JES_VFR Posted August 19, 2014 Share Posted August 19, 2014 RapidBike Race allows 2 maps per cylinder per gear ... 48 maps total! You can switch between two settings with a switch, each setting allows map by cylinder and by gear with ignition adjustability... pretty sweet set-up!!! I can't wait to get my hands on mine!!!!!! RapidBike only lists a #1 module for the 5th gen. Now Power Commander doesn't list a PC5 for the 5th gen either, but one for a Vtec bike works. I guess I need to contact RapidBike and see what they really have for the 5th gen... I'd love to have a tuner that will hold 2 maps per gear (maybe even front bank versus rear bank), including timing and a wide band tuner. That way I could run maps for two different fuels.. Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted August 19, 2014 Member Contributer Share Posted August 19, 2014 RapidBike Race allows 2 maps per cylinder per gear ... 48 maps total! You can switch between two settings with a switch, each setting allows map by cylinder and by gear with ignition adjustability... pretty sweet set-up!!! I can't wait to get my hands on mine!!!!!! RapidBike only lists a #1 module for the 5th gen. Now Power Commander doesn't list a PC5 for the 5th gen either, but one for a Vtec bike works.I guess I need to contact RapidBike and see what they really have for the 5th gen... I'd love to have a tuner that will hold 2 maps per gear (maybe even front bank versus rear bank), including timing and a wide band tuner. That way I could run maps for two different fuels.. Read the Rapid Bike group buy thread... they are programming the fueling and ignition for our bikes. It will be based on the 6th gen and 5th genners will have to adjust accordingly with the factory O2sensors or a TuneMyBike module... read the other thread. All the details are there...Units should be available end of September / Oct I think... Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 19, 2014 Share Posted August 19, 2014 yup plus one, catch up:http://www.vfrdiscussion.com/forum/index.php/topic/78467-official-rapid-bike-race-group-buy/ The Rapid Bike 1, 2 and 3 haven't been officially sold for years. The Rapid Bike racing is being produced now and features everything that you are asking for. Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted August 19, 2014 Member Contributer Share Posted August 19, 2014 Now back to discussing bored, stroked, or both...VFR engines Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 20, 2014 Share Posted August 20, 2014 Hey so theoretically if one were to completely bore through the frm liners and coat the bare aluminum walls with nickisil, what size bore would we be looking at. Also with everything that you guys have learned so far, would the 75mm 954 pistons still be doable? And then furthermore what about 76mm cbr1000 pistons? I take it that's about where you need to full bore through the frm liners and press in steel liners?? Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted August 20, 2014 Member Contributer Share Posted August 20, 2014 I'm familiar with the MMC liner nomenclature that Honda uses... what are frm liners? Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted August 21, 2014 Author Member Contributer Share Posted August 21, 2014 CR, the MMC liners are 2.5mm maximum wall thickness, so 72mm bore + 5mm to bore out the MMC means that 75 & 76mm bores are NOT doable without liners ;( but a 77 or 78mm bore is. Wiseco do a 78mm big bore piston for the CBR1000RR (40069M07800) that weighs 228grams (bare piston + wrist pin) which is 10 grams lighter than stock, so throw in the rings & circlip a & it's about the same as stock. With these you could do a 917cc. If you used a 6th gen engine you could keep the compression ratio reasonable by using 2 head gaskets or the parts of two to make one the correct thickness, or have Cometic make one the right thickness. You could then probably get & fit two sets of CBR adjustable cam sprocket carriers so you could play with degreeing the cams. If we assume that the head gasket has a compressed thickness of 0.8mm then two would give a CR ratio of 11.32/1, if they are thicker it would be less if thinner slightly more. One gasket would give 13.45/1 which would require more valve overlap to keep the dynamic compression sensible. The only other concern would be the cylinder wall thickness would now be 5mm (down from 8mm) so I use a heat shrink fitted 2mm thick alloy sleeve over the outside of the cylinders. Or 1.5mm stainless if you didn't want to risk chunking the cylinder wall. The reinforcing only needs to be 20mm high. Alloy would keep the good cooling characteristics of the MMC. Link to comment Share on other sites More sharing options...
