jpindy3
|
| posted on 20/5/09 at 07:31 PM |
|
|
got some bike carb Qs
right i have my iva today,thats another story.when i had the emission test done it read not even 1% "of what i dont know"
be the bloke said it was very low,and also said that ment that it was running lean.witch was good as it got me through that part of the test,and
home.
so when i got back,i thort i would have a go at sorting it out,i got some realy small washers and loaded the neadle up with about 5 witch was 5mm,that
ran far to rich,so i ended up with useing 2,on each neadle of corse.the zx9r carb neadle has a 10mm leval bit on it before it gos to a point,is that
what that bit of the neadle is for?anyway it runs fine.
i did forget to say also on my way home,towards the end of the drive i was going around a roundabout in 3rd and diving quite hard out of it,took it to
about 5000rpm and a horable kind of splutring came from the exhaust and a loss of power,any ideas what this could be?was i pushing it to hard?
thats the other reason i made it a little richer,but after doing that,i wormed it up and took it around the block,and it happend again.
so i a bit worried that i may have fooked it?
|
|
|
|
|
GaryM
|
| posted on 20/5/09 at 07:57 PM |
|
|
As I understand it, with CV carbs.....
The needle and needle jet control fueling (richness/weakness) from above idle to about 75% of the needle (not throttle) being fully raised. The needle
will rise and fall independently but related to the throttle position and engine revs .By fine adjusting the needle height (in the slide) you will
adjusting the mixture in this range.
If you've started using more throttle and higher revs then you've probably starting exploring the area of carbueration above 75% fully
open. This area is controlled primarily by the main jet.
I would guess, that in your case, your main jet is too small causing the mixture to go very lean and hence the loss of power above 5000 revs.
What size are your main jets?
I'm currently trying to road tune my 1600 xflow/FZR600 carb setup and finding if very
challenging even with the assistance of a wideband oxygen sensor and guage.
I'd hate to try and do it without one!
Cheers
Gary
|
|
|
jpindy3
|
| posted on 20/5/09 at 08:08 PM |
|
|
quote:
Originally posted by GaryM
As I understand it, with CV carbs.....
The needle and needle jet control fueling (richness/weakness) from above idle to about 75% of the needle (not throttle) being fully raised. The needle
will rise and fall independently but related to the throttle position and engine revs .By fine adjusting the needle height (in the slide) you will
adjusting the mixture in this range.
If you've started using more throttle and higher revs then you've probably starting exploring the area of carbueration above 75% fully
open. This area is controlled primarily by the main jet.
I would guess, that in your case, your main jet is too small causing the mixture to go very lean and hence the loss of power above 5000 revs.
What size are your main jets?
I'm currently trying to road tune my 1600 xflow/FZR600 carb setup and finding if very
challenging even with the assistance of a wideband oxygen sensor and guage.
I'd hate to try and do it without one!
Cheers
Gary
hi mate thanks,my main jet is 1.8mm,do you think this is ok??? 
|
|
|
jacko
|
| posted on 20/5/09 at 08:37 PM |
|
|
When the tester did the emissions was it at idle? if so its not the needls that need ajusting its the air screws under the carbs
[Edited on 20/5/09 by jacko]
quote:
http://www.locostbuilders.co.uk/viewthread.php?tid=104526&page=2
Read this under my name
[Edited on 20/5/09 by jacko]
|
|
|
jpindy3
|
| posted on 20/5/09 at 08:53 PM |
|
|
of course,thanks jacko,
how meny turns out is it 3.5???
|
|
|
jacko
|
| posted on 20/5/09 at 09:05 PM |
|
|
It depends on your engine tuning mine is one turn out i also think your jets are to big at 1.8
Look at the link i have put on my last post
|
|
|
coozer
|
| posted on 20/5/09 at 09:11 PM |
|
|
Air inlet on the face needs blocking to prevent severe leaning off at high revs, done that?
Then you need to take it to Blogg Brothers for a set up. No substitution. Worth every penny in fuel savings.
Then an English grammar course if I may suggest.
1972 V8 Jago
1980 Z750
|
|
|
jpindy3
|
| posted on 20/5/09 at 09:15 PM |
|
|
quote:
Originally posted by coozer
Air inlet on the face needs blocking to prevent severe leaning off at high revs, done that?
Then you need to take it to Blogg Brothers for a set up. No substitution. Worth every penny in fuel savings.
Then an English grammar course if I may suggest.
well i didnt know that,do you mean the face below the main intake??there is some kind of air hole
|
|
|
jacko
|
| posted on 20/5/09 at 09:18 PM |
|
|
Its inline with the main needles a brass hole
 
carbs on manifold
[Edited on 20/5/09 by jacko]
|
|
|
jpindy3
|
| posted on 20/5/09 at 09:27 PM |
|
|
what the one below or boath?
|
|
|
coozer
|
| posted on 20/5/09 at 09:43 PM |
|
|
The one in the middle directly below the needle. Its an air bleed for the main that needs blocking.
1972 V8 Jago
1980 Z750
|
|
|
jpindy3
|
| posted on 20/5/09 at 09:49 PM |
|
|
quote:
Originally posted by coozer
The one in the middle directly below the needle. Its an air bleed for the main that needs blocking.
thanks cooza and jacko,
i shall do it sometime in the morning,thin is i will want to see what it can do,but that might get me into truble,i could get away with it today coz
it was my iva
it will so want it though!
thanks jamie 
|
|
|
