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GS1000 Turbo, attempt no 2

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A few years back I started to build a turbo charger on my already rebuild GS1000.

A had a lot of bad luck, but in the end I had it going.... and then I got some more bad luck..



I had the bike on the dyno and it cranked out only 150hp on the rear wheel, still 60hp more as without turbo.

Main reason to put it on the dyno was to see how the carbies were adjusted, bike was running way to lean!

After fiddling around with the carbies and advancing the ignition the bike came back to life, it was even faster as the first time I had it going, it lifted it's front wheel in 3rd while not even on boost. It had never done that before, hence, this bike weighs at least 260kgs.

Same day/night (friday the 13th - seriously) I took it for a test ride at the local industrial area, at about 180km/h I wanted to shift into 4th gear and I miss shifted, I heard a bang and then RRRRRRRRRR, and it lost power.....    Then, a lot of words you never hear in the bible.. ;)

Con rod gave up, destroyed the crank case, and one piston, valve shim came out what destroyed the rocker cover, long story short, I felt like crying...  ;) .


Was in doubt for quite a while if I wanted to rebuild it with or without turbo, decided to rebuild it with turbo, or else it would be a waste of my previous efforts, and that turbo power, it's addictive, but the turbo riders know that. ;)



GS1000 has a roller bearing crank, means these engines have hardly any oil pressure, about 6 psi at a lot of revs, not enough for a turbo charger, I have been playing around with it, oil pump gears from a GS750 in it, restrictor in the feed line to the gearbox didn't help much, I even build a 5mm wider pump from a GSX750 with plain bearings in the crank case, but even that raised the oil pressure not high enough, then I decided to  put some effort in it (and lots, and lots of time)...

At that time I worked at a place with a lathe and a milling machine, so I build a new bottom plate with a turbo feed pump incl. oil pressure regulator, and a scavenge pump on the side of the crank case.

To my surprise this worked absolutely perfect, of all the trouble I had with my bike, all the handy work I did myself worked ok.


So after the crank case got destroyed I had to build everything over to the other set off crankcases I have, there was quite some difference in the 2 sets of crankcases, but now I have the 2nd set finished.


- The GS has a 1245cc big bore kit (78,25mm) with JE pistons, CR 8:1, 34mm GSX1100 carbies.

- I extended the drive shaft of the oil pump to the other side of the cranck case, milled material from the outside of the crank case, bolted a home made scavenge pump on it.

- I mounted a 90 degree sprocket on the drive shaft, and the rest you can see in the photo's. ;)

- On the sprocket side of the drive shaft I cut about 4mm of thread and screwed a nut on and welded the nut on the shaft, reason being, while I was busy fitting it in I tapped the shaft, and the clip fell of straight away... Then I got scared that clip falling off while engine was running (what didn't happen before) and causing havoc, and decided to play it save.


Plan is to rebuild a stock crank with 493 Katana rods, billet clutch basket and reinforced backing plate and straight cut gears, this is all very expensive, but I can't afford another time it goes wrong. With all that it should be able to handle at least 300hp. I'm not aiming to get that kind off power, if I get it at the same level as when it f*cked up I'm happy, main goal is to keep it in one piece.

I've got a bad paid job, and I'm busy fixing up my Land Rover (Discovery V8), so it's going to take some time before it's going again.


I'll keep you informed. :)


Bottom plate needs to be cleaned, and I want to spend some time on the oil pressure regulator, crank up the pressure a little.





note; seat isn't finished yet ;)


Also a photo included of the &750.000 machine I milled the side of the crank case off ;)






Zitje r.JPG


bottom and side.JPG

bottom plate.JPG

carter inside.JPG

drive shaft.JPG

carter top.JPG


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Very impressive and innovative! Can't say i've ever seen anyone use a bevel driven oil pump but if it works then why not!

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Thanks guys. 


@ Gixxer1460; I didn't want an electric oil feed and scavenge pump, wasn't sure if the alternator could handle that, and those pumps are reasonably big, so mechanical was preferred, a decision to extend the drive shaft from the oil pump was soon made, figuring out how to do it was the challenge. (those little sprocket costed me $90!)

This was the only way to do it, room was also the issue.


Bottom plate is 5mm thick, that "tower" is screwed in the bottom plate, and then secured with 3 M6 bolts, it's all quite sturdy.

Scavenge pump is also a few mm wider as the feed pump, idea was that the wider pump moves more oil from turbo charger into sump as the feed pump moves from sump to turbo.

I had it all disconnected, feed line and scavenge line into a measuring jug, and then fire up the engine, jug stayed almost empty, all works absolutely perfect!



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This morning I spent some time behind my little lathe, just some improvements on the bottom plate.


