I dont know if this has been posted previously, a review of Rex Wolfenden's FJ powered Bimota http://www.motorcycle.com/manufacturer/bimota/1987-bimota-yb5-racer-tested-on-track.html (http://www.motorcycle.com/manufacturer/bimota/1987-bimota-yb5-racer-tested-on-track.html)
Also a short vid about the man himself. Look out for the other very tasty FJ at 5.10 https://youtu.be/AL0ubC7GwcE (https://youtu.be/AL0ubC7GwcE)
I wonder what they did to the FJ power plant that was in that Bimota in 1987 to squirt out those extra dozen or so horse power?
Much thanks for the post. What a testament to the Fj.
Quote from: gumby302ho on September 29, 2016, 04:59:55 PM
I wonder what they did to the FJ power plant that was in that Bimota in 1987 to squirt out those extra dozen or so horse power?
More than a dozen...150 rwhp is about a 30 hp bump vs the FJ stock ~120
According to the article:
1220cc 1mm overbore, JE forged pistons, Carrillo rods
ported head with +1mm valves
custom cams
Keihin 37mm CR (flat slide) carbs
Dyna 2000 ignition
4 into 1 header
Nothing too fancy....The FJ engine wakes up with headwork, cams and carbs.
Interesting that they fitted a slipper clutch to eliminate the back end chatter upon deceleration
A stock FJ would be lucky to put out 100 rear wheel HP. The Bimota put out 130 so there were some mods over stock and Rex has upped that to 150 with the mods listed. Very approximate figures when you take into account differences in Dynos and a heap of other variables. The slipper clutch would be a great asset for a high performance road or track bike
(http://fjowners.com/gallery/10/7_01_10_16_7_20_51.jpeg)
103.5 at the rear wheels, with an OEM paper air filter and stock exhaust, at 22,000 miles. The pull was done in 4th gear. The readout was given in mph because the $25 "Dyno Day" special didn't include hooking up anything to the ignition to get engine rpm.
Someone joined us here to try and sell his a scruffy YB5 a couple years ago. Would have been a nifty bike to buy, but the guy was pretty off-putting if I remember correctly; there seemed to be an underlying attitude of "your bikes all suck, here's the one you really want."
Quote from: Pat Conlon on September 30, 2016, 01:14:28 PM
Quote from: gumby302ho on September 29, 2016, 04:59:55 PM
I wonder what they did to the FJ power plant that was in that Bimota in 1987 to squirt out those extra dozen or so horse power?
More than a dozen...150 rwhp is about a 30 hp bump vs the FJ stock ~120
According to the article:
1220cc 1mm overbore, JE forged pistons, Carrillo rods
ported head with +1mm valves
custom cams
Keihin 37mm CR (flat slide) carbs
Dyna 2000 ignition
4 into 1 header
Nothing too fancy....The FJ engine wakes up with headwork, cams and carbs.
Interesting that they fitted a slipper clutch to eliminate the back end chatter upon deceleration
A 150 rwhp, wow, talk about a mover from good old 1987!!! Any idea of the loss of hp at the crank through the drive? I could guess maybe 35hp so that Bimota FJ plant could be making 185 horse power sitting on the bench. To have a dyno golden standard and go back in time and see how close the old boys figures were compared too modern times, how accurate were they in the 40's, 50's, 60's etc to the present.
According to Hank Scott my 1350 was 163hp/114ft lbs. no cams, nothing lightened. Stock carbs. On crank dyno. But. All dyno are not created equal.
My 86 1350 is at least 55lbs lighter than stock (weighing what was changed -remove) Sure is fun. But the t Rex would be so much more.
Quote from: giantkiller on October 01, 2016, 03:26:33 PM
According to Hank Scott my 1350 was 163hp/114ft lbs. no cams, nothing lightened. Stock carbs. On crank dyno. But. All dyno are not created equal.
Are you running a freshened up stock clutch with that beast or ? Not trying to compete with you Killer but first week in Aug I came off my XR doing about 80 clicks at night and broke number 3 rib and punctured lung on my right side and broke my clavicle(collar bone). My big problem is where the clavicle broke which is right under my chin, now it sticks out and up and is causing all kinds of problems. My bigbore XR is running fairly good now but not perfect, alot more torque down low as I am sure you feel in your bigbore 1350. I am sick of taking pills, sometimes I think beer does a pretty good job on pain. :drinks:
Quote from: gumby302ho on October 01, 2016, 03:14:59 PM
Any idea of the loss of hp at the crank through the drive? I could guess maybe 35hp
According to the dyno technician that did mine, a loss of around 18% is not uncommon at the back wheel.
