FJ Dragbike Project

[fj1289]

I was infected a couple of years ago by the dragracing bug.  It is extremely infectious and creates major complications when coupled with the modifier bug.

I've raced my 89 FJ1200 off and on for a couple of years (started as a result of a fairly bad traffic stop).  Both the rider (me  ) and the bike made improvements.  I had a lot of fun, learned a lot, and figured out it is better to have a street bike and a drag bike vice doing both with the same bike - if you're fairly serious about doing both.  About a year ago I started planning and gathering parts to make an old FJ1100 parts bike I had into a strip dedicated bike. 

The 89 eventually morphed into this:


Mostly street/strip style mods quickly changed back to "street" settings or easy to live with on the street -- mostly a fork strap, two position dogbones, and airshifter (running off CO2 paintball bottle). 

Here's the "start" of the FJ1100 strip dedicated bike.  Not exactly the "start", but it is where things are starting this weekend!

This is with most things mocked up for the original build to sort the details for some of the bigger changes.  Still plenty of details to go. 


Everything apart again for some final tweaks, paint, and start putting it back together. 


Threw some paint at the frame and swingarm today - plan to start putting the chassis back together tomorrow. 

[ren-dog]

Either your not married or there is a fireplace in the garage 
That's one long swingarm you've got there.
Does it run the original rear shock still?
Oh, and where's the foot pegs
Hope it all works for you.

[Cloudninefj84]

Its to bad I like the twistys cause man does the fj look good stretched, Have you thought about turbo.
  Looks sweet tho, good luck with that moditis

[turbocamino]

WoW, i wish my shop was cozy like that...the mat-black on the 89 looks pretty cool...gives me some ideas for when i get tired of the original (dark blue)paint i have now. Is that a PM anodized wheel?   Also, do you have any worry's about the trans on the dragbike?...My turbo FJ 1200 was a street only ride...that decision was made after i had trans out for undercut and saw it next to a KZ and a GS trans....quite a difference. 

[andyb]

That looks like it'll 60 pretty well, now to see how it does downtrack!

[Mark Olson]

That is a great work space ya got there. I don't see the tool boxes yet, is the coffee table a motor cycle stand?

[higbonzo]

What kind of times did you/have you run.  I am going to put a 17 countersprocket on mine with a 40 rear.  I hoping to run some low 11's.   I used to run a car down the 1/4 several times a year, but it cost so much to get a car to run in the 11's.  The best I ever built was a high 13's car that I drove on the street.   Cars start getting a bit tempermental when you get them down in the 10's and 11's in the quarter.  That is why I like bikes so much, they are fast all the way around with built in dependabiliy.

Later.....

[andyb]

A 17/40 on the FJ is a good gearing at the track.  If you're running pods/pipe, it's a little tall but can work if you're light.

With a strap and lowering the back, high 10's is doable with practice.  Stock ride height and a 200lb rider can go 11.teens or so like that.

Looks like I see a lockup/slider cover above too....

Keeping the dual discs or dropping one for weight?

[fj1289]

Actually, I am married, but I'm a geo-bachelor right now (not uncommon in the military when they station you in the middle of nowhere).  I'm actually living in my father-in-law's ranch house -- finally evicted most of the mice, got rid of the bat a while back (that'll get your attention in the middle of the night!), but the spiders and rattlesnakes will continue to be occasional nuisances!  There is a garage, but I only have about a quarter of a small two car garage to use for both storage and work space.  The 89 occupies that space right now.  Very close getting that one back on the road again!

On the 89, the PM rims were just scuffed and painted (black wheel paint if I remember correctly).  Figured polishing them would have been out of place on the "Battleaxe". 

The swingarm is an FZ1 swingarm extended 0-6" and narrowed to fit the FJ frame.  It uses an R1 6" rear rim.  The rim sits all the way to the left in the arm, but is still offset to the right in the swingarm.  By taking the entire 8mm cut off the left side of the swingarm, it centered the tire in the frame.  Still have to confirm the chain alignment, but it looks like it may be good with just the TRAC offset countershaft sprocket. 
The shock is an Elka drag shock spec'd for a ProStreet Busa.  I picked it up second hand for a real good price.  Had to take the mounts out to 12mm to fit the FJ.  Originally I used the link from the 89 to convert to the dogbone style suspension linkage, but am now using an adjustable ProLink (again, second hand spec'd for a Busa).  The ProLink should make it a lot easier and quicker to dial in the rear suspension. 

Unfortunately the bottom half of my tool box is still in FL with my aircompressor.  The top half of the tool box was in the trailer that was stolen in Dec.  Lost a lot of tools and parts in that deal.  I still get upset when I go to use a tool and realize it was in the trailer too (latest things I've realized I'm missing is my "standard" sized torque wrench and my dial indicator and stand). 

Thought about going flat black on the dragbike too, but I'm planning on going with a stock paint scheme instead – thought it would add to the "surprise factor".  Anyone know a good match for the "smokey silver quartz" color on the 84?  I've picked up a couple of cans of the Rustoleum Sunrise Red to closely match the stock red color.     

[fj1289]

Andy is spot on about setting up the bike – strapping the front and lowering the rear are cheap, easy, and quickly reversed.  The first couple of times I went to the track it was at stock height.  Strapping the front and lowering the back made a big difference – not only in performance but more importantly in how it felt.  Much more controllable and predictable.  With the stock engine (with carbs, 4-1, and Dyna ignition) I only raced on 1/8 mile tracks.  My best were some 6.8's at 103mph – that roughly equates to a 10.7 or 10.8 1/4 mile.  Best run I made was with the used 1314 kit (that didn't make a real good ring seal) and a ported head with oversized valves and mild cams.  Turned a couple of 10.79's at 125mph, but this was at Bandimere (Denver, CO) when the DA (density altitude) was 7600'(about a 25% horsepower loss)!  The NHRA correction factors put that at a 9.75 at sea level.  Truth be known I'd probably would had run closer to a 10.0 a sea level – don't know how well I would have launched with the additional horsepower!  

