If you have the stock SU carbs then rejetting of any kind should not be
necessary but the damper springs should be changed. The std spring has a red
paint mark at one end. My '78 Spit 1500 has round K&N's and uses 'Yellow'
springs. As the K&N are more free flowing the carb piston rises more readily
hence a stiffer spring being necessary.
The TriumphTune (Moss UK) catalogue lists springs:
Red (std) 4.5oz load
Yellow 8oz
Green 12oz
Changing the spring will definitely improve the low speed / idle.
______________________________ Reply Separator _________________________________
Subject: K&N on my Spitfire
Author: hargrave@somtel.com at INTERNET-PO
Date: 25/04/97 21:15
Hi All,
I just installed my new K&N air filter on my 77 Spitfire. I was all set to
see a real difference in performance, well not really a big difference but I
really liked the idea of the chrome cleaner. Any way I got in, fired up the
Spit and went for a ride. I went for about a mile down the road and the car
acted terrible. It seemed starved for air. Thats something I didn't expect.
As I gave the car gass the RPMs came up to about 3000 then would drop back to
2000, if I let up on the throttle the RPMs would come back up somewhat. At
first I thought it was getting too much air but it runs fine with the stock
air cleaner and with no air cleaner. I washed all the oil out of the K&N
filter filter and tried it again it seems to run better but still limits my
speed to about 65mph and the RPMs will drop off somewhat. The only difference
I can come up with is the square hole above the air intake is restricted on
the K&N but I'm not sure why it is there. The hole is above the piston. I am
inclined to cut the base plate of the air cleaner but if I can't use it I
would not be able to return it if I modified it. Has anybody had a problem
like this? O if you have any ideas on this problem please let me know.
Thanks in advance.
Herb Hargraves
Cannan ME
77 Spitfire
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