Topic: 71 CB500 project.

[cafehonda500]

Hello everyone.   This is my first post on here and I figure I should start out with my bike.  Its a 71 CB 500f based off the numbers on the plates.  bought it from a guy who claimed to work on it a little.   It did run though.    Wiring harness looks choppy though.   After about 10min of idle it would die though.   So something with electrical.  It came with extra exhaust so put on the 4-2 sidepipes.   Put uni foam pod on for air Intake (no hate please I know what mess I just got into).    Had a guy drill out my jets.  Idle to 42 and main to 120?(I think he said that.  He knows his #$%*). New spark plugs.  New Dyna 5ohm coils.  New wires.  New NGK 5ohm boots.   Right now having carb issues.  They keep leaking lol.  Have *fixed* them many times still leak.    Here's some Picts too.  Sorry can't find my good ones of it.

[rb550four]

Hello and welcome.
 Dies after 10 mins. of idle , carbs are leaking like crazy,and you suspect electrical?
Is it left to idle on the centerstand or the sidestand?
What part of the carbs are loosing fuel?
Have you cleaned the petcock to ensure proper flow? inspect the inside of the tank for debris and condition?
What have you done to the carbs so far?Have you done a proper cleaning?
Are all your pipes hot? Try it on both centerstand and kickstand , see if all the pipes are hot in each position. I'd suspect fuel starvation on the kickstand well before electrical being the trouble.
Why is the wiring choppy? I see new aftermarket coils,plugs boots and wires , do you suspect that or other wiring issues.
  How well did it idle before the pods and jet drill?

[Retro Rocket]

Keep the airbox, you'll thank me later....

[cafehonda500]

Hello and welcome.
 Dies after 10 mins. of idle , carbs are leaking like crazy,and you suspect electrical?
Is it left to idle on the centerstand or the sidestand?
What part of the carbs are loosing fuel?
Have you cleaned the petcock to ensure proper flow? inspect the inside of the tank for debris and condition?
What have you done to the carbs so far?Have you done a proper cleaning?
Are all your pipes hot? Try it on both centerstand and kickstand , see if all the pipes are hot in each position. I'd suspect fuel starvation on the kickstand well before electrical being the trouble.
Why is the wiring choppy? I see new aftermarket coils,plugs boots and wires , do you suspect that or other wiring issues.
  How well did it idle before the pods and jet drill?

thanks for the fast reply!  Ok First off i guess i did not describe the issue properly.  I could putt the bike up and down my driveway (1/4 mile) for once or twice at about 10mph if that.  was low rpm in 2nd gear.  The bike would start sputering and die.  from what I could tell it was getting gas.  would let it sit for another 10min and she fired back up after doing nothing to it.
Next.  carbs were only leaking from 1 overflow stem.  took it off made sure float wasnt horribly off (wasnt so i left it alone) put it back on now 3 carbs leaking out the overflow and even through my pods.  wayyy overfull.
Carbs were taken apart and cleaned individual in an ultrasonic cleaner, new bowl gaskets, and re assembled.  did a bench sync and had it idling at about 1300rpm.
I would normally test it on the center stand unless i was too lazy to pull it on than side.   
it idled the same before i did pods as it does now with pods and jets.
I just did the new coils, wires, boots, and plugs last week.  my thought was that the coils were going bad, thats why i replaced them.
harness looks choppy because it is spliced all over with normal blue and yellow autowhatever crimps.  some wires are not even connected and some liike brittle/aged.   sorry for rambling so much just wanted to try anwsering you properly.    thanks for any help everyone!!

[rb550four]

Overflowing carbs are still an issue.
    Do you have electronic ignition or points? If you have points have you checked on the condition of the spark advance while you were there to make sure it functions properly, are the points new, factory or aftermarket, have you set them properly with a light (on 1-4 and 2-3), are you sure the timing is correct? Are you using a fresh battery or trying to resurrect a dead one?
    Have you cleaned the fuel system yet? Tank,petcock,fuel lines...are you running fuel line filters, do you have excess line, is there any hard bends or kinks in the line, are they running on a downward plain from petcock to the carbs and not wrapped around them. Are you sure you didn't get any crap in the fresh carbs from an unclean fuel delivery system.
Sounds to me like the carbs will be coming back out and blown out (at least), at that time you may want to recheck float height on all 4 and possibly change jets ( your call).
    Are you going to purchase another wiring harness or will you take those crappy crimps out, solder the splices ,and shrink wrap each repair?
    I would suggest doing only one of these things at a time so you can isolate the problem/problems starting with the fuel delivery.
    And I didn't ask before but, is this fresh gas  or gas that was waiting for the lawn mower, there hes been issues with shelf life on fuel.
    Just trying to get a better picture of where you 're at  exactly.

