szrdave Posted February 7, 2010 Report Share Posted February 7, 2010 I won these on ebay recently and collected them today, I think they're Mikuni RS34s but there are no identifying numbers I can see. They're 34mm flat slides with accelerator pumps on two of the carbs. They were advertised as 'spares or repair', and the seller wasn't joking! A quick look has shown 2 float assys missing, one broken jet needle, one broken carb body, the top of one slide lifting arm missing and all manner of mangled bolt and screw heads. Luckily I only need to make two good ones out of the four, as they're to go on my SZR660. I'm sure I'll need to order a few parts though, so I'd appreciate it if someone tell shed some light on what model they are?! Link to comment Share on other sites More sharing options...
fran9r Posted February 8, 2010 Report Share Posted February 8, 2010 I think RS too...but if you photo the carb tops then I'd be able to say. Sounds like quite a project... Link to comment Share on other sites More sharing options...
Basil Posted February 8, 2010 Report Share Posted February 8, 2010 What are these? Not working is what they are... Link to comment Share on other sites More sharing options...
blow_away Posted February 8, 2010 Report Share Posted February 8, 2010 SZR Dave, they look exactly like the carbs I had on my 1985 GSXR 750 F (slabside). I should recognise them, had them apart enough times! If they are from a 750, they will not be 34mm. Standard they were 29mm, I bored mine out to 31mm, by which point the bodies were wafer thin. I guess carbs from a GSXR1100 of the same vintage had a larger bore? Try PM'ing Banoffee or AndyJ, both of whom run 1100 slabbies. Or try Oldschoolsuzuki. Or Ronayres for fiche info (you can check the part numbers on RA, but use care, the fiches are for Yank models are sometimes the carbs differ) Link to comment Share on other sites More sharing options...
lorenzo Posted February 8, 2010 Report Share Posted February 8, 2010 The 2 being different from each other, and the fact that they've already been tweaked about a bit kinda points to that they might be 2 halves from 2 different bikes, stuck together. A kinda carb cut and shut, if you like. Link to comment Share on other sites More sharing options...
fran9r Posted February 8, 2010 Report Share Posted February 8, 2010 The slabby carbs are very similar to the RSs...looking again I'm sure they are RSs. Nice screws on the brackets too! Link to comment Share on other sites More sharing options...
szrdave Posted February 8, 2010 Author Report Share Posted February 8, 2010 SZR Dave, they look exactly like the carbs I had on my 1985 GSXR 750 F (slabside). I should recognise them, had them apart enough times! I think you're right, I measured the carb outlet yesterday which is 34mm, but looking at the inlet side it's definitely smaller. I'll strip one apart and measure it tonight. 29 or even 31mm will be too small for what I need. Crap! Link to comment Share on other sites More sharing options...
fran9r Posted February 8, 2010 Report Share Posted February 8, 2010 I think you're right, I measured the carb outlet yesterday which is 34mm, but looking at the inlet side it's definitely smaller. I'll strip one apart and measure it tonight. 29 or even 31mm will be too small for what I need. Crap! You don't need to strip them to measure them...calipers as close to the bore as possible from the engine side will be fine. Edit -looked at the float bowls...as someone said above, they are slabby carbs, so VM29SS is the code. Link to comment Share on other sites More sharing options...
Andy J Posted February 8, 2010 Report Share Posted February 8, 2010 SZR Dave, they look exactly like the carbs I had on my 1985 GSXR 750 F (slabside). I should recognise them, had them apart enough times! If they are from a 750, they will not be 34mm. Standard they were 29mm, I bored mine out to 31mm, by which point the bodies were wafer thin. I guess carbs from a GSXR1100 of the same vintage had a larger bore? Try PM'ing Banoffee or AndyJ, both of whom run 1100 slabbies. Or try Oldschoolsuzuki. Or Ronayres for fiche info (you can check the part numbers on RA, but use care, the fiches are for Yank models are sometimes the carbs differ) Deffo not GSXR1100 carbs. They all used CVs Only slabby 750s had slide carbs as standard. Link to comment Share on other sites More sharing options...
