5000 RPM

[Tuned forks]

So I'm still really new to this motorcycle platform.  There are a number of idiosyncrasies that are being figured out.  However, one has me intrigued.  As you might have guessed, it's related to high rpm.  When I grab a big ol' fistful of throttle and the engine hits 5000, it's like Han Solo engaging hyperdrive on the Millennium Falcon.  The first time I felt it, the increase in rpm acceleration was so strong I thought the clutch was slipping but the bike was pulling hard.  I backed off, slowed down, checked that everything was working correctly and hit it again.  Same thing, 5000 and it revs really quickly and pulls like the locomotive you guys keep writing about.  The hit is so hard and sudden that it still surprised me this past Saturday.  I have already discussed with Randy my carb/jetting issues.  In a nutshell, the FJ has V&H 4 into 1 exhaust with Uniflow individual air filters.  The plugs are burning so lean they are white or really light grey.  This is the way the bike came to me. 

So maybe I'm just hitting a throttle point/rpm that is an enrichment point and the air fuel ratio becomes what it should be.  Anyone else has this type of rpm/throttle response?

[rlucas]

So maybe I'm just hitting a throttle point/rpm that is an enrichment point and the air fuel ratio becomes what it should be.  Anyone else has this type of rpm/throttle response?

Congratulations. We have a name for that phenomenon.

It's called "The Kookaloo Zone", and you've found it. 


rossi

[ribbert]

The FJ's certainly come alive around 6000rpm but the difference you describe sounds a bit much. The high end surge isn't that marked. Maybe it's bogging down at lower revs?

Noel

[Pat Conlon]

 The plugs are burning so lean they are white or really light grey.  This is the way the bike came to me.  

Hey Joe

White/grey plug color is common: http://www.fjowners.com/index.php?topic=11690.0

As part to the emissions system, when the throttle plates close, the higher vacuum signals an ignition advance to the igniter which flashes off any unburned hydrocarbons in the cylinder, thus your white plugs.

Your FJ should pull strong at all rpms. Who knows what jetting the PO installed? New pilot/main jet's are cheap, easy to install, I would start with new jets so you know exactly where you are in the tuning process..
Yes, there is a mid-range/high end surge with our FJ's (aka Kookaloo zone) but when this happens, keep an eye on your tach needle.
If you see the tach needle jump then 2 things could be happening: 1) You are losing traction on your back tire and it's spinning or 2) your clutch is slipping,
We have a fix for a slipping clutch condition: http://www.fjowners.com/index.php?topic=1808.0

[Country Joe]

I know that my old 1990 FJ with the full suite of V&H hop up parts had a much more ferocious top end rush than my mostly stock 1993 FJ has. I believe that the 4 into 1 has a very pronounced effect on the power band as compared to the OEM exhaust.

[Tuned forks]

[/quote]
Congratulations. We have a name for that phenomenon.

It's called "The Kookaloo Zone", and you've found it.  


rossi

[/quote]

I've been Kookoloo'ed then.  Kinda disturbing for someone that lives in SF.

Ribbert, seems that the phenomenon is part of the FJ personality then but perhaps mine is enhanced if the air/fuel ratio is not correct at lower revs.

Country Joe, (could be my name after I retire) the V&H pipes were a PITA when I changed the oil.  Another winter expense is the RPM exhaust although I do like the V&H muffler.  I have the same muffler on my FZR 1000.

Pat, I have read many of your posts.  I recall running across the ignition timing mechanism although I didn't realize it was for emissions.  Randy has also told me that US spec models were lean from the start.  The engine doesn't pull as smoothly as it should from idle to 3000rpm.  I'm thinking the mods have made the engine extra lean.  My plan is when the weather turns cold and wet, to take it to RPM or mail my carbs to them.  BTW, the bodywork vibrates/buzzes around 3000 until 4 or 5000 depending on throttle input.  Gets kinda annoying too.  Even with a helmet and earplugs I can hear it buzzing.

I kinda doubt I was spinning the rear tire but who knows.  I'll have to have one of my buds follow and watch the tire.  Clutch slippage was my first thought and was reinforced when I read your treatise on clutch limitation and clutch mods.  34k miles on the bike but I don't know if they were hard miles or not.

