FJ1346 from ashes to... Well, we'll see...

[Dan Filetti]

If longevity and reliability are your target, leave it stock (internally anyway) and treat it well.

I have been simmering on this idea for a while.  I agree with this more than not.  For mass-production motorcycles, chief among the list of fundamental design principles, simply MUST be longevity and reliability.  Manufacturers have warranties on their products.  They do not wish to be giving customers new engines, and they have to account for a wide variety of users in a wide variety of circumstances in order to keep from giving some users new engines. 


So you have a team of talented engineers working on a bike for the mass market, who have a primary design principle of longevity and reliability.  They honer this so much so, that they are willing to compromise things like performance and excess weight, even sometimes: cost (gasp!).  Do we mere mortals really think we're smarter than that team of smart guys that spent 1000's of man-hours making our bikes what they are?  The very second we start changing the assumptions they have made, without understanding necessarily, the related assumptions, we are ADDING entropy, NOT reducing it, seems to me.  It's virtually impossible to know all of the assumptions and the inter-relativity of those assumptions when you start making changes. 

Can it be done?  Rebuild a stock motor and make it MORE reliable and long lasting?  I'm not seeing it.  I rather figure the best most (all?) of us could accomplish is to achieve parity.  Further, to put a finer point on it: I contend that longevity/ reliability parity with a stock motor while also gunning for more power/ less weight -a bigger/ stronger/ faster machine than was from the manufacturer originally, is ~impossible for the layman.  Who among us rebuilds a motor without the goal of more power etc. and I contend that the second you start down that path, you are doomed to have a motor that simply will not last as long, and/ or be as reliable as a heavier/ less strong OEM machine. 

I remember reading about an automotive metallurgist who was talking myopically, about con-rods in performance motors.  He was discussing deflection and the need to explicitly include greater deflection (lower performance) in the metal for the con-rods in order to make the con-rod last longer.  A motor that was designed for one race, and to be re-built after that one race, (dragsters etc.) can have VERY rigid con-rods with very little deflection with very high performance, but at the expense of longevity and reliability beyond that one race.  He was saying if that motor is intended for more than one race, then less rigidity/ more deflection/ less performance needs to be introduced: compromise/ trade off's.  Ringing more power out of a given motor therefore, necessarily introduces/ engages the builder in these sort of trade-offs.       

Where my idea seems to get weaker, is that this is not true (or less true) when we graft newer, well thought-out, add-ons to our machines, parts form modern machines: brakes, suspensions, wheel sizes etc, seems to be tried and true and many of the bugs are worked out. But in my mind these are vastly different and more 'superficial' than the internals of the motor.  I'd be curious if the engine builders among us can provide us with examples where this idea can also be applied to engine internals, along the lines of grafting on more modern parts or ideas to our older engines that actually allow for greater performance, while still supporting OEM style longevity and reliability.  To date, I really have not seen much in the way of this.  Feel free to correct/ enlighten me though.

Dan

[racerrad8]

I'd be curious if the engine builders among us can provide us with examples where this idea can also be applied to engine internals, along the lines of grafting on more modern parts or ideas to our older engines that actually allow for greater performance, while still supporting OEM style longevity and reliability.  To date, I really have not seen much in the way of this.  Feel free to correct/ enlighten me though.

Dan

Here is my latest example of greater performance from an FJ engine:

Removed her heart...

Randy - RPM

[jscgdunn]

I agree with Dans' approach and am pretty intimidated about taking on a motor job.  I find it interesting how technology has improved power output on modern engines, and am really curious to see how fuel injection and programmable ignition could boost power in an FJ engine.  For example, could an R1 system work on an FJ motor?  I think I saw Randy mentioned that the XJR FI is not so great though.  Musing and dreaming...all part of the moditis condition I am afflicted with.

[Dan Filetti]

I'd be curious if the engine builders among us can provide us with examples where this idea can also be applied to engine internals, along the lines of grafting on more modern parts or ideas to our older engines that actually allow for greater performance, while still supporting OEM style longevity and reliability.  To date, I really have not seen much in the way of this.  Feel free to correct/ enlighten me though.

Dan

Here is my latest example of greater performance from an FJ engine:

Removed her heart...

Randy - RPM

This is a valid example.  I will watch Flints maintenance reports going forward with keen interest.  It is entirely possible Randy, that you are indeed as, or more smart than the team of engineers at Yamaha -circa 1982...

I think most of us can agree that you are not the norm...

Dan

[racerrad8]

This is a valid example.  I will watch Flints maintenance reports going forward with keen interest.  It is entirely possible Randy, that you are indeed as, or more smart than the team of engineers at Yamaha -circa 1982...

