Carbs/fueling advice required

[MexicanGringo]

Be done with it! The bike will never run 100% with dirty carbs, you can adjust idle screws with carbs on but its a bit of a bitch.It makes good sense to spray carb cleaner through everything to clear all air fuel passage ways, check float heights etc.. like drunknmunky suggested, soak rubbers in warm water before refitting

[Cammo]

^ What he said!

@ Mr Fen: I sent you a pdf copy of the carb jetting guide.

You might as well take the carbs off and clean, adjust, rejet etc. It's the only way you can guarantee the carbs are clean and working properly. The source of your problem might be something as simple as a blocked jet.

[Mr_Fen]

thanks guys, I'm going to sort the screw out today (hopefully) and order replacement gaskets etc once I know what I'm looking at.

If the oil level is too high, it should be easy to drain a bit out right? The dipstick shows its close to the top mark, but not over it.

[Mr_Fen]

I have drained some oil out as it was a bit high

I used the dremel to cut a straight line across the screw head and get the air cover off, I would rather replace the screw than use it 'as is' but where do you get odd screws from? I'm assuming a lower airbox might come with screws but the price would be silly for one screw.

The carbs popped off without much resistance, that guide is excellent! I have written everything down as advised with the details below:

front right:
jet 115, 4 emulsion holes, J51B needle with 1x0.5mm shim
front left:
jet 115, 4 emulsion holes, J51B needle with 1x0.5mm shim
back right:
jet 118, 5 emulsion holes, J51A needle with 1x0.5mm shim
back left:
jet 118, 5 emulsion holes, J51A needle with 1x0.5mm shim

The jets are the standard Japanese sizes, I have an after market blue flame can and have been told the exhaust is not a standard one. The carb guide advises:
Main jet sizes: If you run a nice sounding aftermarket exhaust and/or pipe, then the common consensus is to run 118 size front and 120 size rear (often referred to as 118/120). If you run a very high flowing/loud exhaust or full exhaust system then you may wish to consider running 120f/122r size main jets.

based on this, should I get a pair of 120 sized jets for the rear, moving the 118 jets to the front, or get a set of 120f/122r jets? What would be the noticeable difference?

I will be getting a set of 0.5mm shims or the 1.0 shims from Rick Oliver along with some new gaskets and a 'stainless carb allen screw kit' as the previous owner has killed these screws too, requiring the dremel method of opening. The pilot jet heads have been 'worn' by a screwdriver so will be getting replaced too.
I have drilled each slide out to 2.5mm following the instructions, the slide diaphragms have a white residue on them, I'm assuming its from petrol, does this need to be washed off or should I leave them alone?

I adjusted the pilot jet screws, they were all set to different levels from 2 turns to 3.25 turns out, I'm positive this has something to do with my problems

As soon as you guys post some feedback on the jet sizes and performance differences I'll email/PM Rick Oliver for the parts

Cheers!

[Cammo]

based on this, should I get a pair of 120 sized jets for the rear, moving the 118 jets to the front,

I'd go with 118/120, fairly safe bet that it will run fine.

I have drilled each slide out to 2.5mm following the instructions, the slide diaphragms have a white residue on them, I'm assuming its from petrol, does this need to be washed off or should I leave them alone?

Wash any parts that need it in petrol (old toothbrush is handy too!), it certainly won't do any harm.

[Mr_Fen]

I have had a chat with Rick Oliver ( http://www.rvf.dk/rickoliver/" onclick="window.open(this.href);return false; )
and he has advised I get the following parts:

4x120 Dynojets £15
2x35 pilot jets £8
4x NC30 carb float chamber gaskets £5
NC30/35 stainless carb allen screw kit £7
1x airbox mounting screw (as attached picture)
not to worry about the shims unless I have a flat spot around 5500rpm, as I am not aware of one its best not to fiddle with it.

should hopefully get them before saturday to have the bike running this weekend

[CMSMJ1]

So what exhaust have you got then?

Uncle Rick is the top man and his advice is always worth listening to.

Reminds me to bug him for some more bits soon as I get paid....

[Polisher]

Mr Fen, I got exactly the same as you are getting from Rick

His advice was spot on but I used the shims under the needles. It runs spot on now, but a tad rich in the midrange, so I'm taking the shims out and trying that

The allen bolts for the carb tops and the float bowls are a must. I had to chisel EVERY single one of mine out!

PS - I used some silicone lubricant (from Halfords) sprayed around the carb rubbers to ease the re fitting of the carbs, slipped on better & quicker than KY!!!!

[padawan]

Hey Mr_Fen,

Hat's off to you for getting in there and having a go. I was pretty daunted the first time I had a go and to my misfortune had all sorts of mishaps that in the end has made me become very exprienced at building whole sets of carbs.

Anyway, not sure if anyone has mentioned this yet but once you've changed the jet size's and pilot screws you may need to balance the carbs when you re-fit them - this may assist you in resolving said issues with idle rev range.

Also a big +10 for heating up the carb rubbers I use a paint stripper to get them nice and warm and then you can pretty much push them on by hand

[Mr_Fen]

the bike apparently had a full 'Ethos' system on it before this happened November 08:

I have since fitted a cut down 'Blue Flame' end can


Does the carb cleaner spray damage the rubber gaskets/diaphragms/plastic floats or is it safe to leave them on?

@ Padawan, you mean a heat gun/hair dryer thing? that sounds a lot easier than boiling them or buying more goo.