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FJowners.com > General Category > FJ Project Writeups > FJ Dragbike Project
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Author Topic: FJ Dragbike Project  (Read 82965 times)
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andyb
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Re: FJ Dragbike Project
« Reply #150 on: May 10, 2014, 01:04:06 PM »

Not to be a dick, but I'm gonna be a dick.  At least I'm honest (don't you hate when people start with a disclaimer like that anyhow?!)

Why Q16 fuel?  Why 113?

Are you really running that much compression?  I realize that the silly elevation isn't doing you any favors, but I think you're shooting squirrels with an elephant gun.

If you can't run a replacement-lead fuel, such as U4.4 or MR12 due to stupid laws, and still want a reasonably high octane... Have you looked at VP's Streetblaze 100?  Yes, it's a motor octane of 96 instead of 116, but if you're under 14:1 I'd feel safe to wager that you're pissing money and power down the drain.  There's some more unusual VP fuels that also fit the bill, like SV-05 (98 MON and oxygenated).  There's no reason to run a nitrous/turbo fuel if you're running on motor.

In my own racing, I found that with a DA of 2500-3000, going from pump 87 (also known as "partially water") to proper 100 octane fuel cost me a solid 4mph and 0.15s.  With a 735lb combination, that equated to nearly 10% all on its own, or 12-13hp worth!  U4.4, even with a weak oxygenation package and far too much octane gave me back half of my losses (better than 87 pump, but not as good as the DA correction would imply).

You can't swap fuel around without getting it  dead on.  It's arguably the cheapest power you can make, and a consistent and important part of your tuning package.  Dont' skimp!  It's as important as setting your squish, but easier to fix when you jack it up.  Get some spare plugs and a pail of appropriate fuel, and make some tuning decisions.

You KNOW the suspension, gearing, and clutch make a difference.  Getting the motor to output as much as you can, consistently, makes tuning the rest of the combination that much easier.  The whole trick is removing as many variables as you can and getting things as close as possible quickly.  Once you've got the fuel done, the motor gets jetted and timed appropriately, and is done.  Then the focus shifts to the suspension and tire (which I must say... you're looking to me like someone racing on a tire that's had two lifetimes worth of heatcycling... Just sayin!  I know it's not cheap, but as you start getting closer, it's going to become non-optional to have a tire that's sticky every single pass, and you know that as well as I do).  Once you can eliminate all these things as being variable, then you can begin choosing between 0.010 and 0.015 shims in the clutch, with some security that it's a trustworthy and repeatable change.  Look at it like a bracket racer, step one is consnstency.  Once you've achieved that, the tuning changes don't get lost in the noise of the variabiltiy of the runs.

And you better get a move on.  The shim kit is in my dining room right now, and within a week I expect to have my FJ doing breakin miles.  I'm hoping for very low 10.70's on motor, and once the compression checks say I've seated the rings I'll be doing my damnedest to beat your ass into the 9's, on a stock wheelbase and displacement no less.  Get to work!!! Smiley

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Re: FJ Dragbike Project
« Reply #150 on: May 10, 2014, 01:04:06 PM »

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fj1289
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Re: FJ Dragbike Project
« Reply #151 on: June 24, 2014, 05:38:44 PM »

Sad night last night for the dragbike -- started tearing it down for the parts I'm going to borrow for Bonneville. 

Pulled the head for the cams and whole shim under bucket setup.   Really wish I could use the whole head, but the welded on spigots for the Lectron carbs make adapting the throttle bodies a difficult task.   

Tonight I'm pulling the swingarm and in a few days I'll swap the forks out too. 

Looks like it'll be September sometime before the dragbike sees the strip again... cray
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fj1289
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Re: FJ Dragbike Project
« Reply #152 on: November 21, 2020, 05:31:44 PM »

Have you ever seen such a mess?!

I was concerned when I first looked at this engine due to the orange “stripe” around the case seams.  







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FJmonkey
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Re: FJ Dragbike Project
« Reply #153 on: November 21, 2020, 05:55:29 PM »

Spluge everywhere, yuck....
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Re: FJ Dragbike Project
« Reply #154 on: November 22, 2020, 01:05:55 AM »

THAT'S SCARY
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ribbert
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Re: FJ Dragbike Project
« Reply #155 on: November 23, 2020, 07:42:00 AM »

Quote from: fj1289 on November 21, 2020, 05:31:44 PM
Have you ever seen such a mess?!





Haha, I feel like I've met that guy many times in my life. He's the same guy that over fills everything, over tightens nuts and bolts, uses a torque wrench on everything then adds a quarter turn to be sure, puts Loctite on every thread on the bike, over greases everything, tells everyone what a rip-off mechanics are and that he can do a better job himself and save $1000's while he's at it.

Omg, the thought of all that floating around inside the engine!!!! dash2

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Re: FJ Dragbike Project
« Reply #155 on: November 23, 2020, 07:42:00 AM »

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FJ_Hooligan
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Re: FJ Dragbike Project
« Reply #156 on: November 23, 2020, 11:32:16 AM »

Gotta seal those main bearing journals, lest there be a massive internal oil leak!

At least most of the overflow is on the inside of the motor where you can't see it.  (YIKES!!!)

Some people shouldn't be allowed to buy wrenches..... or RTV!
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DavidR.
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Re: FJ Dragbike Project
« Reply #157 on: November 23, 2020, 05:32:16 PM »

Quote from: fj1289 on November 21, 2020, 05:31:44 PM
Have you ever seen such a mess?!

