Arttu

There seems to be always some amount of black magic involved with the clutches A lockup on a turbo engine complicates things a bit more. Since clamping force depends on rpm, the clutch shaft rpm to be precise, you may need quite hard setup if the boost and torque come up early. At mid / low rpm there isn't yet too much centrifugal force on the arms so you may need quite a lot of weights and base springs to make it hold full torque. That also brings up one more variable for clutch slipping. If you make boost a bit earlier on one day, for any random reason like weather change, it might be enough to make the clutch slip. I have also had that kind weird occassional slips sometimes. Usually if the setup is on the edge. Oil temp seems to be one variable, it slips easier at low oil temp. Like mentioned the cure is to use more weights and springs. And naturally making sure that everything is in good condition in the clutch.

Yes you can replace it without splitting the cases. Most likely you need to drill a hole on old one and pry it out with a wood screw or something similar. But the new one should go in by gentle tapping. I have done that once.

The EF service manual says 160-170Nm. I have had problems to hold the rotor for that torque, especially with the GSX1400 rotor that doesn't have provisions for holder tool. So I have just tightened it with a wrench as far as I can and then "some more" with a rattle gun.

Almost correct, a GSX1400 rotor on EFE and other large taper cranks. More info in my project thread: @Gammaboyand @coombehousehave documented nicely how to fit a GSX-R600 (K6) rotor on small taper GSX cranks:

Now you got me curious... How the adjuster screw can end in the cylinder?

I have never tried single TB personally but I have seen few that kind setups. So yes, it can work but usually throttle response is worse than with individual TB's. The response will depend on volume between the TB and engine so you may end up making less optimal compromises between plenum size and throttle response. If you have the throttle between the charger and engine you won't need a huge TB. I would guess that something around 50-60mm should be fine for 200-300hp. On intake side of the charger the TB causes more restriction so you may need larger size there. Based on my limited experience having the throttle on intake side of a supercharger is a bad idea on bikes. @Blower1can tell much more about different throttle solutions on a supercharged engine.

I would try to heat them as much as you dare. Maybe several cycles and soaking them with WD40 or similar in between. As last resort you can drill the heads off. Usually it's relatively easy to wind the stub out once the head is gone. But in this case the remaining stubs will be pretty short so it might be difficult get a grip on them...

The plug would be on the side of the engine, above the ignition timing cover. I can't see from the pic if there is one on your engine. Here's a oil circulation diagram of the 1100 engine for reference. The plug is inside the green circle.

Not 100% sure since I'm not that familiar with 750 engines but I think you are taking unfiltered oil to the head now. If the engine is similar than a 1100 there should be a blanking plug on right side just behind the cylinder block. That's the main oil gallery that originally supplies the head and crank. So that would be a good place to connect the external oil lines.

The gap between the sensor and cam lobe is about 1-1.5mm. There's nothing special inside the cam cover, just all the normal bits like on every EFE engine Here's one pic from setting up phase that shows how the sensor is relating to the cam. I don't remember if I ever measured the triggering position of the sensor. With my ECU (MS3) the exact position isn't important. The cam sensor only needs to tell on which cycle the engine is going. Actual timing is done by missing tooth wheel on the crank.

Yes. Some additional info on my project thread, 2 first pages.

Also when checking the clutch it might be a good idea to check straightness of the hub and pressure lid. Some years ago I had persistent clutch judder problem that didn't go away by replacing the discs. Finally I found out that both the lid and the hub bottom had some warpage. Straightening them on a lathe fixed the problem.

But for turbo applications you preferably need a boost referenced regulator. Regulators used on in-tank pump assemblies don't have that option. In theory you could use suitable regulator and still keep it in the tank but then you would need to route a boost reference hose inside the tank. Or you could keep using a non boost referenced regulator and pressurize the tank by boost pressure. That should work too. Until the tank explodes

Both options should do the same thing. So in that sense it's up to your preferences. If you like more the version with take-offs at the oil pressure switch housing just go for it. Only problem might be finding the take-off block. Naturally you can also make your own if you are handy. Personally I would prefer the original cooler ports in the front of the engine. Simpler installation and shorter hoses. If you go this route just remember to use an EFE filter cover or make a blanking plug to force the oil to go through the cooler.

