Topic: Old Skool Turbo CB750

[masonryman]

cool stuff

[Sporkfly]

I'm pretty intrigued. Still watching, waiting. Hope it works out for you! Really looking forward to your progress.

[voxonda]

I don't know if anyone had mentioned this. the drain for the cartridge (section section) shoud point down. the oil is gravity drained.

Speaking of drainage, how are you routing the oil lines?

Hey scartail,
You have a trained eye! The drainplug will face downwards, but because of the hasling to line everything out I have not yet rotated the centersection to it's right place. But that will happen within a few days.
Have mounted a adaptor to a clutchhousing where the drainline will be connected to. The oilfeed will come from the maingallery.

Cheers mate.

[scartail]

Hey scartail,
You have a trained eye! The drainplug will face downwards, but because of the hasling to line everything out I have not yet rotated the centersection to it's right place. But that will happen within a few days.
Have mounted a adaptor to a clutchhousing where the drainline will be connected to. The oilfeed will come from the maingallery.

Cheers mate.

Very nice build. Keep up the good work.

Is there much benefit in having equal length runners for the exhaust manifold on motorcycles? Asthetically, they are just beautiful. But I wonder about the gains versus the drawbacks (space).

[voxonda]

IMHO I do not think there is much benefit from equal length of the runners, at least with a Turbo. For a normal aspirated engine the length, diametre and the way you collect them, influence the characteristics of the engine. In my case to "balance out" the engine it will certainly not hurt him either.

Cheers, Rob

[voxonda]

Today purchased the "frame repair kit" from Ilbikes, so that will make life easier when swopping head's or even engines. Can't wait to install it.

Cheers, Rob

[johnny_from_bel]

I have allways wondered how turbos and carbs work together. By the looks the turbo is between carb and engine. Is that correct ?

[voxonda]

Hey Johnny,
Zie ik dat je uit Holland komt?

In this case that is correct, what is called a Draw-through setup. The Turbo draws the air and fuel mixture, thru the carb, in.
On the modern EFI equipped bikes it is more common to use a Blow-through setup, wher the Turbo is located in front of the carb's or EFI system and blows the mixture through into the engine.

Cheers, Rob

[johnny_from_bel]

Hey Johnny,
Zie ik dat je uit Holland komt?

Bijna, ik kom uit Belgie

[voxonda]

Hey Johnny,
Zie ik dat je uit Holland komt?

Bijna, ik kom uit Belgie

No problemo, heb een paar hele goede kennissen uit het Belgische! Leuk je te spreken.

Groet, Rob

[voxonda]

Received my "frame repair kit" today. All looks fine and will install the kit within a few weeks. Thanks Gordon for the fast delivery.

Cheers, Rob

[dp2275]

IMHO I do not think there is much benefit from equal length of the runners, at least with a Turbo

depending on the situation, there can be benefit.  when running a split pulse setup, equal length runners joined just before a split pulse flange combined in pairs of opposite firing cylinders can actually help to spool the turbo faster.  it works by shooting 'blasts' of exhaust into each side of the devided entry turbine in opposing pulses.  equal length helps here as the pulses are timed to hit the turbine wheel at equal intervails.  i used a setup like this on my bmw to get good spool time from a very large turbo (i used a deisel based schwitzer turbo with a t4 style .84a/r turbine housing capable of 600+hp and had full boost from 3500 till 7200redline on a little 2700cc motor). 

of course, you only really take notice of this when using a huge turbo with spool problems.  id rock whatever fits best in your case 

anywho...lets see this 'frame repair kit'!!  ive been interested in picking one up too!

[voxonda]

Hey dp2275,

You're right, but given the fact that the T2 is a 'small' turbo and I am trying to make the path from head to turbo as short as possible, think the T2 will spool fast. But still try to make the runners equal lenght. Think that will 'balance' the characteristic.
But I keep in mind that I am not building a bike for the strip, but make a fast 'roadburner'.
Kit looks OK, will show pic's installing it.

Cheers, Rob

[JLeather]

Man, don't know how I missed this thread.  I'm just getting back into a shelved project of mine, an ATP kit on a 750A engine.  I picked up an almost complete ATP turbo kit (rajay B-series compressor) that had everything but the wastegate (external) a while back.  I'm putting it on an auto for several reasons.  For starters, the trans is bulletproof on a 'matic.  Ask anyone who's dragraced one before.  They've also got the hi-vo chains which are stronger, and the 'matic starts out at a lower compression.

Biggest problem I'm about to face is oiling.  Since it's a wetsump engine it's only got a set amount of oil.  If I start running turbo lines and oil cooler lines, I'm worried it might have a tendency to suck the pan dry on a hard pull.  I want to modify it for a deeper sump and a longer pickup (lots of TIG welding gonna be involved in this one).

Or, can anyone figure out how to extend the oil capacity of the 750A without cutting and welding the pan?  Some way to utilize an external tank without it just draining back into the pan?