[cafehonda500]

Update.
Me and my guy are working on the bike more.   Tinkered with the carbs more.   Learned the hight was about 1-2mm off on the floats.   Also the float pins are kinda worn and causing  floats to stick every now and than.   We did get them adjusted and put back on and it fired up easily (heated shop).  New coils worked great.   But one float still leaks a tad due to the pin making it stick.    We are currently  working on getting new float pins but may end up with new carbs as he is seeing many worn parts that will need to be replaced soon.    New floats and pins are $40/each so $120 needle and seat may be bad too.   Might be looking at some Mikuni carbs for it now....
And suggestions on new carbs?   I can do my own research on parts for the old ones but know nothing about what kind of new carbs to put in.

[rb550four]

+1 on sending out the carbs like Cal said.
  All this tinkering with old carbs/ new parts or new carbs/no idea will be costing you big bucks, send them out , you'll be way better off.
  It'll give you some time to clean the tank  (and seal it if it needs)and petcock properly,get new fuel lines  to make ready for soon to be  returned clean carbs.

[cafehonda500]

new update!!
first off thanks for the advice again guys.
so we worked on the bike again and we learned a few bad things.    1 the gas tank has a leak in it, can feel gas dripping on the seam.  2 the fuel petcock is bad.  it is not giving enough flow for the carbs to work properly.  3 the floats in the carbs are bad.  they are absorbing gas and getting heavy.   here are a few pictures of the carbs, this is why im asking about new ones.  as you can see there is some major pitting and chips around the main jet.  carbs 1 and 4 are like this  carbs 2 and 3 both look very good though.  but other than these few issues we had the carbs adjusted near spec and had the bike running very well, it drank fuel though,due to the heavy floats, so we didnt run it too long but she sounded very nice.   on a side note if your exhaust doesnt seal properly make sure you have the collars on the right way lol  i blame the other guy, he blames me but who knows.

[Stev-o]

Sounds like your tank is rusting and your petcock could be clogged. 
I recommend Caswell to seal the tank.   

[SOHC4 Cafe Racer Fan]

Sounds like your tank is rusting and your petcock could be clogged. 
I recommend Caswell to seal the tank.

+1

[cafehonda500]

First off thanks for the advice guys, you're all great!!   So I ordered 4 new carb floats, hope this fixes it.   Live in MN so im gunna have to wait a month or 2 so seal the tank up.    few questions now.   1. Were can i find a nice fuel petcock for the tank?   2.  What is the best tank sealer to the tank?  I see a few liked Caswell.  My guy told me to try Kreem but i read a lot of bad Kreem seals that dont last.    3.  how do I prep the tank for the sealer?  What works best for cleaning any rust.  How can i attempt to seal the leak on the outside (if needed, idk if the sealer will do it)     

[SOHC4 Cafe Racer Fan]

First off thanks for the advice guys, you're all great!!   So I ordered 4 new carb floats, hope this fixes it.   Live in MN so im gunna have to wait a month or 2 so seal the tank up.    few questions now.   1. Were can i find a nice fuel petcock for the tank?   2.  What is the best tank sealer to the tank?  I see a few liked Caswell.  My guy told me to try Kreem but i read a lot of bad Kreem seals that dont last.    3.  how do I prep the tank for the sealer?  What works best for cleaning any rust.  How can i attempt to seal the leak on the outside (if needed, idk if the sealer will do it)   

Buy a genuine Honda petcock; the cheaper reproductions sometimes leak.  You will need Honda Part #16950-300-020  You can find one on ebay for about $45.  http://www.ebay.com/itm/GENUINE-HONDA-PETCOCK-CB500-CB550-CB750K-KAWASAKI-KZ400-/201073426760?pt=Motorcycles_Parts_Accessories&fits=Make%3AHonda&hash=item2ed0e90148&vxp=mtr

I have had very good results with Caswell and very bad results with Kreme and Red Kote/Coat (clogged carburetors and rust).  That was with proper application.  I know some others might like these products, but that's just my experience.

