Boging when warm
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Cruiser
Joined: Nov 2005
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Boging when warm
Have a little problem. After setting the points the bike stopped popping through the carb s,o I decided to take it out for a little farther ride around the neighborhood. About 3 miles into the ride I noticed that when doing 25 to 30 mph the bike was running great. I accelerated to cross a busy street and the bike lost power and bogged until I backed off the throttle. pretty sure the timing is right and the points are set right.Only happened after the bike warmed up. Before the ride I set the idle at about 1100 rpm's it would start to die at 950. Then I adjusted the low speed idle screw until it smoothed out. Again everything was smooth until the bike warmed up. Thanks
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
RE: Boging when warm
Jimbo.....
It could be any of a number of things.
First off, did you ever adjust the valve push rod clearance? I do not recall you saying that you did.
If you did not, then make that the first thing you do.
I would check the points gap one more time, just to eliminate that.
Make sure you have good spark plugs installed.
If the bog is still there after doing all of the above, then the next thing you want to do is make certain the float level is set to the correct height. If the problem is with the carb then the float level is the first thing to check to make certain it is correct.
I will go no further for now. Lets see what the above does for you, if anything.......pg
It could be any of a number of things.
First off, did you ever adjust the valve push rod clearance? I do not recall you saying that you did.
If you did not, then make that the first thing you do.
I would check the points gap one more time, just to eliminate that.
Make sure you have good spark plugs installed.
If the bog is still there after doing all of the above, then the next thing you want to do is make certain the float level is set to the correct height. If the problem is with the carb then the float level is the first thing to check to make certain it is correct.
I will go no further for now. Lets see what the above does for you, if anything.......pg
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Cruiser
Joined: Nov 2005
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RE: Boging when warm
Update: I checked the push rods. adjusted correctly. Had to take one out and replace the top cork gasket and readjust. For kicks I rechecked the timing and can now say that the bike is timed perfectly. I had to do it by myself just moved the timing plate a little counter clock wise. tightened it down and shot through the plastic plug. The vertical line splits the window and it's very easy to see. But, the bike still bogs just like it did before. I have now set the points, checked the timing, adjusted the push rods. still looking for the cause of this. The bike starts up very easy and in neutral on the kick stand will rev great. Any ideas? starting to think it's the carb but why would the bike rev good on the kick stand and not when running down the road?
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
RE: Boging when warm
Did the bike begin to bog down only recently? Or has it always been like that?
The reason I ask is because I went back to your original post on 8/30 and looked at the photo you had posted of the machine.
It looks like you have a Bendix carb on the bike. Is that correct?
It also appears that you have a 2 into 1 exhaust set up on it. Is the large pipe open (without baffles) or is there a baffle installed?
The reason I ask is because if this is a large diameter open pipe, that may be the reason you have the bogging. A pipe set up such as that has zero back pressure and the result is a great loss of power and torque at lower speeds.
If you are running a baffle in it then that is not an issue, and the place to go look at next is the carb.........pg
The reason I ask is because I went back to your original post on 8/30 and looked at the photo you had posted of the machine.
It looks like you have a Bendix carb on the bike. Is that correct?
It also appears that you have a 2 into 1 exhaust set up on it. Is the large pipe open (without baffles) or is there a baffle installed?
The reason I ask is because if this is a large diameter open pipe, that may be the reason you have the bogging. A pipe set up such as that has zero back pressure and the result is a great loss of power and torque at lower speeds.
If you are running a baffle in it then that is not an issue, and the place to go look at next is the carb.........pg
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Cruiser
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RE: Boging when warm
Yes it is a bendix carb. The two into one still has baffles in it. When I say bogs I mean the bike falls on it's face. I get out of the throttle and at slow speed it runs great. 20 to 25 mph and no problems. open up the throttle any more than that and the bike slows to a crawl. The carb was rebuilt. i set the float level with a drill bit as per the rebuild instructions. Blew compressed air through the passages. to me it acts like it either is being starved for gas or spark. It has a new coil in it, I know for sure that the timing is dead on(very visible vertical line in the dead center in the hole) I have set the points three times and the last time it smoothed out all but a couple pops through the carb now and then. . Is there a chance that this could be voltage regulator/generator related? or does this sound more like a carb issue?
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
RE: Boging when warm
I will say with certainty that it is not a regulator or generator issue. The generator is used as a means of recharging the battery and the regulator is part of that circuit. They have nothing to do with, or related to the engine ignition system. The ignition system only requires one thing that is electrical.....that is a 12V current to the points, coil and condenser. It is getting that now. If it were not, then the engine will not start or run. Period.
The generator/regulator just recharges as the battery is being used.
This puts the carb in the spotlight.
It sounds like you have the points, timing and valve clearance set to spec. That leaves the carb as the possible cause.
The Bendix is a really simple carb.
First, what type of Bendix do you have? That is to say, is it a fixed main jet or an adjustable main jet? A fixed main will have one screw on top, along with a button looking plug over the top center of the carb.
