I put in a #80 MJ and left the Snorkel as is for now.
Went for a test drive and i am relieved to see that everything has improved.
Almost nearly no bogging anymore. I also could drive WOT and man that thing goes fast.
It is not perfect yet but very close to good steady performance without touching the CVT yet.
After the ride I took off the Spark Plug and it looked very lean to me. Similar to the Pics that posted previously when they almost didn't show any color. Maybe I just need to drive a bit more...don't know...i'll see...
I might consider to put back the #84 or an #82 and remove the Snorkel. Not sure yet.
What would be better keep the Snorkel and adjust to a smaller Jet or remove the Snorkel and try to adjust to a larger Jet? Does this has any effect on the performance?
Thanks tsimi for taking us on this journey with you.
It's great to hear that you have achieved a performance gain....... kudos to you for recognising something isn't quite right vis a vis the plug colour.
I've just scanned back over this thread, and I didn't manage to spot a reference to the carb you are using.... if I missed it, then my fault, but it is important.
From what you've said, the motor bogs when you increase the main jet size....... yet at optimum performance, the plug shows no colour.
This fact alone is both interesting and worrying.
If you're interested.... here's the nightmare basics:Primarily the plug provides a spark to ignite the fuel/air mix.
To keep that spark in good condition, the plug should be just hot enough to burn off the deposits left over from combustion.
If it gets too hot, it will melt, and also often the piston will melt.
If it is too cold, the deposits build up, and it becomes black with carbon...... which allows the HT voltage to track to earth and cause a misfire.
What has been discovered (over the decades) is that an ideal colour will/should grow on the spark plug.
Typically this colour is a light tan.
It should begin to appear within around 3Km of riding.
The plug temperature is defined by:
- The temperature of the explosion
- It's ability to conduct the heat away
Clearly this creates an 'impossible to diagnose' scenario.
The temperature of the explosion is governed by fuel/air (needle/jets).
The ability of the plug to conduct heat, is governed by the heat rating of the plug (ceramic contact etc.).
You can imagine the nightmare scenario:
You could have a cold plug (protecting itself by conducting the heat away), and a very lean mix that could melt the piston.
How do we resolve this conundrum?
We rely on the spark plug manufacturer, and engine designers, to establish (through lab testing), the ideal heat rating of the plug.
This eliminates the question over the plug........ and any colour, or lack of colour can then determine the correct fuel/air mix. (phew!)
This allows every forum on the planet to advise users that, with the correct plug installed...... look at the plug colour
So...... pre-defined spark plug specs, are the only thing that we have, to base our calculations on.
Note:
In my experience.... fitting BBK's does not immediately modify the spark plug spec.
It could...... changes in timing could...... but it tends not to be the case.
Therefore... having the pre-defined spark plug in your motor is the first thing to establish.
So buy a new plug, as specified in the manual, even though you've fitted a BBK.
Let's assume that you've done that (double check
)...... and check it is gapped correctly.
SummaryYou have a new plug (the previous one produced unexpected results {it may be okay... but.......}).
It's gapped correctly.
The motor produces maximum output, at a setting that is so hot, that no colour develops on the plug (indicating that combustion is too hot, due to a lean fuel mix).
You are running an air cooled motor, therefore it has less tolerance to heat.
If all the above is true...... then it is clear that you do have a carburation problem.
My view is that we must start looking at the carb.
There could be a problem with the seals, but a closer examination of the carb is the way forward.
In the meantime, with no colour developing on the plug..... I'd be very wary of riding up hills, or riding with a pillion.
In fact.... better to go up a jet and bog a bit, until the problem has been solved.
Prior to tuning..... I'd remove the carb.... dismantle it completely..... log the main jet, and idle jet numbers, the needle number, and it's notch position, the atomiser number, and slider number (and obv the carb type and number).
Leave all the dismantled bits and carb body soaking overnight in carb cleaner...... and then find a local garage with compressed air, and blast out every duct you can see, and every jet.
This just to re-set everything to zero.
If the spark plug still gains no colour, and bogs with bigger jets....... I would suggest that the carb specs will indicate the problem.
Put them in your sig, and we can start....... if you want
