Author Topic: Did I buy a Yoshima? cb400F (Read 5831 times)

kyre · « **on:** November 13, 2011, 03:09:35 PM »

Went on eBay like I always do looking for a race exhaust for my cb400F (which are never listed) and I see an exhaust listed as a vintage Yoshimura taken off a race bike "from back in the day". Looked closer, doesn't look like Yoshimura, I think that's a Yoshima! a bit of surface rust and no dents. Oh look a Buy it Now for $250, sure why not.

It should be arriving in the mail tomorrow, anything to look for to see if it's a Yoshima or not?

Owned · « **Reply #1 on:** November 13, 2011, 03:29:18 PM »

Not sure...These were all hand made and I'd bet there are variations. Anyway, for the price it looks like you'll have a nice exhaust when you refinish/install.

Good find.

kyre · « **Reply #2 on:** November 14, 2011, 06:27:29 PM »

Got it in the mail today. Looks like a Yoshima!

no dents, surface rust which can get cleaned up pretty easily. The only problem so far is the rusted in baffle. I went to unscrew the bolt and the head ripped off way too easily.

Any recommendations to freeing up the rust? I wanna get this ceramic coated and the baffle needs to be removed. I sprayed some WD40 (as that's all I had on hand right now).

kyre · « **Reply #3 on:** November 14, 2011, 06:45:32 PM »

I found this photo on the web. It's definitely an Ontario Moto Tech. Same bends, same mounts. Now with the rusty baffle....

ekpent · « **Reply #4 on:** November 14, 2011, 07:56:49 PM »

Keep working it over with your penetrating oil,Kroil,PB Blaster etc and don't be afraid to put a heat gun or propane torch to it also.Have you drilled out the bolt yet and is there much to grab on there to give it a twist as you pull.Gently tapping around the outside with a rubber mallet or soft pine may also help to vibrate and loosen as long as you don't dent it.

grcamna2 · « **Reply #5 on:** November 14, 2011, 08:00:44 PM »

That looks like a VERY high flow performance exhaust for your CB400F S.S.,it should be great w/ a High Performance ported engine !

geminimotors · « **Reply #6 on:** November 14, 2011, 09:03:20 PM »

A bizzarre secret rust buster- Bees Wax. If you resort to applying heat, find a chunk of bees wax and melt it onto the hot parts. I don't know the molecular particulars, but with heat, bees wax boldly goes where all other penetrants have failed me. It can be found at ol' timey hardware stores(not Home Depot or Lowes) or the local beekeepers. Give it a whirl.

kyre · « **Reply #7 on:** November 15, 2011, 04:13:31 AM »

bees wax eh? Well I'm gonna soak in some PB Blaster overnight and if still a no go I'll apply heat and will try the bees wax. The wife has some bees wax candles laying around, she won't mind...

lone*X · « **Reply #8 on:** November 16, 2011, 12:00:16 PM »

You really mean "She won't KNOW" right?

jessezm · « **Reply #9 on:** November 16, 2011, 12:49:33 PM »

Damn you Kyre! That was my bid on there before you hit "buy it now"!!!! But seriously, congrats on a really cool exhaust.

fang · « **Reply #10 on:** November 16, 2011, 04:25:23 PM »

It is little known that MOLASSES is an incredible rust destroyer! Yes -- normal old molasses, the kind folks cook with, etc.. IF you dilute it 9 parts water to 1 part molasses, you can soak stuff in it for a week or so, and all the rust will magically go away. There is something in it which creates a chemical reaction inside the rust that creates a film of phosphoric acid, which you probably know is the primary ingredient in most of the rust converter chemicals.

It is 100% non-toxic, and 100% effective. It's slow, but it totally works perfectly, every time. Plus it smells good too.

peace and grease,
Philosopher

kyre · « **Reply #11 on:** November 16, 2011, 05:47:31 PM »

seriously fang? I'll try anything, the baffle is so rusted in. Gonna go to the store now and get some. (just did some research and I guess ya need farm grade molasses with sulfur, not store bought sugarcane... not many farm supply stores in nyc)

I haven't tried heat yet but even when I get it out I'm not sure it's salvageable. Might have to make a new baffle, we'll see. The rest of the exhaust is in great condition other than cleaning and getting them ceramic coated.

Sorry jessezm, too good of a deal to not grab instantly! Even if it wasn't a Yoshima I've been wanting a pipe like this for 7 years. stoked.

jessezm · « **Reply #12 on:** November 16, 2011, 06:02:28 PM »

I would have hit "buy it now" in a second if I hadn't just spent $700 on this:

kyre · « **Reply #13 on:** November 16, 2011, 06:10:09 PM »

I know I saw that! I was planning on getting the cheaper one flat black one before I saw the buy it now while looking for something else on ebay. I always have the habit of looking for exhausts first when I go on ebay, it's just that 99% of the time there aren't any I'm interested in.

When you think you'll get that nice exhaust on your bike?

kyre · « **Reply #14 on:** November 16, 2011, 06:38:08 PM »

ok, it's official. I just found a "YRS" stamped in the metal exhaust hanger.

