YOSHIMURA 4-1 Help

[posplayr]

Found this on Ebay; contact sellerr for a "reproduction" Deffuser pipe

http://cgi.ebay.com/ebaymotors/HONDA-CB750K0-K7-F1F2-EXHAUST-BLACK-YOSHIMURA-TYPE-M011_W0QQcmdZViewItemQQ_trkparmsZQ7c301Q3a1Q7c293Q3a1Q7c294Q3a30QQ_trksidZp4634Q2ec0Q2em14Q2el1262QQhashZitem1e56ee3745QQitemZ130307471173QQptZMotorcyclesQ5fPartsQ5fAccessories

HONDA CB750 K0-K7 F1F2 EXHAUST BLACK YOSHIMURA TYPE NEW M012with a Diffuser Pipe and six Bolts.6mm hexagon wrench is required.
Yoshimura of those days had many kinds of exhausts.
The type bent by the hand of the first stage in it was reproduced faithfully.
In addition, deffuser pipe is different.
Old Yoshimura type deffuser pipe is 5250JPY separately.

[duaneage]

Nice pipe if you have 600 dollars for it.

Gotta love the Engrish in that listing.

[maro]

Is the the diffuser pipe in question: http://cgi.ebay.com/ebaymotors/HONDA...Q5fAccessories

[posplayr]

Maro, that sounds like a reasonable alternative assuming your pipe is in good shape. Exhausts can be a baich especially if you are hooked on Yoshi

stuff is out there. recent find NOS pipe for CBR600 but can is identical to my ED

[maro]

Actually, I gotta say, the baffle Duane put together is pretty sweet and really quiet. Plus I can continue to play with it for better flow if need be. For less than 20 bucks, I'm extremely happy. I was over at Duane's garage last night and we pulled it out and sliced some more notches into the flange that meets the mid-pipe to help the flow even more. I should have taken a photo of it. I will take an updated shot of it ON the bike this weekend. Looks great!

It's nice to see however that the possibility of acquiring a yosh baffle that would fit this old pipe is achievable.

FYI, We also studded the head block where the header bolts on. This was done as I have to take the whole header off in order to change the oil (which I did as well last night). There is always that fear of stripping those aluminum threads inside the header. Now that we studded it, I can just screw some bolts on and off the studs (like the oil filter cover). I will say this though, getting that 4-1 on and off is a PITA. I can't imagine doing it alone.

[posplayr]

I have been using SS bolts with plenty of anti-seize. What was your source for studs? The last supplier I spoke to said I would have to cut them out of all thread stock.

My Ysohi comes down the center as well, but there is a mid pipe which allows the can and mid to be removed with one bolt. The header is a bit of a pita, and studs would be a little easier and probably much safer in the aluminum head.

[posplayr]

is this one similar?

http://cgi.ebay.com/ebaymotors/1983-GS-1100-ES-HEADER_W0QQitemZ230344106913QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item35a19423a1&_trksid=p3911.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

[Big T]

I did a bit of a variation on Duanedge's set up, with a reducer and a 1/2" flange in the front and skipped the 1" flange in the back, substituting a bolt, a big washer and using the ceiling fan mount. I think the ID of my can is somewhat smaller than Maro's, I had to pound the fan mount into place.

It still seems kinda loud, but nothing like the open pipe

I may pack more steel wool in there.

I've got 68 1/4" holes in the nipple

[duaneage]

The replacement baffle maro posted about is too small, about 2.75 inches, for the Yosh pipe he has. It runs about 3.25.

The muffler on Maro's bike was so quiet I did not even hear it go past me on the road. So we can punch a little more out without getting tickets. It's fun to pull the baffle and modify it, we have the option of starting over if we go too far with another 7 dollar part.