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$800 ktm 250


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Look what I found. The cylinder has gouges in it and the head has chipped metal grooves/gouges. Do I need to replace the head?

What's the best option for the cylinder? eBay new/used one? Send it off?

What's the cost and options for sending it off? Any suggestions on a good company to do it?

Thanks

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Look what I found. The cylinder has gouges in it and the head has chipped metal grooves/gouges. Do I need to replace the head?

What's the best option for the cylinder? eBay new/used one? Send it off?

What's the cost and options for sending it off? Any suggestions on a good company to do it?

Thanks

I would send the cylinder to powerseal, millenium, or anyone of the other reputable nikasil plating companies. The head may be able to be cut by someone like Munn Racing, Slavens, Wildcat racing, RB Designs etc to have the squish band corrected and the bowl reshaped. However, it may be toast as well. 

 

More importantly I'd darn near gaurantee you that the the reason that cylinder looks like that is because the big end of the rod of one of the crankshaft bearings has let go and you need a whole new lower end. 

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I would send the cylinder to powerseal, millenium, or anyone of the other reputable nikasil plating companies. The head may be able to be cut by someone like Munn Racing, Slavens, Wildcat racing, RB Designs etc to have the squish band corrected and the bowl reshaped. However, it may be toast as well. 

 

More importantly I'd darn near gaurantee you that the the reason that cylinder looks like that is because the big end of the rod of one of the crankshaft bearings has let go and you need a whole new lower end.

Is there an easy way to check that or would I need to split the engine? Why does the inside of the head need to be smooth? I thought it was only to cover the cylinder. Obviously I'm in learning stages for rebuilding. Appreciate the help

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Is there an easy way to check that or would I need to split the engine? Why does the inside of the head need to be smooth? I thought it was only to cover the cylinder. Obviously I'm in learning stages for rebuilding. Appreciate the help

pull the cylinder off and pull up and down on the rod, it should have 0 up and down play.

I've seen that before though and it's a classic sign of a bearing letting go and getting pushed out.

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pull the cylinder off and pull up and down on the rod, it should have 0 up and down play.

I've seen that before though and it's a classic sign of a bearing letting go and getting pushed out.

Ok I'll test it and see. Ty

The cylinder head needs to be smooth because it will cause hot spots where there is the jagged edges.

Good to know, I'll see if it's cheaper to buy new or send off

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Look what I found. The cylinder has gouges in it and the head has chipped metal grooves/gouges. Do I need to replace the head?

What's the best option for the cylinder? eBay new/used one? Send it off?

What's the cost and options for sending it off? Any suggestions on a good company to do it?

Thanks

With damage like that, I would be more concerned about the bottom end than the top end. Millinium does really good work as far as the fixing of guoges and replating and send the bottom end off to Cooksey Cranks in Texas. He is on KTM Talk.

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  • 2 weeks later...

So what got sucked into your top end and smashed between your piston and head?

No clue but the cylinder had to be welded too. During break down I had to punch the piston downward it was so stuck when I took off the cylinder. I made sure no metal chips fell in the lower. I'm rolling the dice not sending the bottom off to be checked.

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Yeah you are. Let me put it this way, something did get sucked into your top end. Whether the previous owner dropped his car keys into the air boot when he had the air filter off, or a bearing let go in the bottom end, you need to figure it out before you put it back together. Think of it like this: say you put it back together without checking the bottom end. If it is a fluke, and the previous dude dropped something down the spark plug hole, by your current plan, you're out the cost of piston, cylinder repair, and a head. If you're wrong, and it was a bottom end bearing, to get running again, you will have to send the bottom end off, and then you'll need another piston, cylinder repair, and a head because the ones you just put on there are munched. Your bike. Do what you want, you're gonna do it anyway. 

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Gotta agree with the above.  A case split really is not that big of a deal...

 

You know what they say about opinions but...  If it were my $800 find, after seeing that I would split em and slap a new crank and bearings in there.  Your out what, another $300 and it wont grenade on you in 3 months and blow a hole in the side of the case.

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Yeah you are. Let me put it this way, something did get sucked into your top end. Whether the previous owner dropped his car keys into the air boot when he had the air filter off, or a bearing let go in the bottom end, you need to figure it out before you put it back together. Think of it like this: say you put it back together without checking the bottom end. If it is a fluke, and the previous dude dropped something down the spark plug hole, by your current plan, you're out the cost of piston, cylinder repair, and a head. If you're wrong, and it was a bottom end bearing, to get running again, you will have to send the bottom end off, and then you'll need another piston, cylinder repair, and a head because the ones you just put on there are munched. Your bike. Do what you want, you're gonna do it anyway. 

 

Very true.  I'll order a case splitter and learn about the bottom end.  Thanks

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  • 6 months later...

It's been awhile - ty all for your help.   I received the new cylinder and put the new upper on the bike.   It starts easily but it's smoking bad and dripping oil out between where the  exhaust connects to the cylinder.   I believe the dripping is due to a sealing issue.  The one thing that concerned me was there was a decent amount of oil in exhaust when I took it off.   Is it normal for oil to be squirting like that into the exhaust? 

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