Keihin carb butterfly valve stuck closed

[Trimac]

Hi I have drained carbs after storage
The pilots are 38 and mains 98
With standered air box
I want to go up to 40s and102 mains
I've got two problems
Firstly the butterfly valve stuck closed
I don't want to force anything  been spraying w40
Last two weeks and still no movement
Secondly where can I buy keihin jets in UK
Looked on eBay but not sure who to buy from
Thanks again for all the help
With coolant in oil

[JayDub]

Look up motocarb, Liverpool. Also Jack Lilley

[GavD]

Trimac,

I have Keihins also, and mine were 38/98 standard. Went up to 40/105 - much better. Got them from this place

http://www.allensperformance.co.uk/

[Trimac]

Thanks a lot
And 2.5 turns on screw air screws?

Then I'm still stumped on how to get the butterfly valves open
All three butterfly valves are seized closed.
I've got the carbs off the bike been on the net but not much info.
Thanks

[JayDub]

I've never been impressed with WD40 as a penetrating oil, its primarily a water dispersant.
I use 'Carlube penetrating and anti-seize' oil and its always been good to me.
Even home-made penetrating oil is more successful than WD40
The mix is: 40% Acetone (nail varnish remover) and 60% vegetable oil or Auto tranmission fluid is very good if you have any - careful though, its flammable 

[GavD]

And 2.5 turns on screw air screws?

It was a little while ago, but I think I started at 2.5 then ended up somewhere near 3. But I've got Motad Venom cans on mine because the originals rotted out, and they're a bit more free flowing than the originals. Airbox is standard.

As for the butterflies - I don't know of anyone who's posted about that in the past. I think you're our trailblazer on that front. Please post some pics for us if you get the chance. Although most people on here have the earlier Mikuni carbed bikes.

[Trimac]

Hi thanks
Looks like I won't be bored over the winter months.
I will keep updated going to South Africa for 9 weeks
Hopefully in that time someone will come up with some ideas.
I'm taking air box with and will be cutting it and might take carbs with too.
Thanks again for all help

[ram33]

is it 1 valve or all 3 that are stuck?
you may need to separate the 3 carbs then work on the stuck one. maybe a hot air gun on the bush ends where the butterfly spindle goes will help

[Trimac]

Hi it's all three valves sticking
The strange thing is when I drained the bowls
There was no varnish and all other parts
Moving nice and freely
I first thought it might be throatle cable
But cable free.
I was realy hoping not to have to seperate the carbs
As I'm new to doing the work myself been following
This forum a long time and sounds like a lot of backup
So thought ill start with the basics.
Yea right..... Everything I've started  has led me out my comfort zone
Starting with simple oil change and finding coolant
In oil so shelved that for next season
Thought I'd rejet carbs what could go wrong
Just to find all three butterfly valves stuck
Anyway think I will try the heat gun

[Sin_Tiger]

Yup I think you just won first prize for this one.

Go easy with the heat gun, not so familiar with Keihin's but I'm certain there will be plastic and rubber in them. Did you find some rubber for the air box split?

[Trimac]

Hi Sin tiger
Nope I've got the air box packed and downloaded
The  brilliant instructions how to do
And hoping to get some at a company
South African rubber products
They were good when I lived there 9 years ago
I'm sure that sould be quite straight forward  fingers crossed

[Fulingbusen]

I had the same problem.  I forced them to open but on one carb that meant twisting the shaft and warping the disc.  I had to replace those parts.  If I was in your situation, I would submerge the carbs in a good lubrication oil. 

The good news is once the shaft starts to move it was easy to get them to move the way they should.

[Sin_Tiger]

Diesel oil mix, warm, wiggle, repeat, patience 

[BruKen]

Re butterfly valves. I've had that issue before but not on K carbs to be fair. If you are able to loosen the two retaining screws on the shaft (may take a bit of heat to loosen the locktite) and pop the butterfly out the shaft can be removed relatively easily and cleaned up with less chance of damage as you can start a small wiggle which you cant if fully closed with the butterfly in. Be sure to replace the screws with locktite on.

[ssevy]

Use caution when removing those plates...I removed the butterfly plate in a Rochester carb on my Chevy car, and I applied lots of pressure so as not to strip the screw slots and ended up bending the shaft😧