FJ Dragbike Project

[fj1289]

Opened up a set of 1100 for the big bore "extra thick" sleeves.  The sleeves will take up to an 83mm bore - but only going to 80.5mm.  This should give a very thick wall that will be strong and will be able to be bored 2 or 3 times if there is an "oops" on the nitrous ...

Marked out the base gasket opening:


After grinding with 50 grit sanding drum.   Also followed up with 80 grit and 120 grit.


Looked back at some old posts - did this 5 month ago ... sure is dragging on!

[FJ1200W]

Looked back at some old posts - did this 5 month ago ... sure is dragging on!

Time warp!

Thanks for the posts and info, always enjoy them.

Also, it's not (?) a bad idea to smooth the air passages in the block.

Not sure if it really does much good (or bad) but it seems like it could help with the flow as the cylinders rise and fall.

[Pat Conlon]

Chris, is there a difference in case thickness or case strength between the 1100 and 1200 cases?
I seem to recall in the past that 1200 cases were stronger and had more meat for the cylinder studs.
I think it was APE mentioning their heavy studs would only fit the 1200 case, not the 1100.
Something like that....

Cheers, keep up the good work. I enjoy your posts!

[fj1289]

Chris, is there a difference in case thickness or case strength between the 1100 and 1200 cases?
I seem to recall in the past that 1200 cases were stronger and had more meat for the cylinder studs.
I think it was APE mentioning their heavy studs would only fit the 1200 case, not the 1100.
Something like that....

Cheers, keep up the good work. I enjoy your posts!

Pat - I don't know the answer to that one!  Years ago, Andy York (built Frank Moore's Brutus) told me it was advantageous to use the 1200 cases due to the three mounting bolts for the alternator vice two on the 1100 cases - less likely to break the bolts or bosses.  Never mentioned anything else. 

I'll have to phone a friend on this one - Randy?  Robert?  Any input?

[fj1289]

Just looked at the APE website - it lists their studs for FJ1100 (late) and FJ1200.  So it seems like there was some kind of change in the cases during the FJ1100 production run.   

I knew it was better to start with 1200 cylinder for oversized sleeves - casting was thicker so less chance of oil leak/seep with larger sleeves installed.

[RPM - Robert]

I know the stud lengths changed at some point. Besides the 2vs3 bolt alternator and the clutch cover ventilation being diffferent. I don't think there is a difference but we haven't built many 1100s mostly 12s. Pop might know better in this one.

I know we had an 1100 case in my legend car bored to 1200 and it broke the top alternator stand off for alternator stand off. It Was the first race I led in a legends car. Every time I turned right the oil would flow to the left and get on the header and smoke like a son of a gun. Pop was waving me in so I didn't ventilate the crankcase but being 13 or 14 at the time and it being the first shot I had at winning a race outright. I kept trucking. Ran 5-6 laps like that at Sonoma, finally broke an axle and ended up getting towed in. When we drained the oil, the whole half a quart that was left, we decided to rebuild that engine. Sleeve and pistons were all scored up. Welded the stand-off back to the case and ran that motor for another 2-3 years before rebuilding again.

[fj1289]

Big win in the Wyatt garage today!

Clearanced the cases for the drag clutch.  Took off a bit less material than the last time I did this (9 or 10 years ago!). 



Then rotated the crank around to check for rod clearance.  The rod bolts used in Carillo H-beams used in the original drag engine build hit the basket.  Had to grind the head of the aft bolt of the #4 rod to clear the basket.  Somewhat less than ideal....
Using XJR rods in this build.  The reversed design of the rod bolts give more clearance.  It clears!  Just barely - but it does clear - and this is with the rod "tipped" more forward than it will be in reality (and there is a bit more room than it looks in the pic).





Later this year we'll start "stress testing" the XJR rods with a "bit" of nitrous ....

[fj1289]

Robert - missed your post earlier


Good to hear - no reservations at all now with using the 1100 cases!  After finding a second minor "issue" with the 1200 cases I started with I decided to jump ship and go with this set of bare 1100 cases I've had in the garage for 10+ years. 

[fj1289]

Finally got the racebike back out last Sunday!

Very successful as far as a first outing goes - no major electrical or mechanical issues.  Lots of teething issues - but working through most of those this week. 

Low points - no good clean runs so no real data to move from.   High points - first time it's been WOT since getting it running again, and the rear suspension seems to be in the ballpark.

