Topic: Turbo Billet Block CB750 Hits the Dyno!

[gpzkat]

Curious too - and I have a S&S Super B filter setup you're asking about, with the carb too, but the butterfly is stuck so it may be junk.

[Cb750 Racer]

Sorry guys it's been awhile. Not much too much progress I ended up getting the throttle linkage completely installed. Digging into the wiring now i made a complete power supply in and under the battery tray. Its powered from the battery going straight into a power distribution/ fuse block. The 6 fused wires go into the 6 relays on the underside of the battery tray. 4 of the relays are triggered together and are going to power on with the ignition switch( the 4 white wires soldered to the 10 guage brown wire). The plan is to have one power coils, one power engine ignition, and other 2 will power accessories like lights and guages.The other 2 relays will be for accessories, one for the boost activated water/meth injection. The other will be closed off for now bit may be used as a trigger for the rear brake light. The setup seems a bit unconventional but should get the job done nonetheless. The water/meth tank is going under the knife over the next couple days. I'm gonna open it back up and add a return and breather as well as the filler cap I was supposed to add before we sealed it off the first time.

Sadly due to lack of space and technical support I may end up ditching the powerarc ignition but we'll see how the next few weeks play out. Even if I find the pace to fit their unconventional coil shapes the lack of technical support is making it impossible to get everything i need to get it all together.

Just got my fish tank pump from Alibaba. https://www.alibaba.com/product-detail/New-Priming-Diaphragm-Mini-Pump-Spray_60683818914.html?spm=a2700.galleryofferlist.normal_offer.d_title.40a6405fjzDzQn
very similar to this unit. The pump actually flows an insane amount of water for the size. It supplies a 3/8 line with atleast 5lbs of pressure so the volume is more then enough. I originally planned on running a deadhead setup with a #45 pilot jet at the end of the nozzle but it just flows far too much. The pressure the jet creates makes a strong enough stream to flow across the garage. It's not very atomized either. With a y pipe fitting inserted in the line the flow is much more sensible so a return will need to be fitted. but the flow isn't quite atomized enough either so so i'm gonna start looking into emulation tubes and fittings like that I have sitting around. More updates to come soon.

[Cb750 Racer]

Disgusts me how much I've been turning this thread into a blog. So back to the building. Started the bike for the first time last night for only a few seconds before fumes filled the garage. I'll get some footage in the next week when it's warm enough to pull it out. The shotglass of oil down each hole a month back didnt help the first start. But the engines been sitting for 2 years now so it needed it.

Made some oil cooler mounting brackets out of 2 inch angled aluminum i got at home depot and got the whole oil cooler assembly finished the other week. The oil cooler adaptor is one of Cycle X's that I bored out some 1/2 inch npt to -8AN fittings with a 3/8 drill bit for maximum flow. running 8AN up to the cooler.


Also went ahead and got all the wiring ran through the bike which took the better part of a week but it's all there and done. Made up a little gauge cluster using the stock cb750 gauge mounting bracket. Decided to keep the original Krober for a tachometer and AEM gauges for boost/wideband. The boost activated water/meth trigger is all wired in and working as well. Just need to find room for the pump/ regulator then have an adaptor plate made for the hsr42 but that coming in the next 2 weeks hopefully. Also glued in two LED stripes under the seat cowl to make sort of an underglow running/tail light.






The powerarc ignition ended up being pretty simple to setup once you have all the parts but certainly is far from a ready to go kit.

The bike sounded badass the first startup, still a few things to wrapup before it hits the road. I'm sure im missing a few details along the way but like I said, Not a blog anymore it's gonna be a build thread.

[scottly]

Just got my fish tank pump from Alibaba. https://www.alibaba.com/product-detail/New-Priming-Diaphragm-Mini-Pump-Spray_60683818914.html?spm=a2700.galleryofferlist.normal_offer.d_title.40a6405fjzDzQn
very similar to this unit. The pump actually flows an insane amount of water for the size. It supplies a 3/8 line with atleast 5lbs of pressure so the volume is more then enough. I originally planned on running a deadhead setup with a #45 pilot jet at the end of the nozzle but it just flows far too much. The pressure the jet creates makes a strong enough stream to flow across the garage. It's not very atomized either. With a y pipe fitting inserted in the line the flow is much more sensible so a return will need to be fitted. but the flow isn't quite atomized enough either so so i'm gonna start looking into emulation tubes and fittings like that I have sitting around. More updates to come soon.