Dan

No, not smarter. I am just able to take what Yamaha gave us, apply today's knowledge & technology to improve what is already there.

But, thanks for the compliment, it makes up for the mistake I made yesterday on the adaption & modification of a wrecked bike shock for the FJ.

Rear shock

Randy - RPM

[Pat Conlon]

I agree with Dans' approach and am pretty intimidated about taking on a motor job.  I find it interesting how technology has improved power output on modern engines, and am really curious to see how fuel injection and programmable ignition could boost power in an FJ engine.  For example, could an R1 system work on an FJ motor?  I think I saw Randy mentioned that the XJR FI is not so great though.  Musing and dreaming...all part of the moditis condition I am afflicted with.

Yep, sequential fuel injection would be a significant improvement in power, durability and fuel economy.

Cost is another matter... So you gotta ask....How many FJ'ers would put a $1,200-$1,800 FI system on their $2,000 bike?

I suspect....Not many, and certainly not enough to justify the time and cost of developing and supporting such a system.

[jscgdunn]

Hmmm....I have noticed a polished red and silver 84 that has a bit invested?

[jscgdunn]

I agree with Dans' approach and am pretty intimidated about taking on a motor job.  I find it interesting how technology has improved power output on modern engines, and am really curious to see how fuel injection and programmable ignition could boost power in an FJ engine.  For example, could an R1 system work on an FJ motor?  I think I saw Randy mentioned that the XJR FI is not so great though.  Musing and dreaming...all part of the moditis condition I am afflicted with.

Yep, sequential fuel injection would be a significant improvement in power, durability and fuel economy.

Cost is another matter... So you gotta ask....How many FJ'ers would put a $1,200-$1,800 FI system on their $2,000 bike?

I suspect....Not many, and certainly not enough to justify the time and cost of developing and supporting such a system.

I agree that's why I am wondering if thhe R1 system could be adapted

[Pat Conlon]

Not readily, R-1 has a different cylinder spacing than the FJ.

IIRC, Steve Conklin used modified Hayabusa throttle bodies on a custom manifold.
He had a Microsquirt ECU and had to install a return line to his fuel tank for the high pressure fuel pump system. He got the bike running with a rough tune but stopped development and went back to his FCRs
The bike ran in 'batch' injection mode which I suspect is problematic in the idle/low end range.
Batch injection: think of it like wasted spark, except squirting gas thru fuel injectors instead of spark.
The best idle, low end performance would come from sequential injection but to do that, you need a cam angle sensor signal to the ECU. You can't do it off the crank signal.
This is something the new XJR cylinder heads have the ability to do...but the head design of the XJR introduces other problems.

[Dan Filetti]

Yep, sequential fuel injection would be a significant improvement in power, durability and fuel economy.

Cost is another matter...

Yup, this is very true/ good point Pat.  I used to use the expression: "Time, Cost or Quality... choose any two"  Enough money will indeed invalidate 98% of my theory.  To that point, Flint's bike could not have been cheap -on par I'm guessing, with buying a more modern day/ higher performance bike.

Dan

[jscgdunn]

Thanks Pat...sounds like you have thought about it.

Bes regards and happy to hear you did not get burned out.

Jeff

[skymasteres]

What with all the bolts that 'backed out' in this build, would be fitting that a loose bolt was the end cause.

Well, I disagree with it being "fitting" at all. Especially with how much time I spent aganozing over making sure that I had the bottom end of this thing PERFECT. I mean, I checked, rechecked, and checked again all of the torque on ALL of the connecting rod and main bolts when I put the bottom end together the second time. I was soooo paranoid about making sure that I wouldn't have a bottom end problem that I spent the extra time to make sure it was right. When I had a connecting rod that was a little "sticky" it removed it, re-burnished the coating, re-lubed it, and put it back in to make sure everything was right. The bottom end of this engine was something I didn't want to have to go back into again... Ever.

If longevity and reliability are your target, leave it stock (internally anyway) and treat it well.

I have been simmering on this idea for a while.  I agree with this more than not.  For mass-production motorcycles, chief among the list of fundamental design principles, simply MUST be longevity and reliability.  Manufacturers have warranties on their products.  They do not wish to be giving customers new engines, and they have to account for a wide variety of users in a wide variety of circumstances in order to keep from giving some users new engines. 

You're exactly right. But with that being said, technology continues to advance and there is no reason that these advancements cannot be incorporated where possible into the engine.  Sometimes they are simple things like putting XJR rods in place of the originals (i.e. Taking advantage of the OEM's development budget) or doing a complete fuel injection conversion.

