CB750C with a semi failed modification

S

saben

New Member
Long time lurker here jumping into a project. Getting ready to drop some cash on a nice looking 81 cb750c. The guy is selling it pretty cheap because it doesnt run as well as it should and is having a few electrical issues he is annoyed with. He bought it from someone that tried a super bike mod for it (Superbike bars, PODS, 4-1) Unfortunatly, it now doesnt idle worth crap and will not charge the battery.

The electrical I believe is a bad alternator rotor (Battery isnt charging, bike will start up with a charged battery just fine but once the bike is warmed up the bike will not start until it cools again. Battery just barely turns, once it cools it will start up again) I'm pretty comfortable testing that with my good ol' multimeter.

My guess is the Carbs were not rejetted for the 4-1 and pods (Rough to start, Idles really high once warmed up). I want to keep the 4-1 but will probably buy a stock airbox and remount. Question is how do I know what size jets are currently in there? Are they numbered on top? I have never opened the carbs on a bike before and want to have an idea before I crack into that. Any recommendations on carb adjustment for just the 4-1?

Pretty excited about the bike. Little spit shine and it could be a nice ride.
 
Re: New bike with a semi failed modification

saben said:
Question is how do I know what size jets are currently in there? Are they numbered on top?
Click to expand...

Only way to confirm is to open up the carbs and remove each jet. The size is usually stamped on the side or top of the jet.
 
Check out 6 sigma for a jet kit or dynojet. You can make the pods work, drilling the slides helps a bunch on the cv carbs.
 
Some if the best advice I wish I had taken on earlier here was to try to tune to stock jets first. Of course its not going to be possible on all applications but I spent a month tweaking the jet sizes and tune on some new pipes and air filters. After being close many times, tearing my hair out, I took the advice and had her dialed in within an hour. Keep a log book of all your sizes and settings and how the bike responded At different positions and temps. Its easy to get confused about what worked best or distracted. If you have it all written down it's easy to "get out" once you get lost and return to workable settings if you've gone too far.
 
Thanks for the quick replies!

Good deal, I figured they would be marked in some way but did some searching and couldn't find any info. I'll tear the carbs off there and see what it looks like.

I have no concerns with getting pretty involved but based on the shear amount of posts complaining of pod whoas I don't see that all the pain is worth a little extra horse power. I don't mind the look of the stock box especially on this model as it has the slick chrome covers. Am I missing something? Do pods add some magic I am unaware of beyond a bit more umph?
 
best thing to do would be fit stock airbox, much easier than trying to jet for pods.
To get pods and power, you need to change carbs but that gets real expensive
 
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