blow_away Posted February 8, 2010 Report Share Posted February 8, 2010 Deffo not GSXR1100 carbs. They all used CVs Only slabby 750s had slide carbs as standard. Makes sense I suppose - racing homologation? Link to comment Share on other sites More sharing options...
banoffee Posted February 8, 2010 Report Share Posted February 8, 2010 they do look very much like GSXR slabby 29s (as mentioned, measured on the inlet side of course) Link to comment Share on other sites More sharing options...
szrdave Posted February 8, 2010 Author Report Share Posted February 8, 2010 As if I didn't already know it from the collective PB wisdom, the intake side of the carb measures exactly 29mm. Arse The main carb body in the picture below measures 34mm at the end where it would meet the intake manifold, and tapers down slightly to about 33mm towards the slide. I couldn't get the verniers in there, but the trusted 'bend a bit of wire to fit and measure that' should be close enough. Taken with the 'front' of the carb and the slide removed The next two pictures show the front section, which the slide runs through. It only measures 29mm where it meets the slide, and opens out either side. The external wall at this point is 40+mm diameter, I guess it's hollow from what blow_away said about boring it out to 31mm max? The back face of the 'front' of the carb From another angle. The ring in the middle is Ø29mm As far as I can see I've got three options: 1 - Replace the front section with one of a larger internal diameter. Is this possible? 2 - Bore the offending front section out a large as possible. 3 - Give up and use them as a paper-weight. Polite suggestions please Link to comment Share on other sites More sharing options...
fran9r Posted February 8, 2010 Report Share Posted February 8, 2010 As far as I can see I've got three options: 1 - Replace the front section with one of a larger internal diameter. Is this possible? 2 - Bore the offending front section out a large as possible. 3 - Give up and use them as a paper-weight. Polite suggestions please 1. No. Well, not unless you make your own... 2. Maybe. 3. Or use them anyway. What BHP will the SZR be, and would 29mm be restrictive? Your dealing with one half of a GSXR, so unless you are aiming for massive BHP they would be acceptable. Link to comment Share on other sites More sharing options...
banoffee Posted February 8, 2010 Report Share Posted February 8, 2010 There's some comments on boring them out on http://oldskoolsuzuki.info but it's down at the moment Might be some folks knowledgeable about that either on or I can't remember the max bore from memory, sorry. Howevert do remember they CAN be bored. I'm running them at the stock 29mm on my mildy tweaked GSXR750 and it's good for just over 100bhp at the rear wheel. Feels in no way restricted and goes like hell Link to comment Share on other sites More sharing options...
banoffee Posted February 8, 2010 Report Share Posted February 8, 2010 oh and PM me if you need some more official workshoppy type stuff on these carbs Link to comment Share on other sites More sharing options...
szrdave Posted February 9, 2010 Author Report Share Posted February 9, 2010 oh and PM me if you need some more official workshoppy type stuff on these carbs Thanks banoffee Link to comment Share on other sites More sharing options...
szrdave Posted February 9, 2010 Author Report Share Posted February 9, 2010 1. No. Well, not unless you make your own... 2. Maybe. 3. Or use them anyway. What BHP will the SZR be, and would 29mm be restrictive? Your dealing with one half of a GSXR, so unless you are aiming for massive BHP they would be acceptable. Option 2 is looking the most likely now, oldskoolsuzuki has a number of reports of people taking the inlet out to 33mm to match the outlet The SZR was making 39bhp when I first got it, up to 44 with an end can and k&n with no airbox lid. I'm hoping for high 40s with new carbs and an IgniTech programmable ignition, I'd be ecstatic if it hit the heady heights of 50bhp!! With regards to the size of the carb, I guess a single cylinder pulling in big slugs of air needs a bigger carb. The recommended size for a mildly tuned engine is about 34mm, with highly tuned bike normally using something like a pair of FCR39s! Link to comment Share on other sites More sharing options...
fran9r Posted February 9, 2010 Report Share Posted February 9, 2010 I think the reason people go for such big carbs on the singles (in racing at least) is that 0.1 bhp is worth a good few hundred quid of enqine development. At your expected power, I'd get them to fit, and try them at 29 to start. Remember the larger the carb, the more compromised the midrange. You'll benefit with having slide carbs over CVs anyway. I'm sure the FCR 39 application is best suited to highly tuned bikes. Link to comment Share on other sites More sharing options...
