Topic: Aftermarket rods??? And other Hi-Po engine Q's

[Sam Green Racing]

Ya might want to think about an upgraded oil pump if anyone makes them, you're going to need a feed to the turbo.

Sam. 

[sohc4]

...and upgrade the primary drive with an 750 A crank and a hy-vlo chain.

[MRieck]

...and upgrade the primary drive with an 750 A crank and a hy-vlo chain.

Or CR750 primary chains (good luck there).

[JLeather]

I've got a complete 750A engine.  Doesn't it use a hi-vo cam chain as well?  Does no one sell a hi-vo chain that fits on a regular crank?  New stock-style primary chains aren't good enough?

Anyone know a company that sells a better oil pump?  The kit was designed to be run on the stock engine, though.  It feeds the turbo off of the tapped hole in the center of the oil galley and returns the oil to the clutch basket.  Possibly a new-stock pump is good enough?  Or maybe someone out there is blueprinting stock SOHC pumps. 

As a side note I'm going to run atleast one oil cooler, maybe even a second one in the return line to the oil tank.

SatanicMechanic, how did your turbo project ever turn out?  I remember reading about it on your website, but the updates on it dropped off soon after you started.

[sohc4]

The 750A has the standard cam chain - this is what makes it an easy swap. I would not trust the standard primary drive in a turbo engine, at least not in a 'serious' engine.

My turbo project still has a long way to go - I am still looking out for a A crank (the Auto has never been sold over here in Europe, so they are hard to find. I have a couple of options to get one from the US, but none of them has materialized yet).  I have a source for a primary Hi Vlo chain in the correct length (instead of making one out of two). Then I need a chain tensioner.

I gave up looking for a used set of Carrillos, I am about to bit the bullet and order them right now.  I do have a set of special reinforced cylinder studs (even better than the readily available reinforced stuff).  Pistons are not decided yet, most probably something between 812 and 888cc.

So, basically I am still collecting parts and ideas...

Axl

[paulages]

I've got a complete 750A engine.  Doesn't it use a hi-vo cam chain as well?  Does no one sell a hi-vo chain that fits on a regular crank?  New stock-style primary chains aren't good enough?

?? a hyvo chain is a totally different style chain. the crank sprocket itself has to be totally different. i'd go with the A crank for sure.

[JLeather]

So, if I get a 'matic crank what else needs to be done to run it?  Do I need to do anything to the sprocket on the tranny end of the chain?  Do I use the chain from the 'matic?  Where can I get a new hi-vlo chain?  BTW, satanic mechanic, I can prolly find you another 'matic crank if you're willing to ship it from the states.  I know a guy who's parted out a couple.

[paulages]

So, if I get a 'matic crank what else needs to be done to run it?  Do I need to do anything to the sprocket on the tranny end of the chain?  Do I use the chain from the 'matic?  Where can I get a new hi-vlo chain?

that's a good question. i don't know anything about the transmission on the A models. looking at the microfiche, i can't tell whether the primary drive sprocket on the transmission is even removable, let alone compatible with the K or F trans shafts. maybe someone who knows these transmissions will chime in?

[754]

There is a wider bearing that goes on later sprocket shafts. use it.

I am just going to look for a decent set of primary chains for mine have several sets to chose from, but I am not going turbo either. In the seventies I never heard anyone worrying avbout primary chains.. and I dont recall ever hearing of any breaking..

[super pasty white guy]

If you're having a hard time finding your crank, you might try sending a request for the part at http://motosalvagenet.com/

When I was looking for an alternator cover, I got 8 or 10 responses ranging in price from $20-150. 

Dave

[MRieck]

So, if I get a 'matic crank what else needs to be done to run it?  Do I need to do anything to the sprocket on the tranny end of the chain?  Do I use the chain from the 'matic?  Where can I get a new hi-vlo chain?

that's a good question. i don't know anything about the transmission on the A models. looking at the microfiche, i can't tell whether the primary drive sprocket on the transmission is even removable, let alone compatible with the K or F trans shafts. maybe someone who knows these transmissions will chime in?

