EFI Conversion

[blandit600]

Good evening all!

Hoping someone may be able to help!? For the past week I've been trawling through forum posts about carb spacing and inlet rubbers for various oil cooled motors, however I can quite find the exact answer I'm looking for.

I have a MK2 600, and it has some sentimental value to me (I have other bigger bikes, but this one I wanted to keep as a 600), however I don't get to ride it much and I wanted to add a few modern touches!

So I'm in the process of doing an EFI Conversion, so far going well, however my plan was to use GSXR 600 K1 throttle bodies for the intake (no problem there, they are individually bolted together so can be spaced appropriately), the spacings are the same for the outside, but the inside needs widening 5mm, no problem.

So, the GSXR inlet side stubs are 44mm, and I'm trying to match up some rubbers I can use to match these OD's. Now I've found a table which has been posted on this forum of various carb combinations, but what I cant find is whether the rubbers are offset?

So for example, the MK2 600 carb spacing is 80-80-80 and the MK2 1200 is also 80-80-80, but....if you were to put the MK 1200 rubbers on a MK2 600 head, will the spacing be different? i.e are the cylinders spacer wider on the MK 1200 and as such the carb rubbers are offset to compensate? or are all the cylinder spacings the same? I don't have any MK2 1200 parts to reference, so I was hoping someone on here may be able to assist!

Thank you.

[TonyGee]

the mk1 and mk2 1200's head spacing is the same but their rubbers have different spacing. all interchangeable though. 

[Gixer1460]

I would imagine that, as the 1200 has larger cylinder bores when compared to the 600 the inlet spacings will vary correspondingly with offsets to get back to the 80-80-80 spacing so finding correct offset rubbers will be a mission! Alternatively use a set of rubbers that works for the head, and respace the TB's to suit !

[blandit600]

Thanks both for your replies, much appreciated!

So my theory may be right then? If I popped 1200 inlet rubbers on a 600 head, the spacing would be narrower in theory, this could still work, as the throttle bodies I have selected are individually bolted together, I can machine them down, a pain, but doable.

Has anyone ever tried squeezing 44mm stubs in a 1200 inlet rubber? or is that just not going to happen?

Thank you.

 

[Gixer1460]

Well 40 or 41mm ID carbs tend to use the 1100M rubbers so I would use those as 38mm ID carbs can be a squeeze in 1200 rubbers

[imago]

As @Gixer1460says, they do go in but it's a bit of a squeeze. If the 1200 rubbers are reasonably flexible it's not a massive problem getting K1 throttle bodies to go in (see pic) if they've gone hard I'd think it'd be more aggro than it's worth trying to shove them in.

[Dezza]

GSXR 750 l,m rubbers are bigger and what you probably need here but are getting very difficult to find secondhand and are unavailable new. Also, GSXR (oil-cooled) rubbers are shorter than B12 rubbers and thus bring the carbs (TBs in this case) closer to the head, which may cause/solve clearance or airfilter mounting issues.

[davecara]

My suggestion would be to sell the K1 bodies, theyre too big for your little 600. 

Double check the bore sizes but 650 Blandit throttle bodies and 2 sets of ali epxress 650 rubbers will see you right with minimal work. Do some searching and have a look at my Slingshot thread

[blandit600]

Thank you for your replies everyone, I appreciate you all taking the time!

So the Bandit 650 Throttle Bodies are 42mm OD on the inlet side, only a couple of mm difference to the K1 bodies, but again still larger than the mk2 600's 38mm OD, and the 650 bodies have a spacing of 80-100-80, so to make those work I would have to shave 15mm off the centre section, which would be very difficult as all the throttle linkage and secondary motor is in there, If memory serves me right its also a return-less fuel system which isn't ideal (debateable, but from my personal experience I would want the return), and just in case anyone else picks up this thread in the future, the 1250 throttle bodies are the exact same spacing, ID and OD of the 650 Bodies, they are interchangeable (I would guess the fuel injectors are different though).

