SP4 not revving

beancounter · 07-Sep-2006, 14:49

Out for a bimble on the SP4 today, everything fine and dandy except that the bike wouldn't rev beyond about 8500 rpm. No other problems, no funny noises, water temp absolutely fine at 70-75 deg.

Anyone got any ideas?

Thanks

BC

keefer · 07-Sep-2006, 14:51

fuel filter ?
blocked breather ?

philthy · 07-Sep-2006, 15:02

Try twisting the throttle a bit more?

beancounter · 07-Sep-2006, 15:23

Quote:

Originally Posted by keefer

fuel filter ?
blocked breather ?

Interesting - why would a blocked fuel breather prevent the bike from revving?

I have to take care not to overfill the tank with fuel as it occasionally seeps out of the filler cap, so there may be a problem with the breather.

Fordie · 07-Sep-2006, 15:28

If the tank is not open to atmosperics and the pump is running it could cause the tank to partially vacuum. stopping the fuel from going to the fuel lines 4D

twpd · 07-Sep-2006, 20:04

I concur with the fuel filter theory. IME a blocked breather is more likely to cause the engine to stop or splutter as it simply eventually fails to get any fuel due to the vacuum that builds in the tank.

bitchinSP4 · 07-Sep-2006, 22:55

I had something similer happen to mine, it just would not rev. I was high up in the Alps at the time. Stoped for fuel a loud hiss as I opened the cap after that It was much better. After that I left the breather off. No probs.

Jools · 07-Sep-2006, 22:58

On a T8 the breather valve is in the pipe that comes out of the top of the tank...it's just a push fit so it would be easy to put it on frack to bunt.

Just a thought...

From the bloke who still hasn't sussed his spluttery ST

MJS · 08-Sep-2006, 07:25

It's probably just getting a bit old... time to get a new one... I'll take that one off your hands for a nominal fee

Cheers
Martin

pguenet · 10-Sep-2006, 00:58

If the problem goes worse and worse, you may want to change the rubber hoses in the tank. I had that happening to me once on a 916, took a month to diagnose the problem. There was a tiny split in one of the hoses in the tank. I would leak fuel back in the tank. Result, not enough pressure in the injectors and fuel starvation as soon as I was opening the throttle.
p

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07-Sep-2006, 14:51	#2
keefer Registered Forum User Ducati Meccanica Posts: 2,518 Join Date: Jul 2004 Location: hants Mood: Found a CR250. Let the bone braking begin fuel filter ? blocked breather ? Reply

07-Sep-2006, 15:02	#3
philthy Registered Forum User Big Twin Posts: 1,028 Join Date: Jun 2005 Location: Wirral Mood: Can't make me mind up Just an idea Try twisting the throttle a bit more? Reply

07-Sep-2006, 15:28	#5
Fordie Regional Organiser - BHCN Ducati Corse Posts: 3,276 Join Date: Aug 2001 Location: Dunstable Beds Mood: Raring to Ride If the tank is not open to atmosperics and the pump is running it could cause the tank to partially vacuum. stopping the fuel from going to the fuel lines 4D Reply

07-Sep-2006, 20:04	#6
twpd Deceased 02/10/2010 - R.I.P. Ducati Corse Posts: 3,170 Join Date: Feb 2002 Location: Darlington, Co. Durham Mood: NGRRC Minitwins champion 2007 I concur with the fuel filter theory. IME a blocked breather is more likely to cause the engine to stop or splutter as it simply eventually fails to get any fuel due to the vacuum that builds in the tank. Reply

07-Sep-2006, 22:55	#7
bitchinSP4 Registered Forum User Montjuic Posts: 55 Join Date: May 2005 Location: bournemouth I had something similer happen to mine, it just would not rev. I was high up in the Alps at the time. Stoped for fuel a loud hiss as I opened the cap after that It was much better. After that I left the breather off. No probs. Reply

08-Sep-2006, 07:25	#9
MJS DSC Membership Sec. & BHCN R.O. Webteam Big Twin Bikes: None at the moment Posts: 1,948 Join Date: Jul 2003 Location: Pitstone Mood: Feeling old... It's probably just getting a bit old... time to get a new one... I'll take that one off your hands for a nominal fee Cheers Martin https://www.justgiving.com/MJSisley Reply