Prep -- take your tank to a radiator shop to be cleaned and pressure tested.  Acetone before coating.  Sealer may work.  If it is a small leak, you can braze weld it.  If it is multiple pinholes with thin steel, you may have to cut it out and weld in a patch.

[cafehonda500]

great news everyone, the bike runs and is drivable!  the new floats did the trick.   we still think the seats are a little off but everything ran ok.   pulled off the fuel petcock and wow that thing was nasty.   i plan on cleaning the tank soon here but would still like peoples input on a good tank sealer.    with any luck i should be riding on the road in a few weeks!!

[jkminer]

POR15   has a kit that will remove some light to moderate rust, etch, and seal the tank.  Used it a few times, never on anything that had a leak though. It's taken care of some rotten tanks though.

https://www.por15.com/mobile/POR-15-Motorcycle-Fuel-Tank-Strip-Repair-Kit_p_60.html

[SOHC4 Cafe Racer Fan]

I think Vinegar is probably the cheapest solution for de-rusting a tank, and awfully effective. Expect it to flash rust very promptly afterwards though unless you treat with Acetone prior to a liner.

I really like the Caswell liner. I've used it on lots of tanks and been very pleased with it. RedKote has worked too, but it seems to me to take much longer to fully cure. It does remain a touch "pliable" afterwards where the Casell is rock hard when cured.

There are some members who swear by Caswell (me), POR15 or RedKote.  I've had a bad past experience with RedKote and Crème coating on gas tanks.  No bad days with Caswell.  I have the tank cleaned and pressure tested by my local radiator shop before pouring in the Caswell right after.

[cafehonda500]

Update.
ok guys i managed to find and solder the leak in my tank.  it was a small pin hole near the seam NOT on the seam.    to find the leak i added some degreaser and a lot of red food coloring so when i slowly turned the tank i could see a clear red leaking out.   never seen this idea online so try it out if you cant find the exact leak.   than threw in a handful of short/sharp screws and shook that around till my arms couldnt take it.  lots of rust came out but i could see there was still some inside.  than i found a product at Oriley, but can be bought everywere, its called EvapoRust  all you do is pour it in the tank and it eats away the rust.   i added 2 gal to my tank and wow its clean now.   just got my order of Caswell tank sealer that i will be using soon.   any tips on using Caswell?   ive seen videos and it looks easy but id rather learn from others mistakes lol     thanks yours your advice is making this easier

[SOHC4 Cafe Racer Fan]

I prefer to pour into tank from petcock to insure coverage on underside. Split the product and do two coats.

Excellent idea.  Do you do half from the top and half from the bottom, or both coats from the bottom/petcock?

[SOHC4 Cafe Racer Fan]

First coat from petcock, second coat from filler neck. I try to get coverage on the entire tank with both costs, but I do concentrate on the surface in that order.

That makes good sense.

[cafehonda500]

Update.
So I have sealed the leaks in the tank and used Caswell to seal the inside of the tank.   This is the first time I have ever used a tank sealer but it was very easy to do.   I didnt have a funnel to pour from the petcock so I just poured from the filler neck.   I did two coats because after the first I could still see small spots that did not get coated.   This stuff hardens like a rock!!   I poured all the extra I to a cup and after it hardened I couldn't break it stabing with a screwdriver.   Bike no longer leaks nor do I worry it will again.   I also bought a manometer and properly synced my carbs.    Finaly after 2 years I road the bike on the road for the first time.   Man did this feel amazing!!   It runs decent and I had a blast.   I did however notice that it ?surges? At around 6000rpms.   If I slowly accelerate to it it will almost free rev for a second than I have power again?   Not sure what would do this.   My guy said try closing the choke a little but that did nothing.   Any ideas what would cause this issue??   Does not make the bike unrideable just very annoying.   Thanks guys.  With your tips I got my bike running and am enjoying it.   Have also learned a lot along the way

[cafehonda500]

