Keihin Flat Slides

[JohnnyTheCraneGuy]

Does anyone have any recommendations with Keihins? I'm looking at acquiring a pair that I could use when I swap to the bigger pistons and maybe cams. Another reason too is I'vw seen them come up on facebook here and there for a Y\FZR750, a kehins FCR39. But from what FJ1289 was telling me, those are set up for downdraft rather than side. Another was listed as a CR31-3051 for hondas CBFs, I messaged the owner and he said they were down draft as well, so I am scratching my head a little bit here.

If anyone has experience with this and could share the specific models I would need, that would be a huge help for me.

[red]

Johnny,

Can't help with specifics, but I would send Keihin an email direct, and see what they advise.  Website:
Keihin

[JohnnyTheCraneGuy]

Right on Red, thank you sir!

[Pat Conlon]

77-85-77 is the carb spacing you want to fit our FJ's.

The Mikuni TMR36 or 38's roller flat slides have a choke for cold starts
https://www.bikeside.de/MIKUNI-TMR38-flat-slide-carburetor-for-all-KAWASAKI-GPZ-900-R-GPZ-1000-RX-and-YAMAHA-FJ1100-1200



The more expensive Keihin FCR39 roller flat slides do not have a choke.
https://www.bikeside.de/KEIHIN-FCR39-flat-slide-carburetor-for-all-GPZ-900-R-GPZ-1000-RX-ZR-1100-Zephyr-and-FJ-1100-FJ-1200




 

[Bozo]

If you are on a budget I bought a set of 2000 model 37mm FZ1 carbies for my FJ with some engine works, they fit direct just require jets. They have bell mouths and a much better setup than the standard carbies. Depends on the day I got mine for A$250 delivered - BARGAIN.

A huge improvement on the standard

[Pat Conlon]

If you are on a budget I bought a set of 2000 model 37mm FZ1 carbies for my FJ with some engine works, they fit direct just require jets. They have bell mouths and a much better setup than the standard carbies. Depends on the day I got mine for A$250 delivered - BARGAIN.

A huge improvement on the standard

Thanks for the tip....IMO for a street bike, CV carbs are the way to go.
My 1380 struggles on the top end with my oem 36mm FJ CV carbs, so I'm always looking for a bigger carb for better top end airflow. A 37mm carb should help.

A couple of Q's
The FZ1 cylinders are spaced different than the FJ, so how did you get the FZ1 carbs spaced out to 77-85-77?
How did the throttle shafts mate up or did you have to use the FJ throttle shafts?
Are there any write up's or posts on this mod?
I see several US eBay listings for 2001-2005 FZ1 carbs, but none for the 2000 year, any differences?
Example: https://www.ebay.com/itm/265996536368
Is there a difference in the sizes between the Australian FZ1 carbs and the US models?
I wouldn't surprise me if the US models were choked down to 36mm.

Thanks again.

Pat

[Bozo]

If you are on a budget I bought a set of 2000 model 37mm FZ1 carbies for my FJ with some engine works, they fit direct just require jets. They have bell mouths and a much better setup than the standard carbies. Depends on the day I got mine for A$250 delivered - BARGAIN.

A huge improvement on the standard

Thanks for the tip....IMO for a street bike, CV carbs are the way to go.
My 1380 struggles on the top end with my oem 36mm FJ CV carbs, so I'm always looking for a bigger carb for better top end airflow. A 37mm carb should help.

A couple of Q's
The FZ1 cylinders are spaced different than the FJ, so how did you get the FZ1 carbs spaced out to 77-85-77?
How did the throttle shafts mate up or did you have to use the FJ throttle shafts?
Are there any write up's or posts on this mod?
I see several US eBay listings for 2001-2005 FZ1 carbs, but none for the 2000 year, any differences?
Example: https://www.ebay.com/itm/265996536368
Is there a difference in the sizes between the Australian FZ1 carbs and the US models?
I wouldn't surprise me if the US models were choked down to 36mm.

Thanks again.

Pat

Pat, I am sure the spacing was ok, they fitted direct into the standard intakes boots, The throttle cables are FJ , the biggest problem was the vacuum tube coming out from the top of the carbs. I used see through PVC tubes with a spring fitted internally to prevent sharp bends, these were directed via "Y" piece into a small breather.
This is done to clear the fuel tank and fuel filter.
Funny part is the dual filters from RPM/Uni filter stretch over the intakes "without clamps = 58mm".
The carbies are a lot shorter than the standard and the intake is a larger bell mouth for better breathing.
My Webcams, ported head, 1219 wiseco's and Marving pipe aren't the hottest but this arrangement puts out a 140 RWHp on Dyno. The CV's are fantastic (I can feel the difference) and better still this is more economical than standard 36mm.
If required when I pull the tank off next I'll post photos. I can go through my log and suggest slide needles jets etc.
Maybe 2000 FZ1? just any FZ1 with carbies have 37mm (in Australia), later have fuel injection.
You can clearly see the difference on the intakes between the 36mm and 37mm

Was it worth doing, HELL yes especially when I got these for A$362 delivered - $250 I previously posted  (they were like new), now they appear to be more expensive

[Pat Conlon]

Thanks for the info. I did confirm the carb spacing is different. The FZ1 engine has the cam chain on the side vs. the middle cam chain on the FJ engine.

Yes, I would love to see how those carbs fit!
Maybe those FJ rubber intake boots stretch?

Thanks again.

