im too rich but...timing is weird.

[madeindetroit]

Trying to get my bike running and I think I have one of two issues, too rich from the carbs or my coil is weak.

Randomly the bike kick over fine and fire right up. Idle and run with choke out.
I push it in and it lowers idle and things are good. Other times I kick and kick and kick and nothing just poofs of fuel.

When it does run
I will then adjust timing to where it says fire on the PMA sticker. Usually by the time I push the timing light out of the way the bike will die.

50/50 shot of it kicking back over and starting. usually it wont start back up and I have to retard timing to get it to start again. then repeat the process above to full circle back here.

I was reading into the cabs but I cant find what style I have. I read that the needle had steps on it and I could make it leaner but lowering the c clip. Well I took my needles out and no luck its non adjustable.

Its a xs650 thats punched over to a 750. Running short open exhaust and no filters (frame is in way).

When it does run I can rev it up and it pops out of the exhaust. Will run good at low RPM but then as I start to accelerate (higher rev) will run like crap.

Any ideas people? Here are the carbs I have.
Can I make any easy adjustments to lean it out some? Or do I need to buy something.

 

[scabber]

Pull the plugs out they should tell you. If you haven't Cleaned the carbs best to do first. Float level setting are critical on the BS 34 carbs and will cause the bike to run poorly. With the exhaust you are running. Tuning and the performance of the 750 kit negated. I ran the BS 34 carbs base line setting 42.5 pilot jet 135 main jet. 1 1/2" pipes and Short cone mufflers on my 750. The bike ran good some minor surging at cruse. A bigger pilot jet needed 45 and a 137.5 main jet. I would retard the timing and check the total advance. You need to get your carbs right then worry about the timing. Hugh can advise you on the PMA and his timing marks.

 

[irristeve]

my only gripe of hugh's P M A is there is no timing mark you have to put your own one on, so if you dont get it right its going to be hard getting the timing right,if the advance-retard meachism isn't right it will be even harder,keep tinkering

 

[pamcopete]

madeindetroit,

Well, I don't see where you said anything about your ignition system or if you are running a battery or capacitor, all of which could be involved in your problem.

I would suggest that you try running the engine with the ignition powered from a separate battery sitting on the floor, not connected to the bikes electrical system. This is a test to separate the PMA from the ignition to see if the PMA is contributing to the problem.

 

[madeindetroit]

Running a cap, the brake light and rectifier/regulator, drain it so each start would be at 0 volts (unless I was lucky enough to just shut if off while running with switch. I understand a kick or two and it starts, and it will do that on a cold start.
It warms up (runs for 3-4 min if that) and its a beast to start again.

I pulled the plugs a bunch and they are black so that leads me to think its real rich or weak spark.
I also pulled plugs, rotated crank till piston was at TDC, marked the sticker at TDC. And started to time it that way.
When it runs and I can time it, it will start better retarded but timing light shows it should be 3/4 toward full advance. Then wont start after I shut it off advanced. I time it where at idle its at fire and when i rev it the timing mark will move to the advance mark like it should.

I was reading about the stock coils and it said that you cant pull one plug off while bike is running because it will ruin coil? Is that true? That was going to be how I shut engine off but decided against that after it didn't work to well So I could of ruined my coil when I pulled a wire off the plug?

Bike ran a year ago with 1 or two kicks in the dead of December when it was stock (now nothing was left stock except carbs). This leads me to think fuel is ok, PO also mentioned he just went through all the carbs and I have all the old ones to prove he fixed these.

 

[pamcopete]

I would suggest that you try running the engine with the ignition powered from a separate battery sitting on the floor, not connected to the bikes electrical system. This is a test to separate the PMA from the ignition to see if the PMA is contributing to the problem.

The fried coil with one wire disconnected is mostly related to the green monster coil

 

[madeindetroit]

How would/could the PMA cause a problem?

 

[madeindetroit]

If its voltage I checked that before I put everything together. all within spec.

 

[gggGary]

Carbs are BS34 can't see the drain so they could be either foam or brass float. Suspect flooding due to bad float valves, float valve o-rings and a leaking petcock.

 

[5twins]

I'm not sure about that, I know nothing of PMAs. What I can tell you is you don't set your timing at TDC. I think you've gone ahead and changed too many things all at once. Now you have a bike that once ran and doesn't anymore. It could probably be straightened out and made to run again but I'm not sure you're the guy for that job. It takes a fair bit of knowledge which you seem to be short of. Study old posts and the shop manuals for a few weeks, maybe that will help.

