Running problems
-
- Member
- Posts: 191
- Joined: Mon Nov 16, 2015 6:08 pm
- Location: east sussex
Re: Running problems
Could someone explain what IT BOGS MEANS
- robcurrie
- Member
- Posts: 957
- Joined: Fri Dec 09, 2011 5:33 pm
- Location: Limpopo SOUTH AFRICA
- Contact:
Re: Running problems
It means it feels like driving in deep mud.
-
- Member
- Posts: 1567
- Joined: Mon Jan 01, 1990 12:00 am
- Location: WEST SUSSEX UK
Re: Running problems
Engine performance is a combination of correct AFR ( Carb setting ) and timing , if either are incorrect the engine will not operate at optimum performance . The manufacture will have determined the best compromise and should be used as the starting point
On a unknown engine, the first check would be to confirm that you have reasonable compression ( resistance to kicking over is a good check )
Then check that the carb is set to manufacturers settings and any filters are clean in the fuel system , before checking static timing at TDC compression
Auto advance mechanisms are prone to sticking if worn and chain is too tight !
The following diagram shows the theoretical effect of incorrect timing and mixture
When tuning an engine the process at every throttle / load setting would be to set the mixture , then find MBT ignition setting and repeat the process getting closer to optimum AFR and timing at each point . The compromise in later years was to worry about emissions , but luckily we don't have to worry about that
On a unknown engine, the first check would be to confirm that you have reasonable compression ( resistance to kicking over is a good check )
Then check that the carb is set to manufacturers settings and any filters are clean in the fuel system , before checking static timing at TDC compression
Auto advance mechanisms are prone to sticking if worn and chain is too tight !
The following diagram shows the theoretical effect of incorrect timing and mixture
When tuning an engine the process at every throttle / load setting would be to set the mixture , then find MBT ignition setting and repeat the process getting closer to optimum AFR and timing at each point . The compromise in later years was to worry about emissions , but luckily we don't have to worry about that
You do not have the required permissions to view the files attached to this post.
- jackstringer
- Member
- Posts: 321
- Joined: Thu Oct 08, 2009 6:09 pm
- Location: Somerset UK
- Contact:
Re: Running problems
Some bikes suffer with an issue where it will fly up to a given rpm/speed then it feels like you have driven into a bog where the bike just fails to carry on with the power but its all of a sudden and not where you would expect it. Just a bit like when you run out of fuel.
-
- Member
- Posts: 1567
- Joined: Mon Jan 01, 1990 12:00 am
- Location: WEST SUSSEX UK
Re: Running problems
your symptom Jackstringer sounds like sticky auto advance or bob weights , where the timing changes rapidly
- jackstringer
- Member
- Posts: 321
- Joined: Thu Oct 08, 2009 6:09 pm
- Location: Somerset UK
- Contact:
Re: Running problems
I have a G3 that sings and spends most of it's time getting annoyed by modern cars that cant seem to reach the speed limit. I was just explaining how bogging feels, I have only had that issue with bikes with 2 stage carbs and one isnt feeling too well.