Cylinder wall thickness

[Fred W]

Rather than trying to eek out a tiny bit of better intake flow with the naturally aspirated engine, have you considered moving to forced induction? (either a turbo or super-charger)

The FJR engine is rather solidly built. I'd imagine it would be able to withstand a reasonable amount of intake boost, reasonable being the pivotal word. And turbos all the rage in automotive engineering these days. Even in relatively inexpensive cars, sticking a small displacement turbo engine delivers good performance while maintaining reasonable fuel economy.

A few pounds of boost would add far more engine torque (and therefore acceleration) than anything you could ever do to the intake ports. And since it would be basically be bolting on stuff would be reversible, so you could return the bike back to stock, as long as you didn't blow it up first.

It is always a gamble with any sort of first-time engine modifying, so if you can't afford to lose the engine to the gods of petroleum combustion you may want to rethink your plan.

 

[RossKean]

Personally, I have no intention to do anything engine-wise with my old and tired FJR but I am interested in what, if anything, comes of this. It would be a huge amount of fun to have a 200+ HP FJR but I suspect the trade-offs would put it into a category of bike I wouldn't want.

For example:

What sort of cost for a rebuild "kit"?

What happens with fuel mileage (when riding conservatively). We know what will happen when being a hooligan!

What happens with rideability? Can throttle response be kept tolerable for normal touring function?

What happens with engine longevity and day-to-day reliability? (The biggest plus for this bike)

Would the clutch and transmission handle the torque?

I don't know enough about this sort of engine makeover to have a truly informed opinion on any of this stuff other than believing that you don't get something for nothing.

I am intensely curious - please report back once you have something!

 

[falsus nomen]

Rather than trying to eek out a tiny bit of better intake flow with the naturally aspirated engine, have you considered moving to forced induction? (either a turbo or super-charger)
The FJR engine is rather solidly built. I'd imagine it would be able to withstand a reasonable amount of intake boost, reasonable being the pivotal word. And turbos all the rage in automotive engineering these days. Even in relatively inexpensive cars, sticking a small displacement turbo engine delivers good performance while maintaining reasonable fuel economy.

A few pounds of boost would add far more engine torque (and therefore acceleration) than anything you could ever do to the intake ports. And since it would be basically be bolting on stuff would be reversible, so you could return the bike back to stock, as long as you didn't blow it up first.

It is always a gamble with any sort of first-time engine modifying, so if you can't afford to lose the engine to the gods of petroleum combustion you may want to rethink your plan.

Well thank you, I didn't know I needed your suggestions, now it has bloody well changed my life, why didn't I ever think of a turbo?

To be honest, I really dont know that I have the words to respond to this post.....

Let me put it this way, similar displacement ZX-14 and Busa engine put down 240-290 HP with no turbos..... On the GROUND, IE, on the Dyno. However, on the Dyno, an FJR puts down about 130.

An engine is an air pump, how efficiently it gets air in and out is the key. The key to getting air in and out is intake, exhaust, valves, and cam. So.... why doesn't an FJR make 220 HP? Cut it like it is..... complete **** heads, and worse cams.

 

[falsus nomen]

Personally, I have no intention to do anything engine-wise with my old and tired FJR but I am interested in what, if anything, comes of this. It would be a huge amount of fun to have a 200+ HP FJR but I suspect the trade-offs would put it into a category of bike I wouldn't want.
For example:

What sort of cost for a rebuild "kit"?

What happens with fuel mileage (when riding conservatively). We know what will happen when being a hooligan!

What happens with rideability? Can throttle response be kept tolerable for normal touring function?

What happens with engine longevity and day-to-day reliability? (The biggest plus for this bike)

Would the clutch and transmission handle the torque?

I don't know enough about this sort of engine makeover to have a truly informed opinion on any of this stuff other than believing that you don't get something for nothing.

I am intensely curious - please report back once you have something!

You sir, sound like you need more cupping and nursing than sucking. Does your walker fit over the top of the FJ?

 

[RossKean]

And are you truly a **** or do you just play one on internet forums?

 

[HotRodZilla]

And are you truly a **** or do you just play one on internet forums?

No, Ross, he's a big-mouthed ******* who has no idea what he's talking about.

So, let's see FalsusStupid, you didn't need Fred's suggestions, but you started this thread, to ask for them. So, maybe all of us lesser people are confused by your expansive knowledge. What exactly do you want? Do you want us to go over and do it for you, because you obviously have no idea what the Hell you're talking about. What did you say? Oh yeah, "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."

CoughBULLSHITcough. You may have been standing in a garage running your mouth, while other guys worked, or handing the real mechanic's tools, but nothing else. A couple posts later you admit this when you say you don't know how to do it, but you can assemble stuff. Ooooooooooh, really?!?! This isn't IKEA, clown, they're motors, and are more complicated than you can comprehend. IF you knew how to do it, you would have done it already, so go troll somewhere else.

Since you don't get it, there is absolutely nothing wrong with the FJR's engine, as it sits, based on its design parameters. The FJR is a SportTourer, NOT a superbike. It makes great power, has great service intervals, is reliable, and gets good mileage; things SportTourer riders want. The engine you want to pretend to make lies in another platform. I for one would prefer you go be a **** over there and stop being such a **** over here.

My input, since you asked for it in post #1? Leave the engine alone. You have no idea what your doing. You were even too ignorant to know the cylinders areally ceramic coated, so boring them would be an issue. If you can't figure that out, you're doomed. Go back to cleaning your wife's kitchen.