I guess that your first decision should be if you want to turbo a GS1000 with a real engine or build a typical mix-up with an oil cooled engine Latter option is much easier engine wise and probably the result will be better and more reliable. But the first one would be more interesting and respectable, IMO. So your call what you want to achieve. I don't have any first hand experience about the GS1000 but most of the issues should be the same than with GSX1100 engines. Like you expected the oil pressure is really low due to roller crank bearings. You should be able to boost the pressure by some restrictor arrangement so an electric pump isn't mandatory. Then the crank will need welding to whitstand any abuse at higher power level. Forged pistons are highly recommended. And the clutch will need some beefing up for sure.

Yep. I would say that if you need ask here I would forget about using an ignition amplifier to boost a stock ignition system...

Well, a solid state relay with some extra components could work in theory. But I wouldn't bother to try since they are relatively expensive and usually they don't have the switching delay specified so you can't know if it adds too much variance to timing. Simplest possible inverter circuit would consist of a couple of resistors and one transistor. First you need a resistor from ignition box output to 12V to pull up the signal when the box isn't grounding it. Then you connect this signal to a transistor that grounds its output when input signal is high. And then you need another resistor from transistor output to 12V to pull up the output signal. And that signal you can feed to the coil driver module (amplifier). So not very complicated but not completely trivial either if you aren't familiar with electronics.

Not that easy if you use stock Suzuki ignition box or anything else that usually drives the coils directly. They ground the outputs when they are charging the coil and the Bosch amplifier expects positive voltage for that. So you would need some electronics in between that inverts the signal for the amplifier.

Congrats! Although I have never seen the bike in flesh I'm sure you have got a top quality machine.

I don't have any specific brand or model to recommend. But if you google "hobbs switch" there seems to be plenty of choice.

Since there is only one signal generator (pick-up coil) it's very unlikely culprit. Fault there would affect on both coils. Have you already checked 12V supply to the coils? Just measuring it with a multimeter may not be enough if there is a marginal connection somewhere. It may give good voltage readings but still can't supply enough current. To be sure you can test it with a light bulb to simulate load of the coil. But otherwise it sounds that the igniter unit starts to be the most likely fault.

At least Garrett specifies minimum 2 bar oil pressure for their ball bearing turbos. I assume others have similar requirements too. But I have understood that this requirement isn't actually for lubrication but to ensure enough cooling for the bearings. So you may get away with lower pressure but naturally there isn't any quarantee. Oil flow through the turbo should be so low that you don't need to worry about robbing that from the engine. And definitely I wouldn't use any addtional restrictor for turbo when feeding from roller bearing GS/GSX engine. What I have done with my GSX is adding restrictor(s) on oil channel feeding the crank and head and taking oil to the turbo before the restrictor. This way I can get more pressure to the turbo. Oil pump speed is also increased by GS750 gears so the engine still gets at least as much oil than in stock form. But this should work fine even with stock pump gears. At least if you don't have some extreme cams that need more oil to survive.

Yes, I would ask why you want to use a restrictor? As general rule the turbos are designed to work without any restrictors if the oil pressure is within normal range. And normal pressure means about 2-5 bars as far as I know. So if you are going to use some restrictor you should really know what you are doing. Otherwise you may risk reliability of the turbo. So unless you know that you have unusual high oil pressure or you have noticed oil leak problems I would forget the restrictor. I have to admit that I often get a bit annoyed when someone asks what size restrictor to use with some turbo without any idea about supply pressure. And usually there are plenty of professionals telling to use size xx or yy without any better knowledge It's true that there are cases when a restrictor is useful or even necessary. With ball bearing turbos too high oil pressure will increase drag of the bearings and slow down spooling. Additionally you may get oil leaks to compressor or turbine side regardless how good oil return you have. With ball bearing turbos experimenting is also somewhat safer since they aren't too strict about minimum pressure. So if you use too small restrictor the turbo probably won't blow up right away. With journal bearings it's more critical to maintain sufficient pressure. In real life I have had few cases where it has been useful to limit oil pressure to the turbo. On my air cooled GSX I had a slight unbalance in oil supply system and the turbo got about 6-7 bar pressure. When I enlarged the restrictors to the rest of the engine to get pressure down to 2-3 bar I noticed that turbo was spooling up faster than before. Then on some race bikes that can have even over 10 bar pressure due to high volume pump and harder relief valve it has been necessary to use 0.5-1.0mm restrictors for the turbo to stop smoking.

I think your D option looks best, if you just can make it working. B would be really compact but I'm not sure how effective it would be. Especially top part of the upper plate looks like it won't have any effect. Just for reference, here's what I did for my GSX1100 frame years ago.

I'm about 99% sure it's M14x1.5 thread.