Burning smell at full throttle and engine knock

[Bigleo]

mileage

Hi, most of my driving is on the highway, usually at about 80 mph, with no fairing, so lots of wind drag. So the engine is under a pretty good load most of the time. I don't think the vacuum advance would have been active under these conditions anyway. So, no I haven't noticed any decrease in gas mileage. As far as top end goes, nothing really noticeable there, except maybe a bit more top end power. I look at it this way, at wide open throttle there is not a lot of vacuum anyway, so the vacuum advance is probably not doing much of anything anyhow. So with the initial timing set at 10 degrees more than stock, I figure I have 10 degrees more advance at top speed as well, so therefore a bit more power. I do run the highest octane gas I can find, I would not recommend running regular gas, set up like this. The only time you would start losing gas mileage with the vacuum line disconnected, would be running with light engine loads for extended periods of time, say 40 to 50 mph on a level road.
Leo

[xssidecar]

hi all,
I am a new member and have not posted anything before.I hope I am doing this correctly in asmuch as I would like to introduce myself first.I live in NewZealand and have a 1980 XS1100G.I recently removed my timing advance parts to clean and check everything and after refitting and resetting the ignition timing I discovered a light knocking/tapping noise at idle and light throttle settings.When I accelerate the noise disapears.I discovered that it is indeed the vacuum advance unit.A simple test is to simply squeeze the rubber hose when the engine is running which effectively stops it working and presto the noise dissapeared.When I then released the hose the noise came back.
What I don't understand is why the noise started after I had removed and reinstalled the unit.The engine is still running well with plenty of power.

Thanks

ps I also own a BSA A7 1951
BMW R100/7 1977
Kawasaki KLR250 2001

[fredintoon]

hi all,
I am a new member and have not posted anything before.I hope I am doing this correctly in asmuch as I would like to introduce myself first.I live in NewZealand and have a 1980 XS1100G.I recently removed my timing advance parts to clean and check everything and after refitting and resetting the ignition timing I discovered a light knocking/tapping noise at idle and light throttle settings.When I accelerate the noise disapears.I discovered that it is indeed the vacuum advance unit.A simple test is to simply squeeze the rubber hose when the engine is running which effectively stops it working and presto the noise dissapeared.When I then released the hose the noise came back.
What I don't understand is why the noise started after I had removed and reinstalled the unit.The engine is still running well with plenty of power.

Thanks

ps I also own a BSA A7 1951
BMW R100/7 1977
Kawasaki KLR250 2001

Hi xssidecar,
is it possible that you reconnected the vacuum advance hose to one of the vacuum connections on the carb manifold instead of to the vacuum connection on the #2 carb body? That'll do that.
And a '51 A7? That the rigid frame that shook your kidneys loose or the plunger frame that cornered like a dinghy in a choppy sea?

[xssidecar]

Hi Fred,yes you were dead right.I had the hose on the wrong fitting!!!!.
And yes my BSA is the plunger model.It does buck and weave but not as bad as the 650---not as much power!.
Thanks for your help and I should have known as I have had it off before.
Cheers from down under.