Frankenstein’s guide to oil cooled engines

Before anything, I would like to have it said that I wrote this in my best knowledge and do
not want to be held responsible for any mistakes. I’m confident about what I’ve seen and done,
but since I’m not the only one messing around with gixxers, I can hardly ever be sure that
the engine I find in a 89 1100R is really an 89 1100R. I’ve left the types before 88 out,
since I have not much experience with them.

There are mainly 2 types of 750’s, the 88-89 short stroke, and the pre-88 and 90-91 long stroke.
(The 750F is basicly the same motor as the 88-89 short stroke, the B6 and GSXF600 are basicly
the same as 90 long stroke with a smaller bore).
1100R motors from 88-92 are similar to the 1100F and B12 motors. The 1100G is also similar,
but has an axle drive. They all have the same stroke, and only the B12 has a 1mm bigger bore.

Apart from the color, all the GSXR, GSXF, GSXG and Bandit ignition covers are the same (except
the 750RK).

The clutch covers are depending on the clutch operation, there are 3 possibilities:
(The dry clutch is left out, to avoid making it more confusing).
1.The GSXF600, GSXF750 and B6 have the clutch cable connected to a mechanism on the sprocket
cover, and the clutch is operated by a push pin through the primary gear box shaft.
2.The 750R has the clutch mechanism in the clutch cover (on the right side). The 88-89 clutch
cover is recognizable by a smooth clutch cover, the 90-91 has a bubble in the center. They are
very similar, but since the engines have a different clutch, I don’t think these covers can be
swapped, I haven’t tried though.
3.The 1127’s and B12 all have the clutch mechanism on the sprocket cover, like the 600’s and
the 750F, but then hydraulically operated. The mechanisms on the sprocket cover can all be
swapped, so it’s possible to put a cable operation from a B6, F6 or F750 on an 1127 (and v.v.),
although it might need some adjustment of the length of the pushrod.
This also means that, since the clutch covers on the 600’s, 750F and 1127’s are nothing but
covers, they can be swapped.

The startermotor covers from the 1127’s are all the same (The startermotor covers from the 1052
engines are not the same) The 1127 covers can be recognized by a kind of bubble, to accomodate
the bigger starter motor. The 600′ and 750’s have a smaller starter motor, and the top line of
these covers is straight. (I believe the 1052 motors also have this smaller starter motor and
cover). Covers can be swapped among the 600’s and 750’s, but an 1127 cover only fits an 1127.

The oil pan on all 1127’s are the same, but the B12 is different. The 750F and 750R 88-89 have
the same oil pan as the 1127’s. The 91-750R and B6 have a similar or same oil pan as the B12,
I’m not sure. However, it is possible to swap these oil pans, as long is you change the oil
pickup as well. Oil hoses on the 1127 pans connect at the front, the others at the bottom.

The valve covers are different depending on the cam chain type, and the cylinder head size.
The B6 cover only fits the B6, the B12 cover only fits the B12. The 750R-90 and 91 covers
are the same. All the 1127 and the 750R-88/89 cam covers are the same.

There a 3 main items which make the difference in crankshafts.
1. Stroke
2. Clutch gear
3. Camchain type

1. The 1127’s and B12 all have the same stroke. The 600’s and 90-91 750R’s have the same
stroke. The 88-89 750’s and the 750F have the same stroke.
The stroke is important because this directly reflects on the number on teeth on the
clutch gear (ie. the gear diameter).
2. All GSXR1127 crankshafts are the same. The GSXF and G have a helical
cut gear, so when using a GSXF1127 crank You will have to use a GSXF1127 clutch basket as well.
3. All GSXR’s (both 750 and 1127) have the same type camchain, but the B6 and B12 are
different. Since the cam chain is driven from the crankshaft, this means these crankshafts
are not interchangeable with GSXR crankshafts, unless you also change the cam chain, tensioner,
guides, cam sprockets, cam covers, cam guiding between cam shafts.

All the 3 items above have to match. Swapping a crankshaft with a type that has the same
stroke, clutch gear and cam chain is no problem. If you start mixing, you have to match
clutch to the crankshaft (and in some cases gearbox), or cam chain stuff to the crankshaft.

Connecting rods from B6, 750R-90 and 750R-91 can be swapped. 1127 rods are all the same.
I have used B12 rods in 1127’s; I found there was a minor weight difference, but they could
easily be matched. This difference might have been incidental.

I left out the dry clutches on purpose, since I have no experience with them.