[PaulG]

The engine doesn't pull as smoothly as it should from idle to 3000rpm.  I'm thinking the mods have made the engine extra lean.  My plan is when the weather turns cold and wet, to take it to RPM or mail my carbs to them.  BTW, the bodywork vibrates/buzzes around 3000 until 4 or 5000 depending on throttle input.  Gets kinda annoying too.  Even with a helmet and earplugs I can hear it buzzing.

I learned through this site if your carbs are out of balance you can get some vibrations around 3000rpm. You can feel it up through the seat.  Also put on your list this winter to remove the front rubber engine mounts and clean and grease them.  Seized up mounts will cause numbing vibes after 4000rpm through the bars.  You can also feel it in your feet if you press your boots into the pegs while riding.

You can make up a tool using threaded rod, washers, and nuts.  There are a few posts in the maintenance files section re this, even a drawing for the tool.  Just make sure you make up several tools. I went through 6 or more due to stripping the threads on the rod cuz my mounts were never serviced by previous POs.  The grease hardens into taffey not allowing the mount to rotate and absorb the vibes.

Once done you will notice a big difference at the higher RPMs.  As far as the buzzing body work... check all your fairing mounts and make sure they're all there with the bushings on the lower ones behind the air scoops.  I've tried putting rubber washers everywhere with limited success.  My right side of the upper fairing buzzes like crazy esp at idle, while my left side is fine.  Something I'll chase this winter also.

[Pat Conlon]

Good stuff Paul However, Joe has a 1990 so the front engine collar service does not apply to him.

Hey Joe, do us a favor, go to your Profile and put in your signature line that you have a 1990 FJ1200. That will helps us, help you.

Cheers

[PaulG]

Good stuff Paul However, Joe has a 1990 so the front engine collar service does not apply to him.

Cheers

DOH! I even double checked Joe's intro to see what year he had and still got it wrong.    It's only been mentioned a few hundred times on this site, but eventually it will sink in what years are different from each other. Even though there's barely any difference in the scheme of things.

I think I learn more stuff on this site than I did in high school.    But back then my only concern was how much money I could scrape together for beer (and such...) for the next weekend.    ... and the next.. . and the next....

[Tuned forks]

Yessir Mr Conlon, done and done.  Even added a picture.  Whoo boy I'm getting fancy schmancy here. Lol.

Paul, I agree about synching the carbs and the loose bodywork.  I think the side fairing button head allen bolts are too long.  They seem to be bottoming out before tightening the bodywork.  The FZR is very similar so I'm familiar with how it's supposed to be.  I read elsewhere on this site that vibrations can be out of synch carbs.  I see RPM sells a very nice synching tool.  I'm cool with buying it cause both bikes need the carbs synched.

I was wondering if the earlier solid mounted bikes had vibrations and if that's why Yamaha went to rubber mounts.

Paul, I've learned a ton on this site and I've only been here a couple of months.  Amazing library of FJ information.  Are you sure that beer was the ONLY thing you were spending money on in high school? 

[PaulG]

Are you sure that beer was the ONLY thing you were spending money on in high school? 

That's where the "(and such)" comes in....

[Mark Olson]

Yessir Mr Conlon, done and done.  Even added a picture.  Whoo boy I'm getting fancy schmancy here. Lol.

Paul, I agree about synching the carbs and the loose bodywork.  I think the side fairing button head allen bolts are too long.  They seem to be bottoming out before tightening the bodywork.  The FZR is very similar so I'm familiar with how it's supposed to be.  I read elsewhere on this site that vibrations can be out of synch carbs.  I see RPM sells a very nice synching tool.  I'm cool with buying it cause both bikes need the carbs synched.

I was wondering if the earlier solid mounted bikes had vibrations and if that's why Yamaha went to rubber mounts.

Paul, I've learned a ton on this site and I've only been here a couple of months.  Amazing library of FJ information.  Are you sure that beer was the ONLY thing you were spending money on in high school? 

The VH pipe seems to enhance the Kookaloo zone ... I run one myself and enjoy the burst of power .   
If you want to know my carb setup send me a PM.

[Tuned forks]

Thanks Mark.