Author Topic: MC5 TOP END  (Read 3776 times)

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Offline Grunter215

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MC5 TOP END
« on: July 13, 2013, 07:34:22 pm »
PULLED THE BARREL OFF MY 1976 KTM 250 MC5 TODAY...LOOK INSIDE...AND THE LINER IS CRACKED BETWEEN PORTS!! QUESTION IS ARE THE '76-'78 BARRELS THE SAME, IM THINKING THEY ARE BUT NOT 100% SURE.ARE THE HEADS ALL THE SAME? CHECKED AL BUEHNER KTM FOR LINER BUT SOLD OUT.CHEERS

Offline MauriceR

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Re: MC5 TOP END
« Reply #1 on: July 14, 2013, 02:49:49 am »

Offline Slakewell

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Re: MC5 TOP END
« Reply #2 on: July 14, 2013, 09:32:41 am »
Yes the 78 top end is a direct bolt on with a little bit more power as there is a extra port.
Current bikes. KTM MC 250 77 Husky CR 360 77, Husky 82 420 Auto Bitsa XR 200 project. Dont need a pickle just need to ride my motorcickle

Offline ozktm

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Re: MC5 TOP END
« Reply #3 on: July 16, 2013, 03:36:55 pm »
Guys, you need to look at the base of the barrels where the transfer joins the cases.
The early barrels are and eliptical shape.
The late barrels are square shaped. Need to confirm when this changed.

If you use either on the wrong style cases they wont match too well in this area.
Picture coming later to show you.

Just check this area before you purchase one, as some guys don't even get the year model of their bike correct when they part it out.

Cheers,
Adrian.
Regards,
Adrian Goold #101

'72 KTM 175 |'74.5 KTM 250 |'74.5 KTM 400 |Hagon/KTM 250 proj|'76 MC5 250 Project |'76 MC5 400|'78 KTM 250 Project |'81 KTM 250 MC | '81 KTM 495 MC

Offline Grunter215

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Re: MC5 TOP END
« Reply #4 on: July 26, 2013, 08:25:47 pm »
The markings on top of piston.....71 - 2 - ELKO - 1274a. Whats the 2 mean??

Offline ozktm

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Re: MC5 TOP END
« Reply #5 on: July 27, 2013, 05:52:08 am »
Basically there were two types of pistons.
Single ring and twin ring with the top ring being a dykes 'L' ring.

Depending on what size you need, Al B could have new modern wiseco pistons that are twin thin rings.

But the Mahle piston you have is getting harder to find in oversizes.
Regards,
Adrian Goold #101

'72 KTM 175 |'74.5 KTM 250 |'74.5 KTM 400 |Hagon/KTM 250 proj|'76 MC5 250 Project |'76 MC5 400|'78 KTM 250 Project |'81 KTM 250 MC | '81 KTM 495 MC

Offline Grunter215

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Re: MC5 TOP END
« Reply #6 on: August 01, 2013, 06:33:58 pm »
Thanks Adrian. Looked at another barrel but that was square transfer so anybody got a good usable oval transfer barrel to sell ??? Or a bore sleeve to suit ??

Offline ozktm

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Regards,
Adrian Goold #101

'72 KTM 175 |'74.5 KTM 250 |'74.5 KTM 400 |Hagon/KTM 250 proj|'76 MC5 250 Project |'76 MC5 400|'78 KTM 250 Project |'81 KTM 250 MC | '81 KTM 495 MC

Offline ozktm

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Regards,
Adrian Goold #101

'72 KTM 175 |'74.5 KTM 250 |'74.5 KTM 400 |Hagon/KTM 250 proj|'76 MC5 250 Project |'76 MC5 400|'78 KTM 250 Project |'81 KTM 250 MC | '81 KTM 495 MC

Offline Grunter215

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Re: MC5 TOP END
« Reply #9 on: August 22, 2013, 12:56:34 pm »
Thanks Adrian. Question KTM boys...My 1976 250 MC5 motor and a 1978 250 GS motor, whats the same/different??Are MC/GS 250 54 cases the same. Will internals swap over? Rather than chase a barrel ,the whole motor option might be better. I contacted the above ebay items,asked about condition of bore etc, contact stopped,no replies. Also looked into getting bore liner made...thats a possible option. So now a GS motor come up,so hence the question...are they the same?

Offline Slakewell

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Re: MC5 TOP END
« Reply #10 on: August 22, 2013, 01:10:56 pm »
Someone on here the other day was selling a 78 motor. Yes you can just keep the bottom cases and swap them over. There is no real power advantage.
Current bikes. KTM MC 250 77 Husky CR 360 77, Husky 82 420 Auto Bitsa XR 200 project. Dont need a pickle just need to ride my motorcickle