Carbon build up!

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josho89

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After discovering smoke coming from my crank case i realized it had to be the head gasket failure!
took the head of on found this!!
DSC00019.jpg

DSC00136.jpg

DSC00137.jpg


Would this carbon build up be from when it was burning oil? should i be concerned?
After replacing the headgasket seems to be running great!
i Will be pulling the head of again in the near future to port + polish, install new valve springs and cam!
should i try to get it off? or just leave it?

cheers
 
running 95 prem in it! could that be why?
or would the burning of oil cause that?
 
try using 98 and get a decent spark plug

maybe get a new piston a rings to freshen it up a bit
 
if it runs good , keep riding :) the more build up = more compression wouldnt it ? hehe
 
seems to run fine!!! would running a higher octane fuel lean it out abit?
 
If the carbon is black and feels like Tar (bit sticky) than its caused from oil burning....

If its caused by fuel itll be dry and very hard to remove,

Those pics look just like oil burning casing the build up, cause it looks wet
 
carbon build up can cause it to run bad.... miss even backfire and split and pop maybe Just clean it with a lil bit of rp7 and a soft rag and keep rubbing till clean worked good 4 my bike runs good now :p
 
That doesn't look too bad at all ...... if it's blowing smoke when you rev it then either your rings are worn or the oil level could possibly be too high ..... A puff of smoke on start up or when backing off indicates leaking valve stem oil seals ......

If it was smoking before you changed the head gasket but has now stopped ... then the oil was leaking from the pressurized oil supply gallery (bottom RH cylinder stud) .....

That pic is a great example because it shows that the flywheel has been externally balanced by the factory .... Fools remove the flywheel and fit an IRK straight out of the box without getting the crank or IRK rotor rebalanced to the stock balance factor ..... then wonder why the crank breaks ...... They then blame it on the engine being made of crappy under par metal ... :p
 
take piston of get sand blasting gun fill it up with bi-carbonated soda and blast the carbon of the head and piston.

then lean it out a bit. or if its oil residue maybe you rings are worn heaps how long ago did you change them?
 
looks fine too me... bit oily is all, and that gasket looks rooted:p note the clean patch near the top of the piston?

shell be right after some running time with a new gasket.

and lowering the octane will help actually... premium is a premium waste of money in my opinion...

higher octane burns slower! and is less likely to detonate with hi compression ratios...like 12:1 etc... so at hi revs, it wont have finished burning completely...equalling a waste of fuel... that means wasting energy...

ie, a lower octane will burn faster, hotter, and produce slightly more power... with standard comp ratios... though you do have a high comp piston i see...what ratio? probably 10? still not excessive though...

now watch...someone will argue and say but but but i always use 98 in my bike:p
 
headsmess,

sounds like a fair argument were the scientific research data behind this? sounds bit of a wild call to me!! :/
 
tomsta...do you know what octane is? iso octane? cetane? pentane butane propane and heptane?

me thinks not. i explained everything in my post if you read it....

do you know what detonaation, or pinging is?
do you know why you can put n2o into an engine but not co2? or straight 02 or 03 for that matter?
cyclo hexane, hexanol, iso propyl alcohol, lithium aluminium hydride:p

dammit...now im having flashbacks of me old schooldays:mad:
 
Ha ha ha ha ... Yes Headsmess is right about the fuel ... higher octane fuel burns slower than low octane fuel so it needs higher compression OR increased ignition advance than low octane fuel ... Most pitbike engines have a fixed ignition advance that's timed to suit the factory recommended fuel and the stock compression ratio ... Ignition is started early so that the maximum cylinder pressure happens just after TDC ... IF a slower burning fuel is used without re-adjusting the timing ... the max pressure and push on the piston will happen later as the piston moves further down the cylinder ...

That will show up as a power loss on a dyno ... it might only be minimal ... but it's a power loss none the less ... the exact opposite of what you want ...

That's actually how fuel with too much ethanol in it stuffs motors ... it's still burning hot when the exhaust valve opens so the valve can overheat and burn ... Alcohol fuel requires a greater degree of ignition advance and higher compression to suit the slower flame travel ... Also ethanol makes the engine run leaner and hotter because it's displacing the baseline petroleum by 10 % or whatever ... Alcohol fuel needs to be run at a higher fuel to air ratio than straight petroleum ... often requiring a doubling of the stock jet sizes ... Computerized fuel injected engines can compensate for those factors but carbed engines can't ... they'd need to be re-jetted and tuned to suit the ethanol mix fuel ...

I tried running a fully worked XR75 on Avgas and felt a noticeable power loss due to the fuels slower burn rate ...

As for alcohol fuels ... you only need to go to the drags to listen to a straight alcohol engine and you can hear as plain as day that they sound more sluggish and less crisp than say a Pro stock engine which runs on straight petroleum ...
 
well hey you suplied me with the scietific stuff there mate it kinda makes sence to me lol :D haha so what you say is if you use high octain in low compresion engine all the fuel doesnt get burt?? and if you use low octain in high comp engine it will burn it all up and want moore??? makes sence kinda lol cheers for that info mate ;)
 
not quite, but close...

low octane has the tendency to go woof(quick), while hi octane goes woooooof(slow). not so much how much it burns, but how quickly it burns. the amount of fuel to air is still the same though.

low octane in a hi comp engine causes knocking or pinging, which is when the fuel detonates. or lights up BEFORE the spark occurs:) not good for a petrol engine. detonation is an uncontrolled explosion.

another good thing to look up is guns and what they use as a charge.. same idea...you dont want them to go bang all at once, but to progressively burn the fuel as the bullet travels down the barrel. else you get a face full of metal shards...

avgas is high octane for a few reasons as well, and i am not explaining that....
 
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