Quote from: gumby302ho on October 01, 2016, 08:30:15 PM
Quote from: giantkiller on October 01, 2016, 03:26:33 PM
According to Hank Scott my 1350 was 163hp/114ft lbs. no cams, nothing lightened. Stock carbs. On crank dyno. But. All dyno are not created equal.
Are you running a freshened up stock clutch with that beast or ? Not trying to compete with you Killer but first week in Aug I came off my XR doing about 80 clicks at night and broke number 3 rib and punctured lung on my right side and broke my clavicle(collar bone). My big problem is where the clavicle broke which is right under my chin, now it sticks out and up and is causing all kinds of problems. My bigbore XR is running fairly good now but not perfect, alot more torque down low as I am sure you feel in your bigbore 1350. I am sick of taking pills, sometimes I think beer does a pretty good job on pain. :drinks:
I've the Barnet with heavy duty springs. It's been a while. Was just thinking the other day. I need to take it apart and check the clutch.
Haven't broken a clavicle yet. Would probably be bad. Pretty much involved with any upper body movement. I only take the pills to sleep. And only for the first few days. My Liver kind of exploded. Several rips, in the one that I was dead @ the scene. So my Liver doesn't work too well. I get all the bad side effects. I don't drink at all anymore either.
Hope you heal up fast.
I've found that once the bones get set enough. That they won't come apart. Usually just a few days. If I constantly move what ever is broken. Through it's full motion You'll have better use of it. And sooner than If you just do the therapy. I'm talking like every few minutes or at least every hour. It's painful. But pain is just a tool. It's too tell you when something is fffd up. If you already know. Just ignore it.
Thanks stua for posting this. If he did mass produced them. I sure would want one... But would never be able to afford one.
Quote from: oldktmdude on October 01, 2016, 09:41:23 PM
Quote from: gumby302ho on October 01, 2016, 03:14:59 PM
Any idea of the loss of hp at the crank through the drive? I could guess maybe 35hp
According to the dyno technician that did mine, a loss of around 18% is not uncommon at the back wheel.
Around 10 years ago, I recall Marsh, Marc Rittner and Gazza took their FJ's to a Dyno Jet to see who would win a bet. With a pipe, Unipods and jetting they came in around 110-120 rwhp.
Very true, not all Dynos are the same.
After the Renegade Rally where I will put a few more miles on my FJ, I will dyno mine for curiosity.
Randy's 1380cc engine is running great. I absolutely love the torque.
Leaned over, coming out of a corner, You've gotta be careful with your right hand.
She suffers no fools.
So Pat has the 1380 cured the oil consumption problem? And I don't remember what happened to cause the rebuild?
Quote from: oldktmdude on October 01, 2016, 09:41:23 PM
Quote from: gumby302ho on October 01, 2016, 03:14:59 PM
Any idea of the loss of hp at the crank through the drive? I could guess maybe 35hp
According to the dyno technician that did mine, a loss of around 18% is not uncommon at the back wheel.
Pete, wouldn't the loss at the back wheel be a constant, not a percentage?
Noel
I was thinking the same thing. If you have a 10hp motor you wouldn't lose much. But those turbo guys must have a brake locked up.
Quote from: ribbert on October 02, 2016, 07:49:29 AMwouldn't the loss at the back wheel be a constant, not a percentage?
No, the more you put into a mechanical system that has friction losses, the more you lose. I can't think of a way to build something that always needs a fixed amount of power to move. A fixed amount of FORCE, maybe, but the faster you apply that force, the more power it is.
If you had a system with a constant loss of, say, 10 hp, you wouldn't be able to move it at all with a 10 hp motor. I'm having trouble even picturing a thing you couldn't budge with a 10 hp motor. That's a motorcycle that you and half a dozen friends couldn't push, because each of you makes maybe 1 hp max.
But on a normal actual system of parts, if you put in a little power, you lose a little and get the rest out; if you put in more power, you lose more.
