Topic: Just a fair warning and another ?

[Duanob]

Let s try the basic things first. Does the 77 750 fuel tap have two drain pipes? If it's anything like the 76 550 you have one pipe feeds the 1&2 and the other pipe feeds the 3&4. If the gas tank is fairly empty and leaning on the side stand there is a chance that two carbs aren't getting enough fuel. Easy enough to check, put a bowl under the fuel tap and pull the lines and open the tap to see how much fuel flow you get. *It might just need more gas in the tank. Cold cylinders only means they are not firing it doesn't mean an electrical problem.

*Trust me it happens. I had a shrug shoulders/slap forehead moment just like this (right after pulling the carbs and recleaning them, going through the entire ignition system and doing a compression test!) All it needed was more gas.

[kjdelaney]

Let s try the basic things first. Does the 77 750 fuel tap have two drain pipes? If it's anything like the 76 550 you have one pipe feeds the 1&2 and the other pipe feeds the 3&4. If the gas tank is fairly empty and leaning on the side stand there is a chance that two carbs aren't getting enough fuel. Easy enough to check, put a bowl under the fuel tap and pull the lines and open the tap to see how much fuel flow you get. *It might just need more gas in the tank. Cold cylinders only means they are not firing it doesn't mean an electrical problem.

*Trust me it happens. I had a shrug shoulders/slap forehead moment just like this (right after pulling the carbs and recleaning them, going through the entire ignition system and doing a compression test!) All it needed was more gas.

No it has one hose. It goes to the 2 carb. It is the master and the others are slaves. I just did the starter fluid thing on 1 and there was no change. As of right now if i pull the wire to the 1 cylinder there is little change to how the engine is running. if i pull the 4 wire the motor dies. As far as my compression I misspoke. If my memory serves me it was @ 85. However i want to check it again just to be sure. All carb bowls have fuel. Honestly i believe they are all running but the 3 and 4 side runs hotter.

I just went out and started the bike. Let it run for a minute or so and touched the 1 and 2 pipe and they were hot. The 3 and 4 side was by far WAY hotter. So much so that the heat radiates off that side. Honestly im afraid to let it run too long out of fear of seizing it up!

I don't understand why if i pull the 4 wire the engine dies and if i do the same to 1 it barely makes a change. There's a slight noise difference but i had to do it a couple times just to pick up on it.

[cgswss]

It simply means that the engine is running off of #4, but #1 is not doing anything.

When you use the started fluid, it is taking the place of any gas in the bike.  That's why I use it- to see if the cylinder is ready to run, but just isn't getting gas.

Do you have an inductive timing light?  I'm not interested in the timing, I want to make sure the #1 cylinder is still firing under compression.  Also, if you have enough length on the spark plug wires, just for grins, you might switch the wire going to 1 with the one going to 4.

Do we know that spark plug in #1 is a good one?  If you have another, you might want to switch it, or just swap the #4 plug to #1 (as we know that one is working)

[kjdelaney]

Do you have an inductive timing light?  I'm not interested in the timing, I want to make sure the #1 cylinder is still firing under compression.  Also, if you have enough length on the spark plug wires, just for grins, you might switch the wire going to 1 with the one going to 4.

Do we know that spark plug in #1 is a good one?  If you have another, you might want to switch it, or just swap the #4 plug to #1 (as we know that one is working)

I do not have a light. i swapped the plug wires and the same thing continued to happen. However this time, after I swapped the wires back the way they should be, i pulled 4 and it kept running. All the plugs are brand new. I'm at a loss. I do think its over heating though. After having it run for a couple of minutes it started to just bog down and die (it did have gas) ..... Something tells me i'm going to have to pull this motor out and give it some love. i don't want to but i guess that can be next winters project.

[LesterPiglet]

After reading this I am now confused. It would be a good idea to establish you have the correct ht leads going to the correct cylinders now.

[kjdelaney]

After reading this I am now confused. It would be a good idea to establish you have the correct ht leads going to the correct cylinders now.

You and i both....It is all hooked up as it should be. I'm just trying everything that gets thrown my way. Bottom line is i know something is "off" the bike is running but it gets hot. Too hot on tht right. I'm going to try to get the carbs dialed in. See if that helps. It may be too lean @ 3 and 4. I know its a stab in the dark but it needs to be done.

[LesterPiglet]

What speed is it idling at?

[kjdelaney]

What speed is it idling at?

@1500 rpm. My idle speed is another thing i haven't really brought up. I have to force the accelerator forward to keep the idol where it should be. One thing at a time i guess... any thoughts on that? Ive been looking for a good link for info about the carb adjustment and syncing but i haven't really come up with much.

[MCRider]

What speed is it idling at?

@1500 rpm. My idle speed is another thing i haven't really brought up. I have to force the accelerator forward to keep the idol where it should be. One thing at a time i guess... any thoughts on that? Ive been looking for a good link for info about the carb adjustment and syncing but i haven't really come up with much.

Usually, when you have to force the idle down, the cables are misrouted or otherwise too tight. Since the b cable doesn't have an adjuster, it may be installed with both nuts oon the sme side of the bracket, causing everything to be too tight, or its OK and the A cable is too tight. Assuming the idle screw in the rack is down far enough to let it idle.

One way to tell is to disconnect the B cable altogether and just work with the A. There should be a little slop in the twistgrip, then it should pull open smoothly and upon release, snap back to idle without any help.

Then add the B cable back in. There should be no difference.

[kjdelaney]

Just a quick update! I synced my carbs last night and the 3 and 4 carbs had way less vaccuum. They were way lean. Now it is running alot better. Except for some minor backfiring (poping in the pipes) any suggestions as to where the idol mix screw is on PD carbs?

[bjatwood]

Good news on the carbs & syncing. Now check the timing, adjust the valves,  and THEN do another compression test and let us know what kind of numbers your getting.....