So you have a team of talented engineers working on a bike for the mass market, who have a primary design principle of longevity and reliability.  They honer this so much so, that they are willing to compromise things like performance and excess weight, even sometimes: cost (gasp!).  Do we mere mortals really think we're smarter than that team of smart guys that spent 1000's of man-hours making our bikes what they are?  The very second we start changing the assumptions they have made, without understanding necessarily, the related assumptions, we are ADDING entropy, NOT reducing it, seems to me.  It's virtually impossible to know all of the assumptions and the inter-relativity of those assumptions when you start making changes. 

Sure, you have talented engineers working everywhere. What's your point? Just because someone's pay stub says Yamaha or Honda does that make them a god of engineering? And what's all of this "mere mortals" B.S. that everyone keeps saying? If you don't know something and want to know, you start digging, asking questions, and figure it out. Or you make assumptions and hope for the best. Before the dawn of finite element analysis many hours were spent coming up with near figures, building the thing, then testing it to failure in the quest for further understanding.
No, I don't think I'm smarter than the guys that put this bike together. They have YEARs of continuity in design and theory with its operation on me. With that being said, it's not hard to see places where they really "screwed the pooch" Some of them you can do something about, others you can't. Examples being the starter clutch, main clutch, and combustion chamber design.  With respect to the starter clutch, THEY saw the deficiency and IMPROVED the design saving us the trouble.  With the clutch, there was no deficiency as far as the OEM was concerned. BUT, when you start making more power you need to make other changes to harness it. The clutch guide on fitting extra friction material in the clutch is a PERFECT example of "mere mortals" making an improvement over an OEM with a billion dollar development budget.
The combustion chamber design on these cylinder heads is a KNOWN weakness in these engines. Creative solutions to this deficiency have included fitting larger valves and adding additional spark plugs to fire denser mixtures. The latter is definitely an intense modification, but it's done by people with the time, resources, and desire to do it.
Entropy? That's a fancy way of saying that you're adding heat to a system.  You do that just by changing the exhaust and rejetting your carburetors. There are MANY people, a whole industry in fact, dedicated to "adding entropy" to carefully designed OEM engines.
Things like the XJR rod swap is taking advantage of the OEM's giant design budget and putting it to good use in your old engine. Now, why would an OEM that spend thousands of dollars designing the rods that went into the FJ1100 and FJ1200 go out and make a new connecting rod for the XJR? Was the old rod not strong enough? No, those rods have been demonstrated to stand up to power levels multiple times their original design loads.  Were they expensive to produce? No, they already had the dies and equipment to manufacture LOADS of them. In fact changing the design would cost MONEY. So why on earth would you want a stronger and lighter connecting rod? Why would you spend MORE money designing this when you have a part that'll do the job just fine?
The answer is COMPETITION. There are always improvements to be made in designs.
I know for a fact that while there are many things I have "prototyped" and ended up just using the prototype forever, that they were not the final solution. They were "good enough" that it didn't warrant the time and resource investment to rebuild it so it was perfect.
This is the same thing that happens in the industry. You have a design, and it's great. Until someone comes along with a better design and knocks it out of the water. If you haven't been working on improving your design in the background you get caught with your pants down and your competitor takes your customers.  Incremental improvements and changes to make a better product is what all of this R&D money is spent on.
There have been many times where new "Good ideas" have been delayed to market because they would kill the profitability of the current "good ideas"  Who's to say a "mere mortal" can't have the same good idea?
Of course another way us "mere mortals" beat the OEM's is, WE CHEAT!  We cheat, we cheat, we CHEEAAAT!!!   We are generally not bound by the same requirements that the OEM's are saddled with. You don't like your emissions canisters? Pitch them. The factory air box is too restrictive? Then "The airbox must die"... That stock exhaust it to quiet and heavy for your taste? Get rid of it... Would rather have an HID headlight? Put one in...   It's why there are products like titanium valve retainers and modified camshafts. Too expensive or don't meet OEM emissions requirements, but enough "mere mortals" interested  in better performance to support their development.

Can it be done?  Rebuild a stock motor and make it MORE reliable and long lasting?  I'm not seeing it.  I rather figure the best most (all?) of us could accomplish is to achieve parity.  Further, to put a finer point on it: I contend that longevity/ reliability parity with a stock motor while also gunning for more power/ less weight -a bigger/ stronger/ faster machine than was from the manufacturer originally, is ~impossible for the layman.  Who among us rebuilds a motor without the goal of more power etc. and I contend that the second you start down that path, you are doomed to have a motor that simply will not last as long, and/ or be as reliable as a heavier/ less strong OEM machine. 