18% is pretty typical for a rear-wheel-drive car with a manual transmission. You lose a bit in the transmission gears, a bit more than that in the rear diff, and a little in the drive-shaft and half-shaft's CV joints. A solid-axle car does a little better because there are no half-shafts. A transverse-engine car, like most front-wheel-drive setups or like a mid-engine transverse car, does a little better than that because there's no 90-degree change of rotation in the diff, all the shafts rotate in parallel axes. A typical torque-converter automatic does a little worse. A motorcycle with a chain or belt drive does better (I've read "15%" but a shaft drive is back to 18% or more, depending on whether its driveshaft has a 90-degree gearset at each end or just at one (longitudinal crankshaft like a Honda ST or a Moto Guzzi or a boxer BMW.)
Quote from: Bill_Rockoff on October 02, 2016, 09:10:50 AM
No, the more you put into a mechanical system that has friction losses, the more you lose....
True, but is the increased loss proportional to the increased power?
Noel
Quote from: giantkiller on October 02, 2016, 06:18:53 AM
So Pat has the 1380 cured the oil consumption problem? And I don't remember what happened to cause the rebuild?
The top end coked up from excessive oil. I had the 82mm Hank Scott Prolite short skirt pistons.
I decided to change course and use the conventional Ross 83mm long skirt pistons.
All is well since.
Quote from: Bill_Rockoff on October 02, 2016, 09:10:50 AM
Quote from: ribbert on October 02, 2016, 07:49:29 AMwouldn't the loss at the back wheel be a constant, not a percentage?
No, the more you put into a mechanical system that has friction losses, the more you lose. I can't think of a way to build something that always needs a fixed amount of power to move. A fixed amount of FORCE, maybe, but the faster you apply that force, the more power it is.
If you had a system with a constant loss of, say, 10 hp, you wouldn't be able to move it at all with a 10 hp motor. I'm having trouble even picturing a thing you couldn't budge with a 10 hp motor. That's a motorcycle that you and half a dozen friends couldn't push, because each of you makes maybe 1 hp max.
But on a normal actual system of parts, if you put in a little power, you lose a little and get the rest out; if you put in more power, you lose more.
18% is pretty typical for a rear-wheel-drive car with a manual transmission. You lose a bit in the transmission gears, a bit more than that in the rear diff, and a little in the drive-shaft and half-shaft's CV joints. A solid-axle car does a little better because there are no half-shafts. A transverse-engine car, like most front-wheel-drive setups or like a mid-engine transverse car, does a little better than that because there's no 90-degree change of rotation in the diff, all the shafts rotate in parallel axes. A typical torque-converter automatic does a little worse. A motorcycle with a chain or belt drive does better (I've read "15%" but a shaft drive is back to 18% or more, depending on whether its driveshaft has a 90-degree gearset at each end or just at one (longitudinal crankshaft like a Honda ST or a Moto Guzzi or a boxer BMW.)
Thanks for your answer Bill. That's what my reply would have been but you have explained it far better than I could have. Every dyno figure that I have seen, always quotes the rear wheel hp loss as a percentage. During the first dyno run that I did, my drive chain had a tight spot in it and this showed up as a intermittent loss of around 5 to 8 hp. Just shows how relatively small changes in friction values can effect the output figures.
Regards, Pete.
Quote from: Pat Conlon on October 02, 2016, 11:18:16 AM
Quote from: giantkiller on October 02, 2016, 06:18:53 AM
So Pat has the 1380 cured the oil consumption problem? And I don't remember what happened to cause the rebuild?
The top end coked up from excessive oil. I had the 82mm Hank Scott Prolite short skirt pistons.
I decided to change course and use the conventional Ross 83mm long skirt pistons.
All is well since.
I have an APE block and a Wisco block (cylinders). I can't remember I think one was 1380 and one was 1450? I've had them for while. Was thinking of using the Ross pistons. And seeing if Randy might want to build me a couple of monster motors. In a couple of years If I can gather enough money.
Quote from: ribbert on October 02, 2016, 07:49:29 AM
wouldn't the loss at the back wheel be a constant, not a percentage?
doesn't make sense... let's say it is a constant 15 HP. Would the bike make negative Hp below the "drivetrain loss" Hp of say 15Hp? It is, of course, a percentage. It is not truly linear however... but that's beyond the scope of this discussion.
Frank