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Swiss bike restrictions

Started by brandane, April 22, 2021, 01:40:01 AM

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brandane

April 22, 2021, 01:40:01 AM
Hi, does anybody know what the Swiss did to trestrict the HP? I have a Swiss one and it's terrible. It has a new non restricted CDI, carbs have been rejetted, there are no restrictions in the inlet rubbers or the exhaust headers but it's still gutless.
Any (polite) suggestions?

Old Rider

#1
April 22, 2021, 02:28:44 AM
Quote from: brandane on April 22, 2021, 01:40:01 AM
Hi, does anybody know what the Swiss did to trestrict the HP? I have a Swiss one and it's terrible. It has a new non restricted CDI, carbs have been rejetted, there are no restrictions in the inlet rubbers or the exhaust headers but it's still gutless.
Any (polite) suggestions?
Hi and welcome to the forum!
Are you sure that the intake rubbers are not restricted just posting a pick that shows a restricted intake.

TomJK

#2
April 22, 2021, 03:16:28 AM
Hi
Besides intake rubbers, also exhaust has smaller diameter downpipes. or some restictions welded in...
Cheers, Tom.
Past bikes : BMWR90-S,BMW R100CS, Ducati 900SD, Kawasaki GPZ600,Yamaha FJ1200,Kawasaki ZZR 1100 (4x),Kawasaki ZZR1200, Honda CBR1100XXX,Yamaha Thunderace, Kawasaki ZX10R (3X),
Aprillia Falco,Honda CBR600F4I, bikes today : Kawasaki ZX10R (C1, the best!),Yamaha FJ1200, soon to come Kawasaki Z900.....

brandane

#3
April 22, 2021, 04:34:07 AM
Hi, I already checked both, I even bought spare carb rubbers to change over, only to find they were exactly the same. Exhaust headers aren't restricted either.

TomJK

#4
April 22, 2021, 04:37:38 AM
Hi
Ok, also air inlet is restricted, that is the snorkel is smaller diameter.
Cheers, Tom.
Past bikes : BMWR90-S,BMW R100CS, Ducati 900SD, Kawasaki GPZ600,Yamaha FJ1200,Kawasaki ZZR 1100 (4x),Kawasaki ZZR1200, Honda CBR1100XXX,Yamaha Thunderace, Kawasaki ZX10R (3X),
Aprillia Falco,Honda CBR600F4I, bikes today : Kawasaki ZX10R (C1, the best!),Yamaha FJ1200, soon to come Kawasaki Z900.....

Sparky84

#5
April 22, 2021, 05:23:14 AM
Quote from: Old Rider on April 22, 2021, 02:28:44 AM
Quote from: brandane on April 22, 2021, 01:40:01 AM
Hi, does anybody know what the Swiss did to trestrict the HP? I have a Swiss one and it's terrible. It has a new non restricted CDI, carbs have been rejetted, there are no restrictions in the inlet rubbers or the exhaust headers but it's still gutless.
Any (polite) suggestions?
Hi and welcome to the forum!
Are you sure that the intake rubbers are not restricted just posting a pick that shows a restricted intake.
Quote from: brandane on April 22, 2021, 04:34:07 AM
Hi, I already checked both, I even bought spare carb rubbers to change over, only to find they were exactly the same. Exhaust headers aren't restricted either.
Did you buy the same restricted intake rubbers?
Did you check out Old Riders photo showing you the difference?

Which ones do you have?

1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

brandane

#6
April 22, 2021, 07:14:51 AM

It's not the inlets and there's nothing in the headers.

TomJK

#7
April 22, 2021, 07:19:31 AM
Quote from: brandane on April 22, 2021, 07:14:51 AM

It's not the inlets and there's nothing in the headers.


I mean the inlet of the airfilterbox, not the parts on the carburettors.

