Author Topic: Boosted Applications... Turbo/Supercharger (Read 58935 times)

BLUE71TURBO · « **Reply #125 on:** November 29, 2009, 11:53:19 PM »

Quote from: wannabridin on November 29, 2009, 09:33:00 PM

turbo, every time i see that damn bike i drool, it is SO freggin cool...

do you have a build thread for it by chance??

Thanks for the comment. Here ya go.....http://forums.sohc4.net/index.php?topic=56783.msg612975#msg612975

Bamboozler · « **Reply #126 on:** November 30, 2009, 05:37:45 PM »

Quote from: 23tbucket on November 29, 2009, 08:16:59 PM

Hello. This is my first post on this site. I recognize lots of names here and there seems to be quite a few fellow Canadians on this site as well. Seems like their are more people here interested in similar things as myself. I'm getting a bit disillusioned on some of the BS going on another site i've been on since 2005. Time to move on.... I am in the process of putting fuel injection on a '76 CB 750A, using microsquirt to drive things. This engine is also going to be supercharged and will have an external alternator. I can move some of my other site posts on installing throttle bodies on the SOHC 750 if you are interested. This is my first SOHC build....I've built up 2 CB550's and 1 DOHC CB750, which is fuel injected and turbocharged. It's over at Deuces Wild DOHC if interested? There is also a "how-to" on installing throttle bodies for the DOHC on the same site. If i'm stepping over the line with this first post, please let me know...no offence will be taken.
Thank You; Clifford

Welcome to the board 23tbucket. I for one would enjoy to see what you can do with the FI/supercharger project. Do make sure you create a thread in the project forum when you start. You're probably already versed as to what FI/SC threads there are from searching. I think if you're going the route of adding an external alternator your only real limitations are lifted. Welcome again and post up the goods when you get em!

23tbucket · « **Reply #127 on:** December 01, 2009, 07:58:17 PM »

Thanks for the welcome Blue71turbo and Bamboozler. Beautiful scoot there Jon. No doubt about it...we need more fellows to play around with fuel injection, turbocharging, and supercharging on these old engines. I am no guru on any of this stuff.....just like things different!
Lots of folks on this site.......should be a real good place to find and convert others to go FUELLY!

Jleather will remember this post on one way of installing throttle bodies onto a SOHC CB750..................................
http://www.hondachopper.yuku.com/topic/24588/t/Electronic-Fuel-Injection.html?page=1

JLeather · « **Reply #128 on:** December 02, 2009, 01:32:09 PM »

Oh yeah man. You're truly a pioneer Cliff. I did eventually decide to stick to a draw thru setup on my bike, mostly because I have the whole kit already, but I'm gonna try FI on another bike one of these days. Welcome to the site, and good luck

JLeather · « **Reply #129 on:** December 05, 2009, 04:28:18 PM »

BLUE71, maybe I asked before, but what rods are you running in that beast? Did you switch to bottom-end studs? Any other little mods along the way?

BLUE71TURBO · « **Reply #130 on:** December 12, 2009, 05:49:06 PM »

Sorry JLeather ! I spaced on your question.

The rods in my engine are rare steel R.C. ENGINEERING SUPER RODS.
They are not worked over stock rods, these have larger-wider beams and end caps w/special bolts also.

JLeather · « **Reply #131 on:** December 14, 2009, 03:22:51 PM »

Gotcha. Interestingly enough, I think those are the rods that Ken's "Super Rods" are roughly patterned after.

http://www.cyclexchange.net/Superrods%20Page.htm

Those are the ones I picked up for my turbo build. I'm gonna be starting up a build thread very shortly (soon as my new frame's here).

BLUE71TURBO · « **Reply #132 on:** December 14, 2009, 04:27:04 PM »

Nice rods JLeather !

How high of boost are ya gonna run ?

JLeather · « **Reply #133 on:** December 14, 2009, 08:31:50 PM »

Dunno, I suppose I'll start at 5 or 8 and slowly crank it up til I get scared or it blows

BLUE71TURBO · « **Reply #134 on:** January 17, 2010, 10:18:01 PM »

Hey JL, what type of wastegate are ya gonna use ? Also what carburetor ?