The GSXR1127 89-on and B12 have a diaphragm spring, the GSXF/G have normal springs.
The GSXR and B12 have a straight cut gear, the GSXF/G have a helical cut gear.
Because of the different gear on the clutch basket, the clutch basket is not swappable.
Since the types with a diaphragm spring have a longer shaft to accommodate the bolt for the
central spring, these parts are also not swappable. It is possible to use the internal clutch
parts from a ‘normal spring type’ in the basket (or actually on the gear box shaft) from a
‘diaphragm spring type’, but you need to fill the space on the longer shaft. It is not
possible to use the diaphragm style clutch on a GSXF gear box shaft, since the shaft is to short.

The 88-89 750R have a large (actually the largest) diameter but relatively flat clutch.
Although the gear box shaft is the same, the 88-89 clutch can not be swapped with the 91
clutch because the crankshaft diameter (and consequently tooth count) is different.
Although the B6 clutch is the same diameter as the 91 750R clutch (since they have the
same stroke), there is not a lot to swap there since the plates are different and the
gear box shaft are differently machined.

Cylinders block with pistons from 1127’s can all be swapped. B12 block+pistons fit the 1127
as well, or only pistons+have your 1127 block bored.
88-89 750’s is same as GSXF750.
B6 and 90/91 750R have 18mm wrist pins, whereas 88-89 750R, GSXF750, 1127’s and B12 have
20mm pins.
Since the B6 and later 750R 90-91 have the same stroke, cylinder block dimension, and wrist pin
diameter, the 90/91 block+pistons can be swapped with the B6 stuff (although you’ll have to
check that the pistons don’t hit the head/valves).

The long stroke engines (ie. B6, GSXF600, 90/91 750R) have the same dimensions, just the
combustion chamber and valves in the 750’s is bigger. So somebody who want less power could
fit a B6 top on a 90 750R. Camshaft type on the B6, GSXF600 and 90 750R is forked rocker,
meaning 1 cam for each pair of valves. 91 750R has shim type with 1 cam for each valve.
If swapping the camshafts as well, the 90 and 91 heads can be interchanged.
Both the 90 and 91 750R top ends can be used on a B6, but since the B6 has another type of
camchain, it is needed to maintain the B6 cam chain tensioner, guides, cam sprockets, valve
cover etc.

The 750 short stroke engines 88/89 heads have the same outside dimensions as the 1127/B12,
but the combustion chamber is smaller (although the valves are the same diameter).
The 1127R-91/92 has the same style head as the 750R-91, but
not much to swap; 1100 valve spacing differs (so camshafts can not be swapped), 1100 valves
are bigger, outside head dimensions differ.
As mentioned, 750R-88/89 valves are the same as 1127/B12, exception are the 1127R-91/92 valves.
These heads have shim type adjustment, and therefore different cams and longer valves.

It is possible to modify a 1127 shim head to a forked rocker head. It’s quite some work, and
you’ll need the valves from the forked rocker head, the rockers, cam shafts. You’ll need to
make all the spacers yourself, or in fact I believe there is a company that has or used to
have a modification kit.

Cam shafts from the 1127F, 750F, 90-750R, B6, B12, 88/89 750R are theoretically all swappable,
but of course the profiles are different. The long stroke 750’s have a different tooth count
on the cam sprockets so they can not be mixed. B12 sprockets can only be used in the B12.
B6 sprockets can only be used in the B6. 1127F and 1127R sprockets are the same, 88/89-750R
sprockets are similar, but the timing marks are different. (Meaning they can only be used if
slotted and timed)

1127: Depending on the clutch type there are long and short shafts. Also the gears themsleves
from these boxes are different. It may be possible to swap a few gears between these boxes,
but the gearchanges might not be very smooth.
Apart from the clutch type, the 91-92 1127R has a double row bearing on the output shaft, and
therefore a slightly different crankcase (around the bearing area).

Gear boxes from all 750’s are swapable. I have no experience with swapping gears seperately.

The B6 has a different shaft, so it can only be used with it’s own clutch.

Although it might seem there are so many differences, a lot can be mixed, as long as the right
parts are choosen, a few examples.
(There are some basic guidelines to assemble an engine, like check compression, cam timing, valve
clearance etc., no matter what combo you’re making).

1. A 1052 crank fits in 88-89 750R and 750F cases, but a 1127 crank doesn’t (but the cases can
be modified to take the 1127 crank as well)

2. A 750R-90 or 750R-91 top end on a B6.
It’s actually very easy, and I think all the info you need is above. Both engines have the same
stroke, same wrist pin diameter. Theoretically, it would be possible to put only 750 cylinders
and pistons on a B6. However, the pistons are designed to fit the 750 head and since that also
fits, why not install a 750 head as well (with bigger valves). Since the B6 has another cam chain
the B6 cam chain tensioner, cam sprockets, cam chain guides and B6 valve cover need to be
used. Then there are 2 options: either go for a 750R-90 top end, which uses forked rockers
like the B6 does (so it’s possible to use either the B6 cams or the 750R cams), or go for a
750R-91 top end, which uses another type of rockers so it is not possible to keep the B6 camshafts.