Cheers

Pat

[Bozo]

Thanks for the info. I did confirm the carb spacing is different. The FZ1 engine has the cam chain on the side vs. the middle cam chain on the FJ engine.

Yes, I would love to see how those carbs fit!
Maybe those FJ rubber intake boots stretch?

Thanks again.

Cheers

Pat

Pat, if the spacing is different its not enough to worry about, I had these off a few times for tuning with no problems pushing them in. I'll see if I can do a quick write up with photos.

[Pat Conlon]

Fuck mate, I hate calling you Bozo, but....

I remember about 10-12 years ago a long time forum member David Raforth mentioned FZ1 carbs for the FJ....
He has both bikes.
I contacted him and he confirmed....the FZ1 carbs fit the FJ, but he never put them on...

Look at the pictures he took showing how the FJ carbs (left) line up with the FZ1 carbs (right)


Looks perfect to me....

Bozo, are these fuel pump carbs, or gravity flow?  Yes, when you get a chance, some info. on jetting would be appreciated. I now have a new fall project.  I'll be sure to schedule dyno time in Phoenix to assure tuning.

Thanks again amigo!   Cheers. Pat.

[Bozo]

Pat you were right I did fix the spacing , going from memory. At the time I mentioned the carby change but no-one appeared to be interested so I didn't do a write up BUT it can be done if you are a mechanically minded person -
1. I took the two rods that hold the carbies together (very long bolts) BE CAREFULL I didn't realise one end is threaded into the carby (I stuffed this up and had to use a fully threaded M6 SS rod). At this stage all four carbies will be separated
2. replace the OEM spacers with correct aluminium spacers. The fuel tubes between the carbies should have enough movement to cater for the change. There are small spacers between carbies 1-2 & 3-4 I removed these (from memory).
3. Once the spacing has been done, I did some changes within for a quicker CV response by drilling the hole at the bottom of the slide See "Ivans Jet kit" for modifications. I couldn't buy the kit in Australia so I compromised with some guess work. The slide springs I had are standard - no modification.
4. Running an AFR meter to exhaust my jetting was Pilot=17.5, Starter jet (thats what OEM they call it)=45, Main = 135, idle screw 4 Turns out. Slide needles 1-4 5D130 and 2-3 5D129 This is a start setup NOT the final for other engines. Not sure where the needle clip was fitted but start with the middle position.
5. the hoses on top for Vacuum slides, (these carbies work differently to the FJ that depends on intake to lift slide, FZ1 depends on vacuum to lift the slide) needle to be more flexible to fit under tank with a spring inserted to prevent the tube from "kinking" blocking air flow.
If there are any other mods I don't remember these at the moment (these were done a few years ago). Does sound like a lot of work but its not as bad as it sounds AND well worth the results they give.

[Bozo]

Fuck mate, I hate calling you Bozo, but....

I remember about 10-12 years ago a long time forum member David Raforth mentioned FZ1 carbs for the FJ....He has both bikes.
I contacted him and he confirmed....the FZ1 carbs fit the FJ

Look at the pictures he took showing how the FJ carbs (left) line up with the FZ1 carbs (right)


Look perfect to me....

Bozo, are these fuel pump carbs, or gravity flow?

Haha long story about the Bozo name (I'm a bit of a clown)

Thanks for you info, I did change the spacing a bit but couldn't remember why I changed it at the time (no I'm not losing it).
These carbies are pump.
I you are in the US they are not badly priced, in Oz the courier sometimes can be as much as the item itself but I managed to find a seller in OZ.
I now wish I did a write up when I fitted these.

[Pat Conlon]

Thanks again mate... those are some big ass vacuum hoses...what is the source for that much vacuum?

I assume the throttle position sensor and wires can be removed and blanked off.

Recall any special float settings?

Where is the idle set at?

 I didn't see the typical  throttle shaft adjusters for balancing the carbs.

[Bozo]

Thanks again mate... those are some big ass vacuum hoses...what is the source for that much vacuum?

I assume the throttle position sensor and wires can be removed and blanked off.

Recall any special float settings?

Where is the idle set at?

 I didn't see the typical  throttle shaft adjusters for balancing the carbs.

No need for the throttle sensor
Float level was 14mm mine are slightly richer 13mm
Vacuum hoses need to be big as the slides depend on good breathing for quick response, you could try smaller and they might work??
I now see that the spacing was ok but for some reason I pulled mine apart so I thought I changed the spacing- mystery of life is solved. If the spacing was correct the fitting is easy and probably no more then tuning a set of flat slides, as you said the CV's are probably better for road use.
I'm not sure if the heat plate required a few holes to allow the throttle to turn without hitting the plate.
The butterfly adjusters are the same as on the FJ.
The biggest problem is if the idle jets need adjusting the Alternator makes it hard with little clearance so the carbs might need removing but usually once set they stay good. mine are 4 to 4.5 turns out.
Also you can position the idle screw knob just under the frame so it can be adjusted without jamming screw drivers under the carbies.

With the motor you have these would be perfect, you without doubt notice these. Let me know if you need more info, without ripping the carbies apart I'll help out.

[Pat Conlon]

Thanks amigo, you sure can't argue with the price....

Last couple of questions:

Did you use Ivan's jet kit or Mikuni jets...or a combo?

Where did you get the vacuum from...gotta be the intake manifold some where...

I'll have to finally get off my ass and convert my gravity fed 84 over to a fuel pump.

Cheers

Pat