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FJ Dragbike Project

Started by fj1289, March 22, 2010, 12:39:45 AM

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Looking good so far man.  Any ideas on ducting air in to the carbs?  It almost looks like you could run a heat shield over the head and have a nice path for cooler air to come over the motor, but it'd kill cooling to the head.  Been trying to think of a way to pull it off myself and short of goofy scoops on the sides I can't quite suss it... might end up opening the sidepanels a little and putting a larger mesh'd area in them somehow, but then it's still pulling air from a low pressure area right behind your knees, at best!

Also, you strapping that?  Looks like the front fender could have the holes elongated and slid down to gain a little clearance if you need it, as it's riding high over the tire... (or is that where you're putting a few pounds of stick on wheel weights... heh!)


Have thought about ducting air to the carbs - may try it in another rebuild (will probably "improve" this thing a couple of times!).  Thinking of running from the side scoops back under the tank - since I've moved the fairing forward a couple of inches the old ducts to the head don't pass through the frame anymore anyway. 

Won't be strapping this one - had the forks cut - they are tight, no slack to strap out!  The height right now is about as low as I can get in the front due to tire clearance on the header.  The fender has already been lowered over an inch - it sets about 5/8 inch at front and 3/8 inch at rear.  I'll slot the lower mounting hole at the bottom of the lowering tab I made to even that out.  Don't want to go any closer - at the center there is even less tire clearance since the fender is curved for a 17" tire and I'm running a low-profile 16". 

Started on the engine - rod bearings are tight so I've ordered up some new sizes from Randy.  Will try to mock up the lower end tonight so I can measure the deck height and order the correct thickness base gasket.  Pics to follow - internal engine porn!

Pat Conlon

1) Free Owners Manual download:
2) Don't store your FJ with E10 fuel
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire:
Fuel line:


Pat, not planning on it - I don't think it will push oil without it.  Have thought about doing an exhaust eductor in the exhaustand hooking that up to a one way valve to draw a small amount of vacuume to keep the oil in and maybe gain a horse or two. 

Here's a comparism of the stock vice the JE pistons:

The cast aluminum big block:

Piston is .033" proud without base gasket - spec from the builder is .006 to .007" in the hole with the base gasket, so .040 copper base gasket should do the trick. 


Consider the valve between breather and pipe, yeah... but one more thing to mess with when it's time to pull the pipe off, ugh.

Motor looks good like that!


Some good progress made over the last few weeks!

Finally got the engine assembled.  Took a couple of tries to get the right rod bearings, had to order the base gasket after checking the deck height, had to clearance the #4 rod and bolt for the clutch basket, disovered the heavy duty cylinder head nuts had been with the bunch of stolen parts, etc.  Now I know it takes a month to assemble an engine once you get all the big pieces together!

The clutch setup still has potential to be a problem, but the remainder should be fairly straight forward.

The goal now is to be ready to hit the strip June 4th & 5th. 


Definitely looking like a dragbike there...
Keep it up!


Almost Done!  Feels like I've been telling myself that for 2 months!  :lol:

Plan to start it up this week and start climbing the learning curve on tuning these Lectrons.

The last few weeks had the header pipes cut and rewelded to move the entire exhaust back just over an inch to gain much needed tire clearance.  I also had to redo the right side rearset mount to get the peg above the megaphone.  Had to fab a bracket to mount the shift cylinder in order to get enough travel to let it shift through all the gears.  The shift side works - need to test the kill side.  The kill signal is based off a pressure switch on the shift cylinder vice using the shift button - should shorten the needed kill time and increase shift reliability by momentarily preloading the shift lever prior to the kill.  Mounted the CO2 bottle to the frame for the shifter and mounted an expansion bottle in the subframe to hold a more steady pressure for the shifter.  Fabbed the top end oiler and oil filter mount (additional filter for the unfiltered oilcooler pump oil I'm sending straight to the head).  Finished wiring all the accessories.  Discovered yesterday the DL-32 datalogger seems to work just fine - except it won't respond to the record commands!  Got to get that sorted before hitting the strip - too much at risk to just wing it.  Also got the chain and sprockets on.  The TRAC offset c/s sprocket lined up nicely with the R1 rear once I flipped the rear sprocket.  Who'd of thought a 140 link chain would have ended short!   

