Carbs

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mike738

Carbs

Post by mike738 »

Hi all

Got some carb questions Im sure they have been asked before but any answers would be great

I have a 74 L Model, the carbs that I originally had on the bike were very early ones without the L and R vacum ports, the throttle plates were 120 and the needles were set to the 3rd position. I sold these on ebay and now wish I had not lol.

The new carbs I have have 110 throttle plates and do have the left and right vacum ports the needles are at position 2 which I will change to back to 3.

I have a copy of the suzuki carb manual and it only covers the L model and I would like to re jet the carbs to L spec.


If I obtain 120 throttle plates will they fit and work ok, or do I need an early set of throttle bodies ?

What does the 110/ 120 actually mean ?

Why does the middle jet need to be different on a liquid cooled engine ?

Would My L engine work be damaged by carb settings that were brought in for the M mod (higher horse power and changed porting and exhausts) ?


thanks mike
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MrCertifiable
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Re: Carbs

Post by MrCertifiable »

Damn good questions
.
.
.
Barrrrrry !!!!
Waiting for sanity
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BAZ
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Re: Carbs

Post by BAZ »

The only difference between the L Model carbs and the later ones are the 120 Butterflies also the absence of vacuum take off and the butterfly adjustment is with a screw and bolt rather than a spring some B models also have this arrangement. The 120 refers to the closing angle of the butterflies and is compensated for buy having the pilot screw 1/4 turn out instead of 3/4 turn out but the end result is the same. The smaller main jet in the centre is to compensate for higher temperature on the centre carb also the centre pot is 2cc difference in capacity. Put the needle at mid way on all Carbs and you will do no harm.The best way to get final adjustment spot on is to get your bike on a Dyno I have done this
on many engines and found kettles give most power when running slightly weak. With the mild state of tune and water cooling there is no danger of holed pistons!
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yeadon_m
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Re: Carbs

Post by yeadon_m »

Barry,
If I could find a 'bows down to superior knowledge' emoticon, consider it added :-)
Mike
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astrax
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Re: Carbs

Post by astrax »

yeadon_m wrote:Barry,
If I could find a 'bows down to superior knowledge' emoticon, consider it added :-)
Mike
Hi Mike

You can borrow mine
not_worthy.gif
not_worthy.gif (2.8 KiB) Viewed 1007 times
Ian
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yeadon_m
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Re: Carbs

Post by yeadon_m »

Why thank you Ian!
Oh, while I'm bowing down, will you get time in your busy life to prepare some rear shock washers in glorious stainless for my current project, the GT550?
Cheers,
Mike
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MrCertifiable
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Re: Carbs

Post by MrCertifiable »

Yep , i taught him well.......
.
Waiting for sanity
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astrax
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Re: Carbs

Post by astrax »

yeadon_m wrote:Why thank you Ian!
Oh, while I'm bowing down, will you get time in your busy life to prepare some rear shock washers in glorious stainless for my current project, the GT550?
Cheers,
Mike
Hi Mike, I hadn't forgotten you, just taking longer to get the garage back together, and had an issue with the lathe about a week ago where the motor went pop and a large spark came from it so need to get sorted PDQ.
I have 2 pairs of the top inner spacers if no grab rail fitted, just not got the outer ones, polisher is now working again, just need to get lathe sorted.

If you want a pair of the top inner ones then can send them to keep you going.


Ian.
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mike738

Re: Carbs

Post by mike738 »

Hi and thanks to all

it all makes sense now, I remember comparing the two throttle plates, but didnt think to check the edges to notice a difference, things seem clearer after a few beers right ? Im changing My centre main for the 107.5

does any body have 3 120 throttle plates to sell or swop for 110's ?

In the mean time Barry what would your advice be on the pilot screw setting with 110 plates and pilot jets of 47.5 ?
(it explains the unstable tickover lol)

Mike
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BAZ
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Re: Carbs

Post by BAZ »

3/4 or 1 turn out. I will have a look for some 120 butterflies.
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