banoffee Posted February 10, 2010 Report Share Posted February 10, 2010 Thanks banoffee Link to comment Share on other sites More sharing options...
szrdave Posted February 10, 2010 Author Report Share Posted February 10, 2010 I think the reason people go for such big carbs on the singles (in racing at least) is that 0.1 bhp is worth a good few hundred quid of enqine development. At your expected power, I'd get them to fit, and try them at 29 to start. Remember the larger the carb, the more compromised the midrange. You'll benefit with having slide carbs over CVs anyway. I'm sure the FCR 39 application is best suited to highly tuned bikes. I think getting them to fit is going to be a challenge, as the carb spacing on the SZR is about 65mm (apparently) and these won't go quite that close together. I'll offer them up this weekend and take some measurements, then out with the file* It's quite handy having a set of four as I can leave two face plates at 29mm and take two out to 33mm, then try both when I'm having the bike set-up. One intake into the head is bigger than the other, so one 29 and one 33 may even work quite well. The first step is to work out what I'm missing to get two complete carbs together. So far the list is: - 2 off float to float needle clips - Accelerator pump spring - Throttle cable stay - 2 off pilot jets (i think, from looking at a TM33 exploded diagram) * I may or may not be joking Link to comment Share on other sites More sharing options...
Majik Posted February 10, 2010 Report Share Posted February 10, 2010 I'd suggest the 29/33 combo would be the way to go, having played with the carbs on my 2 old SZR's, they are indeed different sizes, the smaller being the "pilot" carb to keep things sweet below 3500 revs. I'm very interested in this - wondering if I could throw a single one of these at my Goose? The Goose has a 40mm CV on it, but the DR350 engine it uses naturally has a 33mm CV. Hmm... Link to comment Share on other sites More sharing options...
szrdave Posted February 10, 2010 Author Report Share Posted February 10, 2010 I'd suggest the 29/33 combo would be the way to go, having played with the carbs on my 2 old SZR's, they are indeed different sizes, the smaller being the "pilot" carb to keep things sweet below 3500 revs. I'm very interested in this - wondering if I could throw a single one of these at my Goose? The Goose has a 40mm CV on it, but the DR350 engine it uses naturally has a 33mm CV. Hmm... Well apparently the carbs I have are very similar to the TM33, but with a 29mm front plate. And google showed the TM33 to be a popular upgrade for the DR350, so it sounds like it would work. I should have most of a carb left over once I'm finished, which you're welcome to if you want it? How do you find the goose compared to the SZR? I always fancied one, but I still haven't seen one in the flesh. Link to comment Share on other sites More sharing options...
monkeystew0 Posted February 10, 2010 Report Share Posted February 10, 2010 I've just been "tipped off" to chip into this thread. As I now own one and a half of Majik's former SZR660's (and he lives around the corner too) One is a fully running road bike with Arrow end can, the other a partially built trackday special that i'm trying to put together from a frame, swingarm and box of bits that came with the road bike back in December. I have a feeling we could be comparing notes some time in the near future.....Still determined to get the 2nd bike built up before I start spending money on tuning parts though.... Will follow your carb progress with interest..... Link to comment Share on other sites More sharing options...
szrdave Posted February 12, 2010 Author Report Share Posted February 12, 2010 Will follow your carb progress with interest..... Well if works you'd only need to source one bank of carbs and you've got flatslides for both bikes. Bargain! Link to comment Share on other sites More sharing options...
szrdave Posted February 20, 2010 Author Report Share Posted February 20, 2010 I took the standard carbs off last weekend and offered the flatslides up. A couple of things became apparent: 1 -The stock spacing is 64mm centre to centre, the flatslides are 77mm when mounted on the rack and can't be moved much closer. This can be solved by either moving the carbs closer together, which would involve removing the redundant accelerator pump casting from one of the carbs, or making an adapter sit between the rubbers and head. I think the adapter option would be easier as I'd have to remove the casting, make a new float bowl gasket, and cut/drill/tap the carb mounting brackets and throttle shaft. 2 -One carb rubber is too small ID, the other too large. The Raptor quad uses the same engine with 33mm CV carbs so I should be able to use the rubbers to mount the new carbs. I'd probably have to source them from the states, and they might need opening out a bit internally to the same diameter as the carbs. One other solution would be to get a set of custom carb rubbers made, is such a thing is possible? Link to comment Share on other sites More sharing options...
