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Any shortcuts for Carb reassembly

Started by Sparky84, August 18, 2017, 07:35:57 PM

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Sparky84

All ready to reassemble my carbs after a ultrasonic clean, given a them a wash and blown air through all passages.
I have new carb kits to fit.
I have read Randy's way to set A/F mixture screw to level with throat inside and go from there, (mine were 2 1\4 turns out from seated position) but does this mean they will be set to all allow the same mixture through?
Now onto my problem before with #4 plug getting wet after bike sitting for a month, I'm thinking it was float problem or needle and seat letting in too much fuel after awhile so do I set floats to what is in manual ? Or has anyone got a better setting, higher/lower
Checking fuel level in bowls, can this be done on a bench prior to fitting carbs in bike? And do I set it to what's in manual or has anyone got a better setting. Because that's a pain installing them and taking them back out (going inside harder actually, using rubber mallet and timber, if someone has a tip )

I think that's it

Cheers Alan

1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

X-Ray

Hey Alan,

with the mixture screws I just screwed them all the way in till lightly seated then backed them out the number of turns needed. The floats when I just cleaned/rebuilt mine were done to recommended levels (around 22.5mm for me), but then I always bench check the actual fuel level using clear tube, which isn't hard to do. I think I detailed it on the FBook page, haven't put it up here yet. Will see if I can find the link.

oh, here it is https://www.facebook.com/groups/YamahaFJOwnersAust/permalink/1698818777087829/     There is a recommended fuel level as well as float level for early/late model FJs, and I measure it from the bowl gasket line down, there is a photo on the link that shows this.
'94 FJ1200 Wet Pale Brown
'93 FJ1200 Dark Violet/Silver
'84 FJ1100 Red/White

'91 FJ1200 Dark Violet/Silver ( Now Sold)
'92 FJ1200 Project/Resto Dark Violet/Silver (Now Sold)






For photos of my rear wheel swap, heres the link  https://www.flickr.com/gp/150032671@N02/62k3KZ

Sparky84

Thanks Ray, I'll try to make a jig to hold them.

I got the keyster kits and a 40 pilot jets but they are different to original  :scratch_one-s_head:

In picture is original 40, keyster 37.5, New mikuni 40 will it matter
1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

balky1

When installing the carbs, lube the manifolds a bit with engine oil. Carbs go in much more easily.


FJ 1100, 1985, sold
FJR 1300, 2009

X-Ray

If I'm reading right the 1984 1100s outside the US should have 40 pilots, some good info here http://fjowners.wikidot.com/carbs

'94 FJ1200 Wet Pale Brown
'93 FJ1200 Dark Violet/Silver
'84 FJ1100 Red/White

'91 FJ1200 Dark Violet/Silver ( Now Sold)
'92 FJ1200 Project/Resto Dark Violet/Silver (Now Sold)






For photos of my rear wheel swap, heres the link  https://www.flickr.com/gp/150032671@N02/62k3KZ

Pat Conlon

Get the RPM ss screw and O ring kit....the best $22 you will ever spend, hands down.
http://rpmracingca.com/proddetail.asp?prod=carbkit
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

Sparky84

Quote from: Pat Conlon on August 20, 2017, 12:43:16 PM
Get the RPM ss screw and O ring kit....the best $22 you will ever spend, hands down.
http://rpmracingca.com/proddetail.asp?prod=carbkit
Got them but should I need to put anti seize on them?
A nice allen key screwdriver set would be nice with these also
1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

FJmonkey

You don't need AS compound for this kind of threaded assembly. But it also cannot hurt, just adds goo to the assembly and you need to be careful not to over tighten as AS acts like a lubricant. 
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

Sparky84


I won't us AS then.
I set floats to the mating surface not the rib, what a PITA, setting floats
to measure you can see the outside ones as they touch the needle but the
inside ones only just. I did set them on a angle that meant they were just
resting on the pins.
I did look at Carb Files but most pictures were just the Photobucket notice.
I will check fuel level to make sure with carbs level.
1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

racerrad8

Quote from: Sparky84 on August 19, 2017, 01:04:04 AM
Thanks Ray, I'll try to make a jig to hold them.