3. A 750R-88/89 top end on a 750R 90/91 bottom end (or 86-87 bottom).
This is a bit more difficult, since it needs some more work and imagination then the plain
assembling of a B6/750.
The 750R-88/89 have a bigger bore, so the idea of this combo is to increase the capacity of the
engine. (You could also take this combo the ‘other way around’, and fit a 90/91 crankshaft + clutch
in a 88/89 engine.)
Since the dimensions of the heads are not the same, it is not possible to only put the 88/89 pistons
+cylinders on the 90/91; the head of the 90/91 would not fit the cylinder block. So the complete
88/89 top has to be installed on the 90/91. The wrist pins on the 90/91 are 18mm, on the 88/89 20mm,
so the small end of the 90/91 rods have to be bored to 20mm. Now the whole thing could mechanically be
assembled, but since the stroke of the 88/89 is smaller, the height of the cylinder block is smaller.
This has to be compensated by putting a spacer under the cylinderblock. (This spacer would very
roughly have to be 1/2 x the difference in stroke, but the only right way is to measure/calculate the

4. 750R 6 box in a 1127 motor
The only hard thing here is to have a hole drilled through the gear box shaft, for the pushrod.
The 750 6 boxes have a single row bearing on the output shaft, and the clutch does
not have a diaphragm spring. So the easiest 1127 engines to put a 6 box in are the ones with a
single row bearing on the output shaft, and no diaphragm clutch, ie. only the GSXF1127 engines.
In these engines the 6 box drops straight in, only the shaft has to be drilled.
Second easy would be an 1127R engine with a diaphragm clutch, but no double row bearing (88-90).
In this case the box would still drop in, but for the clutch one would have to use the inner
clutch parts from a GSXF1127 (with normal springs) and the outer clutch basket from the 1127R
(with a straight cut gear, not helical).
Most work is in a 91/92 1127R where one would have to match the clutch as above + find a
solution for the double row bearing (the solution is actually to turn the double row bearing
inside out, and make a little hole for the small pin).
Of course the shift drum and forks from the 6 box have to be used as well, but they drop in
any 1127 without problems.

5. 88-89 750R head or 750F head on a 1127 or B12
These heads fit as they are, and give higher compression, better ports, larger squish.
In the case of the 91-92 1127R you’ll need to use the 750 camshafts as well, since the
91-92 1127R uses shim type camshafts and the 750 head is forked rocker type. If you use the
91-92 1127R cam shaft sprockets they can be timed as in the manual.
In the B12’s case you could use the B12 or the 750 cams (although they have different profiles)
but will have to use the B12 cam shaft sprockets because of the different cam chain.
In the case of the 88-90 1127R you can use the 750 or 1127 cams, and use the 1127 cam sprockets
(timing ‘by the book’) or use 750 cam sprockets (timing to be done by yourself)


Bandit Coil Spring Conversion

Words & pics: Lee Workman

Bandit clutch conversionBandit Clutch

The clutch assembly fitted to all Bandit 1157 motors is, frankly, shite.

Based on the same principle as the GSX-R Slingshot unit, it’s diaphragm-sprung with ten driven plates and ten drive plates of 225mm diameter (the GSX-R’s are 230mm diameter which doesn’t sound much, but offers a huge increase in surface area for friction) and has a cheap cast alloy basket with a steel reinforcement strap fitted in an effort to stop it flying apart (as opposed to the large all-steel basket used in the GSX-R).

Under normal circumstances this unit is fine but, as soon as you start giving it a reasonable amount of abuse or tune the engine, it will struggle to cope with the extra demand and eventually slip. Heavy-duty diaphragm springs are available and will slightly improve matters at the cost of a heavy clutch lever, but the whole unit is better off in the bin. Trust me …

To convert your Bandit 12 clutch you’ll need the following parts from Suzuki,

No. Description Suzuki Part Number


Price � (ea.) Source Model


Clutch inner hub



49.46 GSXR1100 G,H & J


Pressure disc



23.49 GSXR1100 G,H & J


Coil springs



1.31 GSXR1100 G,H & J


Spring spacers



1.72 GSXR1100 G,H & J





0.53 GSXR1100 G,H & J





0.71 GSXR1100 G,H & J


Drive plate (Fibre)



9.53 All GSXR 1100’s


Driven plate (Steel)



