Author Topic: Spankin new noob, point me in the right direction.  (Read 1797 times)

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Offline devilinlee

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Spankin new noob, point me in the right direction.
« on: July 08, 2010, 09:15:10 PM »
I am the proud new owner of this 76 cb750, and now that I bought it... I'm not sure where to start. Ive been hanging around on the forum for a week or two and Im decent with a wrench on my car but Ive never dealt with a carbureted engine. The guy who sold it to me says the carbs need to be re-jetted because of the 4 into 1 exhaust thats on there (which btw Im not sure I'm keeping, same goes for what appears to be an f series tank and that fiberglass seat if anyone's interested) which I figure is a good place to start no? The petcock is jimmy-rigged and Im not sure what to do there, the front break has no pressure which I assume I just need a new seal or it just needs bled, the chain rubs on the centerstand so something must be missing, do most of you just remove it anyway? The motor runs, gets through all the gears but sounds like maybe its getting too much air? Overall it seems to be in decent shape. In the end I'm leaning towards going with one of Benjies setups, I particularly like what Bud here did pictured at the bottom. I like carpy's bikes too though the benjie stuff seems a bit more newb friendly. Still, theres a million ideas flying around in my head but I'm just excited to get started! This forum, a manual and my baseline level of intelligence is what's gonna get this done so I appreciate everyones contributions!

traveler

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Re: Spankin new noob, point me in the right direction.
« Reply #1 on: July 08, 2010, 09:26:36 PM »
Welcome!

Do you wnat a Cafe bike?

If so:

the tank stays
the seat stays
the pipe stays

In short....all you need is some tuning and some paint and you're on the road. :)

BTW, I'm partial to cafe's. ;)

~Joe

Offline fastbroshi

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Re: Spankin new noob, point me in the right direction.
« Reply #2 on: July 08, 2010, 11:25:00 PM »
   Sometimes you can get away with not rejetting if you just change exhausts.  It won't run perfect, but it'll get you from A to B reliably.  With those pods on there you're going to NEED to rejet for the best throttle response at all inputs.  As for the chain rubbing, maybe your stand had a rubber bumper of sorts to keep it from going up so far, not sure on the 750s. 
Just call me Timmaaaaay!!!

Offline devilinlee

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Re: Spankin new noob, point me in the right direction.
« Reply #3 on: July 09, 2010, 12:04:18 AM »
Thanks for the welcome traveler. I'm partial to cafes as well, I just lean towards a modern look. In truth, the tank is a little beat up, it holds but it needs to be finished. The seat is just a molded piece of fiberglass, no pad, no screwholes... Im thinking of using it to eat my cereal. I may end up keeping the pipe.

I figured I could get AWAY with not rejetting but point well taken fastbroshi, and I certainly will. Problem is *looks down in shame* I dont know how. Like I said, Ive never touched a carberetor, anything Ive worked on has been fuel injected. I've been looking a little online and searched the forum for a how-to guide but they all assume a certain amount of knowledge. Got a link to a thread with a step-by-step how-to for dummies? Eventually I'm gonna have to find someone in Colorado to give me a hand as I'm sure I'll get stuck somewhere. Any mile-highers out there looking to take pity?

Offline fastbroshi

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Re: Spankin new noob, point me in the right direction.
« Reply #4 on: July 09, 2010, 12:36:59 AM »
Those look like the stock carbs.  A fellow forum member is actually sending me his to rebuild.  I'll take some pictures for you.  He'll probably get them to me by Tuesday or so, and I'm moving, so it'll probably be a little over a week before you see anything.  Maybe I can learn how to do some video editing in the meantime.  Anywho, I'd try to source some Honda gaskets, not even sure if the '76 750 K's are available anymore, but we'll see.
Just call me Timmaaaaay!!!

Offline Zig

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Re: Spankin new noob, point me in the right direction.
« Reply #5 on: July 09, 2010, 03:51:33 AM »
Hay.
Like the bike, your gonna have fun.
As was said, pods/4 into 1 and your altitude will make dialing in carbs an interesting job.
Is engine stock otherwise?
If it sound like is running lean didya try closing choke a little to see if improves?
What colour are your plugs after a run, white...tan..or black??
After you get it close to proper mixture maybe a morgan carb tune to balance carbs.
You can prob find your manual here somewhere, look around.
You came to the right place for info, these guys are the best.
Good Luck.
Zig.
And that B_Morty pic is sweet, where didya find it?
« Last Edit: July 09, 2010, 04:02:31 AM by Zig »

Offline MasterChief750

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Re: Spankin new noob, point me in the right direction.
« Reply #6 on: July 09, 2010, 11:08:10 AM »
your chain rubs because the bump stop for the center stand is on the original exhaust you will need to either remove the center stand or or fashion a stop for it.
1978 CB750 K - Project Red Headed Step Child
1976 CB750 K - Drag Bike
Some things i know, others i dont.
I AM THE STIG
Sam is THE STIG
he said i can be STIG3 tho

Offline brycegp

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    • 1971 CB750 "Mut-N-Chop" Cafe Project
Re: Spankin new noob, point me in the right direction.
« Reply #7 on: July 09, 2010, 11:59:10 AM »
Good to have you!  I was (still am) a noob in your exact position about a year ago.  I started with a Cafe and didn't really like so I am changing the whole thing.  You'll find that these bikes are pretty simple in general...so long as you have solid electrical, engine gaskets and tuned carbs.

My build thread I just started:
http://forums.sohc4.net/index.php?topic=73552.msg819125#msg819125
« Last Edit: July 09, 2010, 02:44:59 PM by brycegp »
1971 CB750K/F - El Toro
El Toro Build Thread - http://forums.sohc4.net/index.php?topic=73552.0

Offline SHORTROUND

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Re: Spankin new noob, point me in the right direction.
« Reply #8 on: July 09, 2010, 12:51:13 PM »
this will get you in the ball park.

130 mains
needle clip one step richer (2nd notch up from the pointy end.)
idle air screw 1/2 to 3/4 turn out