GS400/500 Gr650 Hybrid engine

[Rensdw]

What a COOL! Build!!!!
I knew someone else who used GS450/GS500/GR650 parts to build a six speed 850CC twin.
Cannot wait to here how well it goes!!!
G

thanks

850CC!! ? was he gone mad? did the crank hold up? he did use the 450 plain bearing crank right?
Well....any details will be appreciated

[Rensdw]

An oldie worldie GS750 straight cut primary gear will not work, on the clutch side the big gear is aprx. 20cm in diameter, the GS400 clutch is 16.5cm
Next stop:.........Ducati clutch

[Rensdw]

So here you can see how the dry clutch is build up, I can modify the stock clutch basket to accept the ducati basket and everything that is on top of it.
I will need to modify the stock basket/gear in such a way that there will be enough space for oil seal number 16 in the drawing.
The stock Suzuki gear will be in the wet area, the clutch in a custom made cavity, I think I will keep the stock sidecover.
Another thing is the springs in the gear, I'll have to remove those and stick a solid rod in the holes, the Ducati clutch has dampeners already.
Beside the amount of work I will have to do I don't see any major issues here, I might have to make a custom nut because the gearbox shaft won't stick out enough to get the nut on.
I will take the clutch off my Ducati to make some proper measurements and compare everything, I have to replace the rusted springs anyway.

Now, the second option is to use the whole Ducati clutch assembly including the straight cut gear, I will need a custom SC gear for the GS crankshaft.
This will also complicate things with getting the clutch on the Suzuki gearbox shaft, i will have to look at the stuff IRL to see how to resolve that issue.

And while I'm at it, why not use the whole hydraulic operating gear too? that should be easy to retrofit.
The piston is small, and there is plenty of room there because of the stock clutch mechanism.



Please tell me this is dumb, useless, won't be cool in the end etc. etc. to save me a lot of trouble (<<<please don't)

[gmansyz]

From what I remember, as I did not pay much attention-4 cyl. guy, I think the bore was 85mm. And the cylinder use was a resleeved 650. And the 650 head and cases and crank as well. And I think the 500 6-speed trans was used too. Though there was something about the shifter mechanism being different??? Or was it the 450 was different?
Sorry, I do not know the bores and strokes of these to go any further.
Laters
G

[Rensdw]

Maybe he fitted the 650 crank in the 500 crankcase.

The GS500 has an inverter shifting drum, you can tell by the shifting lever it has no linkages.
If you put linkages on a GS500 you will have: 1 up for first gear and then 5 gears down.

[Rensdw]

Ok, I went to the workshop to dig into this clutch thing, good news and a challenge.

I took the GS400 clutch apart and started on taking the Ducati clutch apart, unfortunately I don't have a 32mm socket so I couldn't take the clutch off the shaft.
Laid all the parts side by side and compared the Suzuki outer basket to the Ducati basket, also I compared the clutch plates.

I laughed because it was funny to see how similar the clutches are, it is unbelievable!
The outer baskets are basically the same, same diameter, spacing is the same, the Ducati one seems to be stronger.
The inners are different though, together with the steel plates, diamters are roughly the same but teeth spacing/count is different.
Now the funny part; the clutch plates are 100% absolutely exactly f*ck*ng the same!
It is possible to fit Ducati plates in the GS400 clutch and the Ducati plates fit in the GS400 clutch, this made me so happy..
The nut on the ducati clutch is big and it looks like it would be easy making a custom nut that will fit the smaller suzuki axle.
The biggest issue here will be modifying the Ducati inner to fit on the suzuki shaft.
I will have to remove the clutch from the engine to be able to compare the inners.

Pics or it didn't happen!


Here you can see a Ducati plate in the GS400 basket


Now the challenge, clearing the ignition system:

This will be the stock position for the C5 system, the dry clutch cavity will start right under the left upper edge of the PCB.


If I make a backplate and mount the ignition like this I would gain a lot more clearance:


Here you can see how close it is to the ignition, the dry clutch cavity will take out a big chunk from the ignition "cavity"



I think I am going to design a thin walled "bucket", the bottom somewhat thicker with an oil seal and weld this into the sidecover, will be the easiest way of doing this.
Not going to use the hydraulic operating mechanism, maybe later but it doesn't have any major advantages over a good cable.

[gmansyz]

Very interesting!

[GregT]

If the ignition space becomes a stumbling block, it's possible to move it to the alternator side. There are Alternator rotors around with a lump on the OD which is used to trigger the ignition. Two ignition pickups needed in that sidecover and it'd work. One like this which is quite common is the Kawasaki 400/500 twin.
just another option.

[Rensdw]

If the ignition space becomes a stumbling block, it's possible to move it to the alternator side. There are Alternator rotors around with a lump on the OD which is used to trigger the ignition. Two ignition pickups needed in that sidecover and it'd work. One like this which is quite common is the Kawasaki 400/500 twin.
just another option.

Greg, I am familiar with those ignition systems, thank you for reminding me about them I hadn't thought about that as a possibility.
Although I would like to keep the C5 ignition, it is fully programmable, And I'm probably going to need that a lot, using an unknown oem ignition curve would be a crime on an engine like this :P

[60ratrod]

I wanna know how well that c5 ignition does and how long it'll hold up. I'm kinda over dynatek stuff. I've had 2 of their green 3 ohm coils take a dump on me, and their 1 year warranty doesn't give me warm and fuzzy feelings

[Rensdw]

I wanna know how well that c5 ignition does and how long it'll hold up. I'm kinda over dynatek stuff. I've had 2 of their green 3 ohm coils take a dump on me, and their 1 year warranty doesn't give me warm and fuzzy feelings

Haven't actually used it yet, the ignition coils are huge and heavy, real quality stuff.
I'm sure you will read all about it here

[Chuck78]

I am interested as well... wife's bike has gone through 2 Dyna-s ignitions, and mine is half of one of those and half of a swap meet broken dyna. Both had the front pickup burnt up. Never had the 3 ohm green coils go bad, but these reports don't make me feel good about them. C5 sounds like a good option.
I'm running "Dynamite" green 3 ohms on my gs750, not so reassuring that the ones they are knockoffs of are failing! I'm buying some old Accel coils from a member, but I have seen a pair of those at the local Vintage Japanese salvage shop with one coil labeled "weak" so I'm not sold on them either... we'll see how this C5 setup works!

[Rensdw]

I am interested as well... wife's bike has gone through 2 Dyna-s ignitions, and mine is half of one of those and half of a swap meet broken dyna. Both had the front pickup burnt up. Never had the 3 ohm green coils go bad, but these reports don't make me feel good about them. C5 sounds like a good option.
I'm running "Dynamite" green 3 ohms on my gs750, not so reassuring that the ones they are knockoffs of are failing! I'm buying some old Accel coils from a member, but I have seen a pair of those at the local Vintage Japanese salvage shop with one coil labeled "weak" so I'm not sold on them either... we'll see how this C5 setup works!

Take note that the C5 ignition is extremely expensive btw, IDK what you pay for a dyna-s system but I bet it's twice as much for the C5, especially if you want the programing module.

[60ratrod]

Yes the cost is about double that of what you would pay for a dyna s, dyna coils, and dyna wires. However, if the system is more reliable, then the cost is worth it. I'm considering getting the c5 system when i get my tax refund, depending on how much i get.

[Rensdw]

And add the costs for a couple of dyno runs to get it tuned in, no special gear required though, just an USB port and some free software.
Anyway, It will be a while before I get to play with it.