I thought an early Goldwing basket works. The tensioner is a whole nother subject.

[sohc4]

So, if I get a 'matic crank what else needs to be done to run it?  Do I need to do anything to the sprocket on the tranny end of the chain?  Do I use the chain from the 'matic?  Where can I get a new hi-vlo chain?

that's a good question. i don't know anything about the transmission on the A models. looking at the microfiche, i can't tell whether the primary drive sprocket on the transmission is even removable, let alone compatible with the K or F trans shafts. maybe someone who knows these transmissions will chime in?

I thought an early Goldwing basket works. The tensioner is a whole nother subject.

Yes, and yes 

[bert96]

 interesting...

http://cgi.ebay.com/ebaymotors/Honda-CB750-Racing-Carrillo-Rod-bolts-NEW-SET-of-8_W0QQitemZ200173723581QQihZ010QQcategoryZ35595QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Jerry Rxman Griffin aka MuthaF'er]

...and upgrade the primary drive with an 750 A crank and a hy-vlo chain.

Or CR750 primary chains (good luck there).

A NOS set of these were on EBay within the past month. I believe they went for about $300. First time I'd seen these.

[MRieck]

...and upgrade the primary drive with an 750 A crank and a hy-vlo chain.

Or CR750 primary chains (good luck there).

A NOS set of these were on EBay within the past month. I believe they went for about $300. First time I'd seen these.

I bid on those Jerry

[JLeather]

Ok, so presuming the 1080 kit might be a bad idea for street use, what about this thought?  I've got a forged 836 kit (ART pistons) that I believe is around 10.5:1.  Double base gaskets would reduce that to just a bit about stock compression, around 9.5:1.  I think double base-gaskets is the best I can do without requiring a longer cam-chain.  That setup could take atleast 5 pounds of boost without the need for anything too drastic.  Assuming I get a real good set of rods (falicon or carillo), micro-polish and chamfer the crank, and rebuild the engine from the ground-up with back-cut gears and new chains and everything, that should make a real nice street-turbo SOHC.  Meth injection just for added protection, along with an oil-cooler.  Run a Dyna2000 with the adjustable advance curve, etc.  I might even be able to pull 20 mpg out of that setup with proper tuning and easy riding.

As another thought, could I mill 10 or 20 thou off of the ART pistons without compromising them?  That would get me all the way back down to stock compression (give or take).  I've decided I really would like more of a street bike than a drag bike that occasionally gets ridden on the street...

[cafebob]

use an F head too....it will drop you into the 8's...no need to machine the pistons.

bob

[JLeather]

I've got a ported/polished/big valve head already that has a good chunk of change in it.  Not really looking to do another head.  Not sure, but I believe it's a K head.

[JLeather]

What about turboing an entire 'matic bottom end?  I've heard you can lighten the torque converter and grind the fins to raise the stall speed.  Something around 3k rpm stall would give the turbo time to start spooling before kicking in, and the give of the converter would save me drive chains.  Anyone seen a turboed 'matic?

[754]

Forged ??  ART pistons.. I am wondering about that...

Why are you avoiding cutting your pistons, pretty well evey turbo build does that unless they order ready made pistons which are also cut down.

 Take a closer look at those pistons..

 Build it right or you will wish you had.. as you are fixing up a pile of broken parts worse than you started with..

[JLeather]

Is there a definitive way to tell a forged piston from a cast?

[Big Jay]

Is there a definitive way to tell a forged piston from a cast?

The easiest way is to see if it says ART on it. If it does, it is cast.

The photo of those Carrillo bolts is not good enough to see if they are genuine CARR bolts.

Jay

[JLeather]

Well, guess they're cast pistons cause they sure say "ART" on 'em...