Mon Aug 20, 2018 5:10 pm Post subject: |
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SB6 never had a fuel pump (vacuum or electric) from factory. Only the 6R had a pump _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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Evilchicken0
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Joined: 12 May 2010 Posts: 2996 Location: London
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Posted: Mon Aug 20, 2018 5:15 pm Post subject: Re: SB6R |
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SuziEngine2 wrote: |
When I had to get my carbs cleaned it would idle fine but respond to throttle very badly between idle and 6000 rpm. Twisting the throttle killed the engine when still cold, warm it would cough and splutter all the way up to 6000rpm and then go like a rocket.
I keep reading about that vacuum powered pump. The one on my SB6R is electric. It runs for a second or so when the ignition is switched on and I assume it is running when/after the engine is started. AFAIK the electric pump is standard factory. Maybe the vacuum one is SB6?
The fuel cock is vacuum driven, but that's a different component.
Unfortunately, the workshop manual shows both the pump and the cock (Fig. 01-9), but does not discuss the pump anywhere. It discusses the fuel cock briefly and then switches to the carburettors. |
Up to 6k revs would suggest the idle jets. _________________ Don't read everything you believe |
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Evilchicken0
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Joined: 12 May 2010 Posts: 2996 Location: London
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Posted: Mon Aug 20, 2018 5:17 pm Post subject: Re: SB6R, question |
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lorenzo wrote: |
guys good morning to everybody.
my name is lorenzo, writing from Italy.
sorry for my bad english..i'm italian, driving on the ...wrong side!!
anyway i have three motorbike BMW K 1200GT, RGV 250 gamma, and....bimota SB6R.
the bike is old 1998, but only 1493 km are on the cockpit !
now in general motorbike is ok the only problem is the following:
- i clean all bike, changed oil, oil filter....and air filter
- i bought a new filter apparently a good one, double side (one is with big structure and the second is much more fine)
- and now i'll explain you the problem.
installing the new filter the engine is not rising well, at 3000 rpm i'll get an huge hole ...
but if i'm putting a small piece of cotton (tshirt) on the foam's filter the engine is perfect.
it is clear that probably the filter is to much ...open !!
my question is ...the engine is really so sensible at air filter ?
i can change the filter ...but before to do that i would like to get your comments.
thank you to welcome me in this forum !!!
th |
This is a flat filter that has been adapted to fit the standard airbox ? It sounds like you need to have the bike set up - take it to a Dyno Tune _________________ Don't read everything you believe |
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lorenzo
Joined: 20 Aug 2018 Posts: 35
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Posted: Mon Aug 20, 2018 7:04 pm Post subject: |
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thank you guys
appreciated all comments
i have SB6R, but tomorrow i'll try to taking out the pump and go with gravity
i'll let you know !!!
th |
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lorenzo
Joined: 20 Aug 2018 Posts: 35
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Posted: Tue Aug 21, 2018 2:58 pm Post subject: |
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guys quick update.
this morning i removed vacuum pump and ok, a little bit of work to be done but ok.
concerning my problem...no differences.
i remove the portion of textile in the filter and again same trouble around 4000 rpm.
later on i try to move the position of the setger in the needle (position 3 or 1 or 2) but every time same huge flession around 4000/5000 rpm like the engine is without gasoline !!
now i back again at original position (3) and there is a small hole around 4500 rpm but not bad.
maybe this winter i'll try to clean deeply the carburetors
th |
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Evilchicken0
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Joined: 12 May 2010 Posts: 2996 Location: London
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Posted: Tue Aug 21, 2018 10:16 pm Post subject: |
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Take it to a dyno and it tuned _________________ Don't read everything you believe |
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