long ride and now what?

[Steve Best]

The chrome cylinder will not wear measurably at all (at least by caliper).
Once it wears at all it tears the chrome and hits bare aluminum, game over, no replay.
The rings wear considerably however, and if they get hot they get soft.
I still use a dial caliper for most measurements around the shop down to half a thou.

Eyes are getting bad so I find it hard to read a verier these days. Love the dial.
Hate electronic. Dead batteries, offset zero, etc, etc.
I like the Mitu has inch and metric on the bar, although the dial is inch only.

You are a head-popper too? Four nuts, why not? Tells a lot looking in there.
You must be running synthetic if the carbon wiped off.

I like to run the last kilometer at full throttle so I can read the plug and piston wash.

Wet fuel washes the carbon off the top edges of the piston at the ports at WOT.
This piston above is pretty darned good, I'd like to see less wash.
No wash means too lean or you were not running it hard enough for long enough.

If you have no scream at WOT top end you have to look at your main jet.
Probably not lean or you would have toasted the engine long ago.
It is all down to looking at your plugs.
I look at the well worn plug after a long WOT blast.
Black? need to go leaner on the jets.
Tan coloured? You are close. Time to get a new plug and do a plug chop to be sure.

My opinions...

Steve

 

[Street Ryderz]

yes i have had a cheap digital one had to set it to zero every time hated it!but am I right to question spark strength would that not make it rich in top end at its highest demand?

 

[Steve Best]

yes i have had a cheap digital one had to set it to zero every time hated it!but am I right to question spark strength would that not make it rich in top end at its highest demand?

Spark on these is pretty weak, but if your compression, plug and mixture is right, you don't need much spark. It will auto ignite if it runs hard and warm. This is called homogeneous charge compression ignition (HCCI) and happens when you have everything right. Top Fuel cars have the plugs burnt off half way down the track. Some of you may have pulled the plug off a runaway 2 stroke and had it keep running, with no plug wire!


So if you are running it too rich it will cool the flame and put out the fire at top end.
Same if your plug is too cool.
It all gets back to reading the plug. I love this graphic, it explains it all:

 

[Street Ryderz]

Ok so i forgot about the heat range my hot weather plug is a ngk b8hs 10 and its now unreadable

 

[Street Ryderz]

I agree and understand your right!what is baffling me is that the plug did read well before and the piston looks like the far right illustration and the wash points are same size as shown but at the front edge of each transfer. that set up ran great before Tuesdays ride!

 

[Steve Best]

Temperatures down?
We are in the single digits now.
I think I run a NGK B7HS. Plugs are cheap, play!

 

[Street Ryderz]

Thats true two! And you know i will,still its puzzling because like i said it ran strong on the way there!set up was great throttle responce was there and pulled hard! stopped twenty mins or so refueled and dog in the topend any pull after 3/4 was gone.

 

[Steve Best]

Thats true two! And you know i will,still its puzzling because like i said it ran strong on the way there!set up was great throttle responce was there and pulled hard! stopped twenty mins or so refueled and dog in the topend any pull after 3/4 was gone.

That's got to be a warning something else is at play, if weather didn't change.
Junk in the carb or tank blocking flow? Loose jet? Air leak? Something new happened. What?
Fuel? Winter gas?

Steve

 

[Arty]

Steve:
That plug chart is right on. I am copying it, and putting the picture in my "MoPed" book.

 

[Street Ryderz]

Air leak would have made it go leaner,loose jet richer yes but when i changed it after that run it was tight. so junk in the tank i think would deplete the carb and then go lean if not ample flow,it ran for an hour each way no problem always had bottom end torque,and i took the fuel that i got on the rez out thru the pet cock and fuel line flow was normal its not that.the weather did change but like 7 degree drop but yesterdays temp was 18.5 c i went down two jets and same outcome.like I said its puzzling!if my air filters flow rate changed from dust and sand on the side of the road clogging it up would make it richer going to clean it maybe ill get lucky thanks for helping ill post results if any lol.