Weak Midrange RPMs. Loss of "Pull".....goes flat...

[EvenmoreXS]

Plugs didnt look so lean tonight. Picking up new plugs tomorrow so I will be able to tell more then.

Voltage was 12.25 . I turned things on and off a couple times getting things ready.

Test starting voltage was 12.17 . Voltage at the coil was 11.91 . Drop of 0.26v .

Its charging when revving. Guess it hasnt had time to charge back up to 12.5 or so.

I plan to charge it to full and see how she runs in the morning. I'll keep track of the voltage to see where it settles.

I dont currently own a battery tender. Is that wrong of me........Should I wire one in and plug it in at night? I just assume that would help on the really cold nights here in florida.........If we ever have one of those..........

Pictured is my new gizmo...courtesy of Ggggary...Its a color changing diode that lets you know your charging status and voltage by colors and flashes. Jury is currently out. It cant be a bad thing, just gonna see how accurate it is for a bit.

 

[EvenmoreXS]

Charged the battery this morning. Rode the same.

Found this thread.


Originally Posted by ace79xs650
James,

I'm not sure if this is the problem but I had something similar happen to me that ended up being my advance weights were sticking. I removed the advance rod, greased it with moly grease and then ordered new springs from mikes to place on advance weights. Again I'm not that experienced as others on here but that was my issue.

Andy

+1. I've read in a couple of other places that if loading the engine against the brake brings the revs down and they stay down, it's the ignition advance. If the revs drop and then pick up again when you pull in the clutch, it's the carburation.




That makes me wanna grease my rod.

 

[5twins]

Many fuel filters restrict flow. You may get enough at idle and low speeds but not at higher speeds. If you have a spare length of fuel line, I would take the filter out for a few days and see if that makes any difference.

Yamaha never made any mention of servicing the advance rod in any of the manuals. I guess they didn't expect these bikes to be around this long, lol. It's not something that needs to be done often but it needs to be done, maybe like every 5 or 6 years or so. Now, that's assuming you used the proper grease on it in the 1st place. I see Pete recommends just putting some oil on it for his Pamco installs. I doubt that will last long.

 

[EvenmoreXS]

Many fuel filters restrict flow. You may get enough at idle and low speeds but not at higher speeds. If you have a spare length of fuel line, I would take the filter out for a few days and see if that makes any difference.

Yamaha never made any mention of servicing the advance rod in any of the manuals. I guess they didn't expect these bikes to be around this long, lol. It's not something that needs to be done often but it needs to be done, maybe like every 5 or 6 years or so. Now, that's assuming you used the proper grease on it in the 1st place. I see Pete recommends just putting some oil on it for his Pamco installs. I doubt that will last long.

I will be picking up some extra fuel line later today and ordering a new filter. I will run without a filter to see if that betters my flow. Never found anything bad in my bowls or jets or filters or lines....so I think my tank is ok. Not perfect for sure, but I dont think the filter has a shit load of work to do as it is now. So no filter for a short time should be ok.

Used a moly grease I got from advance auto. I will see exactly what when I get home tonight.

These bikes will be around for a while longer. They have longevity.

 

[weekendrider]

Fuel flow isn't your problem. Plain and simple you are barking up the wrong tree.
If it gets enough to run well at speed then it (flow) isn't starving the motor at idle period.

 

[5twins]

You should be fine on the advance rod then. You can do that quick "snap back" test to check it.

 

[retiredgentleman]

Plugs didnt look so lean tonight. Picking up new plugs tomorrow so I will be able to tell more then.

Voltage was 12.25 . I turned things on and off a couple times getting things ready.

Test starting voltage was 12.17 . Voltage at the coil was 11.91 . Drop of 0.26v .

Its charging when revving. Guess it hasnt had time to charge back up to 12.5 or so.

I plan to charge it to full and see how she runs in the morning. I'll keep track of the voltage to see where it settles.

I dont currently own a battery tender. Is that wrong of me........Should I wire one in and plug it in at night? I just assume that would help on the really cold nights here in florida.........If we ever have one of those..........

Pictured is my new gizmo...courtesy of Ggggary...Its a color changing diode that lets you know your charging status and voltage by colors and flashes. Jury is currently out. It cant be a bad thing, just gonna see how accurate it is for a bit.

There's no need to own a battery tender to charge the battery over night. If you have a good battery, and a good charging system, that charges at 14.1 volts around 3000 rpm, your engine will start up using the starter motor, every day of the week.

 

[EvenmoreXS]

Fuel flow isn't your problem. Plain and simple you are barking up the wrong tree.
If it gets enough to run well at speed then it (flow) isn't starving the motor at idle period.