The adjustable mainjet carb has 2 screws on top.
I am going to scan the instructions for adjusting the Bendix as a jpeg and attach it here, so you know how to do the adjustment.........pg
[IMG]local://upfiles/8331/7F251D2F0CF240B084DF59FEDB319701.jpg[/IMG]
[IMG]local://upfiles/8331/9E0A95E6E6754D8890138DBF45221007.jpg[/IMG]
The generator/regulator just recharges as the battery is being used.
This puts the carb in the spotlight.
It sounds like you have the points, timing and valve clearance set to spec. That leaves the carb as the possible cause.
The Bendix is a really simple carb.
First, what type of Bendix do you have? That is to say, is it a fixed main jet or an adjustable main jet? A fixed main will have one screw on top, along with a button looking plug over the top center of the carb.
The adjustable mainjet carb has 2 screws on top.
I am going to scan the instructions for adjusting the Bendix as a jpeg and attach it here, so you know how to do the adjustment.........pg
[IMG]local://upfiles/8331/7F251D2F0CF240B084DF59FEDB319701.jpg[/IMG]
[IMG]local://upfiles/8331/9E0A95E6E6754D8890138DBF45221007.jpg[/IMG]
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6th Gear
Joined: Aug 2007
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RE: Boging when warm
I had one act up this way once...
It might not be the problem, or worth checking, but is the fuel valve in good shape?
It might not be the problem, or worth checking, but is the fuel valve in good shape?
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Thread Starter
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Cruiser
Joined: Nov 2005
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RE: Boging when warm
It has one screw on top and a cap over the other. When I rebuilt it I didn't pull the cap out but, I soaked the this down with carb cleaner and blew it out with compressed air. Do you think I should pull this cap out and clean it? If so how do you get the cap out? I have considered that it may be the fuel valve in the tank. I pulled it out yestarday and cleaned it with carb cleaner and compressed air. The fuel valve is the stock two valve. It has one handle for fuel and one for reserve. I did notice a drastic increase in the amount of fuel that would flow through when I had them both turned on vice just the fuel side. I haven't run it yet since I cleaned out the fuel valve. I guess tonight I will try to run it as it is now with both fuel and reserve turned on. If that doesn't work I'm going to pull the carb apart again.
Stellar HDF Member
Joined: Feb 2006
Posts: 3,035
Likes: 17
From: Houston Texas
RE: Boging when warm
Jimbo....
That tells me that you have a fixed jet carb.
NO, DO NOT remove the cap! This will break the seal and you cannot get that back.
Instead, take off the float bowl and remove the main jet tube. This is the brass center spindle inside the carb. There should be an O-ring around the body of the tube. This O-ring is what seals the fuel in the float bowl from leaking into the venturi. As long as the seal is good, the fuel is forced to flow through the main jet. This is how it should be.
If that O-ring is damaged in any way, the fuel will leak past and dump directly into the venturi as raw fuel. The result is a super rich condition.
I have a long sad story relating to this O-ring failure myself. It took me a long time to find the problem, which was fuel fouling the plugs at highway speeds.
If you need a replacement O-ring, just go to Lowe's plumbing department and buy a 10 pack of O-rings for about $1.27.
As I recall you want to get a #5 (but that may be a #6) so take the old one with you or measure what ID you need.
I have attached a photo of my carb (which is an adjustable jet Bendix) showing this O-ring. The long large needle is the mainjet adjustment needle on my carb that goes where you have the cap on yours.
Your carb will be similar, except you will have a fixed jet on yours........pg
[IMG]local://upfiles/8331/9DC7FE2E8B484E108882487CE790D95A.jpg[/IMG]
That tells me that you have a fixed jet carb.
NO, DO NOT remove the cap! This will break the seal and you cannot get that back.
Instead, take off the float bowl and remove the main jet tube. This is the brass center spindle inside the carb. There should be an O-ring around the body of the tube. This O-ring is what seals the fuel in the float bowl from leaking into the venturi. As long as the seal is good, the fuel is forced to flow through the main jet. This is how it should be.
If that O-ring is damaged in any way, the fuel will leak past and dump directly into the venturi as raw fuel. The result is a super rich condition.
I have a long sad story relating to this O-ring failure myself. It took me a long time to find the problem, which was fuel fouling the plugs at highway speeds.
If you need a replacement O-ring, just go to Lowe's plumbing department and buy a 10 pack of O-rings for about $1.27.
As I recall you want to get a #5 (but that may be a #6) so take the old one with you or measure what ID you need.
I have attached a photo of my carb (which is an adjustable jet Bendix) showing this O-ring. The long large needle is the mainjet adjustment needle on my carb that goes where you have the cap on yours.
Your carb will be similar, except you will have a fixed jet on yours........pg
[IMG]local://upfiles/8331/9DC7FE2E8B484E108882487CE790D95A.jpg[/IMG]