Topic: Yoshimura? Cam Identification

[Jerry Rxman Griffin aka MuthaF'er]

Bill, yes it does have a B stamped in it. Now wouldn't it be nice a find a legit Road Special that had say an A stamped in it. That sure would make ID'ing this VERY simple!

[Greggo]

IIRC, the only A stamped cams I've heard of were in 500/550 bikes.

[cavebear]

Greggo, PM sent

[Bill/BentON Racing]

Had 500/550 A & B's.Have A 750 now in Calendar Girl,but did not ever see an A 750....doesn't mean their wasn't one,but Pops usually offered just 2 cams,the 750's were Road Special and Daytona Special.Daytona has a B stamped on the end.Bill

[Greggo]

Had 500/550 A & B's.Have A 750 now in Calendar Girl,but did not ever see an A 750....doesn't mean their wasn't one,but Pops usually offered just 2 cams,the 750's were Road Special and Daytona Special.Daytona has a B stamped on the end.Bill

Hmm, Satanic Mechanic has #'s for a "Road & Track" cam listed as .378" & .341", but no "Road Special", so is that just a misprint on the name?  They've also got a "Stage I" & "Stage II" listed, none of which match mine.  I'm happy I've got a good cam, I just wish I knew who made it. 

http://www.satanicmechanic.org/yoshicam.shtml

[Jerry Rxman Griffin aka MuthaF'er]

My Daytona is listed as Stage II on the sheet I posted. 

[Bill/BentON Racing]

And the hot cam for 500/550's was listed as Isle of ManTT/B.Bill

[Greggo]

Okay...here's the part where I bow my head in shame.  I misread the lift number on the intake that my dad's friend wrote down...It's .391" intake, .353" exhaust.  This is much closer to the Daytona's .392" and .360" 

Mike, do you think I could still use this with just a good 836 kit?  Or would I need heavier valve springs?

[Sam Green Racing]

Greg, your new figures still put the cam between the Megacycle 60 and 70 cams but something you need to consider, it's got NO markings and you were only TOLD it was a Yosh cam.
Another thing is, when you had it measured, you only gave the lift figures.
It would help if you could give the opening and close figures that you said you will get.
The lift figures alone will not tell you how a cam will perform.
The opening and close figures will give you the duration and combined with the lift figures, it would make it easier to to figure which cam you have.
I know for a fact that the figures given by the manufacturer are at times hard to replicate when setting the cam up. When this happens, it's a case of balancing out the lobe centres.
Perhaps some of the expert set up guys would like to comment.

Sam.

[Greggo]

Greg, your new figures still put the cam between the Megacycle 60 and 70 cams but something you need to consider, it's got NO markings and you were only TOLD it was a Yosh cam.
Another thing is, when you had it measured, you only gave the lift figures.
It would help if you could give the opening and close figures that you said you will get.
The lift figures alone will not tell you how a cam will perform.
The opening and close figures will give you the duration and combined with the lift figures, it would make it easier to to figure which cam you have.
I know for a fact that the figures given by the manufacturer are at times hard to replicate when setting the cam up. When this happens, it's a case of balancing out the lobe centres.
Perhaps some of the expert set up guys would like to comment.

Sam.

Sam, I totally agree on all points.  I would love to hear from someone with a known, unmarked Daytona cam, but that doesn't seem to be happening.  As far as what Mike was saying about them all being billet, that does seem to be the case for Yoshi's new stuff, but the pics I've seen of the NOS stuff, and vintage pics seem to be just like mine (hardwelded).  My dad's friend said the cam would have to go to a real cam place to get all the duration figures and such.  Megacycle is actually just across the Richmond Bridge from me, so I'll give them a call and see if they do measuring.

[gschuld]

I know this is a old thread, but I have info to share for future reference regarding Yoshimura cams that I didn’t know for sure before now.

Yoshimura was unique in that they got genuine unfinished Honda cam blanks, had their own lobes cut, then sent them back to Honda for finishing.  This is unique in the cb750 aftermarket cam scene as the common deal was to use CWC aftermarket billet cam blanks for new grinds.

The excerpt was from a March 1973 article.  It’s possible Yoshimura did something different later on, but this way apparently the way it was done early on.

George

[bwaller]

Well George I'm no expert on the topic, and that might be the first time I heard Honda co-operated with Yoshimura re cams. Quite interesting if so. I was told by Barbara a long time back that they made the Yosh cams, at least for a time. Possibly when Alexander became involved in NA?

[gschuld]

I read something similar in another article, but once I saw this one PLUS now owning a cam that is clearly a Honda blank, yet has a Daytona profile on it, and it wasn’t hardwelded.  It simply has the “B” on the end and no other ID markings on the cam other than the R1 cast into the blank.

Standard base circle, so no regrind.  The engine is from just a few weeks into K1 production and it appears to be an early period build with what appears to be Yoshi ported head. The engine formally had a hand bent stove pipe style Yoshi race exhaust on it as well.

[gschuld]

http://www.hondachopper.com/garage/articles/yoshi_750/page3.html

Another source...