Marb Posted April 8, 2010 Report Share Posted April 8, 2010 I need to know 2 things from the steelie owners. 1st: Are the CBR600 engines in the steelies all the same or are there major differences along the line? 2nd: Does anyone know the piston pin diameter. Cheers! Link to comment Share on other sites More sharing options...
heds954 Posted June 14, 2010 Report Share Posted June 14, 2010 The F2 was announced in late 1990 at $4998 and it promised to be a worthy follow-up to the original Honda Hurricane that debuted in 1987. The CBR600F2 had a liquid-cooled DOHC engine with a 65mm x 45.2mm bore and stroke that was even more over-square than the original at 63 x 48mm. The cam chain was moved to the right end of the crank to eliminate one crank journal, and compression was bumped up from 11.3:1 to 11.6:1. The new bike also featured 34mm flatslide CV carbs vs. the older model's 32mm round-slide units. With lighter pistons, crank and con rods, it was able to achieve a 500-rpm bump in the rev-limit to 13,000 rpm. The bike also had side mounted air scoops but they fed cool air under the tank and not directly into the 6.2-liter airbox. The engine was known for making good top-end power without sacrificing the midrange, which is one of the things that made it so special. The cams were actually designed with midrange power in mind and the excellent cylinder head flow was rumored to be the secret to the top end power. The included valve angle was shrunk from 38 to 32 degrees, and a shim-under-bucket valve actuation replaced the old rocker arm assembly. This also allowed valve adjustments to jump from 5000 to 12,000-mile intervals. Although the F3 looked similar to the F2, it was only skin deep, as both the engine and chassis were revised. The new 1995 F3 featured another bump in carb size up to 36mm. With the addition of ram-air induction, new fueling and breathing requirements were necessary in order to serve up another five horsepower over the older F2 (this included a system of hoses to maintain the same pressure in the float bowls as the airbox, otherwise when airbox pressure rose above ambient there would be no fuel flow through the main jet). Compression was bumped to 12.0:1 and the intake runners shortened by 5mm to increase intake velocity. A new exhaust was also part of the mix, as was a new low friction coating on the piston rings and crank bearings. Honda revised the ignition system to help control detonation with the higher compression engine. All the engine changes allowed a bump in the rev limit to 13,300 rpm and peak power of about 90 horsepower arriving at 12,000. From here Piston Pin diameter (amongst other measurements) here (PDF) section 1 - page 9 WARNING - PDF is large (approx 30Mb) Link to comment Share on other sites More sharing options...
fran9r Posted June 14, 2010 Report Share Posted June 14, 2010 Oh oh! Is this related to the FCRs? If so, sounds very interesting... Link to comment Share on other sites More sharing options...
heds954 Posted June 14, 2010 Report Share Posted June 14, 2010 If it is FCR related the FCR33 are good to go for the F2 but you need the FCR35 for the F3* *I may have looked into this myself Link to comment Share on other sites More sharing options...
fran9r Posted June 14, 2010 Report Share Posted June 14, 2010 It'd need a lot of tuning to justify 35mm. What power would that be heds? Link to comment Share on other sites More sharing options...
heds954 Posted June 14, 2010 Report Share Posted June 14, 2010 There's a 2mm bump on the carbs between the F2 and F3 as standard, I can only assume that's down to the ram air on the F3. Link to comment Share on other sites More sharing options...
fran9r Posted June 14, 2010 Report Share Posted June 14, 2010 There's a 2mm bump on the carbs between the F2 and F3 as standard, I can only assume that's down to the ram air on the F3. That might not (but then I don't tweek F3s for a living) mean 35mm FCR are required though. I think 33.3% of the reported ridability problems with FCRs is down to using slightly too large a bore -they flow better than CVs, so you would expect to drop a mm or two. The other % I would split equally between poor setup and poor riding. Link to comment Share on other sites More sharing options...
heds954 Posted June 14, 2010 Report Share Posted June 14, 2010 Well, in the process of running off to my web browser favourites and retrieving the Keihin.com website URL to show you what Keihin themselves recommend they show the following... CBR600F2 32 MM D CBR600F2 33 MM D CBR600F2 35 MM D CBR600F3 35 MM D However if you go to the UK distributors BR Special Tuning they show... CBR600F2 91-94 33 016-446* CBR600F3 95-98 35 NLA Hmm, not conclusive is it I guess, like you say must depend on the state of tune... Searching through my communique with my local Dynojet bloke in reply to my question... "What size would you recommend for a 94 engine, this place ( http://www.brspecialtuning.co.uk/Keihin.htm ) recommend 33mm for the f2 and 35mm for the f3, but why, as essentially they are the same engine, I'm guessing it has to do with the ram air, is that correct? I can upgrade the f2 engine to an f3, IIRC it doesn't take much doing, so would the 35mm be a better bet or stick with the 33mm?" he said "I would definately stick with 33 mm carbs on that bike youll get much better traction out of corners etc. Much better to set up as well. Ram air will defo be better on that engine with those carbs." Link to comment Share on other sites More sharing options...
fran9r Posted June 14, 2010 Report Share Posted June 14, 2010 Well, in the process of running off to my web browser favourites and retrieving the Keihin.com website URL to show you what Keihin themselves recommend they show the following... CBR600F2 32 MM D CBR600F2 33 MM D CBR600F2 35 MM D CBR600F3 35 MM D However if you go to the UK distributors BR Special Tuning they show... CBR600F2 91-94 33 016-446* CBR600F3 95-98 35 NLA Hmm, not conclusive is it I guess, like you say must depend on the state of tune... Searching through my communique with my local Dynojet bloke in reply to my question... "What size would you recommend for a 94 engine, this place ( http://www.brspecialtuning.co.uk/Keihin.htm ) recommend 33mm for the f2 and 35mm for the f3, but why, as essentially they are the same engine, I'm guessing it has to do with the ram air, is that correct? I can upgrade the f2 engine to an f3, IIRC it doesn't take much doing, so would the 35mm be a better bet or stick with the 33mm?" he said "I would definately stick with 33 mm carbs on that bike youll get much better traction out of corners etc. Much better to set up as well. Ram air will defo be better on that engine with those carbs." The problem being, it's a £1500 investment. Why people think that is a lot for something such as a bank of 4 carbs is beyond me (in the context of the same amount for a quality exhaust anyway), but I can see why they would want to buy both to see. Another way of looking at it is this...what is the mechanical difference between an F3 and 3? Unless it's moving a lot more air, it's not going to do a whole lot. Anyone got some 41s I can try on my 9? I have the 39s to play with. Anyway, whats the project? Link to comment Share on other sites More sharing options...
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