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Discussion Starter · #1 ·
Hey there forum,

I'm in the process of supercharging a 1976 GL1000. I'm 3d printing an airbox, running roughly 5lbs of boost. This is my first attempt at forced induction. I'm not looking for insane power gains or anything, I'm more concerned with the engines longevity.

I've been following what Randakk did with his Supercharged gl1000 build. I was going going to add an external oil cooler to the engine and run a single carb off a VW Beetle that I had on the bike before starting this project.

If the above sounds good than I'll keep running with it. What I'm stuck on right now is timing and ignition changes.

I want to prevent detonation in this bike without having to use methanol injection or something. I was planning on getting a CB750 dyna 2000 unit so I could program the advance and set rpm limits. I'm most concerned with boost affecting this bikes rev limiter and me blowing past redline and blowing the engine. That's why the rev limiter programmer on the dyna 2000 unit is so appealing if it's possible to use. Could I program a rev limiter and have enough timing control for my needs with only the dyna S unit? Or do have to go all out and fab a petronix unit up to the cam shift like randakk did in his build? Should I be doing anything else for bike longevity?!

Sorry if this is long winded. I'm stuck at home with covid and have a real urge to finish this project haha!

Edit:
Dyna unit I am referring to: https://www.dynaonline.com/dyna-200...-1978-honda-500-550-750-four-cylinder-ddk1-2/

Randakk build I am referring to: https://www.dynaonline.com/dyna-200...-1978-honda-500-550-750-four-cylinder-ddk1-2/
 

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Welcome to the forum. That sounds like an interesting and challenging project. We do have a number of members that have racing backgrounds. Hopefully some of them will be able to help.
 

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Hey Marsbio - Along with an 84 and 96 GW, I also ride a 83 CX650 Turbo. It's a real hoot when the Turbo kicks in - so I'm sure a supercharged bike would be similar. You must be very technically skilled but is your planned project a trial and error "build it yourself" effort or have you tackled something similar previously ? As I'm sure you already know - if not careful, without some potentially expensive upgrades a supercharger can turn a reliable 1,000 cc GW into a molten chunk of aluminum. If the spirit moves you and you enjoy the doing the work- don't be discouraged to build your bike though.

There are companies that sell bolt-on supercharger and turbocharger kits with all the bugs (timing controller, mixture, compression, HP and Torque curves, etc....) already worked out. Some even offer additional packages that includes inter-coolers and staged nitrous injection. The only problem with installing one of these kits is that the warranty typically ends as you leave their building.....

Here are a couple of companies known to sell very high quality products -
Motorcycle Superchargers Models & Specs | ProCharger
https://www.rotrex.com

Good Luck - Michal
 

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Discussion Starter · #4 ·
Welcome to the forum. That sounds like an interesting and challenging project. We do have a number of members that have racing backgrounds. Hopefully some of them will be able to help.
Thanks a lot! Happy to be here. This project has been on the back burner for years so I've had tike to brew over some of the details.

Hey Marsbio - Along with an 84 and 96 GW, I also ride a 83 CX650 Turbo. It's a real hoot when the Turbo kicks in - so I'm sure a supercharged bike would be similar. You must be very technically skilled but is your planned project a trial and error "build it yourself" effort or have you tackled something similar previously ? As I'm sure you already know - if not careful, without some potentially expensive upgrades a supercharger can turn a reliable 1,000 cc GW into a molten chunk of aluminum. If the spirit moves you and you enjoy the doing the work- don't be discouraged to build your bike though.

There are companies that sell bolt-on supercharger and turbocharger kits with all the bugs (timing controller, mixture, compression, HP and Torque curves, etc....) already worked out. Some even offer additional packages that includes inter-coolers and staged nitrous injection. The only problem with installing one of these kits is that the warranty typically ends as you leave their building.....