JES_VFR Posted August 28, 2014 Share Posted August 28, 2014 yup plus one, catch up: http://www.vfrdiscussion.com/forum/index.php/topic/78467-official-rapid-bike-race-group-buy/ The Rapid Bike 1, 2 and 3 haven't been officially sold for years. The Rapid Bike racing is being produced now and features everything that you are asking for. Okay Sorry for the thread hijack, now that I've the correct info from the correct dealer in the US and will be visiting them in a couple of weeks back to the bore and stroke discussion... CR, the MMC liners are 2.5mm maximum wall thickness, so 72mm bore + 5mm to bore out the MMC means that 75 & 76mm bores are NOT doable without liners ;( Wait, a 75 or 76 mm big bore just means you are boring the MMC liner out and then pressing in a sleeve against the MMC (not the aluminum block). That's what Dynamo Humm did for the 76mm bore of 870cc kit. If you want to go bigger than that just with a big bore, then you need to bore out all the MMC liner, right to the aluminum block and then sleeve the bores against that. iirc - someone here cut up a block and found the total thickness of MMC liners to be 4mm thickness,.. with 1mm steel sleeve, that takes us to 78mm and with a stock stroke would yield the 917cc. The next question is if you are using a Steel sleeve instead of the composite material in the liners, Can you safely bore more than 80mm removing aluminum from the actual block? If you used a 6th gen engine you could keep the compression ratio reasonable by using 2 head gaskets or the parts of two to make one the correct thickness, or have Cometic make one the right thickness. You could then probably get & fit two sets of CBR adjustable cam sprocket carriers so you could play with degreeing the cams. If we assume that the head gasket has a compressed thickness of 0.8mm then two would give a CR ratio of 11.32/1, if they are thicker it would be less if thinner slightly more. One gasket would give 13.45/1 which would require more valve overlap to keep the dynamic compression sensible. I don't know that you would need adjustable cam sprocket carriers, just to get the cams to time properly. I do think it would put a strain on the chain tensioners and perhaps the guide's would need to be altered. But, since none of that is an option on the 5th gen engines, I would look to milling the chamber out to match the larger bore and head gasket opening, as well as starting with a dished piston. The dish in the piston will contribute to complete combustion and making torque, as well as managing the CR. The only other concern would be the cylinder wall thickness would now be 5mm (down from 8mm) so I use a heat shrink fitted 2mm thick alloy sleeve over the outside of the cylinders. Or 1.5mm stainless if you didn't want to risk chunking the cylinder wall. The reinforcing only needs to be 20mm high. Alloy would keep the good cooling characteristics of the MMC. I would put in a steel alloy sleeve with a ceramic coating all round to keep the heat in the cylinder. I'd also coat the chamber of the head and the exhaust ports Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted August 28, 2014 Member Contributer Share Posted August 28, 2014 I don't know that I am as worried about the compression ratio as others. I will be building this engine primarily for a track bike and don't need to keep the compression ratio low enough to run 87 octane fuel. Many other modern sport bikes get by with 13:1 comrpession ration or more... I will find the answer to the 76mm bore question though so thanks for your input on that subject. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 29, 2014 Share Posted August 29, 2014 But keep in mind that the reason that most sport bikes can get away with 13:1 static compression ratio is that sport bikes typically have much more valve overlap and duration and therefore have a dynamic compression ratio that is comparable to our Vfr. Now if you want to run 13plus:1 just be sure to run reground cams with more duration and overlap and or degree the cams for more overlap as well. Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted August 30, 2014 Member Contributer Share Posted August 30, 2014 But keep in mind that the reason that most sport bikes can get away with 13:1 static compression ration is that sport bikes typically have much more valve overlap and duration and therefore have a dynamic compression ratio that is comparable to our Vfr. Now if you want to run 13plus:1 just be sure to run reground cams with more duration and overlap and or degree the cams for more overlap as well. Good point. I am going for stock RC45 cam specs...not the radical race RC45 specs but should do the job with a 76mm bore Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 30, 2014 Share Posted August 30, 2014 235 degrees of duration is still pretty mild when compared to say gsxr750 cams with 270 or 280 degree cams. Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted August 30, 2014 Member Contributer Share Posted August 30, 2014 235 degrees of duration is still pretty mild when compared to say gsxr750 cams with 270 or 280 degree cams.There are other factors at work then simply duration or overlap. You need to consider max engine rpm and cam lift... higher lift cams need more duration so the cam profile slope can accomodate the necessary valve assembly acceleration to reach the higher lift and engines operating at higher rpms need more duration because air acts like a spring when under suction or compression and you won't fill the cylinder at high rpms without the increased duration. What is the redline and lift of the gsxr750 you mentioned? Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 30, 2014 Share Posted August 30, 2014 http://www.gsxr.com/archive/index.php/t-22726.html Man these Gixxer guys got it easy.... Anyways I'll see if we can find the valve sizes and redline too, so we can make a good comparison on what works well with Gixxer 750s and where the power band is with which cams... Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 30, 2014 Share Posted August 30, 2014 So these are the bore and strokes: Vfr800 72x48 Gsxr750 <05 72x46 Gsxr750 >06 70x48.7 Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 30, 2014 Share Posted August 30, 2014 So Mohawk are we sure on the valve sizes of the rc45 vs 5th gen vs 6th gen all being the same 29mm in and 24.5mm ex? Because that is relatively huge, which would explain why our cam specs are so mild... Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted August 30, 2014 Member Contributer Share Posted August 30, 2014 The 2008 GSXR750 bore & stroke is almost the same as the RC30 (70 x 48.7mm vs 70 x 48.6mm)... It needs those long duration cams for the 15k rpm redline... The RC45/VFR800 valve sizes are comparable to the '00 - '04 GSXR750/GSXR1000 shown in the table... why do you think they are huge? Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted August 30, 2014 Author Member Contributer Share Posted August 30, 2014 Jes-VFR, I don't think you understand the dynamics of these or possibly any engines. Dynamo hum bored out to 78mm then added 2mm steel liners & used special JE Pistons suitable for use in steel bores. 1mm steel liners would not be a good idea, unless you only intend to race, but then you have to find custom pistons, as MMC compatible ones won't work in steel. If you space the head out to deal with the over compression issue, then you advance the cam timing, hence the adjustable sprockets. Corner carver, you might like the number, but modern bikes have longer duration cams with greater overlap & its that which reduces the dynamic compression & that is the actual critical number. To high & you'll break the engine. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 30, 2014 Share Posted August 30, 2014 On 8/30/2014 at 1:33 PM, Rush2112 said: The 2008 GSXR750 bore & stroke is almost the same as the RC30 (70 x 48.7mm vs 70 x 48.6mm)... It needs those long duration cams for the 15k rpm redline... The RC45/VFR800 valve sizes are comparable to the '00 - '04 GSXR750/GSXR1000 shown in the table... why do you think they are huge? peak power was at 12,500 rpms, everything after that is just over rev. bump our limiter up 500-1000 rpms and we would be cookin with gas. I think our valves are relatively huge, because we have a 100whp sport touring bike that has valves that our basically the same size as a gsxr1000, that is capable of easily exceeding 160 whp with minor bolt ons.... It is good to know that of all the things that is holding our bikes back, power wise, the cylinder head is definitely not one of them. In fact, looking at the fundamental design of our engine (the bore/stroke, rod:stroke ratio and the valve sizes) it becomes very apparent the the vfr800 is a full on race engine, that honda dumbed down and stuck in a touring bike. I would like to compare our rod to stroke ratio vs the gsxr750 also. VFR800 rod ratio= 101.5/48= 2.11 gsxr750 rod ratio= 95/48.7 = 1.95 ps here is some basic 5th gen vs 6th gen description. Note the valve angle change. The gsxr750 is 12* intake 13* ex for a total valve angle of 25*..... Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted August 30, 2014 Author Member Contributer Share Posted August 30, 2014 It's fairly obvious that some of the people spouting on here have never seen the inside of a VFR engine. It uses a head designed for the RC45, which if you'd been paying attention has the largest valves that will fit in the head with the 72mm bore, so much so that the inlets have a small relief in the cylinder wall, to allow air flow clearance. So bigger valves are NOT an option on the standard bore. RC45 race bikes didn't get bigger valves for the same reason. Then you have those that have said skim the head , well you can't other than to level it, the aforementioned valve reliefs in the cylinder wall are required because the valve head comes right to the surface of the head, so any worth while skim for compression will cut into the valve seat. RC45 race kit included a .2mm thinner head gasket & pistons with raised bumps to fit inside the dish of the valve head for maximum compression. So again if the best of Honda & race teams could not change these, then we have no chance without increasing the bore. That said the CBR1000RR used the same size valves for much of its production. So if an extra 220cc engine can breathe with the same setup our 780cc bikes have, then we shouldn't be short of breath. Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted August 30, 2014 Member Contributer Share Posted August 30, 2014 It's fairly obvious that some of the people spouting on here have never seen the inside of a VFR engine. It uses a head designed for the RC45, which if you'd been paying attention has the largest valves that will fit in the head with the 72mm bore, so much so that the inlets have a small relief in the cylinder wall, to allow air flow clearance. So bigger valves are NOT an option on the standard bore. RC45 race bikes didn't get bigger valves for the same reason. Then you have those that have said skim the head , well you can't other than to level it, the aforementioned valve reliefs in the cylinder wall are required because the valve head comes right to the surface of the head, so any worth while skim for compression will cut into the valve seat. RC45 race kit included a .2mm thinner head gasket & pistons with raised bumps to fit inside the dish of the valve head for maximum compression. So again if the best of Honda & race teams could not change these, then we have no chance without increasing the bore. That said the CBR1000RR used the same size valves for much of its production. So if an extra 220cc engine can breathe with the same setup our 780cc bikes have, then we shouldn't be short of breath. I may have missed something but I don't recall anyone talking about enlarging the VFR800 valves ??? I agree wholeheartedly that our engines have race DNA and huge potential and the heads are not the limiting factor... Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 30, 2014 Share Posted August 30, 2014 yeah I am not sure what that was all about. vtec head vs 5th gen head So mohawk all i was getting at was that you in fact have actually measured the in an ex valves and can confirm that they are the same size as the given rc45 specs? Because I cannot for the life of me find the vfr800 valves sizes any where.... Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 30, 2014 Share Posted August 30, 2014 But yeah looking at the heads I get what you're saying, those valves are about as big as you can fit in a 72mm bore, and even with an over bore maybe +0.5mm or +1.0mm oversize valves might be possible, but probably wouldn't net much gain. Sounds like a set of big cams would make tremendous power on these bikes if the red line was raised some, the valve train was beefed up, compression raised, a good port and polish done, oversized throttle bodies and a matching full exhaust was utilized. With that combo there is no reason why 150 crank hp couldn't be reached while leaving the displacement at 782cc and over 160 with a big bore... Link to comment Share on other sites More sharing options...
Member Contributer HighSideNZ Posted August 31, 2014 Member Contributer Share Posted August 31, 2014 Hi Guys The following shot is of my Gen5 head and the enlarged head gasket (74mm dia) to suit my 929 bore. The standard valve head diameters are: Inlet 29mm Exhaust 24.5mm Even with the 2mm bigger bore the valves are pretty close to being shrouded by the bores. I think it will flow more with the 74mm bores than the 72mm as there is less interference. Cheers Phil Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted August 31, 2014 Share Posted August 31, 2014 This page is pure gold. At the bottom you'll find full valvetrain specs of all modern sport bikes. http://www.aperaceparts.com/tech.html Link to comment Share on other sites More sharing options...
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