my 81 interstate

[81 Gwing]

my stator died. so i did a alt. conversion my way.....works great...not done yet. i have a nicer pulley commin and still have ta cut the hole in the belt cover

 

[joedrum]

cam driven ....looks good :BigGrin:

 

[81 Gwing]

thanks Joe.....i wanna try to get a smaller alt. pulley. need ta spin a lil faster at idle

 

[zman]

I wonder if the belt will be under a heavy load with it running off the cam..looks great though.

 

[dan filipi]

At what rpm does it take to get a positive charge above loads?

 

[81 Gwing]

dan filipi » Sat Jul 04, 2015 3:26 pm[/url]":n3g1lern]
At what rpm does it take to get a positive charge above loads?

i dont know that. ill try to find out

the cam turns 1/2 the engine rpms. so at 1,000 engine rpm the cam is turning 500. i have a 5in dia pulley on the cam and a 2.7in alt pulley(thats what it came with). i need a smaller alt. pulley. it doesnt charge good below 2,000

 

[81 Gwing]

what dia. is the crank pulley on my wing??

 

[dan filipi]

81 Gwing » 34 minutes ago[/url]":3idkwkoz]
what dia. is the crank pulley on my wing??

Not sure but I think the smallest alternator pullies they make is either 2.5" or 2" diameter.
Seems like it was 2.5" for a V belt, and 2" for a flat belt. Been awhile since I built up mine.

 

[81 Gwing]

my 5in dia pulley looks like the same size as the cam gear. so im thinkin if i can find a alt. pulley the same size as the crank pulley,the alt will be turnin at engine speed...i think

 

[81 Gwing]

bike doesnt have 68,000...thats a 83 speedO

 

[joedrum]

hmmm i would try it like it is first ...2000 rpm is not that far from idle ....i for one think its sounds rather good numbers ...you cant forget that the oldwing dose a lot of over 4000 and above running ...making under geared a bit a good thing ..... :headscratch:

 

[dan filipi]

I measured, crank pulley is 2-1/4" diameter, 1/2 that of the cam pulleys.

If you go 2-1/4" alternator pulley you'll still only be at crank speed, which isn't fast enough for a positive charge at idle.
The problem with using the cam speed is you already loose 1/2 the speed.
Seems getting that back requires an even larger pulley at the cam and smallest possible on the alternator.
Possibly there are alternators out there or yours could be rewound for more output at a slower rpm.

 

[dan filipi]

joedrum » 1 minute ago[/url]":1n5s90np]
hmmm i would try it like it is first ...2000 rpm is not that far from idle ....i for one think its sounds rather good numbers ...you cant forget that the oldwing dose a lot of over 4000 and above running ...making under geared a bit a good thing ..... :headscratch:

I agree to a point but around town riding and stop and go, under drive is a loosing battle.

 

[81 Gwing]

im not going bigger in the cam pulley. the belt is already close to the crash bar

 

[81 Gwing]

im tryin to find a 2in alt pulley

thanks for the replys :salute:

 

[joedrum]

wow after looking at pics again the belt and all is real close to crash bar ....hmmmmm i couldnt have that hear unless it was totally enclosed with the gravel roads and all ..... opcorn:

 

[Ansimp]

joedrum » Sun Jul 05, 2015 7:53 am[/url]":2ehebqvf]
hmmm i would try it like it is first ...2000 rpm is not that far from idle ....i for one think its sounds rather good numbers ...you cant forget that the oldwing dose a lot of over 4000 and above running ...making under geared a bit a good thing ..... :headscratch:

+1

 

[Ansimp]

dan filipi » Sun Jul 05, 2015 7:54 am[/url]":1fgvpo78]
I measured, crank pulley is 2-1/4" diameter, 1/2 that of the cam pulleys.

If you go 2-1/4" alternator pulley you'll still only be at crank speed, which isn't fast enough for a positive charge at idle.
The problem with using the cam speed is you already loose 1/2 the speed.
Seems getting that back requires an even larger pulley at the cam and smallest possible on the alternator.
Possibly there are alternators out there or yours could be rewound for more output at a slower rpm.

ReWinding won't change low speed charge rate. Some of the later high output alternators actually draw 3-5 amps if spun too slowly but once up to speed produce higher output at the lower rev ranges.

 

[81 Gwing]

now that i got the (press in) idle jets clean on my stock carbs, i went back to the stock carbs....waaaay better. more power all the way around,and pulls real good in 5th :yahoo:

 

[slabghost]

Glad you are happy with it now.