Here are a couple of companies known to sell very high quality products -
Motorcycle Superchargers Models & Specs | ProCharger
https://www.rotrex.com

Good Luck - Michal
Hey Michael, thanks for getting back to me! I certainly know my way around a bike, normally just need a service manual, but I've never tried any form of power mods besides carb and pipe and weight upgrades. I've spent a little time doing my due diligence regarding keeping the engine safe post-supercharger. The potentially engine destroying issues I've come across that I need to prevent are detonation in the cylinder before TDC which is why I want timing control, and also potentially the head gasket blowing. I'm not sure how likely the headgasket would be to blow or where I could get a copper head gasket to replace the stock one. Should I be using dual head gaskets to reduce cylinder compression?

If there is a kit that includes timing control for supercharger I will sell my kidney for it hahahaha, I could not find one now while googling. I rode one of the turbo 650s, very cool! Boost is definitely a thrill to experience, I'd just like a mild amount here!

If you have any other recommendations for post supercharger mods for a goldwing I'd appreciate it! Was wondering if I would need to add stiffened valve springs or something else too given how fast the engine will be wanting to rev!
 

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Stiffer valve springs and reducing compression are both high on my list when boosting any engine, I would also try to find the cam profile and how much if any overlap it has.
 

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Back in the late '70's I installed a supercharger on a KZ650 Kawasaki. It was a Drouin Supercharger kit for a CB750, I spent all winter modifying the parts to fit the Kaw. Needed to build new mounting plate, modify the intake manifold etc.. It was very fast after completion, for about a week and a half "then boom". I was young and not knowledgeable enough about turbo/supercharging. I put it on a totally stock motor, the KZ650 had too much compression and cast pistons both no-no's for boosted motors. Forged pistons should be used when supercharging, mine did not melt from a lean condition but rather they broke, looked like they had been hit with a hammer (detonation ).
Stiffer valve springs and reducing compression are both high on my list when boosting any engine, I would also try to find the cam profile and how much if any overlap it has.
More good suggestions.
Have fun with your project but be aware it can get expensive if you cut too many corners.

Classic Cycle City Gallery - Drouin Supercharger Honda CB750 SOHC

CB750 Drouin Supercharger

https://www.bikebound.com/2020/11/08/supercharged-goldwing/

https://thekneeslider.com/randakks-supercharger-for-honda-gl1000-gl1100/
 

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To do a reliable boosted engine it should be built from the bottom up as 823jim posted the pistons and the piston profiles along with the connecting rods should be considered when boosting an engine. The stresses that the boost will put on the bottom end are likely more than they are designed to take. I built a boosted ZX11 and put in Carello rods and Weisco pistons, slipper rings and in about 6 to 10 passes the engine had to be refreshed. You should also think about degreeing your cam since the factory tolerances can be +-3%.
 

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Discussion Starter · #8 ·
I just acquired my starting point which will be an AMR500 supercharger. It's really popular with the VW flat 4 guys that run a single carb and it puts out more than enough volume for me.

I'm currently waiting for my next paycheck to pay off another bike I just bought (really cool Honda xt600) to buy any parts but next on my list is a copper head gasket. There was no way I could make stock head gaskets work and I found somewhere where I can get a head gasket of a specified thickness : Honda Goldwing head gasket – Redline Gaskets
Haven't ordered from here so open to suggestions otherwise these will have to do.
I will be ordering one of these to double the thickness of original head gasket to lower compression. I should only get a minor compression reduction but it'll let me sleep at night.

I was going to get some beehive valves and springs for the goldwing to replace the double springs but I'm not sure what size the goldwings valvesprings are. I was convinced on the beehive after reading this article: Beehive Springs Sound Great, But Will They Work For You? - EngineLabs

If anyone knows that information I would be very grateful as I don't want to open my heads to find out yet and I couldn't find the information on and parts vendors sites leading to confusion for me.