Recap/changes from last time the bike was setup for drag racing:
Old setup
1447 cc engine
Lectron carbs
Dynatek electronics for drag racing - shift counter/shift kill, shift light, 2-step, etc
Hays T-3 clutch (custom based on Hayabusa basket, FJ backing plate, modified FJ clutch hub, Hayabusa frictions, modified FJ steels)
Elka shock setup for Hayabusa pro street with a Linkpro adjustable shock link

New setup - based on what we've been running landspeed with (but with the Hays clutch again)
1297 cc engine (with the thickest sleeves I could run).  Plan was to make it easier/less expensive to "recover" from an oops with the nitrous if needed - can simply bore the sleeves out to 1314, then 1350, then 1380 (and probably "retire" it to a street engine then and start all over again...)
EFI - this thing has been through microsquirt (most success with this!), Megasquirt MS3X, Holley HP (never run on track - never really got it fully operational - think the box I got was a lemon - nothing but problem after problem - very expensive education  ) and back to MS3X again.  MS3X controls all functions on the bike as a single integrated system.
2 stages of nitrous - eventually plan to progress a small shot from the hit, the progress a large shot through the gears.
Hays T-3 clutch - I never fully got a handle on the clutch tune.   Researched my butt off on this, went back through my old tuning notes and think I found the error of my ways...)
Elka drag shock and Linkpro - never got a handle on the rear suspension tune - was either too soft and the shock would bottom on launch and then spin like crazy.  Then swapped springs and too stiff - never would bite on launch and would spin.  Found that issue too I think - the heavier spring was an inch too long - way too much pre-load.

[Pat Conlon]

Chris, assuming the stars align and all your systems play nice, what ET's do you expect? Mid to low 9's?

[fj1289]

Pat - yes, hoping to go deep into the nines   Will take some time to work up to it.   Ultimate goal is to take the drag strip setup and tone down the launch a little and let it rip on the half mile!  Really, for the speeds I want in the half - the speed required in the quarter should put the times down in the eights - but that'll require a bit of learning on my part for the clutch and suspension tuning!  I haven't had enough of a handle on it to even find the nine yet!

[fj1289]

Made it back out to the track again this past Sunday.  Last chance for this year.

Tried to fix all the gremlins/teething problems from the first outing the prior Sunday.

Datalog cutting out during the run - hard to tune without good info!  Was setup in the software to datalog anytime RPMs are over 800.  Installed a push button and indicator light to manually start and stop logging.

Air shifter issues - could have been several issues - think it was a combination of air supply problems and clutch problems.  Replaced the pressure regulator (old one was 12 years old) and added a pressure sensor to the system so I can datalog pressure going into the shift solenoid.  Also ensured the CO2 bottles were full.

Clutch issues.  The clutch seems a lot looser than I previously remembered.  Had to add a lot more weight than expected to keep the clutch from slipping until nearly redline on launch.  This drag specific clutch is designed so you launch on a 2-step and "throw away" the clutch lever to launch.  Then the combination of clutch plate stack, static springs, centrifugal arms and weights, and hold-back springs allow the clutch to progressively engage (slip) at the desired RPM and then lockup as RPMs increase.   Get the clutch tuneup right and you are rewarded with consistent launches and long clutch life.  Get it wrong and it is a big headache!  I've only gotten it right-ish in the past.  Last week it wasn't even right-ish.  Very frustrating as I set it up per my old notes.  Went through the clutch this past week and replaced all the frictions (all the slipping the prior Sunday had worn them all a bit) and found a steel with all the internal teeth bent up about 45 degrees!  WTF!?  No wonder the clutch didn't work as expected.  Also saw evidence on the clutch hub where it looked like the uppermost steel in the clutch pack had "jumped" over the top of the clutch hub possibly.  

Run 1 - First run was a repeat of last week.  WTF.  Tear into the clutch - not happy.   I remind myself I wanted a dragbike again ... and here I am tearing into the clutch every freaking pass!  Looked like the uppermost steel had "jumped" over the clutch hub again.   Time to change something - but what?  Go to look through my clutch kit to see what plates I can swap - and can't find the box of clutch tuning stuff.  Left it in the garage.  First thought is to pack up a go home completely defeated.   Then think something must be off for the outermost steel to be that high on the clutch hub.   Do the only thing I can think of - pull out the topmost friction and steel and the next friction.  Put the steel back in double stacked on the second steel and then stack on just on the frictions.  I know this will make the stack shorter than it "should" be - but should solve the problem of the steel jumping the clutch hub.   Since a shorted stack height will delay clutch engagement, I also remove the holdback springs from the centrifugal arms to hopefully bring them in sooner to make up for it.  

Also take a look at the datalog.  It cuts off again at the shift to second like it was doing last weekend.  Ugh.  But it does capture the launch and what should be the run through first gear.  Problem is the clutch slips all the way to the shift point - It pulls some but I have to back off the throttle to get the clutch to engage and get slowly down the track and out of everyone's way.  

Datalog below - white is RPM and yellow is speed (very small blip at end at bottom).  Timescale was cutoff - but clutch release to RPMs climbing to shift point was .385 seconds and speed was about nil - VERY BAD!



Run 2 - Clutch feels a little better riding up to the line.  Get lined up and am concerned the clutch is either going to slip to redline again, or maybe slam in hard without the hold back springs on the arms.  Only way to find out is to twist the throttle wide open and throw the clutch lever away!  The launch actually feels good!  Not stellar but a lot better than any of the launches last weekend.  Ticket says it went  1.889 60'.  That might not be in the ballpark, but I think I can see the ballpark from there!  