Rather than run a pump, which will only give you an on/off amount of flow, consider a boost pressurized water/ alcohol canister, like some of the hot turbo Corvair guys did in the '60s. As the boost goes up, the more water/alcohol injected with a given size jet. The canister has to be lower than the nozzle, or it will siphon.

[Cb750 Racer]

Scottly I'm gonna take you up on that idea I like it alot. I'm sold considering I wouldn't even have to modify the tank any further because the vent is on top. I'm really out of room for a pump/regulater too. I like the idea that preassure would raise with boost as well rather then a wall of water/meth at 5lbs. I was thinking of doing that to the gas tank if fuel supply was an issue but that would be perfect for the meth tank too

[gpzkat]

I have a water/alcohol tank that came with my GS1100E Mr Turbo but was never hooked up. All I have is the tank. I like the pressure idea.  In the limited riding I've done on it I have dipped into the turbo magic in the higher gears only, as 185+ HP scares me (as an old guy  I don't have the reflexes I used to).

[scottly]

Just for #$%*'s and giggles you guys should google the Oldsmobile Jetfire; a turbo 215 cubic inch motor.
They basically bolted the turbo onto the standard 215, with 10:1 compression, and relied on water/methanol to quell detonation. The "rocket fuel", or some similar name was available from the dealer.    

[bigutah]

Disgusts me how much I've been turning this thread into a blog. So back to the building. Started the bike for the first time last night for only a few seconds before fumes filled the garage. I'll get some footage in the next week when it's warm enough to pull it out. The shotglass of oil down each hole a month back didnt help the first start. But the engines been sitting for 2 years now so it needed it.

Made some oil cooler mounting brackets out of 2 inch angled aluminum i got at home depot and got the whole oil cooler assembly finished the other week. The oil cooler adaptor is one of Cycle X's that I bored out some 1/2 inch npt to -8AN fittings with a 3/8 drill bit for maximum flow. running 8AN up to the cooler.


Also went ahead and got all the wiring ran through the bike which took the better part of a week but it's all there and done. Made up a little gauge cluster using the stock cb750 gauge mounting bracket. Decided to keep the original Krober for a tachometer and AEM gauges for boost/wideband. The boost activated water/meth trigger is all wired in and working as well. Just need to find room for the pump/ regulator then have an adaptor plate made for the hsr42 but that coming in the next 2 weeks hopefully. Also glued in two LED stripes under the seat cowl to make sort of an underglow running/tail light.






The powerarc ignition ended up being pretty simple to setup once you have all the parts but certainly is far from a ready to go kit.

The bike sounded badass the first startup, still a few things to wrapup before it hits the road. I'm sure im missing a few details along the way but like I said, Not a blog anymore it's gonna be a build thread.

I’m dying to know what kind of power this thing should make.


Sent from my iPhone using Tapatalk

[Cb750 Racer]

Hoping for around 140ish on pump fuel BigUtah. That should be a good time. I don't see why it couldnt make 200hp with the correct fuel and a heavy water/meth spray but I got other bikes to go nuts with. 140 should make the tire pull up in just about any gear reagardless.

So I ended up rewiring the bike from scratch sorry I left yall hanging. The small 4 cell lithium ion battery just couldn't keep up with the draw, the battery would die before I could even get the AEM wideband heated up. My first decision was to wire all the lights and guages on a switch so I can just power them on when the bikes running to get around the problem. Obviously that would have it's own problems and would have went through widebands every couple of months but it was worth the effort. Decided a bigger battery was the better choice anyway so I ended up cutting away about half of the methanol tank to fit in a giant lead acid unit. In order to make it fit I had to relocate all the relays for room under the tray to make the battery stick out a bit less then it already did.



So now that the electronics are sorted, I could get to actually running the thing. I can get it started for only a moment if I have the choke on and pump the accelerator pump a few times, Nothing more then a few seconds seems too lean. I can keep it going if I crack the throttle right away (I'm guessing the accelerator pump is supplying it with a quick shot of fuel) then it falls on it's face after whether I crack the throttle more or less. I'm gonna try and get you guys a video tonight of what's actually happening.

The current Jet settings are 240 main jet, 35 pilot jet, 96# needle i believe (one richer then stock) middle clip and also a 4.5 float seat. Seems like my pilot jet is too small but i'm honestly not sure at this point. I think there may be something up with the choke mechanism because this hsr42 was converted to left hand throttle

[gpzkat]

I have the HSR42 on my GS1100E and it's running only a 220 main, got 185 HP out of it with 18 lbs boost but the rear wheel wasn't balanced and it was skipping on the dyno.  Guy should have balanced it and tried again.... .  Tuner said a 48 with more adjustability would have been better but it seems to ride fine for everyday not race use.

