what did I stuff up here?

[Slakewell]

This is only my ideas and opinion and years of experience. And thankfully some real testing and shit.
Air cooled engines need to transfer heat between the piston and cylinder ( this is called wick action ) Water cooled bikes dont have this issues. The idea is un-burnt oil and oil itself moves heat between the piston top and the cylinder, new oils, synthetic oil burn to cleanly to do this , the piston over heats in tough going as shown in the photo's. You actually need the old smelly oil to keep your bike running well. You cant transfer heat thou an air cap , new oil burns so cleanly they leave an air cap , old mineral oil dose not.
Sad but true you are better off running super TT castrol than the latest Moterx Oil. But please ignore this advice I will simply ride past when your bike is locked solid , it is much easier for me to pass :-)

[frostype400]

It's not a pe piston it's a maico 490 piston my crank isn't standard and has a different rod in it and you can probably make out the barrel spacer in the pics so it's a pe 400 cylinder yes but the rest is all different.

I will order another one you live and learn with these type of things it didn't really even upset me I was only spewing I didn't catch up to ride with my mates in front of me and I could see how it could cause some havoc being so wet bikes under a lot of load and I got a bit carried away trying to see what it could do and it was flying when it seized.

May not have ran to well for me but it handled and looked good at least.


I will probably run mineral oil from now on and I am going to start at 20:1 the oil I was using I noticed it wasn't making much blue smoke but I just put it down to being a fresh engine.

[Lozza]

Two strokes always run best before they seize Frosty 

[80-85 husky]

Me being stuck in a creek Frosty meant i didnt get to see you get out of the parce ferme in the mighty XB...there was some money on you being stuck ...how did you go?

ive got to sort of agree with Slaky on the Mineral oil and a/c engines, it has a ring of plausible about it. (face it, who wants to cook an engine to test the theory??)

ive had great success running synths at high ratios (i.e no problems at all) but always in watercoolers..I ran the blower vac and chainsaw on 100 to 1 with no probs but they dont get a deep mud workout like the bikes do...

great looking combo the xb and the PE...i was thinking of putting a towbar on the old monaro and bringing the scooter down on on a trailer...might be a 10 year anniversary project...ill start saving for the petrol

[Brian Watson]

FWIW.. those pics look like a lean seizure to me..the fuel does the cooling and the oil does the lubricating..too little fuel (too much air) and you end up with a piston that looks like that.. My first response would be to do a leak down test..these bikes are in a lot of the cases 40 years old..or close to it..check the excess air getting in..
40.1 in my old aircooled banger..Motorex full synth..no problems once the air leaks were sorted..

[Slakewell]

In regards to oil. Most will not notice and apart from quicker wear which does not matter a great deal on a bike ridden a few times a year the difference between Mineral and synthetic. It really only came to my attention when I started putting old A grade riders on my bikes. A good friend of mine having similar issues with A grade riders decided to get real data so he welded a heat censor in the header pipe and did back to back testing with fuel and oil and by far the coolest running was with 98 pump fuel and 25 to 1 mineral oil. Try a test, use your fuel you are using now and listen carefully , now do it again with the mixture above , I can hear the difference less rattles. 

[jimg1au]

dirt track /road racing 20-25 to 1 you are realy reving the motor
and as you will find out frosty oil is cheaper than parts
20 to 1 on methenol ran four years never fouled a plug  just re ringed motor and new bearings and seals
jim

[matcho mick]

Thanks guys I will get some pics of the piston as well and it happened at fairly high speed over shot Where I was supposed to turn and then it died when I was going back through the gears.

nobody really  read this bit apparently 

[80-85 husky]

fairly important im thinking....

[Glen08]

Yeah I did read that but currently have a 400 stripped down now here in front of me I'm more concerned about not seizing...! Good point none the less..Frosty did you just do a fuel stop & forgot the oil in the new lot..

[frostype400]

No I definitely had all my fuel mixed never got to use my spare fuel any way.

And yeah I got medium stuck I didn't need towing out like my mates in the big dodge setup in the same area I just needed a bit of a push to get going thanks those guys if you are reading.

[GMC]

Seems that whenever an engine stuffs up everyone wants to jump on the oil ratio bandwagon to justify their cause.
I think it this case though it was most likely something else.
Did you inspect the base gasket for leaks Frosty?
The problem with spacer plates is 2 gaskets increase the risk of a leak, the gaskets can bed down over a few heat cycles and 2 gaskets may be enough to leak whereas one gasket will be fine.
I'm not a fan of using gasket goo on base gaskets but I think in this case it is probably worthwhile.

[tymes]

Its simple, its becouse all new oils are evil. They are only made for Kawasakies.

[frostype400]

Going to recheck every thing and leak down test etc etc ordered a new piston so I am just waiting now.

Also it doesn't worry me if I am not sure what caused it as long as it doesn't happen to me again.

[80-85 husky]

Also it doesn't worry me if I am not sure what caused it as long as it doesn't happen to me again.
 

Ask Dewy, they tried that process and 3 pistons later they realised the main seal was poohed...i would work on making sure you know why it failed otherwise.... "definition of insanity" doing the same thing over and over and over and hoping it will turn out differently ..this time...

leak down test will sort it out for you.

good luck