Niggling little details remaining include setting up the clutch with the baseline tuneup, fab the exhaust mount, fab and mount a breather bottle, mount the shift/launch light, rebleed the brakes and clutch, sort out the data logger, gas it up, pre-oil the top end, and crank it!  Of course, next weekend I'll probably have to be out of town... :dash1: 


Looks great!

Going with a dragtec instead of the usual shinko?  Be interested to hear how that works, some racers have said that it's really a question of which track you usually go to determining which hooks best.  If you go with a shinko, skip to the usoft though, the base version takes a long long burnout or it's greasy.

Gotta love the look with the big arm on it and a sidewinder  :nyam2:


Actually it's a Michelin Power Race (became the Power One) - about 18 months old or so.  I had to buy it before I went to Iraq so I could roll it into a storage unit!  I think I'll try the new Shinko drag radial after this is done. 

It's setting a little high in these pics - I need to cut this sidestand even more (the foot is going to end up just below the tab for the spring!) - maybe I can use the piece I cut out to lengthen the side stand for the 89 so it doesn't lean as far!  I should be able to drop the front end about and inch, the rear will depend on what it likes - try to balance linkage rate, swingarm angle, weight transfer, and clutch tuneup.

Forgot from the earlier post - had a big issue when I bolted in the clutch basket - the rear most rod bolt on the #4 rod (Carrillo with the bolt on bottom) hit the clutch basket.  Ended up having to grind the bolt head for clearance.  Not a lot of fun making that decision - or doing the work!  Took three tries to get enough clearance!

Looks like on a later rebuild I may need to get the shock shortened so the link doesn't hang as low. 

How's your FJ coming along?  Got her fired up yet?


Flying Scotsman

Awesome looking fj,cant wait to hear some track #'.s
1984 FJ1100
1985 FJ1100
1990 FJ1200
1999 GP1200 (165 + hp)


Not yet, got busy with work and such.  Soon, soon... need to fix an issue with the coils, and do some finish assembly stuff yet.   Not nearly as pretty as yours, looks quite the streetbike... :)


life without a bike is just life


Well, worked every available hour last week to get the bike finished up.  Cranked it up for the first time on Wednesday!  Cranked right up - VERY impressed with the power from the ballistic battery.  This was kicking over the 1447cc high compression motor with the stock starter!  Needed to wait until the top end was pre-oiled and the carbs set up for idle before swapping in the cashio super starter - would require too much extended cranking for the high power starter (and evidently the solenoid too -- see below!). 

Fought some oil leaks - one at the oil filter case, and one at the top end oiler (intake cam of course - can't get to it with the engine in the frame!).  Finally got those sorted (new o-ring on the filter case and made up braided lines for the top end oiler).  Then had a leak at the exhaust cam -- and learned a critical lesson.  I got hold of a couple of banjo bolts that had TAPERED threads - like what a pipe fitting would use.  The issue is the first 4 threads or so are undersized -- perfect recipe to STRIP out the head (or caliper or master cylinder) that you're threading it into!!!  You've been warned!   :mad:  Was able to save it by using a slightly longer banjo with normal threads! 

Unfortunately that took up most of Saturday, so I got to the track a bit later than planned.  Still enough time to get 3 or 4 passes in though. 

Results -- DENIED!  Evidently the stock stater solenoid (or relay if you prefer!) was not up to the task.  It failed in the worst possible way - partially shorting out.  It wouldn't release the starter, but it wouldn't pass it full power either - perfect way to burn up a starter, which I'm pretty sure it did.  This happened after I went through tech, but before making a pass.  I'm really hoping it didn't hurt the battery!

Looks like the smart move is to use an automotive starter solenoid (probably the "universal" Ford) and try it again next weekend!


Pure inspiration,i love this build! :yes: