Author Topic: jetting a 78 750k with pods  (Read 1800 times)

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Offline toddr513

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jetting a 78 750k with pods
« on: June 07, 2011, 05:55:47 PM »
any advice you can give me on the situation would be great, I am running a 4 into 1 exhaust. what do i need to do to get it running great

Offline Blitzburgh207

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Re: jetting a 78 750k with pods
« Reply #1 on: June 07, 2011, 06:04:48 PM »
I've got a stopwatch going to see how fast someone will say "ditch the pods" hahaha.

No, I've got the same setup and I've been tuning it about every other day since I bought it in march  :-\  Right now it's a little lean and I'm running 120 mains and shimmed the needles with one factory "shim" each (2 is too rich).  I'm going to get some 125's and 130's and see where it gets me...

I know I should give up the pods but that would be accepting defeat.
I'm interested to see if your thread can dig anything up for me! (:

Good luck and welcome to the boards!
1978 CB750 K8

Offline Cuts Crooked

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Re: jetting a 78 750k with pods
« Reply #2 on: June 07, 2011, 06:51:33 PM »
I'm running 120 mains with original 4 - 4 exhaust & pods, and 78 750K runs great. I suspect the 4 - 1 exhaust is going to call for something with a higher number, like 125s. But that's just a SWAG on my part.
Cuts Crooked
CB 750K8
Old Bikes 'n Old Guns are my first two loves :)

Offline Coyote13

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Re: jetting a 78 750k with pods
« Reply #3 on: June 07, 2011, 09:27:51 PM »
4 into 2 reverse megs, pods, 120 mains.  Blitz, I'm pretty sure '78's don't have any shims stock.  You CAN shim them, but they aren't already in there.  I'm about to try some new pilot jets, I think stock for our bikes is a press in #35, probably gonna go up to a 38 or 40 if I can find them.  Seems to run a little lean across the midrange, but low and high are solid.  I know siriusconinc sells press in jets but I haven't really done a good honest amount of homework.  Good luck man, it can be a frustrating process.  I've said it before and I'll say it again: plug chops are your friend.  Invest in a good carb sync tool, it could be your new best friend.
'78 CB750K.  Throttle ripper.
'71 CB100.  Grocery getter.
'01 XL883.  Panty dropper. Gone but not forgotten.

Offline dave500

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Re: jetting a 78 750k with pods
« Reply #4 on: June 07, 2011, 11:29:46 PM »
now taking orders for popcorn and beer.

Offline Retro Rocket

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Re: jetting a 78 750k with pods
« Reply #5 on: June 08, 2011, 12:40:46 AM »
any advice you can give me on the situation would be great, I am running a 4 into 1 exhaust. what do i need to do to get it running great

An airbox.....there you go guys..... ;D
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline Freaky1

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Re: jetting a 78 750k with pods
« Reply #6 on: June 08, 2011, 05:22:25 AM »
any advice you can give me on the situation would be great, I am running a 4 into 1 exhaust. what do i need to do to get it running great

An airbox.....there you go guys..... ;D

Just a hair over 6 hours, I'm surprised it took that long!  ;D ;D ;D
That which does not kill you leaves cool scabs which turn into awesome scars.

'77 CB750F Come on...were almost there!

Offline KeithB

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Re: jetting a 78 750k with pods
« Reply #7 on: June 08, 2011, 06:20:51 AM »
'78K 750 - 4 into 1 MAC exhaust with pods
shimmed the needles 1mm and installed 135 mains.
Starts, idles and runs great!
Nanahan Man

Offline geemann

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Re: jetting a 78 750k with pods
« Reply #8 on: June 08, 2011, 07:01:29 AM »
i have actually been looking into this topic a lot lately and two of the biggest chunks of advice that i have stumbled upon that would have never occured to me are:
1) the altitude difference between two members can be enough for one jet size to work for one person and no the other
2) the middle two cylinders are the real problem children b/c after the engine warms up and traveling at certain speeds, they will experience different airpressures than the two outer cylinders.

i am a huge fan of the way four pods look and i do not want to compromise by running cylinders 1 & 2 to one carb with one pod and same for cylinders 3 & 4.  nor do i want cylinders/carbs 1 & 2 to one filter with the same for cylinders 3 & 4.  however, you may be willing to explore these options. theoretically, they should make the tuning process easier.

i am still in the "exploring the idea" phase of my project, but I plan on applying the same methodology to my running four pods project that i do to anyother project:
-research the topic to death*
-equip with the right tools
-double check everything
-drink a beer
-never surrender

ok, those last two are optional, but patience is not.

goodluck,
-g


*for research, i found this article very helpful, a little patronizing at times, but helpful none the less:
ww.aircooled.net/gnrlsite/resource/articles/jetting.htm
my drug of choice has two wheels and 750cc

Offline c(b)hris

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Re: jetting a 78 750k with pods
« Reply #9 on: June 08, 2011, 07:15:57 AM »
...and once you have all that sorted, stay out of the rain  :-\
75 CB550
74 CB750

Offline Freaky1

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Re: jetting a 78 750k with pods
« Reply #10 on: June 24, 2011, 05:13:45 AM »
I have long toyed with the idea of picking up the dual carb setup from Cycle X, that would also solve the two middle carb issues.
That which does not kill you leaves cool scabs which turn into awesome scars.

'77 CB750F Come on...were almost there!

Offline Coyote13

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Re: jetting a 78 750k with pods
« Reply #11 on: June 24, 2011, 06:40:37 AM »
Sure, if you like hacking your frame and have the $$$
'78 CB750K.  Throttle ripper.
'71 CB100.  Grocery getter.
'01 XL883.  Panty dropper. Gone but not forgotten.

Offline Blitzburgh207

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Re: jetting a 78 750k with pods
« Reply #12 on: June 24, 2011, 06:52:22 AM »
haha ya i realized that yesterday when i was looking at that setup. ...guess I just have to build a chopper ;-)
1978 CB750 K8

Offline Coyote13

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Re: jetting a 78 750k with pods
« Reply #13 on: June 24, 2011, 07:42:58 AM »
Something about an inline 4 in a chopper frame just rubs me all sorts of wrong.  Not sure why, just doesn't agree with me.  I really am a big fan of the twin carb setup though, would be cool to see someone utilize it in a more sporty/cafe fashion. 
'78 CB750K.  Throttle ripper.
'71 CB100.  Grocery getter.
'01 XL883.  Panty dropper. Gone but not forgotten.

Offline Blitzburgh207

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Re: jetting a 78 750k with pods
« Reply #14 on: June 24, 2011, 01:41:14 PM »
Something about an inline 4 in a chopper frame just rubs me all sorts of wrong.  Not sure why, just doesn't agree with me.  I really am a big fan of the twin carb setup though, would be cool to see someone utilize it in a more sporty/cafe fashion. 
I saw some kid in his driveway yesterday w/ a hacked up and stretched yamaha 400 that actually looked pretty cool... made me rethink the jap chopper thing.  I agree tho - I definitely like the racer look better.
I wouldn't mind working a working a cafe frame around those suckers  8)
I'm sure some people on here have done it.
1978 CB750 K8

Offline Freaky1

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Re: jetting a 78 750k with pods
« Reply #15 on: June 25, 2011, 05:37:33 PM »
I have already removed every tab on my frame for the stock air box and side cover mounts, what other mods could there be? The one bike I ever saw in person with them on didn't look like there were any other changes.
That which does not kill you leaves cool scabs which turn into awesome scars.

'77 CB750F Come on...were almost there!