Slow top end......

[brcree]

top end

Let me add this into the mix.....upon starting the machine up after it has sat for a day or so......it starts but the right two cycl don't fire at first and after a worm up they finally catch up and fire. Idels ok

[GLoweVA]

Ok, the pairs on the right or left are common to its respective fuel inlet, so if the right 2 are not initially firing, then it seems that those 2 aren't getting fuel, or not enough, fast enough.

Maybe your issue might not be so much fuel line routing/kinking, but could be a clogged up/fouled petcock or petcock inlet screen.

Might be worth a peek and pull the petcock that feeds that side for a good cleaning/inspection.
JAT.

[brcree]

Top end

Thanks to all of you for your help...I will be making a list of all suggestions and looking into them one by one........I need quick release pins for the seat...I've had it off more than on it seems! Will keep y'all posted as to how this works out!......if I didn't like this bike so much...it would have been gone long ago. For the ones that don't know, this is the bike that I restored that didn't have a title. After finding out the hard way here in S.C. ...no title no ride. I had to find a frame with a title and swap everything over. What a pisser.

[TopCatGr58]

Hey again,

Okay, we've got more diagnostic info from you, thanks! After it warms up and you ride it for few minutes, stop, take a squirt bottle and spritz some water on each header, and see if they all sizzle the same...or if the right 2 seem colder than the left 2 cylinders! As George stated, this pairing is usually due to carb/fuel issues more than ignition. You've got the right components...4Ro TCI and just the pickup coils/timing plate with the vac. adv. pot/mechanism, but no mech. cent. adv. parts!

You say all 4 cylinders are firing, so you probably have spark/fire there, but a more rare situation can be corroded wires between the coil and the plug caps. Separate the caps from the wires and check for corrosion, if found can snip off a 1/4" or so to get to good copper wire, clean the screw of the cap and then reassemble.

Can you tell or remind us what you have done to the carbs, how you cleaned them? If you didn't take the bank apart, then the fuel inlet T's were not removed, and they can build up corrosion and crud in them that's not visible if you don't take them out by taking the bank apart. Also, the filter under the float valve seat can also get clogged.

And just to be sure....the fuel filters have an arrow embossed on their sides to indicate the proper flow direction....the small cone end goes to the petcocks, the larger wider end goes towards the carbs.

A systematic approach is what's needed to help you narrow down the possible culprits....FIRE, FUEL, Mechanical/compression. Have you ever done a compression test?

T.C.

[brcree]

top end

Thanks TopCat.......When the rt two cyl finally fire up they are as hot as no 1 & 2. I've cleaned the small screens under the float needles, as for the T's I haven't cleaned them but the float bowels are full up to the same level in each. The comp.is good on all, and I'm getting fire at each plug...nice and blue. The filters are in correct. I will be rerouting the fuel line tomorrow.....lets see how that does.......THanks again man. Will post results.

[TopCatGr58]

Hey again,

Well, if the float bowls are full, then the fuel lines and T's are not clogged.
I can't remember if you told us IF you were running the Octopus valve, or have bypassed/removed it?? But again, the float bowls have fuel!

Did you fully disassemble the carbs to clean them, pull out the pilot and main jets, the emulsion tube, the pilot jet screws from within the tunnels on the top front of the carbs, the vacuum slides...inspected for holes in the rubber?

Both jet towers should be open to the float bowls, no rubber caps. Ensured that your float heights are even and set to ~23mm.

Slow warming up of 2 cylinders sounds like the slow speed jet (Pilot) jet circuit is at least partially clogged.

What are your jet sizes...stock or aftermarket??

Now back to the coils...the 81 doesn't have a ballast resistor, full 12 volts to the coils all the time. You describe a nice spark, but how it looks outside the engine not under compression is different than how it may be in the engine.

Did you pull the caps, check for corrosion on the wires, and then OHM the caps to be sure they are just within the 5k ohm range. If much higher, that can also contribute to a weak spark. Verify you are getting 12 volts at the primary coil wires...red/white. If low volts, can also make a weak spark. Depending on which lead of the coil pair is going to the right 2 cylinders...there has been a rare reporting of weak spark on an otherwise carb related pair..due to poor voltage. The spark travels thru the main high tension lead...thru the first spark plug(good spark)...then thru the engine, then thru the other plug and back to the coil...and if the spark energy is low...can result in poor spark on the second plug of the pair!

Keep at it.

T.C.