It doesn't need choke but given the long path to the cylinders, it's a bit tough to start if left a while.  I shoot a little starting fluid in and boom.

[Cb750 Racer]

I have the HSR42 on my GS1100E and it's running only a 220 main, got 185 HP out of it with 18 lbs boost but the rear wheel wasn't balanced and it was skipping on the dyno.  Guy should have balanced it and tried again.... .  Tuner said a 48 with more adjustability would have been better but it seems to ride fine for everyday not race use.

It doesn't need choke but given the long path to the cylinders, it's a bit tough to start if left a while.  I shoot a little starting fluid in and boom.

GpZKat I'm interested in what you're running for a pilot jet. I was told I'd be closer to a 60 pilot all said and done. Have a 35 in it now. That sounds like like a #$%*in ride anywhere I could check it out?

[gpzkat]

Here is a linkhttp://forums.sohc4.net/index.php/topic,183654.0.html
, I posted some vids and pcis before. It was mainly ridden at Bonneville and El Mirage from '82 to '96, but occasionally on the street. 2K miiles and pretty amazing with all the original take-off parts, plaques and time slips, posters, Don Vesco build receipts, pics from way back when, etc.  Pretty amazing bike.

I'll take a look at the pilot jet size and get back to you.

And a pic from a ride up the Ortega highway the other day plus a couple of glamor shots, sorry to hijack.

I have the HSR42 on my GS1100E and it's running only a 220 main, got 185 HP out of it with 18 lbs boost but the rear wheel wasn't balanced and it was skipping on the dyno.  Guy should have balanced it and tried again.... .  Tuner said a 48 with more adjustability would have been better but it seems to ride fine for everyday not race use.

It doesn't need choke but given the long path to the cylinders, it's a bit tough to start if left a while.  I shoot a little starting fluid in and boom.

GpZKat I'm interested in what you're running for a pilot jet. I was told I'd be closer to a 60 pilot all said and done. Have a 35 in it now. That sounds like like a #$%*in ride anywhere I could check it out?

[Cb750 Racer]

Ended up reading the HSR42 tuning book a bit and was able to get it going by fudging the air idle screw until it was rich enough to run. was only under a half turn out in all (2 turns out is stock) so according to Mikuni I need a bigger pilot jet so that's on the way now. Pumped to finally have it running all on it's own I can't thank everyone who helped along the way enough. Gonna play with the jetting some more and will get it on the dyno the second it's warm enough for me to ride it over.

[Cb750 Racer]

wowow that bike is gorgeous GPZKAT. That exhaust looks incredible I love how the dump sits high I wish my 900r was the same setup. You kept it immaculate I never realized the amount of acc lights on the Kat dash. That think is just oldskool cool I think you have a buyer haha. No rush on the pilot jet. I appreciate you taking the time to help me out. Hope to see that hellraiser in person some day

[gpzkat]

Thanks glad to hear you are on your way to turbo bliss.  Sure hits hard above 7K, ran it up to 11K, 3rd gear power wheelies at 90 MPH. need a rev limiter.

My older brother lives in CT (checked your location) up by Putnam, he rides Harleys and it's a pretty place to ride. I watch those Kaplan America videos on YouTube, that guy is a character, gets all the cool old bikes.   I just picked up a cheap and nice '79 GS1000E with some special parts on it, plus two free GS850's I'm pirating parts off, making it a daily rider. It would look good with the 1100's EPM magnesium wheels, sort of a Yoshimura look.
 

wowow that bike is gorgeous GPZKAT. That exhaust looks incredible I love how the dump sits high I wish my 900r was the same setup. You kept it immaculate I never realized the amount of acc lights on the Kat dash. That think is just oldskool cool I think you have a buyer haha. No rush on the pilot jet. I appreciate you taking the time to help me out. Hope to see that hellraiser in person some day

[Cb750 Racer]

Thanks glad to hear you are on your way to turbo bliss.  Sure hits hard above 7K, ran it up to 11K, 3rd gear power wheelies at 90 MPH. need a rev limiter.