Yes, I did have a lockup clutch (single stage) from Pro Chassis Racing along with the quick access cover.  I lost the clutch and billet basket when the trailer was stolen.  Luckily I didn't have the cover in the trailer.  Nobody (besides PCR) makes a lockup for the FJ anymore.  [I'm not real inpressed with either the quality of work nor the customer support from PCR]  I looked at converting to a Busa basket and hub, but couldn't find anyone who could machine the FJ transmission shaft spline pattern in the Busa basket.  I did find someone who could do custom heavy duty billet transmission shafts and could put a Busa nose on the FJ shaft, but was very pricey.  Especially when you added in the cost of the Busa lock up and billet basket too.  I ended up biting the bullet and went big on the clutch.  Tim Hayes machined a hybrid clutch – uses FJ hub and steels with a Busa basket and frictions.  That thing is definitely metal working porn!

I'm keeping both front rotors.  One, I can probably use a little extra weight out there, and two, I don't ever want to come up short on braking power – especially if there is a short shut down area.  Also, I've tried a single caliper with a master sized for two – downright scary – no feel to it at all, "very wooden" feeling.  A lot easier to keep the extra caliper than find the right master cylinder.

Got the frame back on the wheels!  Still have to fab some spacers for the shock linkage and the swingarm bolt.  I'll be using stock Busa rearsets mounted on aluminum brackets to set them back about 4 inches and down about 2 inches.  


16" Honda CBR rim and rotors with low profile tire.  I was able to lower the fender 1.25 inches – more clearance to the lower triple and the fairing to get lower!


Flipped the lower triple clamp so I could raise the fork tubes higher and the clamps would still properly grip the wide portion of the fork tubes.  



You can see how adjusting the LinkPro changes the leverage ratio on the shock to firm or soften the rear suspension.  Adjustable dogbones then allow you to reset the rear ride height.  

[andyb]

Nobody (besides PCR) makes a lockup for the FJ anymore.

Orient Express has one listed, is that who was supplying them?

You could alternately go by tracing a gasket on 1" plate, but it's not as nice as the quick access covers.

But good lord, that's going to be an interesting setup, hopefuly easy to dial in!

[thors ax]

All your predicted numbers look right to me.  About 10 years ago, I was looking to get a 9 (any 9) with stock swingarm, and my best run was a 10.05 1/4 at Great Lakes Dragaway WI with my 1387 on 114octane, and the experience honestly scared me so badly, I left it at that.  I was ready to put on a 3in extended swingarm (still have it, if anyone is interested) and go at it again.  Somewhere along the line, sanity took over, and I came to grips that 'someone' could do it, but it wasn't going to be me. 

With the stock swingarm, the bike just wanted to stand on the rear tire.  At 200lbs, my 10.05 resulted in a half moon bruise from the windshield in my ribs. The view looked like a long-jump skier sailing with the FJ standing on the rear tire under you.  Very intimidating and not for the faint of heart.

Good luck with the project, I look forward to living that elusive 9 through you!

Good show!

Scott J
85 FJ1387 - Thor
92 FJ1200 - 'minime' for now

[SILVERGOAT]

Dude,
       Serious undertaking. Much impressed with what you have going there. Look forward to following your build and first run. You have inspired me to find(rescue) a neglected FJ and join in the fun. Good luck and keep it going!

[the fan]

I spoke with Kent Stotz a few years ago at the indy dealer show. He was visiting with Dave from world wide bearings who had Kents bike on display.

One of the first things I noticed was that he was running the forks backwards in the clamps placing the calipers in front of the forks. He claimed that it helped with clearance and moved a little weight forward helping his launch. I don't remember how he dealt with the front fender or even if he had one. IIRC he was running both rotors and calipers.

When I worked at Holeshot (not that holeshot, sorry) we had several jockeys from Turfway Park and River Downs as customers. As you can guess we lowered a lot of bikes. Usually this was done with lowering links in the rear and sliding the tubes up in the clamps, but in several cases we shortened the travel and lowered stock forks. This was fairly easy to do on conventional damping rod forks similar to the FJ and was easily reversable.

If anyone is interested I can shorten up set of stock forks.

[andyb]

One of the first things I noticed was that he was running the forks backwards in the clamps placing the calipers in front of the forks. He claimed that it helped with clearance and moved a little weight forward helping his launch. I don't remember how he dealt with the front fender or even if he had one. IIRC he was running both rotors and calipers.

Was that on the blackbird or on the RR?  I actually met him at the track once when he was just tuning and fighting a head gasket leak, ended up holding the flashlight for him a bit.  Really nice guy.

All your predicted numbers look right to me.  About 10 years ago, I was looking to get a 9 (any 9) with stock swingarm, and my best run was a 10.05 1/4 at Great Lakes Dragaway WI with my 1387 on 114octane, and the experience honestly scared me so badly, I left it at that.  I was ready to put on a 3in extended swingarm (still have it, if anyone is interested) and go at it again.

Give me time, that's my goal   One of the tricks is setting the chassis up so that it actually lowers itself under power, making it even more wheelie-resistant.  Still back and forth on an arm, I think 4" is minimum required to get a nitrous/shifter bottle in front of the tire tough.