Intermittent but repeatable issue 03 - SV650n

[sonofabrit]

Hi All,
Thanks for taking the time to read this first of all. So, my bike has had an issue over the last year and a bit and I am lost on where to go to fix it.

Background. I work 4 days on 4 days off and my bike (03 SV650 - 40K miles) is used for the ~70 mile round trip. 4 miles City riding the rest motorway.

On a normal set of shifts my bike is absolutely fine, no issues starting, idling, city riding and motorway riding.

However, if I take a set of shifts off for holiday and my bike sits for those 4 days I would be in work (12 days in total) the first day back in work I have issues with the bike stalling on the initial 2 miles riding in the City to get to the Motorway.

During this first day, starting the bike is fine, once it gets up to temperature and starts to drop its idle speed the revs chugs up and down as if its starving fuel or something; it will stall unless I keep the revs up to 2-3k when coming to a stop and whilst idle at traffic lights. Once I start riding it can chug a little but generally once I am up to speed 30-40 MPH its fine.

Once I have done my motorway trip, I have another mile or two of city riding and the bike is fine, idles fine at traffic (~12-1300RPM) and when coming to a stop doesn't feel like its going to cut out. The remaining 3 days of my shift are fine as well, starting the bike, drop in idle revs once up to temp as well the first 2 miles of city riding all OK. Its only the first day of shifts, after a holiday I have this issue.

I have done so far, oil and filter changes (normal schedule anyway), new spark plugs - added dielectric grease as read about the front spark plug having water ingress issues (have an extended fender as well), completed throttle body sync and tps adjustment. Checked and cleaned fuel filter (all fine).

I am at a loss at what could cause this intermittent, but repeatable issue.

HELP PLEASE.

Thanks

[Craig380]

Hi, it sounds like your idle speed might be just a hair low - I believe it should be 1,300rpm. Try tweaking it up a fraction to 1,300 - 1,350rpm. Also, is the airfilter relatively new and clean?

Depending on when the bike last had a valve clearance check, that might be worth doing too. Although a tight clearance would generally mean poor starting, especially when cold.

[Biker Biggles]

You dont say where you are.Could water in the fuel be a problem?Could there be condensation forming over the "days off" which is enough to cause a slight issue but clears with use?

[Bibio]

does the bike have an alarm?

[sonofabrit]

thanks for the replies. Had a valve clearance check when I did the Tb sync and tps adjustment all were within spec thankfully. I will adjust the idle up a bit.

I am up in Preston. So it does get a bit rainy up here. The bike is kept under an Oxford cover when I come home, but have read things about water in lines. So may need to explore it, however the last week was cracking flags weather when I had my last holiday and had the same issues.

Bike doesn't have an alarm.

The other idea I was bouncing off a mate is my slip on exhaust. It has a tiny hairline break up the side of it. Where the hanger holds it to the pillion foot peg. I wouldn't have thought this would make a difference though?

[Bibio]

exhaust leaks will just cause more popping on overrun.

you dont get water in lines as the fuel is under pressure, if you had water in the tank it would manifest itself every ride. to combat water in the tank just get some Wynns dry fuel and pop half the bottle in.

how well does the bike crank over after an extended break?

when adjusting the idle remember to turn the throttle a little each time.

another fault thats not common is the injectors clogging but again that would manifest every ride.

[sonofabrit]

Forgot to say air filter was replaced in January. It's clean

[fizzwheel]

Moved to SV Talk

[sonofabrit]

Thanks bibio for clarifying. Engine turns over pretty well after the break. Doesn't have troubles starting only after it reaches 30-50 degrees is when the initial chugging/stuttering/blips in revs happen. At this point Im on the bike keeping it from dieing holding the revs up and as above during my starting commute in the city. Once off motorway all back to normal. I've read some threads on potential faulty coil/spark plug boots so I'll measure them on my next set off but would be surprised if it was them the fault would be more regular?

[Bibio]

stick the bike into dealer mode and see if there are any codes.