I got the keyster kits and a 40 pilot jets but they are different to original  :scratch_one-s_head:

In picture is original 40, keyster 37.5, New mikuni 40 will it matter

The jet on the right is a Mikuni jet the other two are aftermarket jets. It may have had a 40 in it when you took it apart but that does not look like a Mikuni brand jet. And no it will not matter the jet opening is measured the same. The tapered end seals against the carb body and fuel is forced through the orifice at whatever rate jet you have (37.5, 40, etc.)

The reason we set the needle mixture screws the way we do, is we have found on new sets of carburetors the amount of turns to seat the mixture screw can be off by as much as 3/4 of a turn, meaning the hole was either drilled too deep or too shallow compared to the others. Not seating the idle mixture screw and backing them out until your thumbnail falls off of it and then backing them off one full turn sets them very close to the recommended factory setting but gives you an exact baseline where they are all identically adjusted out. Not 1/2 off down on carb one, 1/4 more down on two, 3/4 up on three, perfectly set on four.

When we build a set of carbs and are measuring float heights the carbs are still in the separated bodies stage before final assembly that way we can get the heights on both sides correct a bit easier.

Robert - RPM
Randy - RPM

Sparky84

Quote from: racerrad8 on August 21, 2017, 10:59:12 AM
The jet on the right is a Mikuni jet the other two are aftermarket jets.
The Original on the left has the Mikuni Stamp on it also

Quote from: racerrad8 on August 21, 2017, 10:59:12 AM
Not seating the idle mixture screw and backing them out until your thumbnail falls off of it and then backing them off one full turn sets them very close to the recommended factory setting but gives you an exact baseline where they are all identically adjusted out. Not 1/2 off down on carb one, 1/4 more down on two, 3/4 up on three, perfectly set on four.
I did seat one just to mark my original 2 1/4 turns out then did the thumbnail and found from my last settings it was 3/4 of a turn back in and set them all with thumbnail then 3/4 back in.
But you mention backing them off 1 turn but I went in?

Quote from: racerrad8 on August 21, 2017, 10:59:12 AM
When we build a set of carbs and are measuring float heights the carbs are still in the separated bodies stage before final assembly that way we can get the heights on both sides correct a bit easier.

Robert - RPM

Robert that would be too easy and I'm measuring both sides also, as suggested.

Just have to check fuel level to confirm I've set floats correct, I wish those photobucket pictures were there in the Files section

Cheers Alan
1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

racerrad8

Could be a Mikuni I haven't seen one that has had in between the taper and the threads cut like that except the bleed port ones. Learn something new all the time.

We build a couple hundred sets of carbs for motorcycles and also for the race car guys every year. We set them 1 turn out from flush and usually do not have to make more than 1/4 turn adjustment either way once on the bike. If your idle mixture screws are 3/4 into the throat of the carburetor it would be too lean for the set ups we build carburetors at.  But it may be correct for the way your carburetors are set up. The main thing is too establish a baseline, too make them all at the same adjustment to begin with, which is exactly what you did.

Robert - RPM



Randy - RPM

Sparky84

Quote from: racerrad8 on August 21, 2017, 06:18:26 PM
Learn something new all the time.

Robert - RPM

Learning Keeps you alive Robert

Quote from: racerrad8 on August 21, 2017, 06:18:26 PM
If your idle mixture screws are 3/4 into the throat of the carburetor it would be too lean for the set ups we build carburetors at.

Plugs have plenty of carbon on them always and when I did clean carbs a couple of years ago they were about the same, in the throat.

Ill get them set up then take it to get dyno and checked properly

Cheers Alan
1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

Sparky84

I'm changing intake boots o-rings while I'm here, do they require any other compound to apply to o-rings for proper sealing?
Does anyone know torque values for the mounting Allen screws? Do I need anti seize also?

Cheers Alan

1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2