Wanted - MC5 250 exhaust pipe

[tooclose racing]

Yes - an MC5 250 exhaust pipe.  I know - I don't have an MC5 250, do I? I need it for my 175 MC5.  Here's why:  I want to move back to an earlier 7 fin 175 cylinder/top end and (per Gary E) I need an exhaust that will work with that cylinder's exhaust exit AND with the MC5 frame.

Try not to snicker, chuckle, or guffaw. I thank you in advance.

Bob Close
[email protected]

[Larry Perkins]

I guess you are knowing the manifold is a different size?

Larry P

[454MRW]

The earlier 7 fin is the same as a 250. Let me look in the shop and see what I have. 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

[454MRW]

Bob, I actually installed a 77 style MC5 175 MC5 pipe in a 76 MC5 125 chassis with an old-style (1975) 7 fin engine at one time. In order to get that to fit I had to grind some fins from the head and use the 77 6 fin style aluminum finned exhaust manifold. Bear in mind the exhaust manifold where it matched up to the cylinder was a smaller opening than the cylinder port and I would have had to open it up to match the port with a due grinder, if I had completed that application, however the 77 GS6 250 has one like it that has a larger opening, but it would not fit the 77 MC5 pipe diameter. With that said, I do have a MC5 pipe I will send you some pics to your phone. This pipe would require the angled downward 250 standard style manifold. I have only seen a few early MC5 pipes that have used the straight manifold like on the 7 fin 175 engines. 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

[Larry Perkins]

I believe the manifold size of the 175 and the gasket are not the same size as a 250.  Different part numbers also.  I don't believe if they have different part numbers that they would be the same. Bolting up and the same are two different things.

Larry P

[454MRW]

The only difference I have seen are the number of tabs welded to the manifold, I have seen 1 or 2, or whether there are tabs to hold the Springs to the manifold, or if small loop washers bolt to the manifold to hold the springs. The manifold size and how it mounts up to the cylinder are the same on the ones I have had. It is possible that some years are different. 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

[Larry Perkins]

The size of the opening is different.  You can see that in the two different gaskets.  The bolt pattern is the same but the internal hole is different.  Hold the gaskets up to each other and you will see this.  Thus different part numbers.  Part numbers have been different for all years.

Larry P

[454MRW]

The square plate at the back of the manifold may have a smaller opening on the 175 but can be easily opened up with a die grinder to match on the smaller manifold to the larger 250 opening. Where the pipe slips on is the same. I imagine that is why you see people trying to sell a 175  pipe listed as a 250 because they're confused about the size of the inlet since it is the same. 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

[Larry Perkins]

If you are opening it up by grinding then obviously they are NOT THE SAME!  Which is what I said and not what you were stating.

Larry P

[454MRW]

The whole point of this Larry is that the pipe fits on the manifold the same. Since I have fit one to a chassis, I believe using the 77 MC5 175 pipe and grinding the head for clearance with the 77 MC5 alumin finned manifold is a better fit. 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

[Larry Perkins]

Just pointing out that you said and I quote, "The earlier 7 fin is the same as the 250".  You said this right after I said, "I guess you are knowing the manifold is a different size".  Again working and being the same are two different things.  One infers that there is nothing but bolt on and the other infers modification is needed.

Larry P

[454MRW]

No one said anything about taking a early design 175 manifold off of the 175 cylinder he wants to use on his engine, it was only whether the 250 pipe would fit it, which it is the same diameter. The only manifold change that would be required is if he uses the actual 77 175 MC5 pipe. That would require a different manifold. 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

[Larry Perkins]

You can try to say it nine different ways but they are not the same and you said they were which was directly after I said they were different.  You were not correct and I am pointing it out because you often try to correct what people say here and your experience is limited and in this instance it shows.  But it is ok go ahead and try to say it where it sounds different. By the way the 250 pipe fits a bit looser on the 175 manifold than it does on a 250 manifold and it is because the manifolds are different.

Larry P

[454MRW]

All I was stating is the size is the same and it would fit. You tried to make it sound like it wouldn't. 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

[Larry Perkins]

WRONG!  The size is not the same or the gaskets would be the same and both pipes would fit on both manifolds.  I never said it would not work.  I said they were a different size and they are.

Larry P