any one know about reeding pistons

karl · 20-02-2006, 10:12 PM

was told the best way to find out if my xr2 was running rich. was to go on a run flat out then kill the ignition. then look at wot colour the pistons are .so thats wot i done on sunday. to find that the right hand pistons were black and the left hand pistons were clean so clean you could read the number on top of the new piston. when i shut the engine down i was pulling 6 1\2 thousand rpm. dose any one know wot to make of this i.e is there some thing wrong

michaelcaine · 20-02-2006, 10:27 PM

same sort of thing as a plug chop i think except in that respect you check the colour of the plugs,not sure wether you can use this method on outboards?

roofer · 20-02-2006, 10:54 PM

Was it this clean

jw. · 20-02-2006, 11:00 PM

When reading spark plugs, you're looking for the porcelain of the centre electrode to be chocolate brown in colour.

The only time I've seen pistons clean is when there is water getting into the cylinder.

Or when they are new. I wouldn't imagine you've got water in three cylinders though.

Burty · 20-02-2006, 11:13 PM

as i said dude, its wierd. some one will know though dude

karl · 20-02-2006, 11:15 PM

not so. it's all down to the colour of the top of the pston. after doinig wot i did and for every think to be hunky dory the pistons should de darker towards the exaust port taning off at the intake

Matt · 20-02-2006, 11:33 PM

JW, what impact does the oil in a 2 stroke have? Does it change the colour to make it unreadable?

Quote:

Originally posted by jw.
When reading spark plugs, you're looking for the porcelain of the centre electrode to be chocolate brown in colour.

The only time I've seen pistons clean is when there is water getting into the cylinder. Or when they are new. I wouldn't imagine you've got water in three cylinders though.

karl · 20-02-2006, 11:37 PM

Quote:

Originally posted by jw.
When reading spark plugs, you're looking for the porcelain of the centre electrode to be chocolate brown in colour.

The only time I've seen pistons clean is when there is water getting into the cylinder. Or when they are new. I wouldn't imagine you've got water in three cylinders though.

thought of that. but no sigh of water in the bors or on the plugs the plugs are spot on the right colour all 6 and if ther was water getting in there's no way it would pull6.1/2 rmp

michaelcaine · 20-02-2006, 11:39 PM

this makes a good read

http://www.nightrider.com/biketech/readplugs.htm

http://www.maxracesoftware.com/spark_plugs.htm

karl · 20-02-2006, 11:56 PM

two weeks ago i had a miss fire when i had a look i found no6 piston clean and the rest black and found that the green triger wire to the coil was f**cked so just it not sparkin can clean the the top of the piston but its fireng on all 6 now

karl · 21-02-2006, 12:02 AM

Quote:

Originally posted by michaelcaine
this makes a good read

http://www.nightrider.com/biketech/readplugs.htm

http://www.maxracesoftware.com/spark_plugs.htm

all well and good but a murc v6 spark plug dont look nothing like wot you put in your austin alegro

karl · 21-02-2006, 12:17 AM

Quote:

Originally posted by roofer
Was it this clean

thats wot my old 200 looked like after leting burty loos behind the handle bars of my old sharpe

Burty · 21-02-2006, 12:22 AM

errrr no, fink you will find that someone didnt tighten the bolts on the air box and your engine was hungry

karl · 21-02-2006, 12:29 AM

Quote:

Originally posted by Burty
errrr no, fink you will find that someone didnt tighten the bolts on the air box and your engine was hungry

the only lose nut was the one behind the wheel !

Cookee · 21-02-2006, 08:46 AM

Either that one bank was not working at all, which is impossible if it was doing 6 1/2 thousand RPM or that side is very very rich and it has "washed" the top of the piston - does it smoke a lot? must admit it sounds odd?

Anyone else got any theories?

Matt · 21-02-2006, 09:07 AM

Yeh. That it's not too rich - it's too lean and borderline gonna grenade. I reckon it would have to be sooooo rich as to not be firing for no carbon to be deposited, but if the combustion temperatures are too high it'll burn the carbon off.

I'd retard the timing a bit and richen it slightly, then check again.

I definately wouldn't be leaning it out.

Cookee · 21-02-2006, 09:11 AM

Changing the timing would affect both sides though??????????

I agree - richening it is the best way to start - it can't blow anything up - I would also check float cut off valves and look for air leaks .......... something must be wrong!

Why did you do this anyway? Is it down on power or something?

Matt · 21-02-2006, 09:15 AM

Retarding the timing a bit is just an extra safety measure while he investigates - you're right though, it'll affect both sides, but if it's really that borderline, I reckon a bit of extra insurance is OK until he sorts it out.

Burty · 21-02-2006, 10:16 AM

Quote:

Originally posted by Cookee
Changing the timing would affect both sides though??????????

I agree - richening it is the best way to start - it can't blow anything up - I would also check float cut off valves and look for air leaks .......... something must be wrong!

Why did you do this anyway? Is it down on power or something?

its only just been rebuilt and the Guy who built it said after running in he would have to change the jets but didnt tell him what to so thats why he was checking what it was like first.

roofer · 21-02-2006, 10:32 AM

Quote:

Originally posted by Burty
its only just been rebuilt and the Guy who built it said after running in he would have to change the jets but didnt tell him what to so thats why he was checking what it was like first.

There's your answer, its running rich so you dont blow it up again.