Topic: Yoshimura Cam Buying Advice

[Greggo]

I'm thinking of buying a Yoshimura cam for my 750 motor build.  I've read there were different grinds, and I'm going for a hot-street motor.  Are there ways to tell which grind the cam is by any markings on it, that I can ask the seller to look for?  Here are the pics he sent me, and I can't really tell if there are markings.  He's comparing it to a stock cam for some reason. 

[Jerry Rxman Griffin aka MuthaF'er]

Yoshimura made 2 grinds for the 750, what they called their Road Special and their Daytona Special cams. The Daytona is a high RPM high HP cam. Hang on to your grips beginning around 7,000 RPM! The Road Special is an "around town" cam with more mid range power and not so much high RPM. I've had it installed with Yoshi 812 piston kit and nothing fancy except for S & W stronger valve springs to prevent valve float which destroyed my engine in the first place. (I'm finally doing it RIGHT for the first time currently  )

Looking at my Daytona cam. High lift. Cam lobe measurement = damn caliper isn't working! Sorry.

One thing I can tell you is that it's a standard blank just like Honda uses. Mine has R9 on it but that means nothing when it comes to how it was ground. It DOES have the letter "B" stamped on the notched end. Your pictures show lobe profiles and nothing more.

Caliper warmed up, it works. As measured from the very edge of each lobe to try to minimize dimension lost for 25,000 miles wear -  Lobe nearest you is 35.90mm. Next is 35.20. Hope that helps.

Looking at the pictures again I'd assume that the Yoshi cam is on the right based on and comparing it to the profile of mine.

[Greggo]

Hey Jerry, thanks for the info!  I won't buy it if they can't produce a clear pic of the marking.  The cam in question is on the right in those pics.

[Jerry Rxman Griffin aka MuthaF'er]

I wouldn't base it soley on the marking on the end of the cam. I'd be more concerned about the lift and the lobe profile. I have more specs/info if you get it and it doesn't have that.

[Greggo]

Thanks again Jerry.  So to clarify, a real Yoshi cam doesn't necessarily have a marking on the end?  I was sent another pic, which had the R9 stamp, so it was a Honda blank to begin with at least.  And from the other pics, the profile looked more dramatic.  It's a private seller, and it's a decent price.

[RustyJC]

When I bought my Yoshimura cam and kit at Spring Branch Honda back in 1972, I had to return the stock K1 cam or pay a core charge.  I guess I was assuming from that policy that Yoshimura was regrinding them.... 

Rusty

[Jerry Rxman Griffin aka MuthaF'er]

All I'm saying is that MY yoshi cam has a "B" stamped on the end. Don't know anything official. Many of the aftermarket cams are stamped on the end. I'd assume they wanted a way to ID the inventory in their stock in order to sell the correct grind that the customer wanted to purchase.

[RustyJC]

All I'm saying is that MY yoshi cam has a "B" stamped on the end. Don't know anything official.

I'm certainly not questioning that.  I've not had the valve cover off of mine since 1972 (the bike has only 9600 miles), so I don't remember what markings the Yoshimura Road cam may have had to differentiate it from the K1 cam that came out.

Rusty

[Jerry Rxman Griffin aka MuthaF'er]

Exactly, and IF it has any kind of consistent markings at all. Perhaps if we had more guys with known Yoshi Daytona cams (bought mine new) we might be able to make an educated guess.

[RustyJC]

You mentioned the Daytona cam hit at 7000 RPM.  Just for reference, the Road cam in mine hits at 5500 RPM.

Rusty

[Jerry Rxman Griffin aka MuthaF'er]

Hey Rusty, how does it go after 5500? What's the upper limit? My Daytona will easily pull to 10,000. Gotta be careful with shifts in that area though! Stronger valve springs are a must.

[RustyJC]

With my current valve springs (the limiting factor), the upper limit is about 8500.  Valve float sets in very quickly thereafter.  The effective powerband that I use is 5500 - 8200, or about 2700 RPM.  It pulls significantly stronger above 5500, but I'm sure it's nowhere as stout as the surge with the Daytona cam.  It's OK below 5500, but probably a little softer than stock.

Of course, it's all relative.  I can get off my 750 and onto my BMW K1200GT (152 BHP - 6 speed) that redlines at 10,200 and pulls 90 MPH in 2nd gear, and the 750 suddenly feels like my old 305 Super Hawk. 

Rusty

[Greggo]

Just got a call from the seller.  He used to race 750's, and distribute Yoshimura parts.  Told me he's sure it's the racing profile...So, it's a Daytona.  I guess I'm building a race bike 

[MRieck]

When I bought my Yoshimura cam and kit at Spring Branch Honda back in 1972, I had to return the stock K1 cam or pay a core charge.  I guess I was assuming from that policy that Yoshimura was regrinding them.... 

Rusty

That's very, very, very odd as Yoshimura used/uses new billets (and still do). I've bought many Yosh cams and never had a "core" charge.

[MRieck]

With my current valve springs (the limiting factor), the upper limit is about 8500.  Valve float sets in very quickly thereafter.  The effective powerband that I use is 5500 - 8200, or about 2700 RPM.  It pulls significantly stronger above 5500, but I'm sure it's nowhere as stout as the surge with the Daytona cam.  It's OK below 5500, but probably a little softer than stock.

Of course, it's all relative.  I can get off my 750 and onto my BMW K1200GT (152 BHP - 6 speed) that redlines at 10,200 and pulls 90 MPH in 2nd gear, and the 750 suddenly feels like my old 305 Super Hawk. 

Rusty

That's why I don't ride my busa and CB on the same day.

[Greggo]

When I bought my Yoshimura cam and kit at Spring Branch Honda back in 1972, I had to return the stock K1 cam or pay a core charge.  I guess I was assuming from that policy that Yoshimura was regrinding them.... 

Rusty

That's very, very, very odd as Yoshimura used/uses new billets (and still do).

What about Jerry's Daytona cam, which has both the R9 stamping like the Honda blanks, and the B on the end?

One thing I can tell you is that it's a standard blank just like Honda uses. Mine has R9 on it but that means nothing when it comes to how it was ground. It DOES have the letter "B" stamped on the notched end. Your pictures show lobe profiles and nothing more.

[RustyJC]

When I bought my Yoshimura cam and kit at Spring Branch Honda back in 1972, I had to return the stock K1 cam or pay a core charge.  I guess I was assuming from that policy that Yoshimura was regrinding them.... 

Rusty

That's very, very, very odd as Yoshimura used/uses new billets (and still do). I've bought many Yosh cams and never had a "core" charge.

I don't know what to say - this was in 1972, and maybe Spring Branch Honda had another market for used cams (don't know what that would be, though).  I just know that I had to make a trip out there to return my K1 cam.

Rusty

[Greggo]

I'll likely be looking to sell, or trade this cam for something more appropriate.  Once I get it, and can measure the lobes, I'll post in the For Sale, and High Performance sections. 

[Greggo]

Here's a pic of the Webber carbs he used to race with.

[scottly]

Here's a pic of the Webber carbs he used to race with.

Are the Webs for sale???

[Greggo]

Here's a pic of the Webber carbs he used to race with.

Are the Webs for sale???

Nope  I asked if he had anything else for sale, and the cam was all he had left.  Not sure if he already sold 'em, but they weren't available either way.

[scottly]

You tease.