The reason I like the K1 bodies is the secondary butterflies. Even though the bore size is larger on K1, I'm planning on using these secondary Butterflies to tune out some of the air inrush to create a better velocity and varying RPM.

I dabble in electronics, PCB Design / microcontrollers and ECU architecture, and I'm doing this as a hobby / challenge. I love the 600, its was the first big bike I bought 16 years ago, its comfortable to ride and not fast enough to get you into serious trouble ha, I was fed up of the carbs requiring maintenance all the time as I don't get to ride it as often as I would want, and Its missing some modern comforts.....

Not only did I want to make this EFI, but I wanted to add:

1) Secondary Butterflies - Better throttle response, more tuneable power curves etc etc

2) Launch control - I'm heavy into drag racing too, and thought this would be a bit of a laugh

3) Flat shift - I'd like to add a strain gauge, essentially a quick shifter, but instead of adding an additional ignition cut box, I'll let the ECU handle it.

3) Switchable maps - This may end up not being used, but I want to experiment with higher octane fuels. I may just go flex fuel, but with the map switch I can also look at fuel economy or power reduction for the colder months, etc etc.

4) Traction Control - I feel more confident riding my more modern bikes in the winter months as they have ABS, wheelie control, traction control etc etc and Traction control will be the easiest to add, a couple of wheel speed sensors and were good to go.

5) Reliability - As I don't get to ride much, when I do want to jump on this bike, I don't want the hassle of whether its going to start 1st time? or if its not running well etc etc.

I originally started this thread just for a couple of answers, but I may as well keep this going as a reference for the project? I don't see the 600 get a lot of love, but I know it has a little potential and it I know I'll enjoy the project.

Sometimes projects don't have to be about cost efficiency haha

Here's a pic of the bike when it was running on carbs, no exhaust on it for some reason? can't remember why........

Cheers all

 

 

Edited June 7, 2023 by blandit600

[Gixer1460]

3 hours ago, blandit600 said:

The reason I like the K1 bodies is the secondary butterflies. Even though the bore size is larger on K1, I'm planning on using these secondary Butterflies to tune out some of the air inrush to create a better velocity and varying RPM. I would assume you plan on using the K1 ecu? as I don't know of any aftermarket ecu's with integrated secondary throttle controllers!

I dabble in electronics, PCB Design / microcontrollers and ECU architecture, and I'm doing this as a hobby / challenge. I love the 600, its was the first big bike I bought 16 years ago, its comfortable to ride and not fast enough to get you into serious trouble ha, I was fed up of the carbs requiring maintenance all the time as I don't get to ride it as often as I would want, and Its missing some modern comforts.....

Not only did I want to make this EFI, but I wanted to add:

1) Secondary Butterflies - Better throttle response, more tuneable power curves etc etc Most people actually delete them and don't notice significant changes in ridability! And you still have to find a way of controlling them!

2) Launch control - I'm heavy into drag racing too, and thought this would be a bit of a laugh With a 600 it'll certainly be a challenge and 'multi purpose' bikes are a compromise of everything! Lots have tried and disappointed with results.

3) Flat shift - I'd like to add a strain gauge, essentially a quick shifter, but instead of adding an additional ignition cut box, I'll let the ECU handle it. Sounds sensible and easy enough to achieve with aftermarket ecu's

3) Switchable maps - This may end up not being used, but I want to experiment with higher octane fuels. I may just go flex fuel, but with the map switch I can also look at fuel economy or power reduction for the colder months, etc etc.  Unless you build the engine to NEED hi test fuel, using it is a waste of time and money as it will achieve nothing. Building a engine that needs Hi Test all the time 'may' benefit from a 'low power, low test fuel map' if you can't get Hi Test as a safety measure.

