News:

This forum is run by RPM and donations from members.

It is the donations of the members that help offset the operating cost of the forum. The secondary benefit of being a contributing member is the ability to save big during RPM Holiday sales. For more information please check out this link: Membership has its privileges 

Thank you for your support of the all mighty FJ.

Main Menu

rebuilt carbs

Started by bigbore2, May 15, 2012, 06:20:11 PM

Previous topic - Next topic

bigbore2

I rebuilt my carbs [84 1100] and reinstalled them and am trying to figure out how to set the  airscrew? located on the front top of each carb to get engine running before I have carbs synched. The book just says it is preset.

Pat Conlon

Start at 3 turns out (from fully seated) Adjust as the blip test warrants.
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

bigbore2

Thanx Pat, I forgot to put in my other info.   5000 ft altitude-115 main-37.5 pilot-one clip higher on needle.   If I get it working well, do I even need to get the carbs synched?

Pat Conlon

Yes, always, always....always.... sync. those carbs....That should be first on your list.

If you are serious about keeping your FJ and have it run to it's full potential (sounds like you are) invest in a carb sync tool...

A Morgan Carb Tune,  http://www.carbtune.com/
...or a Motion Pro stick like Randy @ RPM sells: http://www.rpmracingca.com/products.asp?cat=49

You really, really need one.

Properly sync'ed carbs make a world of a difference on our FJ's.
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

Arnie

After you have your carbs in sync the first time, you'll be a believer.

Its so quick to do and makes so much difference that I sync every time I have the tank off.

Arnie

Dads_FJ

Carbs should always be synchronized right AFTER a valve adjustment as well.
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'94 Yamaha WR250
'80 BMW R100S/Sidecar
'39 BSA WM20

FJdude

The carbs on my 1200 are set out at around 1 3/4 of a turn, is that not enough??

Also is there a secret to pullin those dam carbs... It's a pain in my rear trying to fit it in there with the air box. And the one time I did take the air box out...well let's just say I'm not soon that again!

Dads_FJ

Quote from: FJdude on May 17, 2012, 03:04:00 PM
The carbs on my 1200 are set out at around 1 3/4 of a turn, is that not enough??

Also is there a secret to pullin those dam carbs... It's a pain in my rear trying to fit it in there with the air box. And the one time I did take the air box out...well let's just say I'm not soon that again!

Swign the sub-frame down and out of the way when R&R the carburetors (you don't actually have to remove it).  Much easier than trying to fit them in.
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'94 Yamaha WR250
'80 BMW R100S/Sidecar
'39 BSA WM20

FJdude

Not quite sure what you mean by subframe???

Arnie

Seat subframe.  Remove the upper bolt next to the battery on each side.  Then push down at the grab handles end of the subframe.

Arnie

bigbore2

I was thinking the other day, oh well, here goes,  synching the carbs is done with the airscrew? or is it done with the part of the carb that adjusts the butterflys so that all 4 open and close exactly the same.  I remember adjusting that by sight before I put them back in when I had all four connected together.
  Thanx for the the reminder to remove the subframe.  I put the airbox and carbs in last night and it was doable but I was just about ready to blow by the time I got done.  MUch, much harder if the subframe is not taken down.

andyb

The latter.  The screws between the carbs adjust their relative positions, and that's what a synch does.  What you are calling an airscrew actually meters fuel with some air in it, and is useful for getting a smooth idle and clean cruise at low engine speeds with the throttle just cracked on (cruising at 2500 revs in 4th for example).

bigbore2

Thank you kindly.  Boy do I love the people on this site.