gixer34
Oviraptor
Posts: 11 
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Post by gixer34 on Apr 2, 2015 10:09:17 GMT
Got some RS38s and the rubbers are a bit stiff on my engine. Anyone got any tips on softening up rubbers? cheers
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Post by captain chaos on Apr 2, 2015 13:14:02 GMT
warm them with a hair drier
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Post by jonny on Apr 2, 2015 15:02:55 GMT
I put mine in a pot of boiling water on the stove for a 10 minutes.  |
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Post by katana on Apr 2, 2015 18:02:29 GMT
38's in 34mm rubbers is gonna be a trial no matter how soft they are! I'd use thin wall silicon - lot more stretch!
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Post by arnout on Apr 2, 2015 18:28:01 GMT
EFE rubbers are 36mm instead of 34mm on earlier 1100's btw, so the hot tip for fitting larger carbs to an ET/EX/EZ/ESD/Kat.. As for struggling with old dried out manifolds, I've given up on that myself and just buy a new set of EFE rubbers (not that expensive).. These are so supple that even Keihin FCR41's will slip in without breaking a sweat..  |
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Post by quazi on Apr 2, 2015 18:55:19 GMT
EFE rubbers are 36mm instead of 34mm on earlier 1100's btw, so the hot tip for fitting larger carbs to an ET/EX/EZ/ESD/Kat.. As for struggling with old dried out manifolds, I've given up on that myself and just buy a new set of EFE rubbers (not that expensive).. These are so supple that even Keihin FCR41's will slip in without breaking a sweat.. I went down this route too, seem to remember them being about £65 a set, save a fair bit of fooking about, they should last another 25 years now.  |
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gixer34
Oviraptor
Posts: 11
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Post by gixer34 on Apr 2, 2015 21:09:39 GMT
Cheers every one.warmed them on top of the wood burner and they popped on nicely.
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Post by arnout on Apr 4, 2015 20:17:08 GMT
I went down this route too, seem to remember them being about £65 a set, save a fair bit of fooking about, they should last another 25 years now. Ah.. Yes, I checked the price too and they're not as cheap as I remember, but still it's well worth the money and should last you quite a few years before these will turn hard again (or perhaps Suzuki may have started to use a different kind of rubber?) Anyway.. Forgot to mention that the inside of these stock manifolds does not follow the shape of the inlet tract very well.. There are rough steps going from the carb venturi to the inlet port that can't possibly be benificial to the flow of the A/F mixture into the head.. Also the diameter is smaller effectively "choking" the engine.. Improving the flow by modifying the rubbers will free up a few HP for no cost and a little effort.. These ridges are easily smoothed out however by grinding them down with a small sanding drum fitted to a dremel-like tool.. Before starting this job you might want to consider first doing some mild working on the inlet ports themselves though.. (On GSX's these ports are often not centered, and for installing bigger carbs a nice tapered tract would be better anyway..) Right.. For modifying the rubbers alone, the trick is matching each side of the rubber to the diameter of where it is fitted to.. So either -gently!- sand down those ends actually fitted in situ, or (somehow) scribe the edge onto the rubber and work on the removed manifold.. (So in turn fit to head and onto the carbs) Dedicating each manifold to each port is the only way to do a good job (esp. as the stock ports are quite offset), so a whitewall marker pen works well for penning down the cyl. numbers.. With the outside diameters done, now work on the inside of the manifold to create a smooth transition between both ends..  Oh.. Stuff the ports with clean rags/paper towels before any grinding to prevent dust/crap/debris from entering the combustion chambers.. After the job, first vacuum out the ports before removing the temporary plugs.. |
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