Yz426 piston seized?Please help

Oil filter doesnt look to bad, I have seen alot worse on running bikes. The blueing on the crank is normal, its part of the manufacturing process. Is the crank hard to rotate?

the connecting rod is sometimes hard to move on the crank.

What year is your bike? I think you need a decompression lever... My yz 01 426 Is similar... These are very high compression engines... So high that when you try to get the piston TDC, you can literally stand on the kickstand and it won't turn through... This is why you need a decomp lever... Especially after it stalls out. After stalling out these things things can be a pain to start...

Of course i have a decompression lever.It was so easy to start before.Start with first kick on TDC even without hotcam conversion.

Edited by peter10

Maybe its hard to kick BC you don't have a auto decompression cam. Is there another lever on your bike that your not sure what is does. And those pics of the crank from what I understand are normal as is the oil filter.

Of course i have a decompression lever.It was so easy to start before.Start with first kick on TDC even without hotcam conversion

with this problem the engine is started with first kick no problem '"not now BC the engine in pieces'' AS SOON AS THE ENGINE GET HOT IT STALLS AND THE ENGINE FEELS LOCKED UP TILL IS GETTING COLD AGAIN.

When i rotate the Rod big end bearing sometimes its stuck and hard to move sometimes alright so thats gonna be the problem?

Edited by peter10
with this problem the engine is started with first kick no problem '"not now BC the engine in pieces'' AS SOON AS THE ENGINE GET HOT IT STALLS AND THE ENGINE FEELS LOCKED UP TILL IS GETTING COLD AGAIN.

When i rotate the Rod big end bearing sometimes its stuck and hard to move sometimes alright so thats gonna be the problem?

Yes

with this problem the engine is started with first kick no problem '"not now BC the engine in pieces'' AS SOON AS THE ENGINE GET HOT IT STALLS AND THE ENGINE FEELS LOCKED UP TILL IS GETTING COLD AGAIN.

When i rotate the Rod big end bearing sometimes its stuck and hard to move sometimes alright so thats gonna be the problem?

I told you that already.

Yes

I told you that already.

Thank you guys for the help,without u guys i cant find the problem.So what i need to buy now to get the bike working again?

Crank bearing,

Full gasket set,

Do i need a new crank?

I would buy a new crank and all the bearings in the bottom end. You should really have that head checked though with all those lose bolts I would suspect some damage to the journals. If it checks out I would still run it but check the clearance in about 5-10 hours of run time. If I were you I would go ahead and get that cylinder replated and a new piston to match the new crank. Good side to all of this is you will have a pretty much brand new motor when your done.:D

I would buy a new crank and all the bearings in the bottom end. You should really have that head checked though with all those lose bolts I would suspect some damage to the journals. If it checks out I would still run it but check the clearance in about 5-10 hours of run time. If I were you I would go ahead and get that cylinder replated and a new piston to match the new crank. Good side to all of this is you will have a pretty much brand new motor when your done. :D

I dont really wanna spend a lot money to her as im gna sell it after is done,i want to sell it also im on low budget now :(

You would be better off just parting it out.

You would be better off just parting it out.

Its gonna take years to sell all the parts here in UK.

Edited by peter10

How much are the 426's going for over there.

How much are the 426's going for over there.

About 1000 pound for a niceone.1500dollar

Pretty much same here. Cheapest crank I've found was 300 from partzilla.com, not sure if they ship to the UK though.

Pretty much same here. Cheapest crank I've found was 300 from partzilla.com, not sure if they ship to the UK though.

What if i just takeit tothe shop my current crank and get it repaired.I think it would be cheaper

You could get a rod kit if you can find someone to put it together. I think there around 150, not sure on that, seems like I saw one for under a 100 somewhere.

Just make sure you find a good shop to do your crank rebuild if you go that route.

I like buying a complete OEM crank when they are available.

I had bad luck with crank rebuilds before but now.

I have a good shop that did a crank rebuild in my old CR500 (They are not available though Honda anymore) the rebuild one works great I just think the other shops did them past did not know what they were doing.

I been told stay away from the Hot Rod complete cranks and rod kits I had good luck with IMS Crank kits.

Like other said as long you have it apart do everything at once you have a new motor it's cheaper than buying a new bike or buying some else's clapped out old bike they trying to dump off to someone else they know it needs a rebuild or something wrong with it they not letting know about.

You have a bike you know it's good.

No, not exactly. Well, sort of. You can use the YZ400 bottom, but you would need to pull the crank out, tear it down, and replace the rod with one from a 426 so that you'd be able to use the 426 piston and cylinder, etc.

Not really a solution here.

No, not exactly. Well, sort of. You can use the YZ400 bottom, but you would need to pull the crank out, tear it down, and replace the rod with one from a 426 so that you'd be able to use the 426 piston and cylinder, etc.

Not really a solution here.

Well its still cheaper then buy a new crank.I spent allday on phone to find a crank for my 426 and the cheapest was 500pound in UK.

If i buy this is half of the price still better,and all i need to buy is a 426 rod whichis 60pound i guess dont needto buy a rodbearing or do i?

So im really think about this solution.What do u think?

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