Top end rebuild (Stuttering, Elec. Issues Prior) (Pic heavy)

CDI? You mean TCI? Or did the Seca II go back to CDI?

Regardless, you need to find a module to swap with; it could very well be a TCI problem.

Completely out of left field: Is there any possibility at all that you have some sort of "obstructive debris" floating around in your gas tank, that wraps itself around the pickup pipe tower occasionally? Like a leaf or a hunk of gas tank liner, or ???

 

Yea it's back to a CDI, got one inbound. I wasn't sure what the difference between TCI and CDI was until recently. That was in interesting read.

I took off the petcock a couple weeks ago while waiting for the head gasket...no irregularities.

 

What I was suggesting wouldn't necessarily be something you'd find just by pulling the petcock.

What if there was a good sized LEAF (from a tree) floating around in there, and occasionally fouling the fuel pickup tube? Then when you drain the tank, it plasters itself against the side and you don't see it...

This is just a shot in the dark. I have a long commute (lots of thinking time,) and I've been puzzling away on your issue for a while. The other evening, I remembered years ago having a giant ongoing fight with an 850 Fiat that refused to run right until one of my buddies noticed a LEAF in my carburetor, stuck to the underside if the throttle butterfly. Then it occurred to me that a similar piece of flotsam could possibly be causing your problem. Like I said, a long shot out of left feld.

It's more likely a bad solder joint in the TCI unit.

 

Ah I see what you're sayin'. I'll dig into the tank a little deeper. This will give me an opportunity find and remove any rust while I'm at it. Might as well since this bike is getting a complete overhaul anyways.

It isn't too much of a shot in the dark. The stuttering started after the Pennsylvania trip, and there were many many rainy, windy, miserable, dark and cold gas fill ups. Something could have very well decided to hop in there without me noticing.

As long as I have things to check and diagnose, I'm happy. It's when I'm sitting there without a clue what to do next that I get frustrated haha.

 

Re: Top end rebuild (Stuttering, Elec. Issues Prior) (Pic he

Ok, so a complete flush of the tank -- no debris inside.

I got the new CDI today. No change in performance.


I've all but given up.

 

What EXACTLY has been replaced, electrical/ignition wise? Did it include new plug caps?

What EXACTLY did you replace in the carbs? Did it include throttle shaft seals?

Since the top end rebuild, have the symptoms changed at all?

It's a machine, an inanimate object. It has to be solve-able.

 

Lemme see if I can get this up to date with what I've replaced since the problem started

Replaced electrical:

CDI box
Regulator/rectifier
Coils w/ brand new caps on all four
Battery
Pickup coil
Stator
Multiple sets of plugs along the whole process

Carbs:

Replaced the whole rack from a running bike
Tried different diaphragms
Verified correct jets
Float levels correct
Cleaned, tuned, synced, adjusted more times that I want to admit

Other:

New carb boots
Replaced intakes
New intake o-rings
New fuel pump
New vaccuum hoses
New fuel hoses
New petcock
Flushed gas tank
Replaced chain and sprockets
Rebuilt clutch

Compression is good. All within 140-150 (there's a previous post with the actual numbers)

Rebuilding the head had ZERO effect on the issue -- actually, nothing I've done or replaced has had any effect on the issue lol. This is all stuff I've done AFTER the problem started.

I'm not sure of the condition of the throttle shaft seals on the old rack of carbs, but there was no change in performance when I swapped the whole rack with a known working one, so I kind of ruled the throttle shaft seals out.

I took the wiring harness off and cleaned all the connectors. That fixed an issue with the battery not holding a charge. I bought a new wiring harness for $10, just to rule out the chance there is a cooked wire somewhere down the line, but I doubt it's that. It's en route, and we'll see if that does anything.

After I hooked up the CDI, it started right up. Started to accelerate pretty fast, and once it hit about 5k RPM, it starts to feel like it's cutting out, losing power, and about to die. After 10 minutes of riding and it's warmed up, it's unrideable. It will still start up, idle, and rev, but any forward motion and it stutters sharply like all the pistons are fighting against each other.

Ok, not fixing the problem is one thing. But nothing I've done has even affected the problem. That's where my mind explodes.

 

>don't shoot the messenger< What if BOTH racks have bad throttle shaft seals; the replacement had them already, and your originals got pushed "over the edge" by the long trip?

It's not uncommon for throttle shaft seals to wear out/fail in such a manner as to not really manifest themselves until the throttle shaft rotates a good bit, as in when you twist it open enough to rev over 5K. Try slathering them with vaseline on the outside and go for a ride. See if the condition "improves" until the vaseline gets sucked in and they start leaking again.

Which rack is on the bike now? Pop the clips and cover washers off the outside ends of the shaft and see what those seals look like. Do the same on the other rack. If the outside-most seals are 'shot' chances are the inners are too. Unfortunately, if the outers are in good shape, it's no guarantee that the inner ones are good though.

