Topic: RE: My $100 dollar CB500 - Thanks to everyone

[chewbacca5000]

 

Did you set the idle speed with the bike fully warmed up?

Yup.  Looks like it might be time to start from the begging.

1. Compression test  / check valve lash if low
2. Adjust cam chain
3. Set valve lash
4. Dump gas tank
5. Reclean / replace aftermarket carb parts with stock.
6. Reset timing.
7. Resync carbs.

Not much I can do about crapy exhaust baffle will not come out.

[chewbacca5000]

I was thinking of what Steve-O said about the exhaust and am wondering if having virtually no back pressure is making the tuning process impossible.

Was looking a quiet core mufflers and they are very pricy and got to thinking what about a Harley exhaust?  They new ones are quieter than what I have so they must have some back pressure?

Found this link http://forums.sohc4.net/index.php?topic=77434.0.  Do you guys think this is worth a shot?

[Tews19]

I really like. Almost as if it belongs....

[chewbacca5000]

I really like. Almost as if it belongs....

That is what I am thinking.  Would still have to fix some holes in my 4 into 2.  Wish I had a 4 into 1 header I would do the same exact thing.

[seanbarney41]

You will be shocked and apalled by how much those sportster mufflers weigh...

[chewbacca5000]

You will be shocked and apalled by how much those sportster mufflers weigh...

Just grabbing at straws here.  Would rather not spend anything at all.  If it idles sometimes can't really blame it on the exhaust no can I?

Strangest thing I am redoing my 3,000 mile tune up and undid the carb before starting so 3 and 4 were just sitting there with a crack between the head and the carb manifold, and I decided to do a spark test as plugs 1 and 2 did not look so good.  Guess what the dam thing ran better on two cylinders 3 and 4!

There is something really screwed up with the mixture on this bike.

[iron_worker]

If your exhaust is blown out and has no back pressure then you will need to jet up from stock as the exhaust gases will be clearing from the combustion chamber more efficiently and thus you'll be able to bring in more fresh air which requires more fuel.

If the back pressure is wildly different from cylinder to cylinder then this will create problems as well since your cylinders are basically out of sync and it will make getting a smooth idle very difficult. I don't think any amount of vacuum sync'ing the carbs will help that situation.

IW

[chewbacca5000]

If your exhaust is blown out and has no back pressure then you will need to jet up from stock as the exhaust gases will be clearing from the combustion chamber more efficiently and thus you'll be able to bring in more fresh air which requires more fuel.

If the back pressure is wildly different from cylinder to cylinder then this will create problems as well since your cylinders are basically out of sync and it will make getting a smooth idle very difficult. I don't think any amount of vacuum sync'ing the carbs will help that situation.

IW

I tend to agree with you.  Cylinders 3 and 4 are the ones with the holes and they ran.  Really think if I can get the fuel air mixture straighten out the bike will be able to idle.

Even with just straight pipes I should be able to get an idle if my A/F is correct.  Currently got the carbs ripped open and am trying to set needle.  For 627bs it says 4th clip positoin.  Is this from the top or bottom?  It's currently in the 4th from the top.

[chewbacca5000]

3,000 mile tune up take II complete.  Found several things wrong with the carbs.
1. Linkage was a little messed up.
2. My sync was way far off.
3. Jets were not pushed all the way down.
4. Float height was a little off.
5. Needle seat needed to be pressed down more. 

Man I hate press in jets!  750s carbs are way easier everything screws in.

What I did.

1. Cam chain adjusted.
2. Valves Ajusted.
3. Main jets replaced with kehin jets
4. Needle 3rd from top
5. Bench synced carbs.

Result ran awesome at first.

Now the gremlins have moved into the electric system.  With a charged battery nothing works except headlight and tailight.  Blinkers, starter, and horn do not work.

[Randy]

aaarrr.. when I got mine home, the first thing I did was print out a wiring diagram off the interweb, and took every connection apart, and clean with automotive wheel aid and electrical greased them all.. Including the start and turning signal swtches on the bars.. I started from back to front and marked them off as I when..

[chewbacca5000]

aaarrr.. when I got mine home, the first thing I did was print out a wiring diagram off the interweb, and took every connection apart, and clean with automotive wheel aid and electrical greased them all.. Including the start and turning signal swtches on the bars.. I started from back to front and marked them off as I when..

I have done that problem is that the wiring harness was melted when I got it.  I am thinking it's time to say good bye to this one.  Too bad at least I got in one ride.  Time to move this puppy over to bikes for sale section. 

[Tews19]

Look for a cheap used wire harness. I found kine on eBay for 35 shipped. Hooked it up once received and it works perfectly.

[chewbacca5000]

Look for a cheap used wire harness. I found kine on eBay for 35 shipped. Hooked it up once received and it works perfectly.

Thanks Tews I guess I just am not a cb500 man.  They sure are fun to ride though!  This one is up for sale http://syracuse.craigslist.org/mcy/3918711192.html.

Been at this project and am not getting anywhere.  Best I can do is to get it to idle at 2,00 rpm.  Sure there is a cb500 /cb550 guru that will make this thing purr.

[rb550four]

PM'd

[rb550four]

 Chew,  Engine numbers on 750's

750E1056375   on 1970 frame  turns over
750E2357417   on 1974 frame  seized
750E2525799   on 1975 frame  seized
 
That is how the numbers  read .

                                RB

[SOHC4 Cafe Racer Fan]

Chew,  Engine numbers on 750's

750E1056375   on 1970 frame
750E2357417   on 1874 frame
750E2525799   on 1975 frame

                                RB

Holy crap!  1874!!!  Now that's an old CB!! 

[rb550four]

yeah that would have been exciting if true ....fixed it.

[SOHC4 Cafe Racer Fan]

yeah that would have been exciting if true ....fixed it.

Sorry.  I couldn't help myself.  I will try to behave better.

[chewbacca5000]

Chew,  Engine numbers on 750's

750E1056375   on 1970 frame  turns over
750E2357417   on 1974 frame  seized
750E2525799   on 1975 frame  seized
 
That is how the numbers  read .

                                RB

Sweet!  I am super stoked!  Gonna have project palozza!  Might have to rent storage or join 12 step program.

[Stev-o]

Chew,  Engine numbers on 750's

750E1056375   on 1970 frame  turns over
750E2357417   on 1974 frame  seized
750E2525799   on 1975 frame  seized
 
That is how the numbers  read .

                                RB

Sweet!  I am super stoked!  Gonna have project palozza!  Might have to rent storage or join 12 step program.

Join the club!

[chewbacca5000]

Chew,  Engine numbers on 750's

750E1056375   on 1970 frame  turns over
750E2357417   on 1974 frame  seized
750E2525799   on 1975 frame  seized
 
That is how the numbers  read .

                                RB

Sweet!  I am super stoked!  Gonna have project palozza!  Might have to rent storage or join 12 step program.

Join the club!

I am going to be like Honda Mc Duck doing the back stroke in CB750s! Can't wait.  Like Christmas in July.

[chewbacca5000]

I would like to say thank you to everyone who came to my aid on this project.  I have decided that I am just not a cb500 man and am letting this one go to work on cb750s.  Thanks Again for all the help.

[Tews19]

Chewy did you get all those 750s for your bike?

Sweet deal if so!

[chewbacca5000]

Chewy did you get all those 750s for your bike?

Sweet deal if so!

Going to pick them up Saturday.  Whatever I don't use I will do my best to pass on.  I like the older ones and 105 is an earlier number which I am very excited about.

Will do my best to get up some pics this weekend.