Past bikes : BMWR90-S,BMW R100CS, Ducati 900SD, Kawasaki GPZ600,Yamaha FJ1200,Kawasaki ZZR 1100 (4x),Kawasaki ZZR1200, Honda CBR1100XXX,Yamaha Thunderace, Kawasaki ZX10R (3X),
Aprillia Falco,Honda CBR600F4I, bikes today : Kawasaki ZX10R (C1, the best!),Yamaha FJ1200, soon to come Kawasaki Z900.....

brandane

#8
April 22, 2021, 07:27:49 AM
I can see that I will have to dismantle and take photos before anybody will believe me.  :Facepalm:

balky1

#9
April 22, 2021, 08:47:45 AM
Quote from: brandane on April 22, 2021, 07:27:49 AM
I can see that I will have to dismantle and take photos before anybody will believe me.  :Facepalm:

Maybe something is just broken? Carbs clogged?


FJ 1100, 1985, sold
FJR 1300, 2009

RPM - Robert

#10
April 22, 2021, 12:06:53 PM
The inlet side of the intake manifold will appear the same because the carburetor bodies are identical to the full power models. So unless you pull them and measure them, you won't know what you have.

I worked on a few XJRs that were imported into the US that were restricted with small intake manifolds, small airbox inlets, the slides had a smaller hole in a different location, main jet needle was larger making the bike more lean, and the jets were way undersized. If you ware taking photos take a picture with some measurements of the main jet needle and let us know what jet sizes you are currently running.

It's not that we don't believe you, you simply haven't show us anything to help guide you.

Pat Conlon

#11
April 22, 2021, 06:41:27 PM
Didn't the JDM bikes also have some sort of rev limiter function in the tach?
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

TomJK

#12
April 23, 2021, 02:21:31 AM
Quote from: TomJK on April 23, 2021, 02:20:43 AM
Quote from: TomJK on April 22, 2021, 07:19:31 AM
Quote from: brandane on April 22, 2021, 07:14:51 AM

It's not the inlets and there's nothing in the headers.


I mean the inlet of the airfilterbox, not the parts on the carburettors.



This part, did you check that?
Past bikes : BMWR90-S,BMW R100CS, Ducati 900SD, Kawasaki GPZ600,Yamaha FJ1200,Kawasaki ZZR 1100 (4x),Kawasaki ZZR1200, Honda CBR1100XXX,Yamaha Thunderace, Kawasaki ZX10R (3X),
Aprillia Falco,Honda CBR600F4I, bikes today : Kawasaki ZX10R (C1, the best!),Yamaha FJ1200, soon to come Kawasaki Z900.....

TomJK

#13
April 23, 2021, 02:22:17 AM
Hi
I attached pic, but it does not show up, sorry.
Tom.
Past bikes : BMWR90-S,BMW R100CS, Ducati 900SD, Kawasaki GPZ600,Yamaha FJ1200,Kawasaki ZZR 1100 (4x),Kawasaki ZZR1200, Honda CBR1100XXX,Yamaha Thunderace, Kawasaki ZX10R (3X),
Aprillia Falco,Honda CBR600F4I, bikes today : Kawasaki ZX10R (C1, the best!),Yamaha FJ1200, soon to come Kawasaki Z900.....

brandane

#14
April 24, 2021, 11:41:22 AM
Ok.. maybe I was not exact enough, the Swiss bikes have 65 HP. Sixty Five, not 130. It's not just a little bit flat or rough.
Inlet rubbers are 31.5mm dia at the engine side, same as the actual inlet in the head itself. The diaphragms have been replaced with new as the old ones were turning to leather after 35 years. The holes in the carb slides were bored out to 4mm from 2 previously. The inlets to the airbox have no visible restrictions, The exhausts (I'm not taking them off again to prove it) have no visible restriction in the pipe headers. The CDI box has been changed for a standard UK model one and the needles and jets replaced with new items in a standard carb refurbish kit off Amazon UK. I forget the air jet sizes but the mains are 112.5. The (now standard) needle is in the third clip position (standard).

I'm wondering if the igntion is retarded or if the Swiss exhausts (you're not allowed to fit aftermarket stuff here or you get no MOT) are severely restricted. I have a set of standard Yamaha German mufflers on order off Ebay which I can adjust if necessary.

I am wondering how they made 65 BHP just disappear, on a bike with no electronic gubbins connected to the tacho or obvious inlet or exhaust restrictions. There's no weird tubing from the CDI to the inlet vacuum either. It all looks normal.
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