Check out my new ride!

[shinyribs]

I ran into this tonight on a set of early carbs. I used polishing compound and a buffing wheel. Cured it. Big difference.Personally,I'd be a bit scared to use sand paper. It really needs to be polished IMO.

[GearBocks]

This must be replaced, totally destroyed. When 1 is bad I'm sure they all are so I purchased a set of 4 replacement cut offs and a new accelerator pump while I have them apart. Can't wait to get the new parts!  

[GearBocks]

How bout tooth paste and a brush? Or is that too harsh? I have semi-chrome polish, is that a good one to use with a buff wheel. I have a dremel with a mini buff wheel?

[shinyribs]

That tooth paste or the other will probably do just fine with your dremel wheel. If the polish doesn't seem to be working the tooth paste would probably be perfect.

You get a +1 for creative thinking on the tooth paste!

[GearBocks]

Hey thanks! I just thought that tooth paste is like 1000 grit or higher in paste form. If it scrubs my choppers clean prob does the same to aluminum. I'll post a pic of the damaged area on the slide after tooth paste scrub.

Sent from Milan's Verizon Wireless 4GLTE smartphone

----- Reply message -----
From: "shinyribs [via Honda CB750&apos;S]" <[hidden email]>
To: "GearBocks" <[hidden email]>
Subject: Check out my new ride!
Date: Wed, Aug 15, 2012 10:49 pm

That tooth paste or the other will probably do just fine with your dremel wheel. If the polish doesn't seem to be working the tooth paste would probably be perfect.

You get a +1 for creative thinking on the tooth paste!

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NAML

[GearBocks]

Ok so I got a fuel tank from a 79F and it works great! No leaks. I dissasembled and cleaned the Carburetors completely, replacing the air cut offs and the accelerator pump. I bench synchronized the carbs by using a feeler gauge to make all the butterfly valves the same. Now here comes the next problem, after installing the carbs on the bike and the new fuel tank its not idling. VERY erratic idle. Seems as though no adjustment will make it ok. Im definatly thinking vacume leak, the idle is so bad :( it was working before the the whole epoxy gas debacle so I'm thinking that all the tinkering I've done has made for a bad seal somewhere. My carb boots are rock hard, even though it was making a seal before I think its a problem so I ordered new boots and a carb sync tool! I am hoping that with new boots and a sync tool ill be able to get the seal fixed and the carbs syncd. The problem with that is I can't get the bike to idle consistantly enough to even use the carb sync (help!) My question is can the carbs be so out of sync that it won't barely even run at all? Or can totally out of sync carbs cause the bike to not idle then jump to 4000rpm then die, then only run with choke on then hit 4000 then sputtered clank and die. It's all over the place! Are there other places that vacume leaks can occur to cause this? I am wondering if when I assembled the carbs if one of the connection tubes orings is not sealing? After assembly I have no fuel leaks from my carbs. I know I spewed a lot of stuff here but any comments are very much appreciated!

[GearBocks]

Also I know its getting fuel to the floats because during the whole process I continually check the float drains. Also all 4 cylinders are firing. I have not done a compression test yet but I will. I really hope that the super bad gas didn't eff up any rings on any of my cylinders causing a massive compression leak and the super erratic idle, although when it does run no oil is being burnt and if my rings were massively out of spec wouldnt I be burning oil like a sob?

[Hellbilly429]

The carbs can make it idle that irradically, mine did, thought it was a vacuum leak and all it was was the idle adjustment screw, these carbs are super finacky. Set the idle screw to where it will stay running when you start it, then when it idles high turn them down til rpms drop to 1-1.5k, then it might idle up again as it warms up, just keep adjusting it as the idle increases and eventually it will stay constant.

If you do have a vacuum leak you can use propane torch (unlit) or wd-40 or some sort of flammable spray gas (axe works) to test for the leak by spraying around the boots and carbs, if the idle increases or decreases you got a leak.

Have you checked your spark plugs to make sure they aren't covered in that liner crap too? Just because they fire doesn't mean they are firing properly.

If you already knew or did all of this stuff I'm sorry for bringing it back up! lol

[GearBocks]

The problem is I can't get it to idle for more than 30 seconds at most! Either its not wanting to start or when it does it will barley run and die quickly. I cleaned the plugs but I have new ones and will install them with the new boots when I get them. The idle is so bad that it must be a leak. You say the carbs can make it really bad but at least it idles. Mine will not idle usually for more than 10 seconds before dying. And for those 10 seconds its a nightmare. It was running really pretty good before all of this. I need to look at what has changed, I changed the carb settings which is going to need to be corrected but something massive has happend to the functionality of the motor for it to basically not run at all. So do you think its all carb work or vacume air leak? Most probably both. I also replaced the valve cover gasket, what if there was a leak in the valve cover? Would that give me a vacume leak?

[GearBocks]

I would love for the bike to idle for more than a minute without me touching it.