Other misc parts I will be aquiring:
Oil cooler + adapter from oil filter. Randakk adapter is too expensive so I'll use an ebay one.
RC51 dual water coolers: I'll use split radiators so the radiator doesn't get in the way of the supercharger. Should help keep the bike cool too.
AFR sensor: I found $150 units on ebay to make tuning the carb easier when things are running.
dyna s + 5ohm coils: I want a strong spark so the stock coil and points had to go.

I've been strongly considering adding a methanol or h20 injection kit after the story 832Jim told of his detonation experience! But maybe the excessive and extra engine and oil cooling would suffice to help avoid this...

I am thinking about adding a blow off valve as well to control boost, mainly because I love the way they sound even though it would be completely unnecessary for this build.

I was only going to advance my timing but I started to read up on degreeing my cams it seems like I can modify the timing more/more reliably through a degree vs just an advance? I still have more reading to do on that front.

I told myself from the start that I wasn't going to do rods or pistons, mainly because I could not find a forged set. Would it be worth just replacing the stock ones with oem stuff when they've shown that they're good enough to put up with 45k original miles? Honest question. I'll think about it. If anyone knows of reasonably spriced forged internals (haha) please point them out!

I'll get photos for everyone soon. The bike is kind of trick imo as is, it's a single carb conversion with a poor cafe job (previous owner), drag bars and awesome Lester wheels. I started a trail master single front unit conversion too. This will be a serious project but hey I've been learning about this for years and waiting to finish school to start this project!

Thank you for all the EXCELLENT advice so far gents!
 

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I had an XT600 but it was a Yamaha, had a coworker turbo a Toyota 2.2 truck engine and used a water injection kit to manage combustion chamber temperatures. It worked out better than we all thought it could, for ‘back then’. He’d run window wash in it in the winter (Minnesota). He liked the setup and it seemed to last for a few years that way. He eventually installed a normally aspirated 6 cylinder engine that brought on all sorts of driveline upgrades due to breakage.
 

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Discussion Starter · #10 ·
I definitely do like the sound of adding methanol as AEM makes good stand alone kits that I can incorporate. Easy way to control temps and detonation IMO but I have a chemistry background so it might sound better in my head than it really is.
 

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It looks like you are on the right track, since Honda made the wing extremely understressed degreeing the cams and adding a thicker head gasket your engine should be able to handle your 5# of boost pretty well. One possible suggestion is to add a dynojet or other tuner to stabilize the A/F mixture throughout the rev range. I do not know if this is possible with your single carb swap.
 
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Discussion Starter · #13 ·
It looks like you are on the right track, since Honda made the wing extremely understressed degreeing the cams and adding a thicker head gasket your engine should be able to handle your 5# of boost pretty well. One possible suggestion is to add a dynojet or other tuner to stabilize the A/F mixture throughout the rev range. I do not know if this is possible with your single carb swap.
I don't believe I would be able to add a dynojet kit because of my aftermarket carb... I'm thinking of getting a pack of different sized jets for it and using a AFR gauge plumbed to the airbox to tune my AFR through the rev range... that is something that seems very tedious to do, but necessary potentially
 

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Hey Marsbio - Are you set on supercharging your Goldwing ? Depending on how much money you plan on investing and how hard you plan on riding, trying to safely manipulate the timing, fuel ratio and boost without some kind of integrated computerized tuner can be pretty difficult. Years ago - I cooked a CX650 Turbo during the High Plains Raceway open track day near Denver even though it's digital fuel injection, timing and boost was controlled by a special computer specifically tuned for high-speed endurance laps. An intercooler with water injection during wide-open-throttle plus highly modified heads and cam had also been added. Still own the bike but detuned her back to the original stock spec's both for longevity and to adjust to my current geriatric riding style. 😊

