Author Topic: Yoshimura Cam help  (Read 1186 times)

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Offline 550Resto

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Yoshimura Cam help
« on: August 08, 2017, 12:43:51 pm »
Hello all, I recently was able to score a Yoshimura Cam from a co worker who had used this in his 78 550 back in the late 70s early 80s and then sold the bike but hung on to the cam. My question is what's a good way to remove the lithium grease he's applied as it's sticky and gooey at this point and is the slight what looks to be rust on one of the lobes ok?

He said he contacted Yoshimura back when he first got the bike and wanted a cam that he could run stock springs with and this is what they sent him. Part number looks to be 121. Not sure if anyone has info on this and whether or not it was a good deal at 50 bucks? He was also running a Kerker 4 to q, pods and 145 mains which was the only way he said for it to wake up. He gave me the pods and jets as well.

Any and all help appreciated!

Offline 550Resto

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Re: Yoshimura Cam help
« Reply #1 on: August 08, 2017, 12:44:30 pm »
Came in the original box to!

Offline flybox1

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Re: Yoshimura Cam help
« Reply #2 on: August 08, 2017, 12:45:21 pm »
I'd reach for the kerosene.
sweet deal  8)
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Offline Stev-o

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Re: Yoshimura Cam help
« Reply #3 on: August 08, 2017, 02:59:28 pm »
Great deal!  The surface rust should not be an issue if you cant feel it with your finger after you get it clean.
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Offline sinister902

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Re: Yoshimura Cam help
« Reply #4 on: August 09, 2017, 05:35:02 am »
camrector recently dug up all the info on degreeing in this cam, hopefully he sees this and chimes in.

Offline MRieck

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Re: Yoshimura Cam help
« Reply #5 on: August 09, 2017, 05:38:17 am »
Every Yoshimura street cam I have installed use 105 lobe centers.
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Offline 550Resto

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Re: Yoshimura Cam help Possibly Toast
« Reply #6 on: September 04, 2017, 07:46:21 am »
 :-\ So I got to removing the grease on the cam and found a love that looks shot. Is this whole cam no good now? Picture of the issue.

Offline BPellerine

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Re: Yoshimura Cam help
« Reply #7 on: September 04, 2017, 08:09:05 am »
if it will polish up without anything sticking up to score things up it may be ok,are the lobes in that condition?bill
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Offline BomberMann650

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Re: Yoshimura Cam help
« Reply #8 on: September 04, 2017, 08:58:35 am »
There bave been worse looking cams shared on here.
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Offline FunJimmy

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Re: Yoshimura Cam help
« Reply #9 on: September 04, 2017, 11:27:49 am »
Fill it up with JB Weld and run the wheels off it.
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Offline 754

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Re: Yoshimura Cam help
« Reply #10 on: September 04, 2017, 11:37:28 am »
It's an oil retention  groove.
All the parts in my 1914 twin HD look like that all over..
« Last Edit: September 04, 2017, 10:23:30 pm by 754 »
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Offline bwaller

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Re: Yoshimura Cam help
« Reply #11 on: September 04, 2017, 04:46:18 pm »
I wouldn't be happy with it.

Offline ts354

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Re: Yoshimura Cam help
« Reply #12 on: September 04, 2017, 05:29:37 pm »
Ha, I just took out my cam today and I have the same pitting on the lobes.  What causes it? 

Offline BPellerine

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Re: Yoshimura Cam help
« Reply #13 on: September 04, 2017, 05:33:31 pm »
rust forms on them if they have been sitting in a damp space for awhile.bill
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Re: Yoshimura Cam help
« Reply #14 on: September 04, 2017, 05:57:09 pm »
I wouldn't be happy with it.

I wouldn't either.
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Offline MRieck

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Re: Yoshimura Cam help
« Reply #15 on: September 04, 2017, 06:07:51 pm »
Me either....it sucks man but reality is harsh.
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Offline 754

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Re: Yoshimura Cam help
« Reply #16 on: September 04, 2017, 10:24:05 pm »
I pay 50 any day for it..
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Offline disco

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Re: Yoshimura Cam help
« Reply #17 on: September 04, 2017, 10:25:43 pm »
Looks to be off to the side a bit, so rocker won't be riding over worst area. Maybe a good machine shop could weld & re-grind?
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Offline 754

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Re: Yoshimura Cam help
« Reply #18 on: September 04, 2017, 10:29:16 pm »
Looks like the journal  looks like 95 percent intact to me..
 40 year old stuff .....get used to it , or get a modern bike..
 Things will get worse, time is not on our side...
« Last Edit: September 04, 2017, 11:01:19 pm by 754 »
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline mj1176

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Re: Yoshimura Cam help
« Reply #19 on: September 04, 2017, 10:50:04 pm »
if you decide you don't want it send it my way  8)

Offline uksparky

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Re: Yoshimura Cam help
« Reply #20 on: September 04, 2017, 11:10:03 pm »
Clean it up with 400 grit paper/wd40 and don't worry it's not spinning 16,000 rpm lol
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Offline 550Resto

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Re: Yoshimura Cam help
« Reply #21 on: September 05, 2017, 09:12:34 am »
Is anyone interested in this cam? I don't think it'll be the route I'm taking and if someone else would like to see if they can get it fixed or repaired I'd be willing to let it go cheap.

