Member Contributer Rush2112 Posted December 22, 2013 Member Contributer Share Posted December 22, 2013 Well the wall is 8mm thick as standard, ... Mohawk, can you do me a favor and measure the cylinder wall length, top to bottom... I just bought a spare 5th gen engine and I was considering trying to stroke it with shorter rods and a stroked crank by Falicon in Florida... my second choice is to build a track bike around it and I don't want to pull the whole motor apart to find out it is not possible to stroke it. This info you are providing in this thread is priceless... Thank you!!! Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted December 24, 2013 Share Posted December 24, 2013 Yeah I don't see this helping with peak hp too much with out supporting breathing mods (torque should increase greatly, as well as hp under the curve, midrange and low end, but with tiny headers and throttle bodies/velocity stacks, there is only so much air that you can get through that engine, regardless of displacement.). But with larger throttle bodies, headers, a good port and polish on the heads and 1mm or 2mm larger valves to take advantage of the larger bore; now you're talking real power. Just thinking... That amount of work to make it breathe better, and leaving the bottom end alone would probably be better bang for buck, without the potential durability issues of the overbore. Add in a custom cam grind to RC45 spec, and the expense of over-boring doesn't make so much sense. Hmmm... How to increase the spark advance to unlock a few more ponies??? ;) All of that being said, it would be pretty cool to be able to say "I have a VFR900" or "I have a VFR1000"... To this end, if someone's going to the expense of doing a 76mm bore, they might as well at least look into stroking it up a bit more while they have the engine apart! I have advanced the ignition curve on my 6th gen and it REALLY REALLY wakes these bikes up in the midrange. This is possible with the rapid bike 2 and rapid bike 3 (I have the rapid bike 2), also you could reflash the ecu which is being discussed on other threads right now or you could make a timing advancer plate (though this wouldn't be ideal as you don't need/want as much advance on the topend and bottomend as in the midrange. Mohawk I really like what you're doing right now. Especially with the bigger cams and over bore, as I will be doing these eventually (I just want to finish the suspension, and drop some more weight off the bike first), but don't overlook finding a real full exhaust, port matching the throttle bodies to 38mm velocity stacks, advancing ignition timing and a good port/polish/mill on the head. I know that you have said a few times that these flow enough from the factory, but they are really holding the bike back and will be greatly holding the bike back after the overbore and in conjunction with your cams. With trap speed being a direct factor of hp and e.t. being more of a factor of technique/skill, I was trapping around 119 mph with the basic power commander/motad header/2bros slip-on exhaust/bmc filter/520 1 down sprocket kit/open air box and custom dyno tune combo. After installing 38mm velocity stacks and port matching the velocity stacks to the throttle bodies my trap speed increased to about 121 mph. Then after installing the rapid bike 2 and advancing the ignition timing, my trap speed increased to around 123 mph. Finally in September, after installing my two brothers racing full system my trap speed is at 125.55 mph. Doing the math, this comes out to about 15, give or take a few, horsepower. Go ahead and try it http://www.wallaceracing.com/et-hp-mph.php Link to comment Share on other sites More sharing options...