Good Luck with your project - Michael
Tire Wheel Plant Smile Vehicle
 

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Discussion Starter · #15 ·
Hey Marsbio - Are you set on supercharging your Goldwing ? Depending on how much money you plan on investing and how hard you plan on riding, trying to safely manipulate the timing, fuel ratio and boost without some kind of integrated computerized tuner can be pretty difficult. Years ago - I cooked a CX650 Turbo during the High Plains Raceway open track day near Denver even though it's digital fuel injection, timing and boost was controlled by a special computer specifically tuned for high-speed endurance laps. An intercooler with water injection during wide-open-throttle plus highly modified heads and cam had also been added. Still own the bike but detuned her back to the original stock spec's both for longevity and to adjust to my current geriatric riding style. 😊

Good Luck with your project - Michael
View attachment 278909
Hey Michael,

That's a sweet ride you got there! I almost snagged a seca last weekend to make up for the last of turbo cx650s in New England. Your story is not inspiring but I will have to persist in this endeavor. I started something and have to finish it LOL :)

I have thought about the many issues I may encounter and have decided that it is cheap enough to blow engines for the time being in the name of learning. I have so many parts engines! 1100s.... 1200s.... this setup should work on them all! I'm going to solely fit the supercharger for now and try to fix the carbs then get then dialed in to idle with the sc... I predict engine will have issues from sitting and supercharger may still have gunk in it after cleaning. Only one way to find out. If things go well I will be moving to longevity mods before giving the engine any juice. Really need that oil cooler!

Here are some updates:

Light Automotive tire Wood Motor vehicle Automotive design



Tire Wheel Fuel tank Vehicle Automotive lighting


Tire Wheel Hood Automotive tire Automotive lighting
 

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Discussion Starter · #17 ·
Motor vehicle Automotive tire Vehicle Tire Wheel

Mock fitting - need to get everything straight and tight before we get to make some boost. I went with a single V pulley for now.

To do:
Tension the belt
Mate carb with supercharger
Make gaskets for carb, supercharger and airbox
Add blow off valve to airbox
Test drive :cool:

Will be a little bit before any updates.

It was a real successful winter break, I got a 81' wing and a 83' vf1100s AND a 1975 RD125 running as well as getting this all fitted. If I wasn't going to sell all of them I could see myself throwing a large supercharger on the sabre with its nutty v4 engine. From the sounds of it though those engines are already more than a little strung out, not much headroom to add extra power.
 

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Discussion Starter · #18 ·
Quick question with possibly a long answer... I've never worked heads before and am trying to find correctly sized and tensioned beehive valve springs for the gl1000. When I go to part sites I can not find much info on the valve springs and I couldn't find any info on them in my manual!

Anyone able to share some knowledge?

Current plan:
1. Make my own thicker head gaskets out of gasket paper because no one wants to machine copper ones for me.
2. Polish valve ports and replace springs with beehives
3. Get an oil cooler and larger rads for the 'wing
4. Blow off valve
5. Boost
 

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Quick question with possibly a long answer... I've never worked heads before and am trying to find correctly sized and tensioned beehive valve springs for the gl1000. When I go to part sites I can not find much info on the valve springs and I couldn't find any info on them in my manual!

Anyone able to share some knowledge?

Current plan:
1. Make my own thicker head gaskets out of gasket paper because no one wants to machine copper ones for me.
2. Polish valve ports and replace springs with beehives
3. Get an oil cooler and larger rads for the 'wing
4. Blow off valve
5. Boost
Not seeing any springs over on Randakks.com , but it doesn’t mean he doesn’t know where to get them. I’m watching your progress.
 

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About the only way you are going to find the springs you are looking for is to mic you old one for length and diameter and then minus any specs from Honda on the tension you will have to find a engine builder that should have a spring gauge to tell you the tension on your springs. If you have a custom engine builder near you be should have access to a book that will list your possible alternatives. When we built balanced and blueprinted engines we would always check the tension on each valve spring. As far as making a thicker gasket out of gasket paper, you are only setting yourself for a blown gasket on startup. If you can double up the OE gasket would be a better alternative. A double gasket can be done and I have done it on engines to reduce compression but again I would suggest running what you will be doing by a builder as different gasket types have to be mated differently. If you go with the double gasket, gasket longevity will be affected. Wish you luck.
 
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