Curvy SV running poorly.
 

Hi Gents. New here, have popped in to try to get some help with an issue, hopefully someone here will have some similar experience. Don't have an SV myself, but recommended them to my teenage sons - so have two in the garage. Both low mile, excellent condition curvies.

The later bike is a 2001, with only 5000 miles on the clock. Only mod from standard is a race collector and a loud can. The bike has run fine since we purchased it last year; last Saturday my son came home saying it wasn't running right. At the time it appeared that the front pot wasn't running. Previous time he was out he got caught in a downpour and put it away wet!

So far I have:

Changed the plugs with new.
Dried out the front plug hole.
Checked spark outside engine, sparking fine.
Swapped coil, wire and cap on front cylinder with another from spares pile (we're now on 3rd and 4th SV's following a write off and a seizure of two less wonderful bikes).
Checked the float bowl and needle/seat in the front carb. Spotless inside.
Fueling doesn't seem to be the problem... putting hand over running inlet generates similar amounts of vapour at both pots.

After all that the bike is running, starts easily (always has) and idles, both headers are hot, so firing on two at least some of the time. However it still won't pick up revs, feeling maybe as if the ignition is not advancing - the higher the revs get, the rougher it runs. It seems consistent even with no load on engine, so again I suspect not fuel starvation.

What else should I be checking/changing? Pickups, CDI?

Any thoughts would be appreciated!

Re: SV running issues
 

Checked the vacuum operated fuel tap and pump? Lift the tank, and the pump is on the right hand frame rail, right next to the carbs. Spin the engine over and make sure you're getting enough fuel to and from the pump. I wouldn't be suspecting ignition at this point.

Re: Curvy SV running poorly.
 

Choke plungers?Air leaKs?Are all the hoses and breathers still attatched?Water in petrol?
There is also the blocked air intake Has the manky old bit of padding under the tank fallen down across the air filter?

Re: Curvy SV running poorly.
 

Thanks for the replies. I haven't checked the fuel system specifically, but there doesn't seem to be any lack of fuel at the carbs. Choke plungers (and the rest of the carbs) are spotless. All hoses and breathers seem to be together and in good nick. As I said before this is a 5000 mile bike. (I accept also 13 years old!).

The other reason I don't think it's fuel shortage is that spraying quick start into the running inlets doesn't seem to improve anything... OK, I realise it's haphazard diagnosis, but the effect is usually quite noticeable!

Re: Curvy SV running poorly.
 

Thought I'd finish this thread off in case anyone else has the same issue.

The problem was simple... front plug and cap corroded and full of water as many threads on here. I'd already fixed it when I wrote the original post. The problem was that I was running it with the airbox off and the mix was so lean it wouldn't rev cleanly. Popping the airbox back on had it running perfectly!

Makes me think I should probably up the mains to cater for the race exhaust!