Anyone help ID this exhaust

Posted: Sat Nov 09, 2013 4:37 am

I bought another 900F as a new project since I was unable to give up the first one I did. I wanted it stock and the kid didn't so now I am working on his bike that has a number of upgrades over the stock 900F.

The exhaust that is one the bike is a 4-1 with no markings that I can see but there are two small holes where a plate of some sort was one attached. The weird part is that access to the drain plug is very tight and that is after someone dented it slightly to get a 17mm socket on it (may still have to use an open ended wrench to remove the drain plug). The downpipes also completely block the oil filter so a filter change would require removing the exhaust. Also no center stand, removed since it must have interfered with the exhaust.

Here are the pics of the exhaust, thanks if someone out there can tell me what I am dealing with.

Twinstar Joined: Jul 24, 2012 Posts: 99 Location: uk

I'm afraid I can't identify it SG but if you decide to sell it I'd be interested in buying.......
Cheers Jonathan

Posted: Sat Nov 09, 2013 12:23 pm

Looks like a Mac maybe?

Posted: Sat Nov 09, 2013 12:57 pm

+1 Larry

Posted: Sat Nov 09, 2013 1:19 pm

Pretty sure it is an early Yosh.
Certainly not a hand bent race model but it looks like one i had on a 900F. I will look for a pic.

Posted: Sat Nov 09, 2013 1:57 pm

The photo above of the Mac shows a gap between the 2-3 pipes for oil filter access. Also would Mac make an exhaust that required the center stand be removed? Maybe but I tend to view these as bolt and go replacements for rotted out stock exhausts (but I don't have the history with these bikes you have).

Since there are competing opinions the mystery can continue. Today the valve covers are coming off to see if there are any surprises there.

Posted: Sat Nov 09, 2013 2:13 pm

The first pic in this old thread shows the Yosh pipe i had on my 900.
It looks like yours, imho.
The Brains of the Organization, Mr Bagley will be along to set us straight.

http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=35609&highlight=yosh+fit

Posted: Sat Nov 09, 2013 3:55 pm

I don't know about the "Brains of the Org" as I killed a few cells last night but... I agree it seems to be a Yoshi system. Here's a link on a similar topic from the archives:

http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=51391

Tony "my head hurts" Bagley

Posted: Sat Nov 09, 2013 3:59 pm

smurdoch wrote:

Pretty sure it is an early Yosh.
Certainly not a hand bent race model but it looks like one i had on a 900F. I will look for a pic.

+1 Early Yosh.

JT in Texas

Posted: Sun Nov 10, 2013 1:44 am

+2 Early Yosh.

Tyson

Posted: Mon Nov 11, 2013 3:03 am

Based on the great tips I went thru the few old cycle magazines I have and one of them had a Yoshimura ad with promising results. The text describes both 4-1 and 4-2 exhausts with the 4-2 having the advantages of keeping oil filter access and the center stand, both of which I am lacking. The lines of the exhaust match up very well so I am inclined to think it is a Yoshi as well (it does not have the abrupt change in diameter the pic of the Mac exhaust has).

The exhaust currently has terrible paint so I think I'll try and get it restored this winter as it does have a very nice sound to it even if oil changes are going to be a pain in the ass. I'll shoot off an email to Yoshimura support to see if they have any info on the original finishes and the period correct decal/plate. I am open to suggestions if anyone has done this before.

I did get the valve covers off and no surprises, 900F cams and shims in the 255-275 range. I plan to put it back together, check the carb sync and then hope for a nice day for a test ride before I start stripping it for a rebuild.

Posted: Thu Jan 02, 2014 11:55 pm

Looks like my Yoshimura. I have to take it off to change the oil...

Posted: Fri Jan 03, 2014 2:42 am

I think I have my answer, time to start looking for something close to this. Longer than I expected, I figured the rivets were toward the end.

Thank you!