New user, new bike!!!

[carpe_noctem]

hey, im new to the forum and new to old honda cb750!
love the way these bikes look
i was wondering since i have 0 experience with cb750 or in that case anthing this ... mature
its honda cb750F supersport the OD says 19,000+
it starts after a few pulls from the throtle and runs for a few mins and dies is not on the throttle
i feel one header is colder then the others and and might hear a ticking sound
when it riding it runs nice motor sounds better

what you guys think about it ?

[TOOLS1]

Nice looking old F model. Is it an F-2 (1977) or F-3 (1978)? Your running problems are due to dirty carbs. They will need to be removed, and thoroughly cleaned.
TOOLS

[carpe_noctem]

oh wow can't believe i forgot the year, yea its a 78
i had someone say to me the cam chain could be making the noise

but thank you i hoping that it will be a great bike for years to come

as for gas ( i hear modern gas is a issue) should i use highest octain as possible? will it help keep things running smooth and clean  
sorry i ask like a million questions i just have this need to dive deep in everything

[Re-run]

Download the manual from here and go through the tune up procedure. Get the bike to a base first.
This means, cam chain, valves, and such. Since you don't know the history of the bike, you will want to do this.

The running is, as TOOLS said, dirty carbs. In particular, the idle jets. They plug very easy. Use a thin strand of copper wire to make sure all holes in the jets are clean. You will need to pull them out for this. Wrap cloth of papertowel around the idle jet, then grab with pliers and twist and pull.
May as well remove all the fuel lines and make sure there is no junk in them, rust and such.
Clean the accel pump while at it. It should shoot a stream of gas into each carb from little brass nozzles in the carb openings.
Get an inline tank filter to stop anything from the tank.

Gas isn't an issue. Ethanol has little to redeem it, but it isn't going to cause the issues you have. I run ethanol perfectly fine. It just goes bad quickly, a matter of a few weeks. It can cause rubber to fail sooner, but running it has not been an issue for me.

Unless you have engine mods, a higher octane than what the manual calls for is not needed. Nor is it beneficial in any ways other than allowing you to give more of your money to the oil companies. Only move IF you hear knocking.

[carpe_noctem]

ok I got the files
before I do this I have another issue, my exhaust looks like its been slaped together by a Neanderthal (it really could be ) there are leeks it looks like and I don't think this is a stock muffler.
that being said I was looking into some new pipes I like the sound and look of the yoshimura style muffler on cbcafe750 .com

http://www.cb750cafe.com/products-page/exhaust/cb750-4-into-1-exhaust-sohc/

what are the steps I should take after I attach this, (rejetting as must?), any engine problems with this style of exhaust ?

ps I have started to do tune up
might go and get the carbs rebuilt and cleaned right after

[shinyribs]

You can do the carbs yourself. Just clean everything how Rerun explained. You might have to have them synched eventually, or do it yourself (its easy), but all you really need is cleaning and all new rubber/gaskets.

The ticking could be clutch rattle. While idling, pull the clutch in and see it the tick changes tone. If so, clutch rattle. Normal on these. Don't sweat it.

As far as Carly's headers, they're probably fine quality, but painted headed are haaaaard to keep painted. I dont care what kind of paint people will brag on, it's gonna heat up and rust. I've seen a few aftermarket puppies that were chrome go for the same , or not much more, than what Carpy charges for his pipes. Just a thought.

Welcome to the forum man. That's a great looking bike you picked up. Good to know you'll be treating her well.

[carpe_noctem]

the sound does change not a drastic as I would like but it does...
I hope theres a way to fix that or maybe just replace the clutch? ill look into that later for now I want her running right first

as for the headers I was just going to get the raw steel and wrap it in some black fiberglass up to the union.

and thank you you for the welcome I was rolling around here for a few days and was hoping you and tools would chime in, you guys are amazing. thank  you ahead of time for all the help!

[TOOLS1]

The rattle might be because the carbs are out of sync. When the sync is off these engines will sound like they are coming apart. If the rattle goes away when you rev the engine, it is most likely the sync. It is the DOHC engines that have the crapy clutch that rattles all the time. As for Crapy's parts. I have never been impressed with them, especially for the $$$$$$$$$$$$$$$$$ he wants. Also I know Re-run likes to endorse the pliers, grip, twist, and pull method for removing the pilot jets, however I have seen bent pilot jets, and cracked housings from people doing it this way. I remove them with a little puller made out of a piece of brake line tubing. There is a write up on here on how to do it. Just do a search for "Removing pressed in pilot jets."
TOOLS

[shinyribs]

Single cam clutches rattle, too. Especially if they seen some abuse. It creates dents in the clutch hub that lets it rattle. But it's nothing to worry about, I've actually come to enjoy the sound. New clutch plates won't help. My chopper had a real quiet clutch, but I think that engine was always babied. My old F had a super rattly clutch and it's hub was pretty dented. I think in general the F's were bought by people that wanted to do more than just cruise around, so it's understandable.

But Tools is right, being out of synch can make weird noises, too. But since the particular noise you are hearing changes tone when you pull the clutch that tells that they are related. Out of synch carbs won't do that.

We missed one of your previous questions. If you change the exhaust only, and don't touch your air filter, you probably won't need to change any jets.