My older brother lives in CT (checked your location) up by Putnam, he rides Harleys and it's a pretty place to ride. I watch those Kaplan America videos on YouTube, that guy is a character, gets all the cool old bikes.   I just picked up a cheap and nice '79 GS1000E with some special parts on it, plus two free GS850's I'm pirating parts off, making it a daily rider. It would look good with the 1100's EPM magnesium wheels, sort of a Yoshimura look.
 

wowow that bike is gorgeous GPZKAT. That exhaust looks incredible I love how the dump sits high I wish my 900r was the same setup. You kept it immaculate I never realized the amount of acc lights on the Kat dash. That think is just oldskool cool I think you have a buyer haha. No rush on the pilot jet. I appreciate you taking the time to help me out. Hope to see that hellraiser in person some day

That's less than an hour out from me if you ever find yourself out here visiting let me know! I'll dust off the old gpz900r and let you take it for a spin its been needing some ride time

[gpzkat]

Thanks, nice offer.... will do if/when I head back East. 

Thanks glad to hear you are on your way to turbo bliss.  Sure hits hard above 7K, ran it up to 11K, 3rd gear power wheelies at 90 MPH. need a rev limiter.

My older brother lives in CT (checked your location) up by Putnam, he rides Harleys and it's a pretty place to ride. I watch those Kaplan America videos on YouTube, that guy is a character, gets all the cool old bikes.   I just picked up a cheap and nice '79 GS1000E with some special parts on it, plus two free GS850's I'm pirating parts off, making it a daily rider. It would look good with the 1100's EPM magnesium wheels, sort of a Yoshimura look.
 

wowow that bike is gorgeous GPZKAT. That exhaust looks incredible I love how the dump sits high I wish my 900r was the same setup. You kept it immaculate I never realized the amount of acc lights on the Kat dash. That think is just oldskool cool I think you have a buyer haha. No rush on the pilot jet. I appreciate you taking the time to help me out. Hope to see that hellraiser in person some day

That's less than an hour out from me if you ever find yourself out here visiting let me know! I'll dust off the old gpz900r and let you take it for a spin its been needing some ride time

[Cb750 Racer]

Finally got the bike on the road but it still needs some serious tuning. The bike pretty much falls on its face after about 5k rpm so I think the 250 main thats in the carbs is still a bit too small. The throttle response is out of this world considering what the bike is. Idle is really smooth too overall I'm impressed. Any jetting suggestions would be greatly appreciated!

[PeWe]

Sounds really fine!

[Cb750 Racer]

Thanks Pewe! I'm honestly really impressed


Sorry gentlemen I had botched the video here's 2.0

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[PeWe]

If it get to little fuel at 5000rpm, the needle can be involved too. Raise it a notch or 2.

[gpzkat]

Just some head scratching... My understanding from reading and also talking to the tuner was that 220 is the largest for HSR42 (?). Maybe there are different versions of that carb though.  It can be jetted larger but needs to be modified/drilled?   I watched a YouTube video on a Z1 running the same carb with the same Rajay as mine, and it had to be drilled out for a 300.  Seems odd because that bike put 40HP less than mine on the dyno 

I had put a fuel pump on mine as it ran one at Bonneville, but my tuner said it didn't need one, and he was right.  All I did was put a main jet extender kit on so it could drink a little deeper, as my carb is not quite vertical.  No idea if that helped, but it didn't hurt.

FYI the video is here: https://youtu.be/x1YbxN1RaVg?t=294

Good luck!

[Cb750 Racer]

If it get to little fuel at 5000rpm, the needle can be involved too. Raise it a notch or 2.

I currently have the richest needle in there Pewe raised 1 position from stock, I think that may even be too aggressive but it's more falling on its face up top and rich down low

Just some head scratching... My understanding from reading and also talking to the tuner was that 220 is the largest for HSR42 (?). Maybe there are different versions of that carb though.  It can be jetted larger but needs to be modified/drilled?   I watched a YouTube video on a Z1 running the same carb with the same Rajay as mine, and it had to be drilled out for a 300.  Seems odd because that bike put 40HP less than mine on the dyno 

I had put a fuel pump on mine as it ran one at Bonneville, but my tuner said it didn't need one, and he was right.  All I did was put a main jet extender kit on so it could drink a little deeper, as my carb is not quite vertical.  No idea if that helped, but it didn't hurt.

FYI the video is here: https://youtu.be/x1YbxN1RaVg?t=294

Good luck!

I appreciate that input I'm going to drill a 300 main jet tomorrow and see what happens. Haven't seen many builds need one that large like you mentioned but we'll see if that's any improvement.

[gpzkat]

Not sure I'd go drilling yet, but then again I'm not a carb expert and I left it to a guy with a dyno who could measure fuel/air ratio etc.  He installed a O2 sensor.  I bit the bullet, it cost me some $ but I would just have been stabbing in the dark.  Good luck whichever way you go.

[MRieck]

 If it is to rich it will fall on its face too.....just something to keep in mind.