Can it be done? ABSOLUTELY! I have no doubt that this can be achieved by the layman. This is not to say that the layman has to start from the bottom up and come up with all of the ideas himself. I know I certainly haven't. (Which is why I give so much of the credit to this board for being the incredible resource that it is)
I mean, individuals like Randy are a good example of this. Does he work for Yamaha? No. Honda? No. How about Kawasaki? No? Wait, are you kidding me? A man that doesn't work for one of the giants of the industry with nearly unlimited resources and can beat the OEM at performance and reliability? How can this be???
Come on guys. It's not magic. It's engineering. It's math. It's making a change and seeing what it does.
http://youtu.be/rp8hvyjZWHs

I remember reading about an automotive metallurgist who was talking myopically, about con-rods in performance motors.  He was discussing deflection and the need to explicitly include greater deflection (lower performance) in the metal for the con-rods in order to make the con-rod last longer.  A motor that was designed for one race, and to be re-built after that one race, (dragsters etc.) can have VERY rigid con-rods with very little deflection with very high performance, but at the expense of longevity and reliability beyond that one race.  He was saying if that motor is intended for more than one race, then less rigidity/ more deflection/ less performance needs to be introduced: compromise/ trade off's.  Ringing more power out of a given motor therefore, necessarily introduces/ engages the builder in these sort of trade-offs.       

You're absolutely right on these tradeoffs. Anything taken to extremes is going to have a major impact on longevity. What I like to so though is to play in the space left by multiple levels of safety factor. (The general rule that a part will stand up to at least 10% over rated capacity...)

Where my idea seems to get weaker, is that this is not true (or less true) when we graft newer, well thought-out, add-ons to our machines, parts form modern machines: brakes, suspensions, wheel sizes etc, seems to be tried and true and many of the bugs are worked out. But in my mind these are vastly different and more 'superficial' than the internals of the motor.  I'd be curious if the engine builders among us can provide us with examples where this idea can also be applied to engine internals, along the lines of grafting on more modern parts or ideas to our older engines that actually allow for greater performance, while still supporting OEM style longevity and reliability.  To date, I really have not seen much in the way of this.  Feel free to correct/ enlighten me though.

Dan

I think I've hit this point enough. But I can tell you that the one MAJOR change I made to this engine was the lightening and balancing of the crankshaft. This is not a new idea. (It certainly wasn't mine) But I know for a fact that balancing is a good thing because it eliminates energy wasted due to vibration.  You don't think that F1 motors spinning at 20K RPM run with unbalanced crankshafts do you? This is an example of making an assumption by comparison. I haven't run any numbers to demonstrate the quantifiable impact of the energy loss due to vibration in the RPM range I intend to operate at. But I assume that if the big boys do it for a reason it must be a good thing...  (What's good for the goose...)



I can say that when it was running I had a couple people ride it to give me feedback on it. The comment that I got back was that it was the smoothest FJ they had every ridden. I am almost certain that this was because I spent SOOOO much time making sure that every piece of the reciprocating assembly was as perfectly balanced as I could make it.  The thing was basically an electric motor from 3000rpm+
Now with all of that being said and getting back to your original point. YES, I did make assumptions about the interactions of individual parts where I didn't fully comprehend all of the factors involved in there operation. Like you may have come to grasp reading some of my other lengthy (sorry) posts, there are many MANY things that come together to make an engine run. They don't all have to be "prefect", but the further from perfect they are, the higher the risk of failure. 

It's not about "what you know" in this game. I "know" a lot about engine theory, operating concepts, and principles. What REALLY matters is how you put it together. It doesn't help to know everything but not be able to draw on that information to see how it impacts the operation of the engine.  This is the main reason that initially I kept all of my "theory" to myself. With this motorcycle engine building stuff I'm the proverbial "babe in the woods"   and I wanted to draw on the experience here to help "put it all together".
I'm hypothesizing here, but I think the root cause of my engine failure was the carburetors.
This may shock you, but it hinges on the comment that Dan made on the interactions between components and fully understanding them. I thought I did, but it turns out it didn't.  I made assumptions that ended up coming back to bite me big time. It's part of research and development. Because I am an individual, and doing this on a tight budget it hurts a lot when the engine that I have invested SOOOO much time and effort in explodes. I was hoping for some sort of failure mode that didn't point the finger at me, but with the engine design and the average reliability/failure rates, it  doesn't seem likely that I'm going to get a pass here.

