i have a spare set of std exhausts i was thinking about cutting them in half and seeing what was inside removing it then re welding them back together has anyone else had a set apart?

i did this years ago on a dt 125 front pipe and had good results lighter system and better mid range power

just a thought thanks jody

I met a guy a few years ago that did it. He seemed to think it worked out ok.
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Why do things simply when you can complicate them

If you do it, take some photos please!

You can see what is inside at an MC21 chamber here at 3:22sec http://www.youtube.com/watch?v=zl2nBXXsPU8

Do not expect to find anything to mod like the DT125,i dont think it is worth the effort.
I had read here at the forum that MC18 has better chambers from the MC21.
As i know the restriction is in the silencer.
Only MC28 has a washer restriction on the chambers.

Check here the differences on a MC18 (R5K-R6K) between the pipes. http://www.nsr-world.com/tuning/250-tuning/ignition/
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Owner of : Honda NSR250 MC28 95sp colours / Honda NSR250 MC18 R6K SP / Honda RS250 NF5 89 in boxes / Honda C50 12V cub / Honda C50 12V super cub Japanese version /Yamaha XT600 89 benetton

Hi guys,
I've got an MC28 I'm rebuilding and when I took the pipes off I measured across the hole which butts up to the barrel. It was something like 32mm or something, I forget now. Then I measures the opening to the carb and it was something like 34mm.

Is the metal at the head of the exhaust the restriction? So can I get like a grinder attachment on my drill and grind it out a couple of mm to get more flow?
I have a lathe and I could use a boring head to ream the hole out but the pipes are such a wobbly shape I don't think I'll be able to hold it squarely in the lathe.

Here's a skanky picture of the pipe hole
I've since de coked the pipes with a heat gun. It melted the heat gun but nice coke free pipes.

Cheers

Rich