The shaft driven by the extended shaft had too much clearance, also the bush in the oil pump was separate from the bush in the "tower", therefor it didn't turn smooth the first time I put all together and I had to make it all go smooth, because off that it got too much clearance, not a lot, but enough to spent some time on it.

Also I had to make a spacer to get the gear at the right height, I didn't like that either, therefor I made the top bush a little bit longer so I can leave the spacer.


So, bashed the old bushes out, turn new bushes, and tap those back in, all fits and works perfect, I'm happy with it, less parts, less clearance, better alignment, and it turns more smooth. :)


Next thing is to improve the oil pressure regulator, it works, but it leaks, and I think/hope it can work better, better adjustable. 



I also should send out my tax return papers so I can order the con rods.. ;)

Bottom plate.JPG


shaft new.JPG


pump on.JPG

all together.JPG

Edited by Reinhoud
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Guys, I need some advise...

I'm looking into what sort of turbocharger to get, I had a TD05-16G on it, that's too big, boost came in about 4700rpm, and took another 1500rpm to get full torque.

Now I'm thinking of a IHI VF one, they're ball bearing ones, the ones I think might be suitable are the 23 - 24 and 29.

Anyone suggestions?



Since a few months I have another job, which what I earn a bit more, and for my new boss I'm working in an aluminium plant for a few months, and with this job I have about 2.5 times more free to spend money as my old job in the orchard, my Land Rover is coming to an end, so I can spend a small fortune on my bike again.


Meanwhile I have build a press, so I can go busy with building a stronger crankshaft

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17 hours ago, Reinhoud said:

Guys, I need some advise...

I'm looking into what sort of turbocharger to get, I had a TD05-16G on it, that's too big, boost came in about 4700rpm, and took another 1500rpm to get full torque.

Now I'm thinking of a IHI VF one, they're ball bearing ones, the ones I think might be suitable are the 23 - 24 and 29.

Anyone suggestions?

Those IHIs look quite ok based on info that is floating around the net. Although difference in spooling compared to your current one might be quite small in the end. One alternative with ball bearings could be Garrett GT2560R. It's about the same size than those IHIs or maybe slightly smaller.

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The idea is that I get a different spooling, the current one is too big.

I'd like to have a TD04 size, but I have no idea what it compares to with the IHI ones. The IHI VF ones are ball bearining and quite affordable.

What I could find on the net, is that the 23,24 and 29 are about the size what I'm after.

If it can make about 250hp on the crank it's good, I'm not after real high numbers, I think when the engine blew up it had about 210/220hp on the crank, that was fast enough.


I'll look into that Garret one.


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Yep, like you probably have noticed published info about those IHI turbos is quite limited. But based on what I found they are probably somewhat smaller than your current turbo. And VF24 and VF29 should be a bit faster spooling than VF23. So if those are easily available they are probably quite good choice. Garrett one is most likely again slightly smaller and faster spooling than any of those IHIs. And you can get them as new for relatively reasonable money :)

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The Discovery is done, the Rangie is done, I had holiday leave paid out, time to buy bike parts, finally.


The big end bearings where quite a challenge to get, a lot of bike shops said the had it, but when ordered they couldn't deliver...


The turbocharger is an IHI VF20 ball bearing one, reconditioned by Kunigawa, it's from a Subaru Legacy, it's smaller as what I had, but that's what I wanted, I couldn't find any specs about this turbocharger, so it's a bit of a gamble, but I think it might be right.


I also got new crankshaft bearings, about a weeks wages, and I'm not even sure the old ones where warn.. 

The conrods are the 493 Katana ones, yes I know, I need to rise the cilinderblock by a mm. ;)



So, progress! :) Took long enough

Bike parts.JPG

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Made some flanges this afternoon, next step is to weld the turbo to the exhaust manifold, and modify the exhaust, but that's for next week.

And as usual, it shows I made it myself. ;)





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3 hours ago, Askamaskinservice said:

I like your bike.

One question, if you are using a turbo meant for watercooling how are you going to do that?

It ain't required!

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Great engineering put into the engine.

The VF20 was the primary turbo on the Legacy GTB sequential twin turbo setup so should spool up pretty quick on the bike ( 4000rpm in the legacy before the second turbo kicked in ) and iirc the oil feed banjo bolt had a 1.5mm delivery hole/restrictor in it being a ball bearing turbo.

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Been a bit busy today..


I didn't want to make a new exhaust manifold, so I used the old one.


Had to buy a new barrel grinder first, old one was broken and I needed one to clean up the inside of the manifold.

I t looks from the outside that it's choked where the 4 pipes go over in 1, but when you look from the inside it looks actually quite alright, no sharp bends, and all smooth.


Next step is to modify the exhaust so it fits on the turbo.






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