chrisexup Posted February 20, 2010 Report Share Posted February 20, 2010 You could have a go at making your own, Frost restoration sell rubber moulding kits. Bloody expensive mind. Link to comment Share on other sites More sharing options...
fran9r Posted February 20, 2010 Report Share Posted February 20, 2010 I'd have something knocked up in ally, a manifold in as much as it bolts to the engine, with a tube that comes out -spec that to a diameter of sleeve rubber such as these http://www.allensperformance.co.uk/products-manifolds.html that fit your carb spigot, and bobs your aunt. Link to comment Share on other sites More sharing options...
Majik Posted March 2, 2010 Report Share Posted March 2, 2010 Well apparently the carbs I have are very similar to the TM33, but with a 29mm front plate. And google showed the TM33 to be a popular upgrade for the DR350, so it sounds like it would work. I should have most of a carb left over once I'm finished, which you're welcome to if you want it? How do you find the goose compared to the SZR? I always fancied one, but I still haven't seen one in the flesh. That'll be a "Yes please" to your offer The Goose and the SZR are totally different animals, although I found the engines pretty close in performance, dispite their 10bhp odd difference. The Goose is like a really nicely done special - strangely like an LC/RGV jobby done very well, but with a thumper engine in. That doesn't make much sense, does it? The SZR I could do many miles on with not trouble - despite being 6'1" I found it really comfy and I was able to sit "on" it rather than "in" it, which suited me fine. Once I had the exhaust done, it freed up the engine no end (and made it sound like rhino sex too, which is good). The Goose is a lot more aggressive and raucious (although the open can probably helps) and it's easy to keep pinned. Not as light as it could be, but damned light nevertheless. Easy to keep the licence intact, for sure. Little needs upgrading on it really - a lot of the Japs put Tokico six pots on (FAIL!!!) or twin discs (nutters - it only weighs 140kg or something). The rear shock needs an upgrade - I'm measuring some up, as the standard replacement is RS250 and people want stupid money for knackered ones. Oh, and it's proper tiny Link to comment Share on other sites More sharing options...
szrdave Posted March 7, 2010 Author Report Share Posted March 7, 2010 I finished moving house last week, so I took advantage of the sunny weather this weekend to pull the SZR apart and measure the ports on the head up. You could have a go at making your own, Frost restoration sell rubber moulding kits. Bloody expensive mind. I have a feeling that would go very wrong! I'd have something knocked up in ally, a manifold in as much as it bolts to the engine, with a tube that comes out -spec that to a diameter of sleeve rubber such as these http://www.allensperformance.co.uk/products-manifolds.html that fit your carb spigot, and bobs your aunt. I have a similar plan in mind, but I'll get a manifold plate made up instead of a tubular manifold. The back of the fuel tank goes down behind the carbs so it's a bit tight for space with air filters fitted. One of the things I love about the SZR is it's so easy to work on. It took less than an hour to take off the tank, airbox and carbs, take some measurements and put it back together again. My CBR600F on the other hand is a pain in the arse to do anything with. 2.5hrs to do an oil and filter change and fit a new cam chain tensioner, jamming plastic fairing clips down behind my nails and skinning my knuckles in the process. A few pics: General layout Inlet shape Standard carb rubbers The standard carb(s) Gratuitous picture whoring! Now I've got the dimensions for the manifold I can draw it and get it made up at work, I'm using Solid Edge 2D at the moment but 2D CAD sucks! Any recommendations for a half decent 3D program? Link to comment Share on other sites More sharing options...
szrdave Posted March 7, 2010 Author Report Share Posted March 7, 2010 That's a nice looking bike. It would be good to have a single cylinder ride-out at some point this summer, think of the sound!! Link to comment Share on other sites More sharing options...
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