4) Traction Control - I feel more confident riding my more modern bikes in the winter months as they have ABS, wheelie control, traction control etc etc and Traction control will be the easiest to add, a couple of wheel speed sensors and were good to go. I'm sure the OEM factories don't think TC is 'easy' and probably spent considerable time and money to get it fool / idiot proof - the mechanical bits maybe easy, the electronics and codemaybe not so?

5) Reliability - As I don't get to ride much, when I do want to jump on this bike, I don't want the hassle of whether its going to start 1st time? or if its not running well etc etc. EFI isn't a turn key panacea! Fuel still goes bad in FI bikes just as easily as carb equiped ones. The require better electrical systems and alternator output to cover the extra loads and whatever you build it'll still need tuning to get 'turn key' reliability!

Some responses to points raised (only my opinions, others may differ!) - Text in RED

[imago]

1 hour ago, Gixer1460 said:

Some responses to points raised (only my opinions, others may differ!) - Text in RED

Just to confirm on your first point, none of the aftermarket ecus control secondary butterflies. I can say that with certainty as I looked at them all when looking for an ecu to use with the 1200 engine. The only way to do it is you use a secondary ecu such as Speeduino with linked inputs. The negatives of doing that vastly outweigh any benefits of having the secondaries. 

The only vaguely noticeable benefit to the secondaries is going from very low or no opening to WOT quickly. You can map 90% of that issue out for anything that's near stock, and anything tuned it can be over come with a pre-pulse on the injectors.

[clivegto]

I have a 600 engine some where, I'll have a measure to compare with my 1200 tomorrow. As @davecarahas pointed out the 650 ones with 2 sets of rubbers will probably fit.

[coombehouse]

I used some gsx1250 intake rubbers on a MK2 bandit as the offset they have gives more clearance in the centre for the repositioned throttle linkage. Came from AliExpress & fitted fine with a little adjustment. 

[blandit600]

Update:

So.......I broke the GSXR 600 K1 ITB's I had..... some of the screws holding the butterflies on sheared off frustratingly.....But I think this was a sign.

Talking to a few of the forum members, I ended up buying some GSF650/1250 ITB's (they both have the same spacing, just different injector size) and be done with it and they fit! near perfect, with a few issues:

So, using some GSF1250 Rubbers, a bit of grease, they fit. I would guess the spacing is off by 2mm using these rubbers, but I don't think Ill get much better than that.

I plan on using some rose joints with adjustable hex bars as a sort of linkage? to help really secure the Throttle Bodies to the engine, but Ill wait until I've sorted out the fuel pump and petcock block off for how much space I've got to work with.

As I originally mentioned, I wanted to use the secondary butterflies, but the where the motor connector connects, it would foul on the alternator, so I may have to give this a miss for ease sake.

Overall, other than wrecking a perfectly good set of 600 k1 throttle bodies, I'm happy with the progress so far.

Thanks for everyone's input 

[Digs]

Looking good, interested to see how you get on. 

[blandit600]

Another small update:

So I've been 3d Printing some various test parts before machining....

First up was the crank trigger:

So I've opted for a 36-1 trigger wheel for optimal resolution, but I was curious as to whether the sensor will struggle with this resolution / feedback due to the small size of the wheel? Would a 24-2 wheel be better? I'd be interested to hear peoples thoughts.

Next up was the fuel system...... So here's the plan. I'm going to blank off the Petcock hole and then drill two new holes for the fuel feed and return. I've tried to incorporate either the inlet / outlet or both onto the Petcock block-off plate, but there wasn't enough room to comfortably accommodate it, so Ill drill those elsewhere on the tank. Again just 3d printed the block-off plate for test fit before I get it machined (I'll have an o-ring groove machined into it for sealing):

 

I'm going to stick with the "Returnless" fuel system from the 650/1200 as I don't fancy getting a new fuel rail sorted, and run an adjustable FPR.

Lastly, would anyone know the CC size of the 650 injectors? Struggling to find that info online.