Offline 754

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Re: Yoshimura Cam help
« Reply #22 on: September 05, 2017, 09:17:58 am »
60 bux plus shipping.. .is my offer....and I don't have a bike that it fits.
I would have no qualms running it..
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My next bike will be a ..ANFOB.....

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Lost quite a few CB 750's along the way

Offline Bodi

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Re: Yoshimura Cam help
« Reply #23 on: September 05, 2017, 09:35:18 am »
I would go over it with an oiled flat fine India stone to remove any high spots and then use it with no worries. There's lots of good surface left, your rockers will be worn in to the original cam anyway, it will run fine... worst case would be some wear on that lobe and its rocker so you would need to adjust clearance fairly soon and see if it keeps getting wider. It is not going to self destruct or cause expensive damage anywhere else.
For a race bike I would be much less inclined to use that... but I would install new or hardfaced rockers with a "new" cam as well.

Offline 754

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Re: Yoshimura Cam help
« Reply #24 on: September 05, 2017, 09:41:55 am »
I agree , but I think it's a journal, even less to worry about. I would not fill the pit.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline mj1176

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Re: Yoshimura Cam help
« Reply #25 on: September 05, 2017, 10:22:20 am »
I'll pay the same as 754 and I DO have a bike it can go in :P

hell, I'd send you the 650 cam out of my 550 too if it makes it easier for you to complete your project :)

Offline BomberMann650

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Re: Yoshimura Cam help
« Reply #26 on: September 05, 2017, 01:30:45 pm »
40 year old stuff .....get used to it

This.

If ya really can't accept a little pit on the cam.  Send it my way, I'll put it out to pasture.
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Offline parm94

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Re: Yoshimura Cam help
« Reply #27 on: September 14, 2017, 10:41:03 am »
My 550 could use that if you've still got it.

Offline 550Resto

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Re: Yoshimura Cam help
« Reply #28 on: September 20, 2017, 03:39:43 pm »
Parm sent you a PM

Offline HondaMan

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Re: Yoshimura Cam help
« Reply #29 on: September 20, 2017, 07:40:29 pm »
If it was on my around-town bike...

...if it is a lobe, it may eventually cause rocker foot wear on that one rocker, but nothing serious. I have seen high-mileage engines with cams like that, and the only place that wore was right around those pits: it lost a little cam lift.

...if it is on the bearing, I wouldn't flinch to re-use it, but not with light oils.

...unless it is for someone else's bike...then it's not good enough, IMHO...  ;)
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Offline parm94

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Re: Yoshimura Cam help
« Reply #30 on: November 08, 2018, 05:34:20 pm »
Specs for the cam are:

1.00 base circle (stock is 1.110)

Exhaust .310
Intake .325

A local shop advised a grind on all the lobes. The base circle is already at 1.00, would this be a good idea?

Offline bryanj

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Re: Yoshimura Cam help
« Reply #31 on: November 09, 2018, 01:23:18 am »
No, i have worked on these for many years and that will run ok for a long time. Yoshi cams need a lot more ignition advance depending on grind and also you need a bigger rear sprocket as the power band is pushed higher up the rev range.
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Offline dave500

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Re: Yoshimura Cam help
« Reply #32 on: November 09, 2018, 03:08:58 am »
I wouldn't say Yoshi cams per say bryanj,and as far as a larger rear sprocket all your doing is gearing it all down,torque is what ya want.

Offline bryanj

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Re: Yoshimura Cam help
« Reply #33 on: November 09, 2018, 03:29:59 am »
Yup, i actually put a yoshi cam in a 500 in the 70's and the paperwork told use way more advance plus with standard gearing it could only just pull away from a standing start, hence the bigger sprocket so you had more revs for the speed to get into the higher powerband
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Offline dave500

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Re: Yoshimura Cam help
« Reply #34 on: November 09, 2018, 03:40:17 am »
so in essence you lost low rpm torque?

Offline dave500

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Re: Yoshimura Cam help
« Reply #35 on: November 09, 2018, 03:56:08 am »
I think Honda got the gearing spot on for the 500/550s?they just lacked a little torque in my opinion?having the little engine try to make more power with more torque just wasn't gonna happen with just an over bore on the 550?but gains can be had with cleaning up head ports and use of electronic ignition.
« Last Edit: November 09, 2018, 01:41:31 pm by dave500 »

Offline bryanj

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Re: Yoshimura Cam help
« Reply #36 on: November 09, 2018, 05:08:01 am »
Yes you lost both torque and power at low revs. Yoshi cams were primarily designed for racing or fast street work where you keep the engine buzzing. Honda did not spend millions on R&D to get a street bike wrong, on the odd occasion they made minor cockups(cx500 cam chain tensione for example) but they mostly got it right
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