Southern Hemisphere Hot Humid Summer is over
 

Things are cooling off weather wise here in Oz.


I went for a Sunday blurt on my local loop to clear the headspace as we do..


With the cooler autumnal weather taking effect going into winter the bike was loving the cooler, denser, crisp air...


However checking the plug read it appear the WOT lean condition is back again. on the 45p/132m mid clip current setting.


I will try a 136m and move the clip to 1st (leanest) position to see how it behaves... then play with the clip position for a bit.


I have ordered a "performance" CDI with DPI switch settings to test.


Though perhaps the dished Boao piston does not like the 4* adv timing key...?


I have also order a new valve and spring set and a Dynop 70mm flat top piston for future proofing and backup. But right now I do not want to remove the head while the bike is running ok for the most part.

I think on average my mpg is about 57mpg US


The big bore might have dropped it a bit but overall the slight pulling power makes up for it.


Yes I have been running mostly lean condition and have not been shy of giving it the beans so I would be safe to say that 56-60 MPG is the average with soft panniers sticking out either side and about 90kg body weight.



I think the cheap X ring chain is robbing some power at the top as 65mph/ 100kmph is not that common to get. So average speed is 55mph.


But its getting the job done and TBH I'm not sure if i want to go any faster on the XL185 running technology...

Ok I think I have discovered the Nibbi 28 and my 70mm dished piston BOAO big bore kit conflict limit issue that has been fish biting me above 7000rpm WOT.


The issue was a lean condition but it was not a result of main jet. The problem appears to be a fuel delivery cap due to the needle.



There seems to be fuel limit above a 135main jet and needle positions 1,2 and 3/mid clip.


I have gone to a 136 main and 4th needle clip position and the fish bite seems to have disappeared with more favorable spark plug reads in the nutty brown zone.


So I now have adjustability again and can actually dial in optimum fuel delivery...



Most users of the Nibbi 28 are not going passed 130 main on stock CG250 engine dynamics which is why the issue did not seem to present itself with other users.


Just thought I'd share my recent discovery.

Can you please explain what you mean by "fish biting"? I've seen you mention it several times but I still don't understand what it's supposed to mean. I'll readily admit that I haven't read every post in this thread, so my apologies if you've already explained it.

Ok when a fish bites and your holding a rod and line there is tug/lurch sensation.


On the bike riding wide open on the flat, was hitting 7000rpm ish and the engine hesitate for a split second which was the lean spot I couldn't get over using bigger jets.


you could call it a hesitation or stumble but it was so acute and repeatable under the same parameters that a fish bite was the best descriptive metaphor.


I was trying to use bigger jets and leaner needle position to 'cure' it.
But it is apparent now leaner jets and richer needle position was the issue all along. At least now I know the engine does not mind the 4th clip...but my jetting might need more adjustment now.