The reason I say carbs were the ultimate failure mode was because of Dan's more power less weight comment. It also ties in with a conversation I had with Pat at the FJ rally about the effect on vibration of lightening the crankshaft.  And JRM's comment on rod bolt failure is the last piece.

Dan mentioned the less weight thing. I took about two pounds of "mass" off of the crankshaft. This effectively reduces the rotational inertia of the crank. Makes it easier to speed up or slow down. Pat mentioned that it also reduces the capacity to dampen vibration. This is because the reduced mass makes the crank more responsive to any force inputs and less able to absorb high frequency vibration. Pat also CONTINUALLY mentioned that I needed to get the carburetors sorted before riding the motorcycle. I didn't do this soon enough because this is my greatest weakness. (I grew up working on fuel injected engines where "tuning" was changing the fuel delivery curve on the computer")

My theory is that number three cylinder was experiencing vibration due to improper fueling and combustion that, in conjunction with the lower mass of the crankshaft, culminated in hitting the connecting rod nuts with a frequency of vibration that allowed them to loosen up. I sincerely doubt that this was an issue with the assembly of the bottom end, but rather an unforeseen consequence of going outside of proper running parameters. Is it possible that had I not lightened the crank that this would not have happened? Sure, but it's also possible that it just would have happened later had I not "sorted" out the carbs. I am actually fairly confident that when I tear down the engine I am going to find that the connecting rod nuts on number 4 are loose as well because of the same issue.
The day it happened I had a long conversation with my dad about the build and told him that if this engine was a total loss that when I rebuilt it I was going to instrument the crap out of it and make it fuel injected. Go the whole four 02 sensor route with RTD temperature probes and camshaft position sensor. I figure the real benefit of going to fuel injection is being able to have TOTAL control over fueling without having to compromise on performance vs. economy. Think about being able to have your "spirited riding mode" with richer fueling and your "cruise mode" where the FAR is backed way off. (Of course with logic on the throttle position sensor to kick it over to richer fueling if abrupt changes are made)

But I digress. Bottom line, the engine died. It's probably my fault. I'm still learning a lot.

[skymasteres]

I agree with Dans' approach and am pretty intimidated about taking on a motor job.  I find it interesting how technology has improved power output on modern engines, and am really curious to see how fuel injection and programmable ignition could boost power in an FJ engine.  For example, could an R1 system work on an FJ motor?  I think I saw Randy mentioned that the XJR FI is not so great though.  Musing and dreaming...all part of the moditis condition I am afflicted with.

Yep, sequential fuel injection would be a significant improvement in power, durability and fuel economy.

Cost is another matter... So you gotta ask....How many FJ'ers would put a $1,200-$1,800 FI system on their $2,000 bike?

I suspect....Not many, and certainly not enough to justify the time and cost of developing and supporting such a system.

Holy crap there were a lot of posts while I was writing my "paper"
Modditis is as good a reason as any as to why people would spend exorbitant amounts of money on a bike that's not worth it. I mean, you're in for $1500 if you put one of Randy's suspensions on the bike...

This is a valid example.  I will watch Flints maintenance reports going forward with keen interest.  It is entirely possible Randy, that you are indeed as, or more smart than the team of engineers at Yamaha -circa 1982...

Dan

No, not smarter. I am just able to take what Yamaha gave us, apply today's knowledge & technology to improve what is already there.

But, thanks for the compliment, it makes up for the mistake I made yesterday on the adaption & modification of a wrecked bike shock for the FJ.

Rear shock

Randy - RPM

Randy is definitely "The Man".  I mean, he puts up a comment or link and it's accepted as gospel while I end up writing thousand word essays to attempt to support my ideas...

I poke fun, but Randy is a good chap. He called me the day after the hole "Hole" misunderstanding to communicate that he wasn't being an wisenheimer.

[jscgdunn]

SkyM,
Sorry to hear about the blow up....the nature of innovation and early adoption is that sometimes things do not work out.  Intersting note on the carbs and your root cause assessment; my temptation also is to change everything but I too have found out the hard way that having too many variables can be tough to manage.

Be great if you took on the FI challenge!

Jeff

[Dan Filetti]

Entropy? That's a fancy way of saying that you're adding heat to a system. 

Hmm that's not my intended use of that word.  I meant "Lack of order or predictability; gradual decline into disorder."  More complex system inherently have 'more entropy'.  Changing an integral part a system that was designed as a whole, necessarily / (almost necessarily?) increases entropy. 

Anyway, my comments were meant generally, and not specific to your build.  I am guilt of not starting a new thread and hijacking yours.  As other have said, I have admired your build and feel saddened that it did not pan out.  I very much hope you re-build ASAP. 

Dan