Topic: What horsepower mods are definitely worth doing while 750 is apart?

[nitsua93]

Let me start by saying I tried to search, but it simply didn't work. What horsepower mods should I definitely do while the engine is split? I'm thinking about porting the top end but I don't have enough info on it. I'm not going to do a big bore on this motor.

Also, if I do some porting and have 4 open drag pipes what jets should I have for my carbs? Don't know a whole lot about carbs yet either. I am an auto tech in training, I've really just never worked on anything old enough to have carbs. Thanks!

[Don R]

There is a rocker shaft mod worth a little HP. It's probably in the tips and tricks section. A port clean up can help, short of a full on porting job. Depending on the year you may have good ports already, the early heads were hand ported to a small degree. You can do some reading on cam timing. The Hondaman book is full of ideas.

[ekpent]

A hone and new rings also if your keeping stock pistons.   

[seanbarney41]

if you are looking for free or cheap horsepower definately get Hondaman's book  (My Cb750 Book, Mark Paris), some stuff can be found on the site, but not all of it, four open pipes?...you may want to consider how much hearing you have left now, and how bad you want to keep what is left, or whether you want to actually ride your bike

[nitsua93]

if you are looking for free or cheap horsepower definately get Hondaman's book  (My Cb750 Book, Mark Paris), some stuff can be found on the site, but not all of it, four open pipes?...you may want to consider how much hearing you have left now, and how bad you want to keep what is left, or whether you want to actually ride your bike

I'll definitely wear hearing protection!

Sent from my A500 using Tapatalk 2

[bjbuchanan]

Smooth and match the head to spigots and clean up the ports if you are feeling adventurous. Plenty of ppl on the forum have done it so a quick search will show good examples of nice blend jobs

[MCRider]

Do not try to remove the intake spigots. Do your porting with these in place. Unless you're prepared to repair fine threads or are OK gluing them back in. IMO

To your question, the quickest easiest course to HP is an overbore. If that's out then porting is next and some minor tricks mentioned above and in HMs book.

Jetting stock carbs is piece of cake. You'll pull the old jet to see it's number and buy larger ones to suit. The needle can be readjusted for free.

[Retro Rocket]

There is more HP locked up in the head than any other part of the engine....

[seanbarney41]

There is more HP locked up in the head than any other part of the engine....

+1...especially if you have a k2 or later head, one look at the intake ports may make you sick...and 4 open pipes is really uncomfortably loud, and will make negligable power over putting a straight through glass pack type baffle in there