My 1989 FJ cutting out

[FJ120089-91]

I have a 1989 FJ with 21000 mi. Stage 3 jet Kit, Timing Advance Plate, K & N Filters, & 4to1 header & SS2R Pipe. I was running against another bike and when I Hit 6900 RPM the bike started to cut out. Later running against GTO and same thing happen. I am running 94 octane fuel from sunoco or shell. Could this be a carburetor problem or wire & coil? Is there large diameter plug wires made for this bike? Is there a hotter plug I can run? Is there a bigger coil I can run? Could it be the diaphragms or the main jets?

[andyb]

What, precisely is in a stage 3 jet kit?  Dynojet, factory pro, or otherwise?  There's a couple options for jets in each of those.  What's actually in the carbs currently?

Cuts out as in spits and splutters but eventually revs past it, or hits an absolute wall?  The former would say the mains are probably way, way too big.  The later would bring something electrical into question.

All the gears or specific ones?

Otherwise stock motor?  (If so you're wasting your money and throwing power away with that fuel.)


Not to be too blunt, but don't start shopping for coils until you actually know what's happening.

[FJ120089-91]

Dynajet and spits and sputters won't and hits wall topped out at 135. it is other wise stock.

[RichBaker]

Jet numbers??  Probably too rich.....

[andyb]

When my FJ wouldn't go past 135, it didn't hit a wall, it just was down on power (i.e., it ran out of puff, rather than hitting a limiter).  Turns out you need all four cylinders to fire (bad plug wire).

That'd have to be hilariously and comically over-rich to run out of oomph that low.  Like 10 sizes too big or something.  Look in the carbs, if that's a DJ kit it will have either 114 or 118 mains.  If you find something silly like a DJ130+, you'll have found the issue.

[SlowOldGuy]

If all you have is a jet kit and no other mods, then use the smallest main jets the DJ kit came with.  I'm running DJ110 mains in my '85 with UNI stock replacement air filter, degreed cams, Wiseco 1188 kit and stock exhaust.

In my '93 with just a UNI stock replacement filter, I'm running DJ108 mains.

Memorize this:  More fuel DOES NOT equal more power!  Also, I agree with Andy, you're wasting money on fancy fuel.

Sounds like it could be starving for fuel at high RPM.  Even with those BIG jets, the fuel tank may not be venting correctly causing a flow problem

DavidR.

[andyb]

K & N Filters, & 4to1 header & SS2R Pipe.

So unless at ridiculous altitude, will need more fuel than a 110 will support.

[SlowOldGuy]

I missed that equipment completely.  Guess I need to read more carefully.

Although the filters would work with a 110 as long as the needle position was correct.

DavidR.

[anson45]

You hit 6900 rpm and it started to cut out on you. Did it pass through and take off again at higher rpm?
Anson

[andyb]

When I bought my fj it had two problems.  A crap spark lead and comically rich jetting (DJ134's).  The spark lead meant that it made perhaps 80hp at best, and idled a bit rougher than you'd think.  At 135mph, that was all it had to give.  Once that was corrected, the damned thing about pulled my shoulders out of socket!  The retardedly rich jetting meant that it had a big soggy spot around 6krpm, but it would pull through it after blubbering for a moment.  It pulled to redline, but not anywhere near as hard as when I leaned it down to a DJ118 main jet.  The leaner jet allowed it to pull through without any farting about, either, and the plugs looked nearly white instead of dirty brown after a WOT run.