Dannytb Posted December 24, 2013 Share Posted December 24, 2013 I have advanced the ignition curve on my 6th gen and it REALLY REALLY wakes these bikes up in the midrange. This is possible with the rapid bike 2 and rapid bike 3 (I have the rapid bike 2), also you could reflash the ecu which is being discussed on other threads right now or you could make a timing advancer plate (though this wouldn't be ideal as you don't need/want as much advance on the topend and bottomend as in the midrange. Thanks for the info. Is there a way to adapt the rapidbike 2 or 3 to a 5th gen? Is there a way to reflash the 5th gen's ECU? I was under the impression that the reflash stuff was for the 7th gen, and maybe late 6th gens. In any case, it's nice to know that the mid-range can be livened up more with spark timing. Now I just have to work out how best to do it. :) Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted December 25, 2013 Share Posted December 25, 2013 yeah the rapid bike 2 and three should plug in the same on the 5th gen just as the power commanders are interchangeable with the 5th and 6th gens, but good luck finding a rapid bike. they have been out of production for a while. as far as reflashing, i dont think that would happen on a 5th gen. a timing plate with 3 or 4 degrees advance would be the easiest route, it might not be ideal timing for the bottom and top end. http://www.ebay.com/itm/RAPID-BIKE-HONDA-VFR-800-VTEC-02-05-/320948668570?pt=Motorcycles_Parts_Accessories&hash=item4aba08089a&vxp=mtr contact these guys and see if you can get a rapid bike 2 or 3. the rapid bike 1 only has fuel control like a power commander so its kinda pointless. the rapid bike 2 splices in between the crank position sensor and factory harness so you have control of the ignition timing. the rapid bike 3 takes it a step further and allows storing multiple maps and launch control etc........... If you can find a rapid bike 3 i would gladly trade you my rapid bike 2 plus a lot of cash. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted December 25, 2013 Author Member Contributer Share Posted December 25, 2013 . Mohawk, can you do me a favor and measure the cylinder wall length, top to bottom... I just bought a spare 5th gen engine and I was considering trying to stroke it with shorter rods and a stroked crank by Falicon in Florida... my second choice is to build a track bike around it and I don't want to pull the whole motor apart to find out it is not possible to stroke it. This info you are providing in this thread is priceless... Thank you!!! I just measured the liner I removed, it is 83mm long. I know that the lower part of the STD piston leaves the bore at BDC, I have not measured by how much though. Hope that helps. FYI the STD robs are 101.5mm long as far as I can measure. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted December 25, 2013 Author Member Contributer Share Posted December 25, 2013 CandyRed, the stock heads are more than up to 150hp worth of flow, save your money, they are the same as RC45 heads in every dimension & the HRC work for the 45 is minimal to the heads. Check forcev4 site for specific details. Larger intakes probably won't make much difference, as Larry proved on his Mr RC45. Matching the TB's with the V stacks & mount rubbers will & I have done that in a similar vain to you. My RC45 based cam grind netted 5hp. I'm toying with ignition advance too. Your Two Brothers headers probably accounted for 95% of your trap gains as the standard headers are a bit small. Motads are 35mm OD & thus 32-33mm ID based on 1-1.5mm wall thickness. GSXR750 headers for comparison are 38mm OD & thus approx 35mm ID. What size are the two brothers headers ? And what length are the primary pipes ? I've been doing some research & 4-2-1 headers are best on an odd firing order V4, that's what they are using on the MotoGP V4's & the Yamaha Crossplane M1 ! Obviously header length affects where Peak torque is placed & thus where peak HP is too. If I could find an exhaust I'd buy it, but as you said, rocking horse pooh is more common ;( I have as few other ideas to test first, so will try those & see where it gets me ! More news form the secret development site once proven ;) Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted December 25, 2013 Member Contributer Share Posted December 25, 2013 You guys are fast approaching a wall but you could start thinking about casting you own block. http://www.youtube.com/watch?v=8KbZ1K9-PSY#t=10 Probably to expensive but who knows until you inquire ... Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted December 25, 2013 Member Contributer Share Posted December 25, 2013 . Mohawk, can you do me a favor and measure the cylinder wall length, top to bottom... I just bought a spare 5th gen engine and I was considering trying to stroke it with shorter rods and a stroked crank by Falicon in Florida... my second choice is to build a track bike around it and I don't want to pull the whole motor apart to find out it is not possible to stroke it. This info you are providing in this thread is priceless... Thank you!!! I just measured the liner I removed, it is 83mm long. I know that the lower part of the STD piston leaves the bore at BDC, I have not measured by how much though. Hope that helps. FYI the STD robs are 101.5mm long as far as I can measure. Thanks Man! Like I said... this info is priceless! Previous reports on rod length C-C was 102 mm... how confident are you on the 101.5mm? I've been searching for Honda rods at 100mm for a 4mm stroke increase without any luck... time to widen my search for 99.5mm rods! Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted December 25, 2013 Author Member Contributer Share Posted December 25, 2013 GUI I have these on good authority, rod lengths rc45 93.8 mm rc30 107.4 mm rc36 104,0 mm Regards Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted December 25, 2013 Share Posted December 25, 2013 CandyRed, the stock heads are more than up to 150hp worth of flow, save your money, they are the same as RC45 heads in every dimension & the HRC work for the 45 is minimal to the heads. Check forcev4 site for specific details. Larger intakes probably won't make much difference, as Larry proved on his Mr RC45. Matching the TB's with the V stacks & mount rubbers will & I have done that in a similar vain to you. My RC45 based cam grind netted 5hp. I'm toying with ignition advance too. Your Two Brothers headers probably accounted for 95% of your trap gains as the standard headers are a bit small. Motads are 35mm OD & thus 32-33mm ID based on 1-1.5mm wall thickness. GSXR750 headers for comparison are 38mm OD & thus approx 35mm ID. What size are the two brothers headers ? And what length are the primary pipes ? I've been doing some research & 4-2-1 headers are best on an odd firing order V4, that's what they are using on the MotoGP V4's & the Yamaha Crossplane M1 ! Obviously header length affects where Peak torque is placed & thus where peak HP is too. If I could find an exhaust I'd buy it, but as you said, rocking horse pooh is more common ;( I have as few other ideas to test first, so will try those & see where it gets me ! More news form the secret development site once proven ;) Post #25 talks about headwork, complete with a dyno chart. http://vfrworld.com/forums/showthread.php/40434-98-VFR800-motor-upgrade-question "Here's head porting and a PCIII in Europe for 13hp" And here is some info on the headers. This was based on my friends Erion Racing full system. I wound up finding a Two Brothers full system. They are pretty close. http://www.vfrdiscussion.com/forum/index.php/topic/74915-i-have-the-measurements-on-the-erion-racing-header-vs-the-motad/ As far as 95% of the gains coming from the full system. No they all compliment each other. That is what I am trying to explain to you. A chain is only as strong as its weakest link and an engine will only make as much power as its smallest bottle neck will allow. The larger headers and velocity stacks will add top end and soften the low end, this would be an issue, but the added ignition timing brings the bottom right back and more. Anyways blah blah blah long story short, I said each of these mods added roughly 2 mph to my 1/4 mile trap speed (function of area under the curve horsepower). While the header gains were very noticeable, so were the throttlebody/velocity stacks and ignition gains. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted December 26, 2013 Author Member Contributer Share Posted December 26, 2013 That dyno chart has NO info & I'm certain there is NO head porting that would add that much flow, based on tried & tested RC45 development. If the HRC head work is only worth it for full race motors with HRC intake & exhaust, there's no way a little porting will add that much power with stock parts. But as I said you have done nothing to improve the intake significantly & have not dyno'd any of your changes so have no comparisons. The exhaust is the only true tuning hardware you have added. The Bazzaz is probably doing a lot of the work ! Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted December 26, 2013 Author Member Contributer Share Posted December 26, 2013 Rush2112, I just measured the VFR STD piston & it's 42mm deep/tall so with an 83mm liner & 48mm stroke the STD piston skirt will protrude 7mm into the void below the cylinder. Checked the rod measurement again & get 101.5mm. STD complete piston weight inc wrist pin is 238grams, stock rod, complete with shells in the big end is 313.5grams. One rod bolt with nut is 27grams. If you used a Ti rod & bolts you could get that down to approx 210grams. Big end is 36mm, small end is 17mm. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted December 27, 2013 Share Posted December 27, 2013 I have a rapid bike 2, not bazzaz. Also I do not understand how trap speed does not show enough proof of gains for you. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted December 27, 2013 Author Member Contributer Share Posted December 27, 2013 Trap speed just means you are going faster & probably getting better. The intake restriction, is not really a restriction, and you have not done any serious modification in that area. The exhaust is known to be a restriction & you have fitted one with better flow, which should lead to better High rpm high speed flow & thus higher speeds. I've seen bike tests where they drag tested the bikes & there journalists who were not drag experts but are fast bike riders, getting as much as 1.5seconds variance on 1/4 mile times. So refining your technique is probably worth half your gains IMO. Not knocking any of it, just want to see a dyno result from a known good dyno house, to see what you have, but as no dyno history, we can't tell what gave you the gains ! Fine for you, but not much help for the rest of us in working out where to spend our cash next. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted December 27, 2013 Share Posted December 27, 2013 1/4 mile times account for rider skill. Trap speeds account for power. Link to comment Share on other sites More sharing options...
Member Contributer mk2davis Posted December 27, 2013 Member Contributer Share Posted December 27, 2013 1/4 mile times account for rider skill. Trap speeds account for power. I know I'm a bit late to the party, and maybe I'm revealing all of my ignorance, but ^^^ doesn't make any sense to me. I can't think of a situation where power and skill don't factor into both. Please educate me. Link to comment Share on other sites More sharing options...