If fuel is readily available and I have weak spark.......Could low spark causing this?

Again, I may not be as lean as I thought, but still struggling to idle. What changed since a month when she was running great? Not sure. Goes through phases. Was starting and Idling like a champ before I had my issue with the reg/rec......solved... But not quite the same since.

 

[EvenmoreXS]

There's no need to own a battery tender to charge the battery over night. If you have a good battery, and a good charging system, that charges at 14.1 volts around 3000 rpm, your engine will start up using the starter motor, every day of the week.

Thats what I thougt too. Shouldnt need tender if charging system is working and I ride most day.

 

[5twins]

Weak spark usually causes what appears to be rich running. The plugs are black and sometimes foul out because the spark isn't strong enough to burn the fuel all up. This sends guys tearing into their carbs all the time when in reality, they have an ignition problem.

 

[EvenmoreXS]

Weak spark usually causes what appears to be rich running. The plugs are black and sometimes foul out because the spark isn't strong enough to burn the fuel all up. This sends guys tearing into their carbs all the time when in reality, they have an ignition problem.

Thats what I thought. Id expect to see wet dark plugs.

So does that only leave an air leak?

Still going to try without the filter. Not filling the bowl fast enough maybe.....


Is there any truth to this quote? I can try this.

I've read in a couple of other places that if loading the engine against the brake brings the revs down and they stay down, it's the ignition advance. If the revs drop and then pick up again when you pull in the clutch, it's the carburation.

 

[5twins]

I never heard that before so I couldn't say.

 

[EvenmoreXS]

Thanks everyone. Your help is invaluable. I know you veterans get tired of going over the same stuff over and over, i see your post in other threads too,...Stick it out, you'll make veterans out of the rest of us. One day we'll drink a cold beer and laugh about this.

Graditude and appreciation.

 

[scabber]

With the big 150 I really don't know how it ran at all. You are running the small tube head pipes. They have been known to have the inner pipe flattened by frozen water. If your carbs don't flood out the bike with the 150 main I would look at the head pipes. No way I would run that big of main jet. I tried a 140 main and it was way too rich. I would work with the smaller jets. 137.5 and try a shim on the needles. If you don't use the 135 mains I would buy them from you. Sent me a PM if you want to sell them. Like 5twins said your bike is unlike most 650.

 

[EvenmoreXS]

Oh well. I Cant sell it. It would cost me. I've put over $1500 in parts, shipping and tools since I bought it. Not to mention what I paid for it. NOT to mention hundreds of hours working on it.

Seems like I am the unlucky owner of a lemon and I should think of a creative way to destroy her so as not to pass it on to another unsuspecting person. Dont want to be one of those PO's.

Cant say I didnt try.

Maybe a rag in the gas tank? Ideas???? Be creative......

 

[Scrambled]

I think you need to put your carb back to near stock spec. and start from scratch . I don't want to read all six pages of this thread. I think 5twins has it pegged ,you have an ignition problem and you over thought the whole thing and went crazy with your carb . Check for simple things ,like cracks in the boots on the coil(s) . That ( cracked boots) can cause all kinds of problems and can act up worse some days and other days your bike will run . Heat ,vibrations and humidity can make it run better or worse . Little things like that can drive you crazy .

My bike is running better than I thought it could . I owe a few guys on here a beer at least .

 

[pamcopete]

EvenmoreXS,

You posted a .26 Volt drop between the battery and the coil which is extremely low and makes me think that perhaps you did not have the coil turned on per the procedure I outlined. Try again??

 

[EvenmoreXS]

I've already tried that jetting. Stock and everyting up to this point. Runs best here, and will continue to until i fix the ignition problem you mention.

What could that be? Im jetted too big and Im lean.

Ready for Ideas.

 

[EvenmoreXS]

EvenmoreXS,

You posted a .26 Volt drop between the battery and the coil which is extremely low and makes me think that perhaps you did not have the coil turned on per the procedure I outlined. Try again??

I cant imagine it being simpler but I'll do it again. Seemed like that would be a good number.

 

[pamcopete]

I cant imagine it being simpler but I'll do it again. Seemed like that would be a good number.

Well, if you measure the difference from the battery positive terminal to the coil, then even 1 Volt would be a good number due to all the potential losses, like the fuse, the ignition switch, the kill switch and various connections. .26 might be just the draw for the PAMCO which only draws about 20 ma.

The drawing you posted seems to show a 90 degree rotor. Newer PAMCO's have a 60 degree rotor and the dwell area where the coil is on is in between either set of magnets that are 60 degrees apart.

Connect your voltmeter as you rotate the PAMCO rotor and you will see a sequence of very low voltage drop followed by what I think should be about 1 Volt.