Topic: half drunk & full stoned

[Joe]

I picked up a whole new points/condenser plate for my 76 750F set my points, and my timing right on the money @ idle and 3000 rpm.  

Took off like a silver back gorilla down the neighborhood.  I was sure I had it this time.  After a mile or so though......disaster.  The same symptoms came back again.  The accelration completely crapped out, like I was running on 2 cylinders.  Also it dies whenever I pull the clutch in.  It's like it's as soon as ig gets warm this happens.

BACK to the shed!

Decided to recheck my timing and my 2 and 3 points were out of adjustment, so I regapped em, and got the timing perfect again.  Same process, fires up first kick and idles perfectly, then as soon as I get on the main road it craps out again.

checked my points again, but they were good this time..

any ideas what could be causing this?  

[Ogri]

It might be something to do with the cam that's opening the points. Or the advance mechanism. You're assuming it's the points that are moving but it just might be the cam that's resetting itself - throwing off the timing.

But that doesn't explain the latter part of your post.
 It sounds a bit like a fuel problem, the bowls could be filling normally but when you get it out on the road you're using fuel faster than it can get it in; blocked fuel supply at the tap or tank or hose.

Pull the hose from the tap, turn on the fuel and see if it comes out in a steady stream or a dribble.

Or, start the bike., if it's running properly immediately turn off the fuel tap and drain all the carb bowls, via the overflow hoses into a jar. Mark the level of fuel. Take the bike out onto the road with the empty jar. As soon as it starts to run badly do the same again and compare the fuel level in the jar to the previous 'good' level.

[Bill/BentON Racing]

Check your ignition coils,very unlikely to lose both @ once,but one might be your problem,Good Luck,Bill

[Steve F]

I agree with Ogri about the fuel.  Check that you're getting fuel.  Next time that happens, crack open the fuel filler cap, wait a few seconds and try again.  I'm thinking a vacuum in the tank is preventing fuel flow.

[Thunder]

I had a very similar problem.I thought it was fuel, cleaned the tank,carbs and petcock MANY times.

nothing, worked fine, then bad agin.

Then i checked the connections to my coils , they looked to be ok,
 but i sprayed contact cleaner over everything, and WOW, it all started working.

[74cb750]

Ok, but how do you check the coils?

[Duke McDukiedook]

Ohmeter and ground sparkplug to the case? Or a spark tester?

[bozo4onion]

Just checking but you didn't say you changed condensers. Sounds like mine when I had a bad one. Good luck.

[camelman]

Coils can be bad even if they check out good.  The only way to truly verify your coils are okay is to swap on a set from a bike that runs well.  The issue is that a cold coil will operate well, while a warm coil might not.  Also, a loaded (operating coil) can have different characteristics than a static coil (which is the case for most bench tests).
So, before you accept that the coils are good, try swapping in a known good pair of coils.

Camelman

[noexit]

What kind of fuel filter are you using? Does it start running okay when you return to idle? Does it run okay if you shut it down for a minute?

[Joe]

Thanks for all the input. 

-I am running new condensers, points, the whole shabang, but I haven't checked my coils, or plug wires, and who knows when (if ever) they have been changed.  I could stand to put a new set of plugs in as well, because 2 & 3 weren't looking to good when I pulled em a few days ago.  Although they're only a few months old.

The spark advancer fly weights came up in conversation with my dad & I, but if that was an issue, it wouldn't advance under the timing light when I rev it up to 3000.......right??

I'm definitely taking a mental note on the gas issue, but I really feel the problem is electrical, but I sure as hell could be wrong. I'll be doing the bowl test if the electrical checks out ok.

I'm gonna clean out the plug wires first and go down the list.

Back to the SHED!!  It's Friday.......time to tap the rockies

[Duke McDukiedook]

Yep, as long as it advances when you rev it past idle it should be OK.
Check the other stuff though.