I was concerned when I first looked at this engine due to the orange “stripe” around the case seams.  

That's over the top ridiculous.......

Well, at least you know you'll have some time cleaning all the passages - and checking them thrice! Wink
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Steve
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Re: FJ Dragbike Project
« Reply #158 on: November 23, 2020, 07:43:31 PM »

Very true!  Going to be chasing and flushing EVERYTHING!

I’m not sure the engine was run in this condition.   Although there seems to be quite a bit of oil on everything, the bearings and journals look great!  When is saw that much crap everywhere I assumed there would be oil starvation issues.   

Haven’t determined why the cases were split - I assume transmission.   I need to look at the shift forks and see if they are new.  Transmission has not been undercut - maybe was R&R’d with a “good” used trans?  Does look to be some dings around the second gear windows, but the dogs look OK to my eye.   Will get an undercut trans  as insurance.   

Hopefully can get this cleaned up this weekend.   
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Re: FJ Dragbike Project
« Reply #159 on: December 04, 2020, 08:57:09 PM »

Little projects continue.

I’ve been stuck on some details on the nitrous system for a couple months now.  Overall plan is two stages - 1st will be smaller used on the hit - right when the clutch is released on launch.  Then the 2nd stage will be progressed through second, third, and maybe fourth gears.  

2nd stage system is set up a lot like my original nitrous system.  The problem has been trying to optimize the system a bit.   Nitrous works best when you manage to get the nitrous into the motor still as a liquid.  Then as it phase changes to a gas state you get the most benefit from the cooling.  Also, as a liquid it displaces less of the air going into the engine - both preserving as much NA (naturally aspirated) power as well as slightly decreasing the change in the composition of the mixture for combustion.  

Anywhere there is a transition or turn in the system, there is a chance for expansion or turbulence - both which can cause some of the dense liquid to start to phase change to gas.  Transitions can’t be avoided - but you want to minimize them and make them as smooth as possible.  I was having trouble in my mind with the transition to the nozzles.  As it was, it went from the steel braided lines (3AN sized) through a 3AN to 1/8 NPT fitting, through a 1/8 NPT junction to the 1/8 NPT nozzle.   The nozzle seems to be set up to seal against a male flare - but short of fabricating a fitting I couldn’t find one.  As it was, it created a fairly large expansion chamber right at the “business end” of the whole setup.  

I bought a set of nozzles - but turned out they were a lot shorter than I realized and would end up well short of the mouths of the throttle bodies.  That would defeat the efforts of eliminating the expansion area before the nozzle by replacing it with a huge one just after!  So back to the old nozzles.

Here is what I finally came up with.  Re-thread the nozzle to accept the 3AN line directly.  Since the 1/8 NPT thread was a bit bigger than the 3AN thread, I was able to turn down most of the old threads on the lathe, the run a 3/8-24 die over it.  The die wouldn’t cut all the way to the base, so I had the flip it over and very carefully thread it over the newly cut threads backwards - then finish cutting the threads to the base.





Next it needed to be counterbored to accept a flare jet.  The flare jet is the sealing surface for the 3AN line.  





Finished job.  Eliminated two transitions and the expansion space.  As a side note - the flare jets are quite large - slightly larger than the inside of the 3AN and slightly smaller than the inside of the nozzle.  The nitrous system is jetted at the solenoid to achieve the best response while progressing the system.  





Also - does anyone recognize these nozzles?  I’m sure they are available from an industrial or agricultural supply, but have not found them on McMaster-Carr or Grainger so far.  
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Re: FJ Dragbike Project
« Reply #160 on: January 06, 2021, 02:30:09 PM »

Recently found what at first appeared to be a very unusual clutch among some parts that came with the billet transmissions that came from Rod Mumford’s estate. 

At first glance it appeared to be a Hayabusa basket with some kind of a slipper clutch and a shaft adapter for the clutch hub.   I assumed it was something that Rod had adapted to an FJ back plate. 









Further investigation revealed the backing plate was not from an FJ - wrong number of teeth on the basket.  WTF?  Then I remember that Rod also had a Kawasaki drag bike.  Started looking through Kawasaki transmission parts.  Found a clutch hub that matched - 83/84 GPz1100.   But, wrong number of teeth on the basket.  Finally got everything to match - Kawasaki ZX-11. 

Unfortunately the shaft adapter doesn’t fit the FJ transmission output shaft.   But, all is not lost.  While trying to figure things out I discovered the Kawasaki clutch steels actually fit the FJ clutch hub AND are slightly smaller diameter than the FJ clutch steels......just exactly what I was getting ready to try to address again for the drag bike clutch:



This was a hybrid clutch - a basket normally used in a Hayabusa drag clutch married to an FJ clutch hub.  It was designed to use Hayabusa frictions and MODIFIED FJ steels.  The FJ steels had to be ground to fit inside the clutch basket without fouling on the sides of the basket.  Looks like the Kawasaki steels will fit without modification.  Kawasaki also makes these steels for various models and are available in different thicknesses - perfect for adjusting the clutch pack thickness to suit the drag clutch requirements!

You never know where you are going to find the next step ahead.   good2
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Re: FJ Dragbike Project
« Reply #161 on: January 06, 2021, 03:03:33 PM »

Love the ingenuity here!

I can't wait for the tracks to open up!!! wacko2
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