 

 

[Gixer1460]

Arttu seems to like 24 - 2 wheels as I believe the sensor can keep up with 36-1 @ higher RPMS! You first describe normal flow and return system then say you'll be using returnless - make yer mind up 

[blandit600]

39 minutes ago, Gixer1460 said:

Arttu seems to like 24 - 2 wheels as I believe the sensor can keep up with 36-1 @ higher RPMS! You first describe normal flow and return system then say you'll be using returnless - make yer mind up 

Yeh I was worried about it keeping up in the RPM range, but I wonder if the 36-1 has been tested at 10,500rpm?

Yes I originally wanted a "Return" fuel system, but weighing up pros and cons, the "Returnless" system will be absolutely fine and then I don't have to faf around with a new fuel rail too....

My original "Christmas list" is dwindling haha but trying to stay on track!

Still after the injector size for the 650 though if anyone knows!?

[Arttu]

8 hours ago, blandit600 said:

Yeh I was worried about it keeping up in the RPM range, but I wonder if the 36-1 has been tested at 10,500rpm?

Still after the injector size for the 650 though if anyone knows!?

I haven't personally tested 36-1 on oil cooled Suzukis. But just looking the resulting teeth / gap size I think it's getting a bit too tight for the stock pick-up sensor. I know that some people are using it successfully but also there are some who haven't got it working properly. 24-2 has been pretty trouble free for me.

Injectors for N/A 650cc engine? Anything between 200-300cc should be fine (roughly 130-200hp) so basically anything from >600cc EFI bike will work.

[Gixer1460]

Company in UK called 'Trigger Wheels.com' does a 50mm 36-1 wheel that will fit a oil cooled engine - they have tested it to 20,000 rpm but don't say with what pick-up - even so, it gives some hope, they are also a good source of all things EFI related. Certainly a 24 tooth wheel in that size is a lot easier to machine on a DIY sized milling machine 

[blandit600]

14 hours ago, Arttu said:

I haven't personally tested 36-1 on oil cooled Suzukis. But just looking the resulting teeth / gap size I think it's getting a bit too tight for the stock pick-up sensor. I know that some people are using it successfully but also there are some who haven't got it working properly. 24-2 has been pretty trouble free for me.

Injectors for N/A 650cc engine? Anything between 200-300cc should be fine (roughly 130-200hp) so basically anything from >600cc EFI bike will work.

Sorry Arttu, I was hoping to use the stock 650 injectors, but I'm trying to find out what injector size they are, would you know?

 

[blandit600]

I'm going to change to a 24-2, its feels more comfortable to me.

Cheers all 

[coombehouse]

3 hours ago, blandit600 said:

I'm going to change to a 24-2, its feels more comfortable to me.

Cheers all 

I used a 36-1 wheel from trigger wheels on a gsx1100 but had resolution issues higher up the rev range. I copied Arttu & went with 24-2 & it works perfectly. I drew them in cad & got some laser cut. Tried water jet first but they were too rough.

Regarding a returnless system, how are you going to fit the pump into the tank?

Edited June 26, 2023 by coombehouse
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[Arttu]

8 hours ago, blandit600 said:

Sorry Arttu, I was hoping to use the stock 650 injectors, but I'm trying to find out what injector size they are, would you know?

 

Ah, ok. Sorry, no idea about them but I'm pretty sure they are suitable for a B600 engine. You can measure the flow quite easily by yourself. And that's highly recommended any ways when using old injectors in unknown condition.

[blandit600]

On 6/27/2023 at 12:35 AM, coombehouse said:

I used a 36-1 wheel from trigger wheels on a gsx1100 but had resolution issues higher up the rev range. I copied Arttu & went with 24-2 & it works perfectly. I drew them in cad & got some laser cut. Tried water jet first but they were too rough.

Regarding a returnless system, how are you going to fit the pump into the tank?

Im going to run an external fuel pump. Drill two holes in the tank, one for the feed line and one for the return.

to clarify this is technically a return system, it’s just the fuel rail is after the fuel pressure regulator rather than before.