[GearBocks]

After going through a lot of other threads on this subject I realize it could be anything from my reg/rec to my airbox. Im just gonna have to go through my bike again and fix/replace anything that looks super old and or bad. I read one thread from someone with almost an identical problem. He ended up selling it and buying something that works. I definatly feel that too, but I have done a lot of motor work on other bikes with great results, no reason why I can't do this... Ugh.. I'm second guessing myself. This 82 cb750 is quite the struggle. My dad always says the harder the struggle the bigger the payoff. I'm ready for the payoff. I would totally take it to a bike shop and have them do it but the shops in Seattle won't work on anything older than 1991. Anybody close to the Seattle area care to help!? I will do your laundry for 6 months if you fix this. Haha lol jk, but I'm frustrated, discouraged, and in a bike hole :(

[Hellbilly429]

It's gotta be the carbs bud, valve cover gasket wouldn't cause a vacuum leak or every older vehicle on this planet would run like shit, lol. The carbs are really the only thing you have messed with, have you tried pulling the plugs out again and seeing what color they are? Can you get someone to give you a hand with the bike for a minute? Someone to hit the gas when it's going to die? Turn the idle up if it seems to run better with the choke on and just have someone rev it up for you to keep it running, then test for vacuum leaks. If you find none, next step I would take would be to pull those spark plugs again and see what color they are so you can get an idea of what way the bike is running (lean or rich).


Have you checked your float levels at all? Might be starving the bike for fuel if you have the floats set too low.

Also, have you washed the bike at all lately? Like since you have taken the carbs off the bike? I have had this problem and have seen others make the same mistake, if you wash the bike and you get water in the ignition it will make the bike run like shit if it will even run at all, so you could always put the bike on the center stand (if it's on the side stand your oil will run out of the bike) and pull the left-hand side cover off the motor and check for foamy oil. if there is some, change the oil and take a towel and some electrical cleaner to the unit and get it nice and dry.

There are no shops in your area that will at least check out and sync your carbs properly for you? I mean it's not like those bike mechanics have never seen a set of carbs on a bike before, jesus....

Also, Tools has suggested many times to check the idle jets and make sure they are not plugged, they are easy to plug up and if you can't see through they they are plugged. Think they said a guitar string works well for cleaning those.

Trying to help tho, I really think it's the carbs man.

[GearBocks]

Hold the presses!    I think a critical error was made on my part in the way of installing the scrunchy gasket for the accelerator pump on the outside of the carb body, not by pushing it through the inside...so obviously no seal there. Also the airbox to carb boot for the #3 cylinder came off the airbox (most likely when I was stuffing the carbs back in). Yes its true, In my frustration I "jammed" the carburetors back in place disloging the #3 boot  

[GearBocks]

Haha, I was concerned about the float level like you were saying but the 82f doesn't have adjustable floats. The float stopper is connected via a part of the plastic float mold. No wire or tab to bend like on my dirtbike. So I think unless the plastic is not broke or bent its fine. Also my plugs are normal, light brown. I think not having the gasket for the accelerator pump in correctly was a big thing and the #3 airbox boot. Also my butterfly valves were pretty off after I tinkered with them trying to get it started all day. I am going through it again and I think I have down this time. It's gonna be a few days before I can get it back together but ill post details and pics when I have success.

[GearBocks]

The rubber smash gasket (whatever its called) that you can see between the openings of the wrench, I installed it on the outside of the rod, I have correctly (i believe) installed it through the carb body. I removed the boots which were hard and cracking apart like peanut brittle!

[GearBocks]

What's the best way to remove this corrosion around the intake manifold? I don't want to scratch it because I want it to make an awesome seal!

[seestheday]

That squishy rubber thing is just a dust boot. It doesn't need a great seal. I don't think that was your issue. If the rest of the accelerator pump was working as intended, then the possibility of a vacuum leak coming through there is minimal anyways.

I bet your problem was your cracked/improperly seated boots. Massive vacuum leaks will definitely cause a bike to run horribly.

Sent from my BlackBerry device on the Rogers Wireless Network

---

From: "GearBocks [via Honda CB750'S]" <[hidden email]>

Date: Mon, 20 Aug 2012 22:37:58 -0700 (PDT)

To: seestheday<[hidden email]>

Subject: Re: Check out my new ride!

The rubber smash gasket (whatever its called) that you can see between the openings of the wrench, I installed it on the outside of the rod, I have correctly (i believe) installed it through the carb body. I removed the boots which were hard and cracking apart like peanut brittle!

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NAML

[GearBocks]

 That's good to know. I thought at first it was a dust boot. Anyway I'm hoping for some better results this time around. I'm definatly paying a lot more attention to the details. Thank you !

[GearBocks]

How critical is the clearance between the accelerator pump rod and the tab that pushes it in? My manual says 0.04mm I have it set to that but it was making contact before.

[Hellbilly429]

Sorry bud, didn't realise that about the floats as I haven't cracked into my '81's carbs yet and was going off from what I know about other carbs I've worked on. I thought you said you had gotten new boots for the carbs already? God those things were cracked, lol.