badgerkdd Posted January 2, 2017 Posted January 2, 2017 Hello all! I'm just after some general consensus advice/ experience before I get into ripping my old engine down. Its my old 750 1994 engine which I've talked about on here before, the one where the piston/ rings have gone in cylinder 2. Unfortunately she also got flooded ( manky flood/ drain water not petrol ) when my work experienced bad flooding a few months ago. I've yet to strip the engine, but have filled her up with diesel after draining the water. Now to the point of this...depending on the general condition of the engine upon strip down, I'm thinking about a rebore and oversize pistons. Having been online and struggling to find oversize pistons for this engine, I'm also unsure whether I would need to uprate the valve train? I would be expecting to go approx. 830 cc ( previously found these pistons, but now can't find again ), and having never gone down this route, I'm now asking for advice on whats the usual changes made when oversize reboring? Its all theoretical at the moment but I'm doing my research early so, depending on what greets me when I open up the engine, I can work out my budget and gather a list of things I need to find/ order. Now, my other conumdrum........ The replacement engine currently in the bike is the 92 motor, same cc but without the magnesium covers etc. Would the gains made to rebuilding the 94 motor, be minor if I instead uprated the 92 motor with new Dyna Coils/ leads, invest in a stage 2 tune, swap the to magnesium covers and possibly swap the cams from the 94 onto the 92? This is possibly the easier route and probably cost similar? Cheers for any advice Quote
Gixer1460 Posted January 2, 2017 Posted January 2, 2017 Isn't the '94 GSXR750 a water boiler as opposed to the oil boiler '92? So most of the parts std or aftermarket won't be swoppable! Quote
no class Posted January 2, 2017 Posted January 2, 2017 14 minutes ago, Gixer1460 said: Isn't the '94 GSXR750 a water boiler as opposed to the oil boiler '92? So most of the parts std or aftermarket won't be swoppable! 92' was the first year water cooled 750 . 1 Quote
alfiestorm Posted January 2, 2017 Posted January 2, 2017 I see no reason to upgrade the valve train unless of course you are going to fit some performance cam shafts then I would fit some orient express or ape heavy duty valve springs to guard against valve bounce. Quote
badgerkdd Posted January 2, 2017 Author Posted January 2, 2017 Thats cool, didn't think I'd need to but wanted to get some sound advice first Quote
Legotoy Posted January 3, 2017 Posted January 3, 2017 Buy an RF900 engine and swap the head for your GSXR one - it goes right on using the RF head gasket. Instant 937cc big bore. There are a few other bits to swap like water pipes, but they all swap over between engines. FYI RF's have a magnesium points cover too. There are loads of threads from people who have done this if you use the search function on here. Good luck. 3 Quote
Madb Posted January 3, 2017 Posted January 3, 2017 Rf9 is the cheapest way as legotoy suggests tho you'll end up with a hydro clutch. Use rf900 gaskets to fit 750 head on. Should be good fir 30 hp gain. ( no wheelie wire to cut, justs wheelies!) Yer 750 water pipes should all fit lovely. ya prefer cable clutch use the rf6 sprocket cover. You'll also need shum down pipes too as the 750 are to short . K1-k3 1000 down pipes/ headers are cheap and are titanium! Uk and europe got the w/cooled from 92-95. State side 93 onwards. No point swaping cams as the same. Magnesium covers are just for added lightness. People charge to much for them!!!! One more thing. You can get a 999cc kit for the rf900 too. Nice. 3 Quote
Legotoy Posted January 4, 2017 Posted January 4, 2017 19 hours ago, Madb said: ... ya prefer cable clutch use the rf6 sprocket cover... Hi Madb - not sure the cable conversion would work. The RF600 lifter is on the clutch cover, not the sprocket cover. So RF600 doesn't operate via a pushrod through the layshaft like the RF900 does. Shame as I'd way prefer a cable clutch on my 9! Quote
Madb Posted January 4, 2017 Posted January 4, 2017 Oh yeah. Me thinking about shum where else i expect. Haha soz about that. I'll have a think ( not too much tho my head goes funny). Me sure i worked something out about using cable instead of a slave cylinder. Quote
Madb Posted January 4, 2017 Posted January 4, 2017 I am toying with the idea of swaping the clutch gears from rf9 to the gsxr750 basket so i can still use the cable. I'll let ya know how it works when track bike done.. It will be a few months as yet tho! 2 Quote
CAPTAIN CRUNCH Posted January 5, 2017 Posted January 5, 2017 Eh guys I'm keen on doing Rf swap also, just wondering is it possible to use the Rf carbs on 750 head in anyway? As don't have carbs from the 750, Quote
bluedog59 Posted January 5, 2017 Posted January 5, 2017 Does anybody know if you can do the swap the other way round, convert a 750 from cable to hydraulic ? Quote
Madb Posted January 5, 2017 Posted January 5, 2017 57 minutes ago, CAPTAIN CRUNCH said: Eh guys I'm keen on doing Rf swap also, just wondering is it possible to use the Rf carbs on 750 head in anyway? As don't have carbs from the 750, Cant use rf carbs as they are down draft type. They would sit at wrong angle. Should get set 750 carbs reasonable price. 1 Quote
Madb Posted January 5, 2017 Posted January 5, 2017 @blue dog. You could change to hydro if you have the later models 94/95 as they have hollow shafts. But then you would need the rf9 clutch case and chain case too but you would need some fettling with the clutch to mate up with the pressure plate. I'll have a look sometime to see if its doable. Unless someone knows diff. Quote
Madb Posted January 5, 2017 Posted January 5, 2017 If ya can make a bracket the guessing you could mount a slave to the clutch lever on the casing. Quote
bluedog59 Posted January 5, 2017 Posted January 5, 2017 8 hours ago, Madb said: @blue dog. You could change to hydro if you have the later models 94/95 as they have hollow shafts. But then you would need the rf9 clutch case and chain case too but you would need some fettling with the clutch to mate up with the pressure plate. I'll have a look sometime to see if its doable. Unless someone knows diff. That would be handy thank you. It's in a none standard frame and I'd rather not have a cable hanging out in the breeze. Could pull the rm from the other side but hydraulic would be neater. Quote
Madb Posted January 5, 2017 Posted January 5, 2017 Something like this. Imagine that as a slave cylinder actuating the clutch. Master clutch of yer choice. Think someone done this on an early oss bike. Quote
bluedog59 Posted January 5, 2017 Posted January 5, 2017 I know the type you mean, using a clutch slave of a car type of thing. I'm looking for a bit neater. Quote
Madb Posted January 5, 2017 Posted January 5, 2017 Yes. I know what you mean. Best kick my ass into gear see if things fit. Quote
badgerkdd Posted January 5, 2017 Author Posted January 5, 2017 Ha ha, that's cool, it just gives me more to think about! Like the idea of the RF conversion, but \i'm a bit confused? If you are just swaping RF barrels/ pistons and head onto 750 bottom end surely the clutch would still be cable ? If I'm missing something out do tell, because this is all new to me Quote
Madb Posted January 5, 2017 Posted January 5, 2017 1 minute ago, badgerkdd said: Ha ha, that's cool, it just gives me more to think about! Like the idea of the RF conversion, but \i'm a bit confused? If you are just swaping RF barrels/ pistons and head onto 750 bottom end surely the clutch would still be cable ? If I'm missing something out do tell, because this is all new to me Haha. Yeah, see where can miss it. The rf900 crank gear and clutch gear are diff size to the 750. And clutch basket is much deeper on the 900 so you lose the cable mechanism from 750 casing as you need the 900 casing. There is a way of using a spacer between the crankcase and the clutch case so you can use the cable but I've been told it won't last long so didnt bother. Unless of some knows better. (Plz) 1 Quote
badgerkdd Posted January 5, 2017 Author Posted January 5, 2017 Is there any write ups on this conversion in the OSS archives, or is it a 'Google it!' job? Really keen to look into this as long as my engine has survived Redruth's finest flood/ gutter water . Alternatively would it be easier to buy a second hand RF900 engine and stick it in the frame, with 750 carbs? or is that a whole different kettle of ball games? Quote
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