cracked piston,ceized big end,scored barrol?cause?

[spitfire123]

hi all,

Took the mito out for a ride yesterday with a mate and the bike wasnt revving past 10k and it was like it was hitting a limiter at 11k and bouncing iraticly?

Anyway it was fine for 40 miles and as i was comming home i noticed the bike temp was climbing a bit (very slowly)from 70 degrees and it ended up at 90 when the bike lost 90% of power and went for another 1/5 mile then made a 'bang'a and came to a stop 2 miles from my house

Now i rebuilt this engine 300 miles ago which included:
new rings (as piston was changed 500 miles before this 300 mile stint)
new crankshaft (was fine in my old engine)

and for 250 miles she was running great!load sof power..smooth and now its completly gone?


i just dont know what the problem was?

the crank looks a bit 'whiteish' maby to lean or the jet was paracly blocked?

and also for the piston to basicly crack in 2...would take quite somthing.

also i checked and there was 2st oil getting to it as the feed was learly full of 2st oil?


any help would be ,uch apriciated a si dont want this to happen again!after the rebuild...


and would anyone happen to have a mito cilinder/crank bearing kit/piston in good cond and a good price?PLEASE PM ME IF YOU HAVE ANY!

thanks all
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You won't be able to eat my dust......As it'll settle before you get there.

[Kickstart]

Hi

First guess would be a blown head gasket (or other gasket allowing water to be used). Sometimes serious overheating isn't that obvious because the temperature sensor lands up not in the coolant.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[spitfire123]

[steo]

from what you said in your post, it sounds like you didn't run the bike in properly & revving the engine past 10k with only 300mls on new parts would certainly not help. what is the 2 stoke pump like? i had a similar problem with an rd350lc which i raced & ended up having to premix all the time as the oil pump was dodgy.

[Timmeh]

erm yeah, after 300 miles you shouldn't even be touching the powerband let alone trying to bounce it off the limiter.

did you change the head gasket after you took it apart to replace the piston? I think not.

And using old rings on a new piston is just plain silly imo, others might disagree with me but if you're going to rebuild a stroker's top end then you do the whole lot in one go, and then take it easy for the first few hundred miles.


____________________
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[spitfire123]

[spitfire123]

[Kickstart]

Hi

Compared to the combustion temp the weather temperature difference is tiny. While is can cause a difference I would expect that to be WELL within what the cooling system can cope with.

The Mito uses a couple of O rings for head gaskets. These can be reused a few times. However they are a pig to hold in position when assembling the engine. Possible that one wasn't seated quite right.

How far past 11K were you trying to go?

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[spitfire123]

[Kickstart]

[Blau Zedong]

The oil pipe being full doesn't mean oil is flowing. If the pump dies the oil will stay where it is rather than flowing into the carb / inlet tract.
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[spitfire123]

yes i agree, it would have.


i was just wondering....i found this on ebay:
https://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=370186400128

top and bottom end rebuild...will this be okay for my bike?its the cheapest ive found!

obv will be with a matching mitaka piston and hopefully mitaka liner

thanks keith
____________________
You won't be able to eat my dust......As it'll settle before you get there.

[spitfire123]

[Timmeh]

[spitfire123]

[spitfire123]

[Bandit650]

I know im new here but to change a piston on a 2 stroke and then run for 500 miles with the same old rings and then to replace the rings on the piston that has done 500 miles and prob been thrashed to within an inch of its life and then you run the new rings in for 200 miles and then used all of the power!!!

Are you surprised your engine blew

my advice mate is when you replace a major component run it in half revs for 500 miles or so and keep an eye on your oil tank and if the level isnt moving much after 1 tank of fuel check your mixture or get a garage to check it make sure you got the mix right and once everything is running smooth and all set up ok after 500 miles take it no higher than 3/4 revs for a further 200 miles then if everything ok blast the ass of it 2 strokes need to be working rite before you rag them to death or they just fry rings etc and the fact your piston broke tells me the mix was wrong and it was not getting the oil mix rite

Im not a smart ass just trying to help out and save you money so more beer tokens for fri nites instead of spending money on engines etc lol

[spitfire123]

[Bandit650]

[Kickstart]

[spitfire123]

[spitfire123]