If you buy black wrap it'll stay black about half of a riding season. Just a heads up. And wrap isn't cheap. lol. But fade black wrap does have a nice look to it, too. ;)

Seeing your bike really makes me want a stock single cam F. Fun, fun bikes man. The best.

[shinyribs]

Oops. Almost forgot. I love how this systems uses springs. Nice, racy look. Just add a slip-on and go. FYI, Carpy's pipes are ear splittingly loud.

[carpe_noctem]

ok so ill pull the clutch on a much later date unless I feel somethings off with it after riding it for a few weeks.

well carbs I want them working right so they will be synched.

and as I see that you guy don't like that pipe I would like some other alternatives to a pipe that sounds like I want blood for gas and well I hate any megaphone whatever looking shaker thingy. I love the straight pipe look. I should mention this now that the Yoshi pipe need the passanger pegs moved an inch and the center stand was rendered useless unless you wanted to damadge the pipe.

im sorry shiny i think some things will be changed i was debating on a fork swap (talking year or 3 )
but a deff handle bar change is comeing up  looking at some 35 mm clip on or straight bar  

seat i want a less bulky and more flat

hate the tail light and turning blinkers too they are way big

don't get me wrong i love the way this thing looks its a BIKE, not a plasticy cereal box toy i see everyone else ride around. im proud of this bike i really am, its from a time when guy wanted burns and bruises not hair gell, tans , and facebook friends (sorry i flew of the handle there) 

[shinyribs]

Nah, man. Im with you 100%.

I got no issues with Carpys pipe. It's one of the best looking systems out there , because like you, I hate megaphones,too. I got one on my '80 that I tolerate because it's the perfect sound for me.

And by stock, I just mean stock bodywork. I've gotten spoiled to modern brakes and 17" tires. If it was mine it get a CBR front end.lol.

Search for "homemade muffler". That might help you out since you don't like the look of a muffler. I was just saying the other night how I missed the exhaust system in that thread.

[carpe_noctem]

i was looking into the fork swap and it seems that the gaxr is the easiest but then ok that's great but im stuck with the stock rear , that i cant find any info on
ps this has disc allaround and dual in the front i was shocked when i fisrt started looking at them

[shinyribs]

Yep. Your bike has the best brakes of the single cams.

I put a GSXR front on my '76. Even retaining the stock 19" front tire, ground clearance was bad. GSXR trees have very little offset,so with a stock front tire your tire will get in to your headers. Ask me how I know.....


CBR F2 and F3 forks aren't USD, but they are 2-2.5" taller than GSXR's. A CBR front end with its 17" tire will lower your bike about an inch. A GSXR front end will slam it a solid 3". I will admit that the GSXR forks rode freaking beautifully. Extremely smooth. But the CBR forks aren't far behind. Definitely an improvement over stock whether you are just doing it for looks or not.

[TOOLS1]

Dibs on that seat if you want to get rid of it.
TOOLS

[carpe_noctem]

good to know on the fork, sad that the gsxr wont work, i love that gold

and yea when i switch seat ill be sure to let you know

ok so i just got home and wanted to let you guys know, i stopped by a shop a friend was at and he told me to swing by with the bike (exciting!!! maybe).  i ran thru it and this is what i cam back with ....

compression test 1=150, 2=160, 3=160, 4=180
new drive chain is worn
burning oil in cylinder 1, most likely worn valve guides and cam chain worn the maybe need to be replaced with the rollers

and after all of this i parked the bike back by me and noticed a oil spot not sure from where ill take a picture tomorrow and how where more detailed, this is bothering me now i didnt think this was there before.
he did run it a bit harsh in my opinion, but i like to baby since i just got it ( you know how it is )

so that all i got for now ill see what i got in-store tomorrow for fun

oh you like this on the ride back i thought they broke the shit out of my bike , it ran like trash, hesitation and hard to start i thought it just completely said " nope im done walk your ass home and leave me to die " i couldnt start it and i tried everything after 15 min i got off the bike and said to my self yup its had it ,..........looked down about to have a moment of silence .......someone turn my petcock off ...ass

[shinyribs]

lol I ran out of gas earlier in the week. It took me brain too long before I realized what happened and flipped to reserve.

Those are good compression numbers. There's a little bot of spread between cylinders, but not horrible. You might have a couple tight valves, so a valve adjustment might fix that. Or, since it's been sitting for a while, it might just need a little time to loosen up. Sticky rings and surface rust on valve seats. Pretty normal stuff. Would explain the burning oil in the low cylinder,too.

The GSXR can work, it just makes the bike low. All depends on what you want. I thought my '76 was too low when it sat stock, so...

[carpe_noctem]

so that leak seamed that it stopped when I walked by it today. not pouring  but its a very slow drip
dark and smells like gas a bit not sure what it could be

its redundant but where the pen is that's where the spot it
second picture is a shot of the spot, its kinda between the gear lever and kick stand  in the shot

[TOOLS1]

That is probably from one of the carb overflow tubes. Dirt can get between the needle valve and seat, and keep them from sealing, so the carb overfills with gas, and it comes out the overflow tube.
TOOLS

[carpe_noctem]

Your right After the petcock incident I think I might have just flooded because after I got it started it was only 5 blocks away from my place.

I took it out for a few hours the first 10 min had smoke come from somewhere no idea could be related to those flooded carbs. Afterwards there where no problems. However I do want it to start stronger, I have to see if the starter is stock.