Thanks for the fast reply and no worry no hate taken. I enjoy learning more about my bike as I go, thats why I didnt buy a complete/newer bike....well that and budget lol. I know a lot of people hate pods on these old bikes/carbs.   I guess a little more clarification is needed.   It normally happens when Im in 5th gear (but has happened in others) and around 5000 rpm which is about 55mph for me.   If I slowly, roll on the throttle it accelerates to 5500-6000 rpm than jumps like its free reving.  From this point I can either hold the throttle and it will rev up a bit than "catch" and I can accelerate OR if I roll off the throttle a little and roll back on it accelerates fine.   If any more info is needed just ask and Ill do my best to answer.
Today I played with the fuel/air mixture screws and got it to coast much better at about 3000-4000 rpm for in town riding, because it use to pop or backfire?? not completely sure the difference yet lol  Screws are about 2 turns out.  I also went and looked at my needle clips and apparently they were set at the highest,near the pointy end (this is higher right?) so I put them in the middle and now notice the Bike surges near 4500rpm.  I am going to try putting the clip up one (near pointy end) and see what that will do.   Question, when syncing carbs with a manometer what should my vacuum pressure be?   I have read before that is doesnt matter as long as they are the same.

[Retro Rocket]

  I guess a little more clarification is needed.   It normally happens when Im in 5th gear (but has happened in others) and around 5000 rpm which is about 55mph for me.   If I slowly, roll on the throttle it accelerates to 5500-6000 rpm than jumps like its free reving.  From this point I can either hold the throttle and it will rev up a bit than "catch" and I can accelerate OR if I roll off the throttle a little and roll back on it accelerates fine

That sounds like a the clutch slipping under load to me....

[cafehonda500]

Hey guys!  So I decided it was time to rewire my bike since its been gloomy here recently.   I bought the Motogadget M-Unit and M-Button.   Bought them directly form Motogadgets website for slightly cheaper than any american dealer will sell them.   My old wiring was worn cracked and looked like 5 people tried fixing the last guys mistake.  There were quick splices into a taped splice into a pigtail all leading to a dead wire.  No Good!!!   So I have ripped off the old wiring and started running lines to the Motogadget.   For the most part using the Motogadget is very easy and even a wiring idiot like me can get it.   So far I have the key switch, horn, blinkers, brake light, and starter button all working.   Now to the part were I am getting confused fast.   I have done lots of searching on forms how to wire this but keep getting confused.  I am not sure how to wire the Headlight controls to the M-Button (using stock 3 way switch).   Also maybe a dumb question, But I keep reading different things on it, What do I run the Factory Black wire to???   Is this just a ground?  looking at the stock wiring diagram it see they all connect but dont see were it goes to.  And Last of all, I am not too sure how to wire my charging system.  i understand you use Aux out for one wire to the coils, but thats it.   I am using the all the stock charging stuff, I think stock, the Regulator is a 5 prong.   any advice, tips, and tricks would be a nice help lol 
Also here is my work in progress.  This is my ideal mounting spot, but if you notice anything wrong let me know.

[cafehonda500]

I was hoping you would reply Calj, but i didnt expect so fast!   I have the key switch wired as you said already.

For headlights do i just abandon the other wires from my switch than and only use the low beam light? 

The black wire is still confusing me with.  Say blinkers, if I ground the black wire they work proper.  So I guess I dont understand how to run the black wire still.

As for the coils, I thought the start button acted as your kill switch, double tap and it kills, and the stock kill was no longer needed.  So with this set up you ran the coil black/white wire from Aux out on the M-Unit?

So I understand the Left side of the M-Unit is all the IN controls, in my case the M-Button, Rear Brake, and Key switch, and the Right side is all your power out.  You run your right side power outs to the power wire from of say your lights and horn correct?   Than ground the other wire to complete the loop?  This is my basic understanding.

So do you run the black to your Aux port for switched 12v?

Thanks for the amazingly fast reply, your past write ups and comments to others using Motogadget are what pushed me to get it and helped me get this far!

[cafehonda500]

Is there any trick for getting the thicker 2.5mm wires into the m-unit.  I can't get any to work.

[cafehonda500]

OK I ran new wire for my coils.   Kept the blue and yellow stock color.   Ran the black/white to kill switch black/white.

Black wire is still killing me.   Ran from aux out to front of bike.   Connected all the black up there (only black). Now nothing works with Aux light up.  If I turn it off (no light on Aux). They work idk what I'm doing.

Headlight is ran with white low light wire to m-button.  Light is off when key on,  switch to low position it jumps to high.   Switch to high it goes to low.  Switch all the way to off and it is at high.