Wanted 77 250 gs6 pipe

Started by rpage11, February 06, 2016, 02:08:41 PM

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rpage11

I'm restoring a 77 250 gs6 and I'm looking for a pipe in good condition.  The bike came with a nice pipe and I thought all I needed was the correct tail piece.  I found one on ebay and when it arrived today I realized that I either have the wrong pipe or wrong tail piece.






This might be an mc5 pipe.  If anyone has a pipe they would like to trade for this one, I'm open.  The tail on the pipe I have is about 2 5/8" dia. and the new tail piece is 3 1/4"

Thanks for all the help everyone provides on this forum.

Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

rpage11

Quotequote:Originally posted by rpage11

I'm restoring a 77 250 gs6 and I'm looking for a pipe in good condition.  The bike came with a nice pipe and I thought all I needed was the correct tail piece.  I found one on ebay and when it arrived today I realized that I either have the wrong pipe or wrong tail piece.






This might be an mc5 pipe.  If anyone has a pipe they would like to trade for this one, I'm open.  The tail on the pipe I have is about 2 5/8" dia. and the new tail piece is 3 1/4"

Thanks for all the help everyone provides on this forum.

Edit  Can anyone tell me if this is the pipe I'm looking for?
http://www.ebay.com/itm/321976888290?item=321976888290&viewitem=&vxp=mtr

Skip Page
Tucson, AZ
//www.robertpagearchitect.com

Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

rpage11

Looking at the ebay pipe closer the inlet doesn't look to be the same as the pipe I have.  Anyone else agree?  Thanks

http://www.ebay.com/itm/321976888290?item=321976888290&viewitem=&vxp=mtr

my pipe


ebay pipe


Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

454MRW

Skip, the pipe you have pictured at the top of the page looks to be a GS-6 pipe that had been cut off short and then the silencer pop riveted to it before it reached its full size. The eBay listing pic is a 78 mc5 style torque pipe. They did not use that style until 1978, and did not use it on either 77 or 78 GS-6 bikes. You might be able to fabricate a shroud extension and have it welded on where the silencer is pop riveted into place to be able to fit the GS-6 silencer. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1976 Penton MC5 400
1977 KTM MC5 125
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM\\\'s
1976-78 125-400 RM\\\'s
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R

454MRW

Quotequote:Originally posted by 454MRW

Skip, the pipe you have pictured at the top of the page looks to be a GS-6 pipe that had been cut off short and then the silencer pop riveted to it before it reached its full size. The eBay listing pic is a 78 mc5 style torque pipe. They did not use that style until 1978, and did not use it on either 77 or 78 GS-6 bikes. You might be able to fabricate a shroud extension and have it welded on where the silencer is pop riveted into place to be able to fit the GS-6 silencer. I have a stock 78 GS-6 pipe at home that I can provide measurements from to verify, but I will not be home till Monday evening. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico


Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1976 Penton MC5 400
1977 KTM MC5 125
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM\\\'s
1976-78 125-400 RM\\\'s
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R

rpage11

Thanks Mike. I know someone in town that can handle that pretty easily. If you could send measurements next week it would be greatly appreciated.  Thanks again

Does anyone know where I might find a center stand?

Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

454MRW

Looking at comparison pics, the pipe you have may actually be a 77 MC5 400 pipe based on the size of the silencer, being larger and longer than a 250. The pics I found have a bigger diameter shroud throughout. Search for a post called Pipe Identification with s couple of GS-6 pipe pics near the bottom of the post. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1976 Penton MC5 400
1977 KTM MC5 125
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM\\\'s
1976-78 125-400 RM\\\'s
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R

rpage11

That's what I thought I saw in pictures too.  The shroud is longer and straighter like the pipe in the Ebay posting.  Might still be looking for a pipe?  Thanks for your help.

Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

rpage11

Mike
I saw the pipe in the post you mentioned.  If this is a 400 mc5 pipe and I extent the tail to fit the new shroud, how do you feel performance will be affected?

Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

454MRW

I'm not sure about the performance different because the 400 pipe has a slightly larger necked down area in front of the silencer than most 250's but only about an eighth of an inch difference in size. The GS-6 pipe although shrouded would probably still have that same necked down area under the shroud. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1976 Penton MC5 400
1977 KTM MC5 125
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM\\\'s
1976-78 125-400 RM\\\'s
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R

slvrbrdfxr

Skip and Mike
After recently building both a 77 250 and 400 GS6, my opinion is the pipe in question is for a 77 250 MC5. I've got exact same pipes on the two 77 250 GS6 that I've built. Doesn't appear that the back end has been cut off either. Someone just pop riveted a silencer on in place of an end cap. One thing I see which tells me it's a 250 pipe is the upward angle of the head pipe going into the cylinder. The 250 and 400 GS6 bikes use different exhaust spigots on the cylinder and the 400 head pipe is noticeably straighter going into the cylinder. I've got pictures of the pipes I used building both bikes and will try to send them to Mike later today so he can post the pics.
Dave McCullough

rpage11

Dave
If you would like to send them to me too, I'll post them.

[email protected]

Thanks

Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

454MRW

This silencer on the 400 is 2 inches or so longer than the 250, besides the necked down area being larger on the 400. I may have the dimensions on another post somewhere and I will look for that and add to this post. Some 400's had the angled inlet and some the straight inlet.
I found the post. Search MC5 250/400 pipes. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1976 Penton MC5 400
1977 KTM MC5 125
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM\\\'s
1976-78 125-400 RM\\\'s
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R

rpage11

According to Mike's post in MC 5 250/400 pipes, this would be a 250 pipe.  Dimensions are: core 7/8", inlet at stinger 1 1/4" and length just over 10".  The new tail piece for the gs6 pipe has a core diameter of 1 1/8".  That seems to settle that.  Anyone have a 77 gs6 pipe?

Skip Page
Tucson, AZ
//www.robertpagearchitect.com
Skip Page
Tucson, AZ
www.robertpagearchitect.com

454MRW

I have a nice one, but at some point I will need one for my 78 GS-6. If you can't find one let me know and maybe we can work something out. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1976 Penton MC5 400
1977 KTM MC5 125
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM\\\'s
1976-78 125-400 RM\\\'s
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R