JLeather · « **Reply #135 on:** January 18, 2010, 07:29:45 PM »

Not sure. I've got 2 of the correct RayJay wastegates in usable shape. But they're pretty old. I'd feel better with a new one, although not one of the cheap chinese ones on eBay (a decent one seems to run $150-$350).

The carb is also another hangup. I've got a Mr Turbo 34mm Keihin butterfly carb courtesy of NitroHunter. Came off one of his old turbo CB750's. I think it's a '76-'80 Sportster carb, and as such parts are readily available. I can rebuild it, and it's already got a port for pre-carb meth injection (which I will be doing as well). I've also got 2 good runable (need bowl gaskets) 38mm Bendix carbs that were on RayJay kits. I contacted Terry at Mr Turbo and asked how they got away with a small 34mm carb on so many kits, and he said it was plenty even though they now recommend a Mikuni 42mm flatslide. I could go with a more modern carb (HSR42, S&S, VM38, etc) but then which one? Does it even matter? The VM38 is quite inexpensive, parts are everywhere. Very simple, etc. But maybe there's a reason the kits always ran fixed-venturi carbs? Also, I like the idea of the accel pump since it's a street app.

I always meant to ask why you ended up with an SU carb. Wouldn't your kit have come with a shovelhead 38mm Bendix as well?

There'll be a build thread starting sometime soon. I'm waiting for Big Jay to find me some sleeves so I can send the upper case and the jugs off for machining. I already bought all new trans bearings. I'm quietly gathering parts, and seriously hope to have this bike up and running by the early summer. Oh, and it's going into a rigid 250-tire'd frame

BLUE71TURBO · « **Reply #136 on:** January 18, 2010, 09:33:21 PM »

What kind of sleeves are ya looking for ? LA sleeve company should have anything you need. What size pistons are you gonna run ?
Yes i have the bendix carb that came with the kit, but the SU carb is a constant velocity carb. It will only supply the amount of air and fuel that the engine will need plus it doesn't have a flat spot. Round and flat slide carbs have a tendency to stick open at idle or when coming back down to idle in turbo applications. All you have to do in that case is to use a stronger return spring. A friend of mine
has a kz1300 6 cylinder thats turbo'd and runs a mikuni HSR 42 and has no problems. Once ya get it going, try different carbs and see which you like the best. As for the A.T.P. wastegates, I'd use them. I've never heard of anything going wrong with them. Mine is 30 years old and works just fine.

JLeather · « **Reply #137 on:** January 19, 2010, 05:05:05 AM »

It's gonna be an 836, J&E pistons. It would fit in a stock sleeve, but Big Jay said he used to do these kits and recommended a thicker sleeve because of all the extra heat from the turbo. He was looking for a set of CB350 or CB900DOHC sleeves.

I know about the slide problems with some of those carbs. It's the same problem a lot of people had with the drouin s/c's back in the day. They had an internal slide-style injector that apparently would stick sometimes. People either put a better spring in, or actually installed a return-cable and used a push-pull throttle.

How did you go about setting up the SU? Since it's a CV carb, did you have to boost-reference it or anything? I've tuned plenty of N/A engines, but I'm not sure how to go about tuning a draw-thru turbo setup. Did you use an O2 sensor, or is it still possible to tell rich/lean conditions by engine performance.

754 · « **Reply #138 on:** January 19, 2010, 09:07:37 AM »

Rivera Engineering (Rrivera/Primo)
was into SUs on bike for a long time. I think at one time they had a turbo kit, they maky be able to answer your questions..

We were selling Rivera products way back, put a brand new SU on a Harley and rode it to Sturgis. it got stupid mileage, like 65 or 70mpg !.. when we took the top end off later, we found 1 standard bore, 1 .010 over!.. it ran fine.. so that is why I never worry much about running 1 oversize piston if you scratch up a bore..