I'm leaning toward throttle shaft seals just because it's about the only thing you haven't touched yet, on either set of carbs.

OTHER POSSIBILITY: It might still be an electrical component of some sort that doesn't like getting hot. Once the bike gets warmed up and starts the "sputtering" thing, throw a timing light on it. Not so much to check the timing, but to see if your ignition is "breaking up" at 5K or above. I had gotten ahold of a bad set of aftermarket condensers for my Norton once that wouldn't "cycle" properly at higher RPMs. I only found it by using a timing light; the ignition pulses just went all erratic and "splattery" as the higher rpm was reached. I know you don't have condensers, but it could be a TCI problem still, or some other ignition-related problem. "Watching" it fire with a timing light might help lead you to it IF it's ignition related.

Can you tell I'm running out of ideas too?

 

The "new" rack is on there now, so I'll investigate the throttle shaft seals on the old one first. I doubt they've ever been touched before on either set.

It just so happens that I have a timing light, too. I'll see what happens with that. Although I'm curious if it will show any irregularities, because I can put the bike in neutral and rev it just fine at the point where it stutters the worst. Ahh we'll see.

Also, I've only put about 20 miles on it since rebuilding the head and I haven't checked the plugs yet. I will do that too.

That may be the case but I greatly appreciate you brainstorming with me.

 

Dude. You're thinking and proceeding in a logical troubleshooting order and getting nowhere. There HAS to be a solution; like I said:

Inanimate object. Physics. Science. We're missing something; WHAT is driving me as crazy as it is you.

This is completely different than trying to "reign in" some newbie squid who's just pulled his whole motor apart to clean it. You're doing everything right, and in order. And getting nowhere.

It just don't add up, to quote Yosemite Sam.

Oh well. About to go light up the Seca for another wonderful round of Deetroit rush-hour dodgem cars. Which gives me another hour and a half to think about this...

Remember what Sherlock Holmes said "...eliminate the impossible, and what's left is the answer no matter how improbable..."

I was so hoping you'd find a leaf in the gas tank.

 

Devil bike, it's possessed.

Nuke the entire bike from orbit--it’s the only way to be sure.

That, or donate it to the Tommy Nobis Foundation......

 

Exactly the mindset I am trying my hardest to keep lol. Thanks Fitz.

GETTING THERE

Except I want to find out where the devil is hiding in there, so I can kick his ass to neverland. Which is more rewarding? Not sure yet lmao

Dude Len, we need to grab a beer soon. I might show up on a Ninja EX500 loaner bike, but dammit I'll get there.

 

What condition is your air filter in ? ( I did not see that in your list)

Kenneth

 

Oh I forgot to add that to the list. It's a brand new K&N.


I investigated the throttle shaft seals on the old rack today. They were a little dried out, but not cracked or disintegrating.



Haven't been able to get 2 and 3 apart yet. The brace screws are on there really good.


This rack was having problems with the enrichment circuity not closing all the way. That can be investigated while I'm at it.


My goal for now: Get this rack in tip top shape and see how it performs.

 

AACK!! You didn't mention that. Was it installed before or since the trip, and/or before or since the symptoms appeared?

Do you still have the stock filter? If it's in even halfway reasonable shape, throw it back in and go for a ride.

Fitz=not a big K&N fan. Let's don't start a whole brand new firestorm; suffice to say if has drastically different "flow characteristics" than the stocker. If you really want to open the can, start a new thread...

 

Lol I usually like to stick to stock as well.

According to my email records, I bought it on March 2nd, and the trip was one month later.

The stockie has got to be in my garage somewhere...

 

Do you know exactly how PO'ed you're gonna be if that's it?

It already gets my vote and you haven't tested yet...

 

I agree with bigfitz......I was having issues with a fresh rebuild, and it was Len who asked me to try riding without the filter in place to see if my problems changed or not...he was right. My old paper filter did not look bad until I put it next to the new one.....and I had to re-colour tune and re-sinc the carbs to get it to run perfectly after the change.

Kenneth

 

Can't find my stockie, OEM is $40 -- gonna see if one of my Seca II pals can loan me one for troubleshooting.

Yesterday at lunch (it's been sitting at my work this whole time), I took the Seca out to try and get a feel for the issue -- just for enlightenment. I heard a loud PINGSNAP, and then it started running crummy.

I looked underneath and the vacuum hose that goes from #1 intake to the petcock wasn't attached on the intake side. Simple. But why did it come off? It gets hooked back up, and I rev it a little while watching the hose. Sure enough, there's a loud PINGSNAP kind of noise and the vacuum hose shoots off the intake.

Kind of like...it's backfiring through the intake.

 

Is your breather hose plugged or pinched?

Is it a new hose? New clamp?