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Author Topic: 78 carb jetting - feels so right but seems so wrong  (Read 841 times)

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Offline Blitzburgh207

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78 carb jetting - feels so right but seems so wrong
« on: September 03, 2011, 05:25:28 PM »
FINALLY got it tuned right and now I can't keep myself off the throttle  ;D  She goes like hell but it seems like it needs an awful lot of fuel??

Setup:
1978 750k
Motor = stock
cheap pods from dimecitycycles
cycle-x 4-2-1 w/ muffler chopped down to about 9"

Jetting:
bored slows per hondachopper walkthrough w/ .45mm bit - Air screw 2-1/2 turns out
needles shimmed w/ 1 nylon washer ea. (not sure but I'd guess 1-1.5mm?)
135 mains

I'm going to buy some 140 mains because it studders a little at wot (plug chop was lean)

So my question is, does this seem like it's too much fuel? - because it does to me haha  :D Plug chops show a good tan color at 1/4 1/2 and 3/4 (wot is lean) sorry - no pics.
Only other thing is #2 pops a little bit at idle. Carbs are synched & all tune-up work done. What's the deal w/ that?

p.s. mpg is about 45.  41/42 if I'm riding like a d*ck all the time haha - if that's relevant info
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Offline Blitzburgh207

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Re: 78 carb jetting - feels so right but seems so wrong
« Reply #1 on: September 04, 2011, 08:09:35 AM »
So not a problem?
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Offline 1timduke

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Re: 78 carb jetting - feels so right but seems so wrong
« Reply #2 on: September 04, 2011, 09:56:55 AM »
That doesn't seem like too much fuel consumption to me, given the larger jet sizes...   If the plugs are a good color your fuel use should be pretty close to optimal I believe.   Install the 140's and enjoy!

-Tim
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Offline Gordon

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Re: 78 carb jetting - feels so right but seems so wrong
« Reply #3 on: September 04, 2011, 09:59:44 AM »
So you've got it running well and you want to know if there's something wrong with that? 


You just can't please some people! ::) ;)
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Offline Danno

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Re: 78 carb jetting - feels so right but seems so wrong
« Reply #4 on: September 04, 2011, 10:12:51 AM »
like he said sounds good to me I only get 36 to 38 on a 750 140 mains will probably be good
the problem with the #2 carb could be either rust coming down from the tank making it flood out intermittently or the old fuel line could be flaking inside the middle two carbs get fuel first so they end up with all the gunk in them from the tank or lines
« Last Edit: September 04, 2011, 10:15:54 AM by Danno »
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Offline Blitzburgh207

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Re: 78 carb jetting - feels so right but seems so wrong
« Reply #5 on: September 05, 2011, 09:08:34 AM »
Haha k thanks guys!

Quote from: Gordon on September 04, 2011, 09:59:44 AM
You just can't please some people! ::) ;)

lol I'm nothing but pleased right now!  ;D I just don't read about many people having to jet that much on here (especially the slows) so I was jw if that was a sign of something being wrong...

I forgot to add that the exhaust is wrapped too - which also requires an increase in jet size right?

Thanks again,
Adam
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