BLUE71TURBO · « **Reply #139 on:** January 19, 2010, 01:13:25 PM »

754 is right. That's where i got my SU carb many,many,many years ago. It is a very simple carb and easy to adjust. Mine does not have the tickler setup on the side, which is used like a accelerator pump to inject gas for cold starts on Harleys. Rivera engineering
already had a baseline for the needle and mainjet and i went a little bigger beyond that. I would just use the bendix that you have
and go from there. I have all of the original paper work that came with the A.T.P. turbo kit. If my memory is correct it has all the info on how to setup and adjust everything.

JLeather · « **Reply #140 on:** January 19, 2010, 02:41:07 PM »

Well, I for one would love to see scans of that documentation if you don't mind. I think I'll be running the 34mm Mr Turbo carb cause it has the water-injection port, although only if I can get it rebuilt correctly. Otherwise I suppose it'll be the 38mm Bendix. There are a couple relatively cheap SU's on eBay. Would a modern sportster 40mm CV behave pretty much the same? I mean, a CV is a CV. Interesting that flatslide and roundslide carbs would have sticking issues but not a CV. Doesn't a CV also use a slide, and with a very weak return spring, for the venturi changes? Or is the SU a different kind of CV carb? I'm not familiar with the internals of an SU.

BLUE71TURBO · « **Reply #141 on:** January 19, 2010, 03:47:51 PM »

J LEATHER, I'll dig out all of the paper work and try to scan it and post it here. As for the sleeves, LA sleeve co. has anything you want.
I've looked at their catalog at my friends shop. They also can make up custom sleeves.

BLUE71TURBO · « **Reply #142 on:** January 19, 2010, 06:50:56 PM »

Here ya go JLEATHER !

BLUE71TURBO · « **Reply #143 on:** January 19, 2010, 06:54:14 PM »

Here's some more.........

NitroHunter · « **Reply #144 on:** January 20, 2010, 08:11:29 AM »

It was my understanding that on a draw thru system, any type of slide carb could stick when the compressor was drawing enough flow (boost)... hense the kit use of butterfly carbs. Hmmmmm, maybe if you chopped the throttle closed, it would want to stay there due to instant mega carb-to-compressor adaptor manifold vacumme?
My guess is that a push-pull throttle set up works just fine - since the HRS 42 is all the rage now.
Well on the 'ancient' draw thru systems.

BLUE71TURBO · « **Reply #145 on:** January 20, 2010, 12:18:10 PM »

From all the info that i have come across it seems that only some flat and round slide carbs have problems. I guess it depends on many situations as in carb size to engine size and specs. The SU carb i use works great. The new MIKUNI HSR carbs are the best for many applications.

HavocTurbo · « **Reply #146 on:** January 21, 2010, 10:59:22 AM »

The old slides would stick from boost and/or friction.

All that air rushing through them would make the carb hesitate long enough to scare people when letting off the throttle really quick.

And in some cases I've had the slide(s) physically stick from the side pressure of the incoming air.

We used to grease them slightly but it never really helped much.

HSR's are ridiculously easy to use and tune. Probably the best thing to happen to Mikuni/Harley combinations.

voxonda · « **Reply #147 on:** January 21, 2010, 11:27:14 AM »

+1,

Used the HSR42 on my 750 Turbo and worked fine considering never build a Turbo before. Still miss the powerboost from that engine/Turbo combo.

MRieck · « **Reply #148 on:** January 21, 2010, 11:41:52 AM »

Quote from: HavocTurbo on January 21, 2010, 10:59:22 AM

The old slides would stick from boost and/or friction.

All that air rushing through them would make the carb hesitate long enough to scare people when letting off the throttle really quick.

And in some cases I've had the slide(s) physically stick from the side pressure of the incoming air.

We used to grease them slightly but it never really helped much.

HSR's are ridiculously easy to use and tune. Probably the best thing to happen to Mikuni/Harley combinations.

RS's are the Chevy smallblock of carbs

BLUE71TURBO · « **Reply #149 on:** January 21, 2010, 11:50:01 PM »

So I guess that makes the DCOE WEBER the big block of motorcycle carbs ? :

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Author Topic: Boosted Applications... Turbo/Supercharger (Read 58935 times)