| Author |
Message |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 534
Registered: 5-2001
| | Posted on Wednesday, September 17, 2003 - 8:25 pm: | |
Thanks Peter. Tha's what I do now. You're right, it takes many tries. |
'75 308 GT4 (Peter)
Advanced Member
Username: Peter
Post Number: 3100
Registered: 12-2000
| | Posted on Tuesday, September 16, 2003 - 1:32 pm: | |
Bill, I haven't noticed as much slop as you have on your ball-joints, but they do have some. Its hard to explain, but when I was into cycling/mountain biking, I'd often have to re-pack the bearings in the wheel hubs, bottom bracket, etc... One develops a sensitive touch, that you screw in the race so far that when you tighten with the lock nut, the compression of the two items on the threads takes-up the thread tolerance slack and it rolls superbly without grinding (too tight) or wobbling (too loose).
Basically, adjust the rod longer than it needs to be, by the amount that gets taken up by tightening the lock nuts. This requires many attempts. |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 532
Registered: 5-2001
| | Posted on Monday, September 15, 2003 - 9:50 pm: | |
Hi Philip,
The /3x series was used on the 74 GT-4 and is very similar to the /4x series used on the 75 GT-4. Differences between the two series are:
1. Float height on the /3x series is 48 mm vs 50 mm on the /4x series. As far as I can tell, the /4x series are the only ones that specify a 50 mm float height.
2. Idle jet is 0.45 mm on the /3x series vs 0.55 mm on the /4x series.
3. Slow running air corrector jets (pressed into carb body) are 1.60 mm on the /3x series vs 1.70 mm on the /4x series.
It's a good thing you posted on this Philip, it made me check the float heights in the various OM's and reminded me the float levels are set without the gasket on these carbs. Of course I set mine with the gaskets so I have to go back and reset them with the gaskets. In view of this, the as delivered float heights were still not right but closer than I first thought.
Thanks, Bill
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Philip Airey (Pma1010)
Member
Username: Pma1010
Post Number: 431
Registered: 7-2002
| | Posted on Monday, September 15, 2003 - 8:08 pm: | |
Bill
On float levels, I've generally found 48mm to work best on my 308 (40 DCNF 4X series). I thought the 50mm height was for the 3X series.
Philip |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 531
Registered: 5-2001
| | Posted on Monday, September 15, 2003 - 5:05 pm: | |
I recently purchased a near complete set of NEW 40DCNF 45/45/46/48 carbs for my 308 GTS. One of the /45�s requires a different lever arm to convert to a /47, for the 3-4 cylinder position. Well of course I had to tear them apart to confirm how they were setup. All the interchangeable stuff was as advertised. I still would like to find a new lever arm to convert one of the /45's to a /47 (left rear) carb so I don�t have to recycle a used one. Anybody have a pristine example of one of these lever arms (has a ball stud and a fork with an adjuster screw and spring fitted)?
Some observations I�d like to share as the question always arises as to what the initial settings ought to be after a rebuild:
1. The idle mixture screws were all 2-2.5 turns open. I set them all to 2.5 turns open.
2. One balance screw in each carb was closed. The other was open between 2-4 flats, then locked. This seems to imply that they may have been flowed on a bench during manufacture to ensure balance within the carb.
3. The float levels were set to between 47-49 mm. Spec for this series of carb is 50 mm, so I reset them to that. Float droop for all was much less then spec for these carbs. The GT-4 WSM cites a stroke of 10.5 mm while my Haynes Weber manual specifies a stroke of 8.5 mm. I reset them to 8.5 mm, as the sin here is to allow too much droop, where they may hang up and not shut down the fuel flow when necessary.
Does anyone have a trick to negate the sloppy threads of the push rod end fittings? When I adjust these things the desired amount by twisting the rod, the adjustment changes when I lock them with the lock nut, this process pushes them outboard (they get longer) a bit. Some ideas are to try some Teflon tape, swage the end fittings down a touch to tighten the threads, make a new rod of slightly larger diameter (requires adjustable LH and RH 5-mm dies) or replace the rod and ends with new ones (they may be sloppy even when new) or fit new spherical end bearing/rod sets (requires all the ball studs be removed).
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