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How does your FJ sound?

Started by petetb154, July 21, 2015, 05:47:49 PM

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Arnie

From your description of what you've done to the engine and the heat of Phoenix, you 'might' have a bit of detonation.  Are you running Premium or Regular U/L (with ethanol) ?
My stock '91 runs fine on 91 octane regular UNLESS its HOT here (and we do get Phoenix temps occasionally) And, I'm able to avoid ethanol fuel in Victoria.
Also, you don't mention if you've lifted the carb slide needles. You can do this either by moving the clip or adding 0.5mm (0.020") washers under the clip if you have (US) single groove needles.
The needles will make much more difference to how your bike feels in normal street riding than either jets or pilots being changed.
When I put DualPod UNI filters on I went up to 115 mains and lifted the needles by 0.5mm

FJ1100mjk

Quote from: petetb154 on July 22, 2015, 10:36:33 AM
Any other thoughts?

Yes. Put a bunch more miles on it. Go back and check your valve clearances and carb synch again.

Careful, because at some point, the Conlon mantra may need to be invoked. "Just ride the fucker."
Platinum Zircon-encrusted Gold Member

Iron Balls #00002175
www.ironballs.com


petetb154

Quote from: Arnie on July 22, 2015, 11:13:59 AM
From your description of what you've done to the engine and the heat of Phoenix, you 'might' have a bit of detonation.  Are you running Premium or Regular U/L (with ethanol) ?

Regular U/L without ethanol, just 'cause it's what I had in the garage. I'll use premium on next tank and see.

Quote from: Arnie on July 22, 2015, 11:13:59 AM
Also, you don't mention if you've lifted the carb slide needles. You can do this either by moving the clip or adding 0.5mm (0.020") washers under the clip if you have (US) single groove needles.
The needles will make much more difference to how your bike feels in normal street riding than either jets or pilots being changed.
When I put DualPod UNI filters on I went up to 115 mains and lifted the needles by 0.5mm

I've got adjustable RPM needles on the middle position. Raising the needles may be the perfect fix, but I think I'll just systematically go through a complete jetting exercise, starting at the mains and working my way down to the air screws. Might use plug reading method, might rent some time on a dyno. But now that I have heard the way it is *supposed* to sound, I have the motivation to tweak it a little.

Thanks!

Brian Peterson
1987 FJ1200

1tinindian

Quote from: petetb154 on July 22, 2015, 10:24:01 AM
Quote from: 1tinindian on July 22, 2015, 12:25:03 AM
Quote from: petetb154 on July 22, 2015, 10:24:01 AM
Quote from: 1tinindian on July 22, 2015, 12:25:03 AM
Here is what my 91 FJ1200 sounded like a few years ago on the dyno.

https://www.youtube.com/watch?v=icuv7DZFS4c

That sounds great! Smoother, like I remember. Definitely more crisp than mine. Are you running the stock air box in this video?

Another note, it cracks me up that he scrubbed a little speed off w/ the front brake after hitting red line.. Must be a forced habit from doing this on the road!

I have the UNI pods on it.

I thought he was full of it, when he said, "Needs a tune up". when in reality, the carbs were a fresh rebuild by Randy at RPM, the valves were adjusted, new plugs, and the pods installed.
If anything, it needed the coil relay mod done to help with high rpm performance.

Trust me, it runs very nice and I'm not always making adjustments, I just ride the damn thing!
"I want to be free to ride my machine without being hassled by the "man"!
91 FJ1200

Pat Conlon

Quote from: petetb154 on July 22, 2015, 12:16:36 PM
I've got adjustable RPM needles on the middle position. Raising the needles may be the perfect fix, but I think I'll just systematically go through a complete jetting exercise, starting at the mains and working my way down to the air screws. Might use plug reading method, might rent some time on a dyno. But now that I have heard the way it is *supposed* to sound, I have the motivation to tweak it a little.

Hey Brian, I also live is the desert (just west of you) and I can tell you that in hot weather, at close to sea level, my bikes run much better with premium gas.

Before carb tuning: Make sure your valves are adjusted. Make sure your floats are set. Make sure your carbs are synch'ed. Fresh plugs.

You are on the right tract on the order your carb tuning:

First: The main jets. The correct sizes for WFO engine performance.

Second: the needle position. You already have adjustable needles so go ahead and try raising the needle position one full notch first. If this makes things better, then you can always go back and try fine tuning with the 1/2 step shims that Arnie suggests. The shims are equal to 1/2 a notch on the adjustable needles. Remember that your bike is running on the needles the majority of the time. Having the needles raised too much will waste gas, but it is still safer than running too lean, especially in our hot climates.

Third: Select your pilot jets. Start with #40 pilots and go up from there.

Fourth: Set your air/fuel idle jet screws on a warm bike. Use the blip test. Start your screws 2.5 turns out and go from there.

Fifth: Adjust your idle speed. 1,000 rpm works well for me.

Do your carb tuning following the above sequence. If not, you will drive yourself crazy. Trust me.  
.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

petetb154

Quote from: 1tinindian on July 22, 2015, 01:09:21 PM

I thought he was full of it, when he said, "Needs a tune up". when in reality, the carbs were a fresh rebuild by Randy at RPM, the valves were adjusted, new plugs, and the pods installed.


I'm going to go out on a limb and guess that he sells tune-ups. He's FOS! You bike sounds good and makes very respectable RWHP. Congrats.
The coil mod is something I hadn't thought of, that could impact how smooth the bike runs..  That's something easy to test.
Thanks.
Brian Peterson
1987 FJ1200

petetb154

Quote from: Pat Conlon on July 22, 2015, 01:20:25 PM
Hey Brian, I also live is the desert (just west of you) and I can tell you that in hot weather, at close to sea level, my bikes run much better with premium gas.

Very cool. We just moved here from Nebraska a year ago and the summer heat is.. well... something!  :diablo: In fact, I might have to buy an oil cooler. :-) I haven't explored the best street bike roads in the area yet, but I do know that this place is a dirt bike & Jeeping Mecca!

Quote from: Pat Conlon on July 22, 2015, 01:20:25 PM
You are on the right tract on the order your carb tuning:

Yup, top to bottom is the only way to go. It seems like a lot more work at first, but as they say, there is always time to do it right the second time. I just needed this conversation to get me motivated to do the work.
Brian Peterson
1987 FJ1200