30mpg Curvy.

[EssexDave]

I have a curvy SV and it's only returning about 30-35mpg currently.

I'm not particularly riding it hard and compared to previous SVs I would be expecting at least 45mpg.

I've replaced the carbs and checked them - all seems okay.

It appears that no fuel is leaking, at least not significant enough amounts to cause such a drop in mpg, but there is quite a smell of fuel.

The chokes do not appear to be sticking.

The bike runs fine - but, the last time I took a plug out the rear cylinder was running quite rich and the front was fine.

I've not yet checked the fuel tap to see if that is leaking - but anybody have any other ideas?

Last tank the light came on 96 miles and I filled up at 120 miles and put it 15 litres.

[Dicky Ticker]

With the amount of black soot on your exhaust they are running far to rich.As you are going to Scotland on Friday it would be worth getting them set up by a specialist or somebody who really knows what they are doing,not just the balance but the mixture--------------IS THE AIR FILTER CLEAN? basic question but this can contribute to bad fuel consumption.
The difference between 30mpg and 45mpg on a 1800mile trip is about £120 so it might be worth the expense as you would save money in the long run.

120miles for 15lts is 36.4 mpg.

[NTECUK]

Carb strip and clean time.
Check your running right jets,float hights for your mods ,and the float valves not leaking

[EssexDave]

C'mon DT don't get your knickers in a twist! I know it's not long!

Air filter is clean and it was only the rear plug that was black, the front looked pretty spot on.

[dizzyblonde]

Revs too high?

Check the boot the carbs sit on for splits. Big rubber circle things that sit on top of the engine under the carbs, have a big jubilee clip round them

IIRC, I had one of those go on me once, its hard to find a split, but 'I think' I remember having stinky fuel out the exhaust.

[EssexDave]

The smell comes from under the tank more than the rear end.

It's not reving to high either, idle is about 1,250-1,350rpm

[jambo]

The last time I saw thins the choke plunger on one carb wasn't moving cleanly, or the choke Y piece was sticking I think, leading to one plunger sticking on.

I know you say they're not sticking though.

[yorkie_chris]

Carbs balanced?

[EssexDave]

Carbs were balanced about a month ago.

[Sid Squid]

Curvy+smell of fuel may = tank filler well drain rusted.

This is a long shot as far as your fuel consumption goes, so I'd start with the above mentioned, particularly the choke as the rear cylinder has a sooty plug.

[NTECUK]

Front plug ok. Back black .
What parts a shared so you can discount it to start with.
I think you can concentrate on the rear for the moment

[andrewsmith]

Curvy+smell of fuel may = tank filler well drain rusted.

This is a long shot as far as your fuel consumption goes, so I'd start with the above mentioned, particularly the choke as the rear cylinder has a sooty plug.

I'd agree with that. Also get the carb bowls off and have a look, if it looks like this it would explain the poor running

http://a2.sphotos.ak.fbcdn.net/hphotos-ak-snc7/p480x480/378767_635449045628_276700376_4470658_1546025928_n .jpg

[Dipper]

Update, I've been helping Dave with this, we lubed the choke cable (although they appeared to be working OK before), removed the rear choke plunger replaced the O-ring and cleaned up the seating in the carb, there was a considerable amount of sandy coloured rust/dirt. Refitted the plunger and airbox making sure the airbox seals were on properly. Dave's now getting 45 to 50 mpg.:-D

[EssexDave]

Different kind of riding though, may have been a bit more gentle with the right hand which may mean it's me :( Still convinced it should be doing more but a 2,000 mile trip to scotland and back should tell me pretty quickly!