 

[XSLeo]

Does your rotor use a key to lock it in position on the crank shaft. If not it may be slipping a bit so you can't time it right.
You say you found TDC then marked the sticker. After finding TDC wouldn't you mark the rotor for TDC.
I think if your PMA isn't creating enough voltage it won't have enough to firte the ignition. The capacitors funtion is not so much to store electricity. It acts as more of a filter to stabilize the output of the reg/rec. If your cap is bad or too small it may be letting the reg/rec go wild and you maybe getting spikes of up to 20 volts.
Also it sounds like your avancer isn't working as well as it should. Do the weights spring closed when you pul them open and release them. If they don't or are sluggish you need to clean and lube the rod and bushings in the cam. Maybe even tighten the springs.
Leo

 

[madeindetroit]

What would make you think the advance is not working? Seems to operate just as it should per how I read to set up the pamco.

Yes my bad, I typed wrong, I marked the rotor to above where the sticker shows TDC per instructions in doing the PMA.

Before wiring everything I did what Pamcopete has said in many threads.
Get the engine running with the Pamco first, and I did that.
Then hooked up the PMA and got it running, did that
checked voltage with engine running and its within spec. (all done with a battery on the ground)

Then installed my cap bike didn't fire as easy but started once I adjusted timing. Voltage still good when running.
Still will fire up with cap, and run, but has issues as explained above.

Here is the cap I am using.

Rotor does not have key and is not moving.

 

[madeindetroit]

I'm not sure about that, I know nothing of PMAs. What I can tell you is you don't set your timing at TDC. I think you've gone ahead and changed too many things all at once. Now you have a bike that once ran and doesn't anymore. It could probably be straightened out and made to run again but I'm not sure you're the guy for that job. It takes a fair bit of knowledge which you seem to be short of. Study old posts and the shop manuals for a few weeks, maybe that will help.

I am confused with this post because you say you know nothing of PMA's but say im doing it wrong?
I am doubly confused what is triggering you to say this, as I feel you do not know me or my abilities. If you see where I have misspoken or missed a step please explain.

You set TDC to the TDC mark on the PMA sticker Hugh supplies you.
You then time it (while engine is running) to fire when running as explained in other threads.

I appreciate and thank any help that people are offering.

 

[TwoManyXS1Bs]

My money is on that cap. I'd say figure out a way to run for a while on a lead-acid battery, evaluate in that configuration.
Long ago I learned a unique thing about capacitors, their ability to handle transients. Ever see a power supply schematic where a large filter cap is paralleled by a much smaller bypass cap of different construction? Caps don't act quite like batteries. Batteries have the ability to sink large transients that many large caps cannot. I'm no longer in the electronics industry, so I can't give you tech data on large cap transient specs. Maybe pamcopete can find/elaborate on this...

My 2 cents.

 

[pamcopete]

Well, I'm also not an expert in PMA science, but TooMany is right. I would somehow install a battery while working on the problem to eliminate the possibility that the PMA is somehow involved.
We could have a long discussion about how or why the PMA could be the source of the problem, but it is just easier to eliminate it for test purposes. I like to get something to work before I break it.

Again, not being an expert, that cap at 10,000 MFD seems a bit small, so one way to see if it is working OK is to use the AC scale on your meter and measure the ripple voltage. Start with the 20 Volts AC scale and downshift.

That theory about using a smaller cap in parallel on a large cap is because the large cap has a bit of inductance due to its construction and the smaller cap is there to kill any possible random oscillations that may develop, but I don't think that will have an effect here.

 

[ProSimex]

yeah i run a 35v 25000mfd cap

 

[XSLeo]

You say that sometimes it starts and runs ok but the next time it won't. If the advancer rod is sticking that might expain why it runs ok sometimes and not another. Not a hard thing to check. And this would eliminate it as a cause.
Leo

 

[pamcopete]

You say that sometimes it starts and runs ok but the next time it won't. If the advancer rod is sticking that might expain why it runs ok sometimes and not another. Not a hard thing to check. And this would eliminate it as a cause.
Leo

 

[madeindetroit]

Oh wow is my cap too small? I got it off here on a bobber thread as a commonly used one.

The tail light will change in intensity as my voltage is low at idle and better when I rev it. I feel that is normal,unless I had a stout battery like a stock bike has.

 

[madeindetroit]

advancer works as video btw