MC5 400 Pipe Suggestions

[Big Mac]

Does anyone have any suggestions on sliencer/spark arrestor solutions for a '77 MC5 400. Current stock pipe has the welded on silencer end with the cap held on by top and bottom springs. Haven't figured out a clean way to adapt an aftermarket spark arrestor to it, don't want to cut on it at all, and would be nice to quiet it down about 5dbs or so.

Does Ace make a '77 400 pipe yet, and anyone know if it can be made up w/ silencer and spark arrestor like the GS6? thanks, Mac

[DKWRACER]

Hello Big Mac, just a FYI...as of 7/13/04 Andy @ ACE has a 76/77 400 pipe I sent him to make a jig and another pipe for me, I have emailed him to discuss silencer options...If you want to make contact with him, his email addy:
[email protected]
Thanks, and Good Luck!!!!

[Big Mac]

Thanks, I'll shoot Andy a note with some ideas or suggestions, and maybe if he can incorporate them into '76/'77 400 pipes, there will be at least 2 of us buyers out there. I saw in Al B's most recent offerings pipe "sleeves" that look to be add-ons to 125 & 175 MX pipes to provide some beneficial noise control. If same could be provided as an optional addition to Ace's 400 pipe design, with some sort of attachement method for a spark arrestor end, it would be a beautiful thing. Even an MX pipe end with round 2" to 3" stinger to attach a Sparky would help get the job done.

Not sure how it's getting to be in other parts of the off-road world, but 96dbs is getting to be a standard for organized events here in the NW, which is pretty hard to hit with an air-cooled, straight-cut- gear mill whiz-banging around.

[john durrill]

Mac,
 We made up a silencer/ spark arrestor for my sons 175 piner from a supper trapp. We just used the end and part of the Trapp. It slides over the stock bolt on my sons pipe and fits up to the stock shroud.
 We made up a few bits and used an accet welder to make  up the Sparkie/ quiet muffler. We can put the stock end cap back on in just a min. and the bike is back to stock.
 We can do a picture or two if it would help and send them too you.
John D.

[Big Mac]

John, thanks for the Supertrapp suggestion. I have a Supertrapp off an early '70s Husky pipe, but the diameter of the end cap is much bigger than the end of the '77 400 pipe, which is only about 2-1/4". The Supertrapp hangs on with a center bolt, and the cap on the stock 400 pipe has 2 springs on the outside to hang it on there. Seems like a pretty tough conversion to adapt.

I found a Sparky for smaller bikes that comes in a 2-1/4" pipe-side size and shouldn't be restrictive, and am trying to fab some internals to hold the inner pipe and packing in place so that it can go on where the stock end cap comes off. Will have to add some ears to hook the springs onto also. Unfortunately, it doesn't help the sound issue at all. Andy at Ace is working on a replacement pipe and maybe a S-A design with good sound like the '74-'76 Penton enduro pipes can be included as an option.

[DKWRACER]

Mac, glad to hear that you made contact with Andy, he seems very interested in helping members of POG...of interesting note, I have seen the Supertrapp conversion on several Pentons and have three or four in the shop unused, they adapt well to the correct pipe, but not the MC5 with the "2-springer" type as mentioned, good luck and stay in touch, I am proceeding with as basic a stock pipe from ACE with the "2-springer" end-cap...glad we could comm on this subject, I hope it opens some doors for us!!!

[wildman]

There used to be a kit that replaced the end cap of the MC5 muffler with just the spark arrester part of a supertrapp. This only extended about 2"and included the end cap printed with "USFS approved spark arrester" to pass inspection and about 6-8 discs. Because my 1975 250 CC pipe had already been hacked I welded a supertrapp in place of the stock big muffler and I think it looks a lot like the MC5 muffler. It is not very quiet,but i added the quiet core insert and keep it repacked often. You can buy the replacement pieces for supertrapp to build your own if you find an extra stock endcap to attach to. Hope this gives some ideas




1975 250 Cross Country, 1974 175 Jackpiner, 1975 125

[Big Mac]

Thanks Tom and Wildman. I'm sending some photos to Andy for ideas and will kick around the Supertrapp options some more. If/when I come up with something on my own, will share it hear for anyone in need.

I rode in the woods with Thom Green yesterday--his '78 400 has a larger diameter pipe end on it. He bought a simple exhaust reducer from an auto parts store, about 4" long, that brought it down to an end that was the right size to accept the Skyway spark arrestor that came off the aftermarket pipe on his '760 250. Got the job done to be forest legal.