Run 3 - Need to increase the clutch height - but don't have a way to do that now since I left the clutch plates at home.   Alternatively I can try adding washers on the arms to bring the clutch in more aggressively - also not an option with the clutch tuning parts left at home too.  Only thing to try is raising the launch RPMs to bring in the clutch a little quicker (as long as it doesn't try to creep at that higher setting).  Increased 2 step from 5,000 to 5,500.  Feels about the same as last launch - but the ticket shows it slowed to 60' to 1.990.  Now that it is launching OK, I now notice how slow the rest of the run feels on just motor.  Forgot to start the datalog when lining up.

Run 4 - Increasing the 2-step didn't help, so try decreasing it to 4,500.  Also decide to spray the first stage of nitrous to test that system.  First stage is set up with a small jet - about 12 hp - and is set to engage 2.5 seconds after launch, so I don't expect much improvement (mostly just a system check).  Car in the other lane before us blows the back window out at the top end of the track, so we all shut down while they clean the broken glass off the track.   When I restart and line up again forget to activate the datalog and the nitrous.   60' was 1.946 so it's a little better, but not much of a change.   Trying to get in more runs before I have to leave means I'm not getting as much cool down time - extra heat in the clutch and oil also effects how the clutch behaves and tends to make it loosen up a bit.  

Datalog from this one shows the clutch engaging and actually pulling the engine back down a little while the speed is coming up smoothly.   Takes 3.257 seconds from clutch release until RPMs climb to the shift point and speed is up appropriately.  On the left side where the white line is flat is where it is on the 2-step.  The sudden increase in RPM is where the clutch is released.  Then the line curves over where the clutch is starting to engage and the yellow line begins to increase as the bike starts to move.  As the clutch locks up the RPMs start to climb as the bike continues to accelerate.  Compare this to run1 and you can see the BIG difference.



Run 5 - last one for the day.  Decide I'm going to go for it.  I plan to use both stages of nitrous - first stage at the launch and second stage (30 hp jets) 2.5 seconds after launch.  Never used nitrous on the launch before - I think I know how it will react, but won't really know until I try it!  Definitely feels like a better launch and runs better down the track.  Ticket says 1.681 60' and 10.96 at 123.63 mph in the quarter mile.   Nothing to brag about - but MUCH happier to go into winter on those numbers and knowing there are a few things working right.  

Datalog from this one shows the effect of increased torque from the nitrous (12 hp shot).   Same clutch settings but the clutch flashes up about 1000 RPM higher than last time.  Takes 2.535 seconds from clutch release to shift point with speed coming up too.  Looks like the tire might have been trying to slip - the yellow line is a lot less smooth - but didn't feel it in the seat of the pants.



Biggest win for the day though is the rear suspension - never even had to think about adjusting it or "fixing" it.  When I first setup the dragbike I used the 650 pound spring that came with the shock and tried to use the adjustable linkage to stiffen up the suspension.  Not enough adjustment - spring was too soft, causing the rear shock to bottom out on launch and the back tire would simply spin.  Replaced the spring with a 950 pound spring and the suspension was too stiff despite adjusting the linkage all the way the other direction.   When I swapped springs again - turned out the 950 pound spring was also 1" longer and had way too much preload.  The new setup is an 850 pound spring the correct length.  Now with the rear suspension in the ballpark, I can focus on a good clutch setup and getting the clutch tune in the ballpark.  Then the real fun begins!

[FJ1200W]

I'm old school, a 10 second slip is worthy of pat on the back - well done, good stuff!

[fj1289]

Made a couple updates to the bike last week based off the previous outing. 

First was adding a solid state relay to activate the shift solenoid.  Almost every datalog cuts off at the first shift.  I'm guessing the solenoid is generating some electrical noise and feeding that back into the ECU when the spoil de-powers.   The traditional why to deal with this is a diode across the power and ground wires o the solenoid.  I ended up with two extra solid state relays and went that route instead to completely isolate the electrical connection between the solenoid and ECU.   

Second was shimming the clutch hub out from the basket to allow the shorter clutch stack to be used without having to order a bunch of thick friction plates or double stack several steel plates.  Most importantly the stack is now short enough it should eliminate the possibility of the upper most steel pate from jumping over the top of the clutch hub again.   Additionally added some more weight on the centrifugal arms to help increase the clamping force in the clutch at an earlier RPM. 

Now I just need to find some place to test the launch again and see if the datalog will record the entire run!

[T Legg]

Now I just need to find some place to test the launch again and see if the datalog will record the entire run!
[/quote]

       It would be nice if you had a remote rarely used air strip like the nearby on we have in alpine count California. Ours is almost 3/4 of a mile. My son has run his zzr 1200 up to 156 mph and still had ample room to safely shut down and come to a stop.