Cylinder wall thickness

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falsus nomen

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What is the wall thickness between cylinders? Or a piston center to center measurement? Skirt length, wrist pin measurements?

Has anyone ever BUILT an FJR motor? There is a ton of room for upgrades. Cam profile, cam timing, ignition timing / tuning, head porting, valve re-sizing, intake runner / throttle body porting. If you really dig into the engine, there is certainly room for compression increase, and piston and rod technology has grown light years since 2003 (or 2000 when the engine design was started).

A properly built, 1300cc oversquare motorcycle engine should be able to produce ~180 HP and ~120 ft/lbs of tq, on the ground.

 
Has anyone ever BUILT an FJR motor?


A properly built, 1300cc oversquare motorcycle engine should be able to produce ~180 HP and ~120 ft/lbs of tq, on the ground.
You'll be the first. A few have talked about it, but none have done it.

Let us know how it works!

 
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I used to build race engines for my top sportsman drag team (4.70 / 1/8 mile breakout), and I have worked with everything from LeMons to pro stuff. If I do that, it would need a slightly longer swingarm. Little bit of a pain with a shaft.

 
I hope that you are serious about this. I'm sure that there will be a few here that feel it can't be done or say why do it.

I say go for it and keep us posted. I would love to have a sleeper FJR.

Canadian FJR

 
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I don't know, I was on a 400+ mile ride today, and on two occasions a quick glance at the speedo resulted in 'oh crap!' & chop the throttle responses. Not sufficiently into jewelry for silver bracelets...

 
I don't know, I was on a 400+ mile ride today, and on two occasions a quick glance at the speedo resulted in 'oh crap!' & chop the throttle responses. Not sufficiently into jewelry for silver bracelets...
Thats an example of why I often use cruise control. For example today I had to pass through an obscenely oppressive 30 MPH construction zone. On what was a 55 MPH road. One where the State Troopers are heavily enforcing as a means of paying for the construction. Cruise control is the only way to get through.

 
I'm probably too frugal to spend the money on parts and machine work, but I'm curious about what can be done without sacrificing reliability.

The question about cylinder wall thickness makes me think that you are thinking about increasing the bore. That would be tricky because the bore is coated with, I think, nikasil.

 
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A lot of umph can be had with a cam and some head work. This is easy enough to do for someone with the right skills and equipment. However, as far as I know, it's never been done. Seems that nobody wants to be the first, or maybe nobody wants to take the chance. Who knows. It's been said before around here that FJR owners don't want to do something like this because it would sacrifice gas mileage, ridability, maybe reliability and perhaps longevity. And with a driveshaft, HA... good luck extending the wheelbase. Could it be done? Sure, with enough money. However, this is. certainly not going to improve handling. However, the FJR has a rather long wheelbase already, and could probably handle a good bit more power before needing to extend it.

H2: LONG ON POWER BUT SHORT ON WHEELBASE

That's one of the reasons a 72 Kawasaki H2 750 Mach IV SEEMED to be so powerful: that short wheelbase. I believe it was advertised as having 74 hp by Kawasaki, just about half of what our FJR's have. As scary as the 69 500 Mach III was, this beast was even more fearsome. And not surprisingly, it inherited several of its predecessor's flaws, namely squirrely handling, a propensity to wheelie, and horrific fuel mileage. It was perhaps the ultimate performance two-stroke of the day,

STEELING MOTORCYCLES DOESN'T PAY

I watched a buddy "launch" an H2 when I was 17. He'd "borrowed" his older brother's H2 without his permission. This brother was a drug dealer and we believed he picked up this bike in a drug deal. He'd put knobby tires on it and ran it out in the fields and woods behind his house. It could pull wheelies for ever and just about rearrange the landscape with that back tire. As far as I know, it had no title and was no doubt stolen. Anyway, little brother Dave decided to take his girlfriend for a joy ride in the field behind the house and I was tagging along behind trying to keep up on my Suzuki 500 twin. I was about 25 yards behind them when he grabbed some throttle, probably in second gear. What happened then is still a fog. The girlfriend started sliding off the back (I think) and panicked. She had her hands on his shoulders and ****** him back... trying to hold on. As he told me about it later through some very fat lips, he figured that caused him to give the bike full throttle just at the moment when he should have shut down the throttle.

3-2-1 LIFTOFF

Immediately, the bike launched in the air, spewing both riders.I would guess that the front wheel reached 8 or 9 feet as the rear wheel shot underneath it like a freight train. It looked like it was all happening in slow motion. It came down squarely on the front wheel, bending the forks up into the motor. David and girlfriend were busy tumbling across the field. After they limped back to the bike and we got it upright again, I helped both of them to push the bike back to the garage.He tried in vain to straighten the forks and various bent levers. Oh, and the fat lips I mentioned? That didn't take place when David crashed the bike. His brother Louie came home about 1/2 hour later. When he saw the bike, he grabbed the nearest thing he could find and beat David senseless with a helmet. I stood there dumbfounded as dad, responding to all the cursing and yelling, came out to rescue David and calm Louie down.