Member Contributer hvfrdave Posted December 27, 2013 Member Contributer Share Posted December 27, 2013 I love it when someone talks sense. :smile2: power is no good without control. :smile2: Link to comment Share on other sites More sharing options...
Dannytb Posted December 28, 2013 Share Posted December 28, 2013 yeah the rapid bike 2 and three should plug in the same on the 5th gen just as the power commanders are interchangeable with the 5th and 6th gens, but good luck finding a rapid bike. they have been out of production for a while. as far as reflashing, i dont think that would happen on a 5th gen. a timing plate with 3 or 4 degrees advance would be the easiest route, it might not be ideal timing for the bottom and top end. http://www.ebay.com/itm/RAPID-BIKE-HONDA-VFR-800-VTEC-02-05-/320948668570?pt=Motorcycles_Parts_Accessories&hash=item4aba08089a&vxp=mtr contact these guys and see if you can get a rapid bike 2 or 3. the rapid bike 1 only has fuel control like a power commander so its kinda pointless. the rapid bike 2 splices in between the crank position sensor and factory harness so you have control of the ignition timing. the rapid bike 3 takes it a step further and allows storing multiple maps and launch control etc........... If you can find a rapid bike 3 i would gladly trade you my rapid bike 2 plus a lot of cash. I don't know about where to get a RB3 for a VFR, but the RB2 for the 6th gen is discounted on the Rapidbike website at the moment: http://www.rapidbikeusa.com/cgi-bin/shopper.cgi?preadd=action&key=1146KRB2054 Link to comment Share on other sites More sharing options...
Member Contributer Rush2112 Posted December 28, 2013 Member Contributer Share Posted December 28, 2013 Rush2112, I just measured the VFR STD piston & it's 42mm deep/tall so with an 83mm liner & 48mm stroke the STD piston skirt will protrude 7mm into the void below the cylinder. Checked the rod measurement again & get 101.5mm. STD complete piston weight inc wrist pin is 238grams, stock rod, complete with shells in the big end is 313.5grams. One rod bolt with nut is 27grams. If you used a Ti rod & bolts you could get that down to approx 210grams. Big end is 36mm, small end is 17mm. Thanks Man!!! Time to track down some 99.5mm Honda rods and maybe some shorter skirt pistons. It's $1160 for a set of lightweight performance rods, not even Ti... I would love to find some from the Honda parts bin and save some costs on an initial build and proof of concept... Anybody come across OEM 99.5mm con rods with 36mm big end and 17mm small end please let me know... FYI - Stroke, lighten, polish, and balance of the crankshaft is $1,575 at Falicon in Florida... with stock bore and a 4mm stroker crank it should produce a 847cc machine with ~12.5:1 compression ratio Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted December 28, 2013 Share Posted December 28, 2013 1/4 mile times account for rider skill. Trap speeds account for power. I know I'm a bit late to the party, and maybe I'm revealing all of my ignorance, but ^^^ doesn't make any sense to me. I can't think of a situation where power and skill don't factor into both. Please educate me. http://www.stealth316.com/2-calc-hp-et-mph.htm "Fox notes that the first two variables, weight and power, are the primary influence on MPH making it easy to use a constant power approximation to determine a formulaic relationship. It is the variability of the remaining variables and their influence that makes it much harder to determine ET based soley on vehicle weight and engine power. What this means is: look at MPH as a determination of engine power rather than ET." Link to comment Share on other sites More sharing options...
