Exhaust smoking and low fuel efficiency. Pointy.

Hi everyone. This is a bit of a long term problem for me.

When I bought the bike in Jan 2014, I was getting about a 95-100 miles before the fuel light came on. I currently get 75-80 miles before the light comes on. This may be due to riding the bike harder than when I first acquired it. (It was my first BIG bike)

At the beginning of autumn, it started to cut out at traffic lights and when it was cold started. Sometimes 4,5,6 times in an hours journey. Being highly concerned, I went to my local bike shop. (very good guys, trustworthy) They asked if I had been doing lots of slow city riding and not giving it a good thrashing once in a while. This was the case. So one of them took it for a thrash around the block and handed it back to me. It was instantly better. "You need to rev it up to the line through the gears to keep the plugs clean occasionally if you're riding slow in the city a lot" was the advice. So that evening, I went for ride as did as instructed. It did make the bike run better but it still wasn't as sweet as I remembered. It was due for a service, and I laughed at how bad the air filter looked when I removed it! So, one oil+filter and air filter change later, relatively, it runs like butter now and the exhaust note is smooth-er.

BUT I am still getting the occasional cut out!??! The plugs are NGK iridium. I took a look at them; they had some carbon around the rim but the, "pin and collar" were clean and chrome looking. They were new in when I got the bike, so 5000 miles is nothing, right? The bike still emits a lot of unburnt fuel through the exhaust when cold starting. I can't provide info when I am riding for obvious reasons. When I have the bike on side stand, and crank the throttle, a lot of light grey / water vapour like smoke emits from the exhaust. I DO have a shotgun exhaust which I am told makes SV's and any bike run poorly.

Do I need to be concerned? My bike bloke said, "you have a good SV there, it pulls nicely" and that was before the service and when it was cutting out. I'm a bit lost and a relative newbie to bike, so any help would be much appreciated. I am thinking to part-ex the bike and get rid of it before something major goes and it becomes not worth keeping a bike of sub 2K value on the road.

Thanks in advance for all replies.

[Bibio]

plug looks a bit rich and the vapour out the exhaust is normal. i would guess that your commute is a short one and the water vapour is collecting in the exhaust (water vapour is a by product of the combustion process) and not getting burnt off due to the exhaust system not getting hot enough.

it would help if you can tell us what the bike revs are when it's ticking over when up to full temp (76-86c).

my guess is that its stalling due to the tick over being a bit low, i have found this the case on a few early pointy's.

have the throttle bodies ever been balanced?

That's very poor fuel economy. Are those plugs the correct heat range for the bike? Or did the previous owner install hotter plugs to try to mask an over rich mixture? If it does anything, your muffler will make the bike run a bit lean, not rich.
Properly operating fuel injection will provide the proper mixture at all throttle settings, there should never be any need to rev up the engine to "clean off the plugs" which in any case clean themselves off very quickly whenever they are subjected to a proper fuel air mixture, whether it's at idle, part throttle or full throttle.
As you might guess, I suspect your engine is being provided with over rich mixtures. Why, I don't know, but it isn't your muffler. A dirty air filter would make it worse, but it doesn't sound like a clean one has cured it.
If you had carburetors, everybody would tell you to check to see if the enrichment circuits (choke) were stuck on.

Originally Posted by Bibio

plug looks a bit rich and the vapour out the exhaust is normal. i would guess that your commute is a short one and the water vapour is collecting in the exhaust (water vapour is a by product of the combustion process) and not getting burnt off due to the exhaust system not getting hot enough.

it would help if you can tell us what the bike revs are when it's ticking over when up to full temp (76-86c).

my guess is that its stalling due to the tick over being a bit low, i have found this the case on a few early pointy's.

have the throttle bodies ever been balanced?

Hi Bibio.

Cold idle revs are 1000 rpm after it settles when started. Lately it has been fluctuating a little and dropping to 950 rpm, then back up to 1000 rpm.

Hot idle revs are the same I believe, 1000 rpm. I will confirm that after my next ride, most likely today.

Incidentally, my oil temp reaches 88-89*C at times, riding hard, inner city / summer, but it does have a slight dent in one side of the radiator, present when I bought it.

My bike shop bloke told me to flick the throttle a little before engaging the clutch to clear the cylinders before setting of from standing as this is a known issue for SV's and V-twins in general. This does help.

I don't know if the throttle bodies have been balanced. I'm not aware of anything in the limited service history. My ride distances can vary from 2-30 miles depending on circumstances.

Originally Posted by wideguy

That's very poor fuel economy. Are those plugs the correct heat range for the bike? Or did the previous owner install hotter plugs to try to mask an over rich mixture? If it does anything, your muffler will make the bike run a bit lean, not rich.
Properly operating fuel injection will provide the proper mixture at all throttle settings, there should never be any need to rev up the engine to "clean off the plugs" which in any case clean themselves off very quickly whenever they are subjected to a proper fuel air mixture, whether it's at idle, part throttle or full throttle.
As you might guess, I suspect your engine is being provided with over rich mixtures. Why, I don't know, but it isn't your muffler. A dirty air filter would make it worse, but it doesn't sound like a clean one has cured it.
If you had carburetors, everybody would tell you to check to see if the enrichment circuits (choke) were stuck on.

Hi Wideguy.

I part-ex'd me Varadero 125 in with cash at an independent dealer in East London. He put the new sparks, filter and oil in prior to me taking the bike. As for the integrity of the father and son shop, I can not say, but I have heard reasonably good feedback when I mention their name and they have been operating for decades.

[ophic]

Tickover sounds too low. Should be 1300ish according to my bad recollection of what's in the manual.

Mine runs nearer 1500 when warm in order to prevent stalling and rough idling when cold, but I'm pretty sure my throttles need balancing.

I've got almost 40,000 miles on my K3 and I don't have to do anything special for it to run right. It spent all summer tootling around London, barely getting revs over 5000rpm, and it still appears fine.

Originally Posted by ophic

Tickover sounds too low. Should be 1300ish according to my bad recollection of what's in the manual.

Mine runs nearer 1500 when warm in order to prevent stalling and rough idling when cold, but I'm pretty sure my throttles need balancing.

I've got almost 40,000 miles on my K3 and I don't have to do anything special for it to run right. It spent all summer tootling around London, barely getting revs over 5000rpm, and it still appears fine.

I thought the idle was a bit low, but I am sure someone told me it was ok, so as a newbie, I believed them.

I have the Haynes manual, so I will take a look today. Is it easy to change? When I was doing the service, I think I saw there is a simple Phillips plastic screw that adjusts the idle? (on the left, front and just below the seat) The same as on my carb'd Vara.

My bike has 28,500 on it.

Yes idle screw can be seen through the triangles in the frame (left side), adjust it then blip the throttle to see how she responds, I'm unsure which way to turn it sorry, experiment with it!

It will be heaps better after you raise the idle, fuel economy is still a worry though:/

Originally Posted by Corny Gizmo

Yes idle screw can be seen through the triangles in the frame (left side), adjust it then blip the throttle to see how she responds, I'm unsure which way to turn it sorry, experiment with it!

It will be heaps better after you raise the idle, fuel economy is still a worry though:/

I will adjust the idle today and feedback the results.

The BIG question here is what to do about the fuel economy?! My bike shop seems to think the bike is fine, from the limited time they have spent hands on with it, but even though I'm a newbie, know something is not quite right. I don't think it's catastrophic because when it's on the go, it rides nicely.

Ho-humm

[LewSpeight]

Screw in / clockwise raises idle on the idle screw