Memories.

Gary

 
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I used to build race engines for my top sportsman drag team (4.70 / 1/8 mile breakout), and I have worked with everything from LeMons to pro stuff. If I do that, it would need a slightly longer swingarm. Little bit of a pain with a shaft.
I'm sure there are a bunch of FJR salvage engines around. Take pictures of your work and show us the dyno runs!

 
Isn't that magical 1300cc 180hp motor already built by Suzuki and available in the Hyabusa? Probably easier and cheaper than the issues one would have with the FJR's motor.

Warchild was doing IB rides on a 'Busa, so it should be easy to find the LD comfort.

 
Isn't that magical 1300cc 180hp motor already built by Suzuki and available in the Hyabusa? Probably easier and cheaper than the issues one would have with the FJR's motor.
Warchild was doing IB rides on a 'Busa, so it should be easy to find the LD comfort.
Close, but I think he did that on a Black/BirdYea I'd buy a different bike with more HP than trying to get more from an FJR...JSNS

 
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A little homework needs to be done! Figure out the intake and exhaust flow/velocity, and valve/piston clearances.

Web Cam could regrind a stock cam. Power Commander could do the fuel, but not ignition timing.

I usually put the whole intake and exhaust system, the head, on the flow bench.

Turbo would be nice, if you could cram it and an intercooler in there.

 
I used to build race engines for my top sportsman drag team (4.70 / 1/8 mile breakout), and I have worked with everything from LeMons to pro stuff. If I do that, it would need a slightly longer swingarm. Little bit of a pain with a shaft.
I'm sure there are a bunch of FJR salvage engines around. Take pictures of your work and show us the dyno runs!
Please tell me where these magical engines are just hanging out, like fruit for the picking. So far they seem hard to find, and pricey.

Powerman...... Yes, lots of homework should be done. Turbo is not what I am looking for, I would rather increase compression, and go for more power across the range, rather than lower compression and find places to put the pipes.

N4HHE, yup, still going that way. Crazy *******s always want more power.

 
The FJR engine is a solid alloy block with ceramic coated cylinder bores. Therefore there is no opportunity to"hog it out" and increase the bore. Increasing stroke would appear to be an even more daunting task. Sorry to be the bearer of such bad news, but I fear this engine is not well suited to hopping up.

 
Turbo or supercharging the deal is a thicker head gasket and leave the bore and stroke as it is. The FJR's thin top pistons probably can't be replaced by dished pistons.

 
Gotta admire people with the skills to even ponder moves like this........I cringe at getting to the battery or sticking in new bulbs.......lol.......IMO the FJR has hit the sweet spot of useable power for the street....in a few seconds you're over 100mph which tends to get you noticed around town. I have after 8 lovely years on my Gen 1 yet to run into a car I can't smoke by a half mile without breathing hard, same for other bikes.......I know on weekends it's just a given any Harleys spotted will be blown away with prejudice. Did that to a couple of Mongols one day......decided not to do that again........lol.....

 
A little homework needs to be done! Figure out the intake and exhaust flow/velocity, and valve/piston clearances.Web Cam could regrind a stock cam. Power Commander could do the fuel, but not ignition timing.

I usually put the whole intake and exhaust system, the head, on the flow bench.

Turbo would be nice, if you could cram it and an intercooler in there.
I am not a pro at that. I know a lot about motors, and I can assemble what someone has already done, but doing porting and flow mods is not my things. I don't have a 5 axis CNC machine.

Luckily, I have a good friend who is taking his Rocket 3 to Carpenter Racing for their 265+ street package. They do BUSAs! So HotRodZilla should be happy. Ironically, the best BUSA kits are not bore, but STROKER kits with improved top end, giving better flow, more torque, and a wider powerband. WOAH :neo:

Also, thank you to garyahouse. I am glad its not 1972 and I am not a complete **** rider. But thanks! for the info. Very helpful.

Also, a big thank you to ionbeam. I am glad to know that NOBODY in the history of the world makes 79mm pistions, and it is physically impossible to produce them in that size.

Fred W is the only person who has contributed something useful that I can use.

I am taking it to these guys:

https://carpenterracing.com/sportbikepackages.htm

They specialize in 1.x+ bikes and porting for maximum flow. I expect them to have a head kit and a cam kit that you chumps can buy soon.

Plan on taking them at least 1, maybe 2 top ends, at least 1 full motor and a working bike, to let the pros go to town. Should be easy to make 220+ out of an FJR with only head and cam work. Would like to swap in the 6 speed gearing and the bigger rear pumpkin for long ratio. Should ride about like a hopped up busa but with comfort and style.

 
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