[Jerry Rxman Griffin aka MuthaF'er]

"anywho...lets see this 'frame repair kit'!!  ive been interested in picking one up too!"

Gordon has been putting these kits together with the help of an old friend and making them available for more than a year. They are not really a "repair" kit as such but rather a retrofit kit that makes doing top end engine work possible without removing the engine. 

If you do a search you should be able to find as much info as you need without having to re-hash all this again.

[dusterdude]

jleather,mount an oil tank on the bike somewhere and plumb in lines and make it a dry sump setup

[voxonda]

...
Biggest problem I'm about to face is oiling.  Since it's a wetsump engine it's only got a set amount of oil.  If I start running turbo lines and oil cooler lines, I'm worried it might have a tendency to suck the pan dry on a hard pull.  I want to modify it for a deeper sump and a longer pickup (lots of TIG welding gonna be involved in this one).

Or, can anyone figure out how to extend the oil capacity of the 750A without cutting and welding the pan? ...?

You could use the oilpan as a template to mill, or have it milled, a ring with the same contours as the oilpan and fit that between the cases and the pan. Depending how much more oil you need, you choose a height. The thickness of the ring is also the extra length for the pickup.

Would like to see a picture of the bike.

Cheers, Rob

[Terry in Australia]

Or, can anyone figure out how to extend the oil capacity of the 750A without cutting and welding the pan?  Some way to utilize an external tank without it just draining back into the pan?

G'Day JL, well from my experience with oil coolers, you can plumb in a tank with both fittings at the top of the tank, so the oil can't drain back, but will allow the oil to circulate from the engine, into the tank, and back to the engine via the engine's oil pump while the engine is running?

Depending on how much you want to increase your oil capacity by, some of the larger Lockhart coolers (or perhaps an auto transmission cooler) hold a fair amount of oil, on their own. Cheers, Terry.  

[JLeather]

Rob, I'll snag pics today.  It's actually going into a rigid framed chopper.  Although, if I had one of those purple frames I'd put it in that   The ring is an interesting idea, but it might interfere with the frame rails (gotta get it in the frame and check).

Terry, the volume of the oil cooler/turbo is the problem.  When the engine's off they drain back into the pan.  So, if I fill it to the normal fill level, once it's primed the turbo and oil cooler the pan level is a lot lower (potential over-sump on a hard accel).  If I fill it enough to account for that it is overfilled and may cause me other problems (leaks and such at startup).  Hence the desire for a deeper pan.

Dusterdude, I actually have an oiltank on the frame (a big one) since it's an Amen rigid frame.  It's got the electrics/battery in it too.  But I'm not sure how I'd go about changing the auto motor into a dry sump.  It's a lot different from a K-motor.  The oil pump is different, the pan is way different, and I don't know if the torque converter needs to be bathed in oil or what.  Any ideas on dry-sumping the engine?

THe last possibility is setting up the oil tank with a high-pressure pump and running a separate look of oil for the turbo with it's own filter and pump.  If I can find the right pump I'm gonna go that way.

Sorry for the highjack.  Soon as I get pics today I'll start my own thread

[martino1972]

hee,rob,in welke stad woon jij???(hey rob,in what city do you live??)

[voxonda]

hee,rob,in welke stad woon jij???(hey rob,in what city do you live??)

Hey Marti, ik woon in Grootebroek tussen Hoorn en Enkhuizen.(Hey Marti, I live in Grootebroek between Hoorn and Enkhuizen.)

[754]

If you extend the pan you need to extend bottom of pump to  be able to pickup (if you are indeed oil starving)

Vox, check out the inline4 header building kit from Cone Eng. come in 4 dia from 1 1/2 =1 7/8 and cost 100$ comes with 4 180deg bends, 2  45 deg and 2 90,s.. they have everything you need.

[voxonda]

If you extend the pan you need to extend bottom of pump to  be able to pickup (if you are indeed oil starving)

Vox, check out the inline4 header building kit from Cone Eng. come in 4 dia from 1 1/2 =1 7/8 and cost 100$ comes with 4 180deg bends, 2  45 deg and 2 90,s.. they have everything you need.

Thanks 754, looks good. Mine is coming along just fine for now, but maybe for a future projekt.

Cheers mate.

[76cb750]

I have a question for you Voxonda, where did you find your turbo and is it set up to be used as a draw thru set up. My understanding is that you need a carbon seal to run as drawthru?Any help would be appreciated! Thanks!

[voxonda]

I have a question for you Voxonda, where did you find your turbo and is it set up to be used as a draw thru set up. My understanding is that you need a carbon seal to run as drawthru?Any help would be appreciated! Thanks!

Hey 76cb750,

You stand correct, if you do not want a 'smoker' you have to run a carbon seal setup. Mine has not! But if I will find time, in the future, to finish this projekt, I'll have the T2 rebuild with a carbon seal. You can however run without but then he'll throw some oil out. The rebuild set is not costly, but putting it in should be done by a pro. The whole setup has to be balanced out.

Cheers, Rob