5.47 All GSXR 1100’s


Clutch Basket



176.53 GSXR1100 K,L,M & N


Yep, you’ll need to replace that crappy clutch basket, they are expensive new, but you could get one from B12 Clutch 1a breaker, you can use one out of any Slingshot model. Beware – they look identical to the earlier Slabside one, but the 1052cc motor has different gearing on the crank. The primary driven gear at the back of the clutch basket of Slabside engine has 73 teeth. The bandit primary driven gear (being essentially a 1mm over bored 1127 motor) has 72 teeth – the same as a slingshot one.
Follow the previous instructions for the GSXR’s then, once the inner hub is completely off, remove the outer basket also.
Pull the basket partially out, then push it back in again, this will expose the needle roller bearing and the spacer, remove these from the shaft then remove the clutch basket and alternator/oil pump drive gears careful remove alternator oil pump gear from the b12 basket and fit it into the slingshot basket
If its still stuck to your clutch basket, you will need to (carefully) remove this bandit drive gear, and fit it to the GSXR basket.
They are totally different; the alternator/oil pump drive gear off a GSXR has different pitch teeth and will foul your bandit alternator driven gear and your oil pump driven gear.

Once you’ve done this you can fit the new GSXR Basket using the original thrust washers in their original places.
Ensure the alternator an oil pump drive gears are engaged with the driven gear behind the basket
When positioning the basket on the counter shaft and sliding it ‘home’ – take extreme care to line up the alternator/oil pump drive gears with the alternator and oil pump driven gears, if they are not fully engaged, and you tighten the hub nut, it WILL snap, and they cost around £80!

Fit the new coil spring hub assy just like the GSXR procedure with one exception, –
The counter shaft of the bandit engine is again longer than the Slabside one, but it’s different to the Slingshot counter shaft, the dimensions for the bandit spacer are 35mm O.D, 25.5mm I.D and 6mm thick. Also as the original bandit hub has a different thickness base to either of the gixxers, it still works out that you need a 10mm ball bearing to take up the slack between your original bandit pushrod, and your push piece.
Again secure the hub using your original nut & washer on the new spacer fit the new GSXR clutch plates and pressure disc assy as above.
And you too have a GSXR spec, coil spring clutch!, Again you can go and fit a lock up straight on if you wished!, Or leave it as it is and go and do stoopid stuff, safe in the knowledge that you’re clutch can take it!
Now, extra hints and tips.
Tip 1: When you do the job, put the bike on its side stand and carefully lift the front wheel and chock it on a brick – this will stop you losing any oil when you remove the clutch cover.
Tip 2: When buying new clutch plates, use only genuine Suzuki parts – I know they’re more expensive, but it’s false economy to put cheapo plates in. I know, I’ve tried ALL the super-trick/heavy-duty ‘performance’ clutch plates and they just don’t compare with the genuine stuff. You have been warned!
Tip 3: With this particular conversion you fine-tune the biting point by changing the ball bearing – if it drags too much (assuming you’re using the correct grade oil and the steels aren’t warped), then you need more travel so try fitting an 11.5mm one instead. If it slips (assuming the fibre plates and/or the springs aren’t worn), you need less travel so pop in a 9mm one. It really does make a difference!

Also take the time to make the special tools, they’re a piece of piss to make, and really make life easier.

Special tool one: You’ll need two pieces of steel bar that are 200mm long, 25mm wide and 5mm thick (ish …), drill two 6mm holes in each bar with the centres 165mm apart then, at one end of each bar, fit a M6x30 bolt and secure it tightly with a nut on the underside. At the other end, open out the 6mm hole to 8mm and join the two bars together with a M8x70 bolt and loosely secure it with a nut on the underside. To use it, the M6 bolts will neatly fit into the slots on the diaphragm pressure disc and the M8 bolt will fit straight into the swingarm spindle – once the slack is taken up, you’ve got both hands free to undo/tighten the big 50mm holder nut!

Special tool two: First get one 400mm long piece of square section (20x20mm) bar and two old GSX-R clutch driven (steel) plates. Put the plates on top of one another and drill three holes equally around the diameter and secure them to the square bar using two M6x60 bolts and 20mm spacers and a couple of M6 nuts (this way, you can support the basket really well and reduce the chances off slipping, as the plates will be deep inside the unit). Finally put a small M6x10 bolt and nut through the remaining hole to secure the plates together. This is a wicked tool to have, when you’re trying to remove/secure the hub nut at 160Nm!

Anyway, in preparing this article I’ve been down to my local Suzuki dealer to get the correct part numbers for you to order and latest prices (all, are + v.a.t.,and correct at August 2002), and to ensure that those of you using second hand stuff from the breakers get the right bits off the right models. I’ve already checked to see which part numbers are superseded by later ones and that the information given is correct to the best of my knowledge and experience etc– aren’t I good to you lot, eh?