Hondawggie · « **Reply #15 on:** November 16, 2011, 07:00:05 PM »

Freeze it after it's lubed up -- worth a try. Freezing + lube then some mechanical force might do the trick.

If it just won't come free try
- naval jelly soak to de-rust
- auto transmission fluid soak
- freeze
- mechanical pulling force

Good luck, that is a cool looking system, great price too. I wonder if Kaz Yoshima is still in business, I haven't heard that name in a few decades until I saw your post.

jessezm · « **Reply #16 on:** November 16, 2011, 07:32:29 PM »

Quote from: kyre on November 16, 2011, 06:10:09 PM

I know I saw that! I was planning on getting the cheaper one flat black one before I saw the buy it now while looking for something else on ebay. I always have the habit of looking for exhausts first when I go on ebay, it's just that 99% of the time there aren't any I'm interested in.

When you think you'll get that nice exhaust on your bike?

Well my head is getting worked over as we speak, and my cylinders re-bored, but I've got everything else to throw it back together as soon as they come in--probably a few more weeks... God I can't wait, though! The one thing I don't like about the M-TEC exhaust is there is no rear mount--it just rides on the flanges. That concerns me a little, although it is a light exhaust.

Lil Red · « **Reply #17 on:** November 17, 2011, 10:45:19 AM »

Here's some pics (though not super conclusive)...it doesnt seem like the collector was as centered...also being all hand made I guess some could have been...about halfway down the page...vintage magazine article.

http://forums.sohc4.net/index.php?topic=95092.msg1058661#msg1058661

kyre · « **Reply #18 on:** November 19, 2011, 03:00:51 PM »

So I got the rusted in baffle OUT and it pretty much disintegrated like I imagined. Will have to make a new one or find one that fits. (If anybody knows a good source for these parts please let me know!)

Maybe this is a silly question but this exhaust came with 3 original exhaust flanges from the cb400f but they don't seem to fit right with these pipes. I want to get some flanges like the original these came with or something that works better. The thing is, they don't function like the original flanges which come with those removable collars that are split in half. How do these mount? Which exhaust flanges would work as these have a larger diameter step (see 2nd photo) at the end than the rest of the pipe. Do the exhaust collars split in half to get around the larger diameter at the end? if the exhaust flange slides around the larger diameter at the end perfectly, when you bolt it on how does it hold the headers onto the engine?

ramble ramble.. am I making sense?

Rick4004 · « **Reply #19 on:** November 19, 2011, 03:31:10 PM »

Yours is an early Yoshima Racing Service exhaust judging by the YRS stamping. I have a later Ontario Moto Tech system where it has it's own dedicated flanges that were installed before the tubes were welded together, ie; they don't come off the pipe.

You might have to modify some stock collars to make the stock flanges work, or make up some custom two pce flanges.

Rick Denoon
www.denoonsp.com

dave500 · « **Reply #20 on:** November 19, 2011, 03:46:22 PM »

you can buy perforated pipe then fashion the support rings etc.

kyre · « **Reply #21 on:** November 20, 2011, 06:37:41 AM »

Thanks Rick. Yeah I had a feeling the flanges either didn't come off or it was a two piece system. If anybody has a photo of a two piece flange or know where to source I'd appreciate.

Also thanks Dave guess I didn't realize you could buy perforated pipe.

CycleRanger · « **Reply #22 on:** November 20, 2011, 07:07:13 AM »

Quote from: kyre on November 19, 2011, 03:00:51 PM

Maybe this is a silly question but this exhaust came with 3 original exhaust flanges from the cb400f but they don't seem to fit right with these pipes. I want to get some flanges like the original these came with or something that works better. The thing is, they don't function like the original flanges which come with those removable collars that are split in half. How do these mount? Which exhaust flanges would work as these have a larger diameter step (see 2nd photo) at the end than the rest of the pipe. Do the exhaust collars split in half to get around the larger diameter at the end? if the exhaust flange slides around the larger diameter at the end perfectly, when you bolt it on how does it hold the headers onto the engine?

ramble ramble.. am I making sense?

Are those flanges removable? Or were they put on before the pipes were welded up?
If they are removable then the flanges may require some "wedge" pieces or whatever they're called to hold the pipes.

kyre · « **Reply #23 on:** November 20, 2011, 07:59:32 AM »

The flanges on there now are from the stock system. Came with only 3. I don't plan on using the stock flanges as they dont seems to fit right. They don't slide off easily but I could get them off. I have a feeling the PO either used heat or banged these on.

I need either a 2 piece flange system or a flange that slides over utilizing a 2 piece removable collar sort of like the originals.

CycleRanger · « **Reply #24 on:** November 20, 2011, 08:16:15 AM »

Quote from: kyre on November 20, 2011, 07:59:32 AM

I need either a 2 piece flange system or a flange that slides over utilizing a 2 piece removable collar sort of like the originals.

Hmm, perhaps that why the PO let it go so cheap!

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Author Topic: Did I buy a Yoshima? cb400F (Read 5831 times)