Dannytb Posted December 29, 2013 Share Posted December 29, 2013 Rush2112, I just measured the VFR STD piston & it's 42mm deep/tall so with an 83mm liner & 48mm stroke the STD piston skirt will protrude 7mm into the void below the cylinder. Checked the rod measurement again & get 101.5mm. STD complete piston weight inc wrist pin is 238grams, stock rod, complete with shells in the big end is 313.5grams. One rod bolt with nut is 27grams. If you used a Ti rod & bolts you could get that down to approx 210grams. Big end is 36mm, small end is 17mm. Thanks Man!!! Time to track down some 99.5mm Honda rods and maybe some shorter skirt pistons. It's $1160 for a set of lightweight performance rods, not even Ti... I would love to find some from the Honda parts bin and save some costs on an initial build and proof of concept... Anybody come across OEM 99.5mm con rods with 36mm big end and 17mm small end please let me know... FYI - Stroke, lighten, polish, and balance of the crankshaft is $1,575 at Falicon in Florida... with stock bore and a 4mm stroker crank it should produce a 847cc machine with ~12.5:1 compression ratio Hmmm... Add a big-bore exhaust collector, larger diameter throttles and inlet funnels, port match and polish the inlets, custom cam grind, and add a Motec ECU (or similar) to get full control of the fuel/spark maps... The VFR850 could be quite a beast! :D Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted December 29, 2013 Member Contributer Share Posted December 29, 2013 Rush2112, I just measured the VFR STD piston & it's 42mm deep/tall so with an 83mm liner & 48mm stroke the STD piston skirt will protrude 7mm into the void below the cylinder. Checked the rod measurement again & get 101.5mm. STD complete piston weight inc wrist pin is 238grams, stock rod, complete with shells in the big end is 313.5grams. One rod bolt with nut is 27grams. If you used a Ti rod & bolts you could get that down to approx 210grams. Big end is 36mm, small end is 17mm. Thanks Man!!! Time to track down some 99.5mm Honda rods and maybe some shorter skirt pistons. It's $1160 for a set of lightweight performance rods, not even Ti... I would love to find some from the Honda parts bin and save some costs on an initial build and proof of concept... Anybody come across OEM 99.5mm con rods with 36mm big end and 17mm small end please let me know... FYI - Stroke, lighten, polish, and balance of the crankshaft is $1,575 at Falicon in Florida... with stock bore and a 4mm stroker crank it should produce a 847cc machine with ~12.5:1 compression ratio Hmmm... Add a big-bore exhaust collector, larger diameter throttles and inlet funnels, port match and polish the inlets, custom cam grind, and add a Motec ECU (or similar) to get full control of the fuel/spark maps... The VFR850 could be quite a beast! :D Any guess on hp's gain. Could you get 150 hp we these mod's ? Link to comment Share on other sites More sharing options...
Dannytb Posted December 29, 2013 Share Posted December 29, 2013 Rush2112, I just measured the VFR STD piston & it's 42mm deep/tall so with an 83mm liner & 48mm stroke the STD piston skirt will protrude 7mm into the void below the cylinder. Checked the rod measurement again & get 101.5mm. STD complete piston weight inc wrist pin is 238grams, stock rod, complete with shells in the big end is 313.5grams. One rod bolt with nut is 27grams. If you used a Ti rod & bolts you could get that down to approx 210grams. Big end is 36mm, small end is 17mm. Thanks Man!!! Time to track down some 99.5mm Honda rods and maybe some shorter skirt pistons. It's $1160 for a set of lightweight performance rods, not even Ti... I would love to find some from the Honda parts bin and save some costs on an initial build and proof of concept... Anybody come across OEM 99.5mm con rods with 36mm big end and 17mm small end please let me know... FYI - Stroke, lighten, polish, and balance of the crankshaft is $1,575 at Falicon in Florida... with stock bore and a 4mm stroker crank it should produce a 847cc machine with ~12.5:1 compression ratio Hmmm... Add a big-bore exhaust collector, larger diameter throttles and inlet funnels, port match and polish the inlets, custom cam grind, and add a Motec ECU (or similar) to get full control of the fuel/spark maps... The VFR850 could be quite a beast! :D Any guess on hp's gain. Could you get 150 hp we these mod's ? A standard GSX-R750 makes close to 150hp at the crank (Edit: L1-L3 are claimed to have 150hp at the crank @ 13,200RPM), but some of that is because the bottom end is happy to rev a few thousand RPM more than a VFR... 150hp at the crank from a "VFR850" might be possible if it's done right, but the rods and pistons would need to be pretty light to prevent the redline from being reduced. Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted December 29, 2013 Member Contributer Share Posted December 29, 2013 You guys mite be on to something .... A lot of people here are wanting the magic 150hp number .. Link to comment Share on other sites More sharing options...
Dannytb Posted December 29, 2013 Share Posted December 29, 2013 You guys mite on to something .... A lot of people here are wanting the magic 150hp number .. Of course, there's an easier way... A group order of a bunch of supercharger kits (to make a batch run viable for the company that has the design of the kit)... But that probably should be a separate topic of its own... ;) Link to comment Share on other sites More sharing options...
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