New engine chirping and running on 2 cylinders

FJ carbs. The engine is identical though, not sure why it would flood. I did try screwing the pilot screws all the way down to lean out the mixture, didn't do nothin'.

Will try the plug wire swap mentioned above and report back. Busy day today so may not have time to do much bike work.
 
Brand new spark plug wires did not change a thing, nor did swapping 2 & 3. Still running on only 1 & 2, PLUS the issue I had when I was running the FJ rectifier is back - 2 seconds or so afer starting, this whirring sound starts building up, and I'm pretty sure it's coming from the starter. Sounds like it's being spun up after the engine comes to life.

Oh ****. One thing I haven't changed over to a Radian component is the diode. Looking at the wiring diagrams, the Radian has an extra wire running straight from the diode to the CDI. The diode shares the same pin as the sidestand relay - I've actually grounded that pin out because the bike wouldn't start at all otherwise. I think I may have found my spinning starter issue, if not my entire problem.

This is fun.
 
So even with a known good spark plug wire #2, it did not work on cylinder #3. But wire #3 worked on cylinder #2 right? Frustrating, but you're making progress.

The previous owner had the bike running so assuming valve clearance is correct (and you have good compression on all 4 cyl), and we know ignition timing is correct, and you have spark to all 4 cyl...we need to look closer at the carbs.

Did anything get knocked off or loosened when installing the carbs?

What are your carb settings on 1&2 compared to 3&4?

Also, do you have a carb sync tool?
 
Last edited:
Valves and carbs are fine. Now I think I just have electrical gremlins caused by an incomplete wiring job.

Looking at FJ and Radian schematics again. FJ has the starter switch AND relay connected to the same diode pin. Radian uses two separate pins. Hmmmm.

My brain hurts.
 
Last edited:
Gonna try running a wire from the CDI's safety switches pin to the corresponding pin on the diode. That connection doesn't exist at the moment.

If it sounds like I'm haphazardly trying random stuff, it's because I am.
 
So disconnecting the ground from the CDI's sidestand/safety pin brought me back to where I was before I started this thread - one spark then no start/ignition shut off. That was expected.

Then, connecting the CDI's sidestand/safety pin to the correct diode wire brought me back to where I was when I started this thread: running on cylinders 1 & 2, chirping and starter spinning up and whirring.

I have a feeling y'all are giving up on me. I ain't mad, this is a bit of a mess.
 
Don't be discouraged Matt. Troubleshooting can be a real PITA. You may not feel like you've made progress, but think of all the different checks that you have done that you can cross off the list.
 
True. Thanks for the moral support. I do feel like I'm slowly zeroing in on the issue. It has to involve the starter wiring and/or the diode somehow.

Here's a vid of the very first "successful" start earlier this week - you can hear the whirring sound start around 0:22:

[video=youtube_share;9ZuoEZYnTew]https://youtu.be/9ZuoEZYnTew[/video]
 
Last edited:
That whirring noise slowly builds while the revs remain constant. Starter shouldn't be able to do that. Could that whirring be the oil pump once pressure builds (assuming it uses a ball on a seat to set pressure)? Did you mention something about a missing oil cooler earlier?

EDIT:
Does it have a fuel pump? It sounds like the noise kept going after the engine shut off the first time.

EDIT 2:
It definitely kept whining until you hit the kill switch (or opened the throttle?) and then it stopped.
 
Last edited:
No fuel pump. I'm pretty damn sure it's the starter, and I think I just found out why it does that... according to the manual, the Radian's starter switch is wired backwards from that of the FJ! So when I let go of the starter switch, the starter relay gets triggered? although it seems like the starter wouldn't engage when I first push the button...
 
Last edited:
Lookit... this is the FJ's schematic:

75898c11c8f8edc959c26c89d41ad029.jpg


See how the ON position is on the right hand side of the connector? Now let's look at the Radian schematic (which is barely legible - Haynes' fault, not mine):

1e883902341c3bb3d84f92e06c4bfc74.jpg


The ON position is on the middle pins, is it not?!?
 
Wait, this doesn't affect me at all since the starter switch and relay are all FJ. Gah. I got a little excited there.
 
wire colours stayed the same, it looks like position in the harness may change.

EDIT: nvm, update already posted.
 
hey matt, still here. at a loss which way to go other than wiring. took a look at xj forum w/o any luck.

my brain hurts too lol. and its motogp this weekend. I'll continue looking on the net for someone who has made this swap successfully along with some wiring tips.

mechanics teaches perseverance. You will get this figured out. this is interesting ...
 
Matt Rain said:
FJ carbs. The engine is identical though, not sure why it would flood. I did try screwing the pilot screws all the way down to lean out the mixture, didn't do nothin'.

Will try the plug wire swap mentioned above and report back. Busy day today so may not have time to do much bike work.
Click to expand...

pilot screw is an air screw? not uncommon. if it controls air flow screwing it in WILL RICHEN the jetting. carb diagram look/see? you may need to do the opposite and screw out. this would sure be nice if its a fix.

edit; maybe leave the spark plugs out overnight to allow the cyl's some time to air out and dry? then try to start with the pilot screws out 3 full turns (from gently bottomed out)?
 
Last edited:
Pilot screws are fuel screws on this bike.

Carbs are Mikuni BS32s, original to the FJ. I really don't think this is a carburetion issue though.

I'm trying to see where the FJ's wiring might conflict with the Radian's. I'm quite possibly the first person to attempt retrofitting a late-model Radian engine into an FJ600. An early-model Radian engine would've been plug and play. #facepalm

Anyway I'm not touching it again this weekend, am out of town and will be watching the Czech GP as well tomorrow AM. Thanks again for the help and enjoy the races!


Sent from my iPhone using Tapatalk
 
So I found a bad diode in the diode block - the one in the neutral switch circuit. (Actually the diode itself tests out okay if I measure directly at the PCB solder joints, but it's open both ways when checking at the pins.) Could that be my issue? Seems unlikely that it would make the starter spin up after starting the engine, but it might account for the misfiring plugs? I read something about the spark advance being different in neutral vs. in gear.

Anyway, I've got a new diode block on the way, let's see what happens.
 
You must log in or register to reply here.

Back
Top Bottom