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

Re: I need your brains (Stuttering, Elec. Issues)

For what it's worth, the plug pull from today. I'll see if getting these gasolinearly balanced makes any difference.

IF I can get them balanced. Mr. Stutters might be preventing that. By the looks of these plugs, the air/fuel mixtures are changing too dynamically during riding.

1-2-3-4

 

Re: I need your brains (Stuttering, Elec. Issues)

Andrewlong, given the exhaustive effort you have made to nail this down, I'm inclined to say that you might be suffering with a heat related issue. Ten minutes into a ride is time enough to heat up parts of the ignition system and start the heat cycle. You may be experiencing issue with your TCI, pickup-coils or ignition coils, even if they ohm out right. Do you have replacements for any of these? Forgive me but I've not kept up with your efforts closely nor have I read each post.

 

Re: I need your brains (Stuttering, Elec. Issues)

No worries lol, this thread is hard to keep up with even if you read it from the beginning. The info is kind of all over the place.

I've already replaced the pickup coil and ignition coils with no change in performance. The CDI box is the last thing in the electrical realm to be diagnosed. I'm willing to try anything at this point before I do anything drastic to the motor.

 

Re: I need your brains (Stuttering, Elec. Issues)

I wish I could offer assitance with your TCI but for your year all I can recommend is pop and swap. BTW, does the case of your TCI appear to have a cover or is it sealed like the '85 and up typically are?

 

Re: I need your brains (Stuttering, Elec. Issues)

It's the very sealed resin-filled type.

Someone might be sending me a good used one in the next couple days.

 

Re: I need your brains (Stuttering, Elec. Issues)

Alright, help me out here so I can cancel my admittance to the crazy house.

According to my hasn't-failed-me-yet manual, the alignment dot on the camshaft is supposed to be centered in this annoyingly small viewing window:



...when #1 cylinder is at TDC....? Wait, that's not TDC.



Am I missing something, or did my cams decide they didn't want to be lined up anymore?

 

Re: I need your brains (Stuttering, Elec. Issues)

The Timing Mark on the Rotor needs to be moved a few degrees Clockwise to line-on with the Mark at the Center of the Pickup

The Line you have the "- T -" ... centered-up on is a cover seam.

Your off a few degrees.
Pull the Number-1 Plug and shine a light in there.
Eyeball the Piston at TOP
Make any correction at the Rotor

 

Re: I need your brains (Stuttering, Elec. Issues)

The bottom picture in the previous post of mine is where the rotor TDC mark ends up when both cams are in TDC alignment. But you answered my question that the timing adjustment is off. I'll double check by eyeballing the #1 cylinder.

Now you say make any correction at the rotor, but the rotor has a pin (in the below picture) to where it cannot be adjusted.

If that's the case, I suppose the only way to adjust the timing is to take the cam chain off, align everything, and put the cam chain back on?






EDIT: I just checked the #1 cylinder by putting a small wood dowel in the plug hole, and it's at the top when the rotor mark is at TDC with the pickup coil sensor. However, the cams are off a little.

When I line up the cams to TDC again, the mark on the rotor is off by the same amount as the above picture.

 

Re: I need your brains (Stuttering, Elec. Issues)

Number-1 at TDC
(The Rotor should be on the Mark)

Lock the Crank from turning.
(Assistant)

Position the EX-Cam with the Dot in the Bullseye
(Use wrench on flats on the Cam)
Pull the Slack up from the Front to the Cam.
Adjust the Chain on the Sprocket's teeth to line-up Sprocket to Holes on Cam
Get a Bolt in with the:
Slack out
Rotor at TDC
Cam Dot in Bullseye
Move everything back or forth to do other Bolts.
Return to TDC w/ Ex cam Dot in Bullseye.

Do the Intake Cam
Same drill
Pull the Chain tight from the Ex Cam
Get the Intke Cam Bulllseye'd
Affix Sprocket

Install Tensioner and release Pawl

Turn-over Engine BY HAND
2 Complete Revolutions
Stop Rotor at TDC
Ck Bullseyes
Yes: Good
No: Do over.

 

Re: I need your brains (Stuttering, Elec. Issues)

Tried three or four times and I just can't get everything lined up.

When the crank and both cams are at TDC, the cam chain doesn't want to go on -- it's kind of mid-tooth. I have to move the cams back just a little to get the cam chain seated. After the tensioner and two rotations by hand, the mark on the pickup coil plate always ends up in the same spot, a couple degrees off.

I might be doing something wrong. Gonna try again.

 

Re: I need your brains (Stuttering, Elec. Issues)

THIS is why I fasten the Sprocket to the Chain, ... without ever removing the Sprocket from the Chain ... when I have to take a Head off.

Go back to Square One.
Then, make sure you are at Square One.
Look for ALL the Marks.
Make sure the Exhaust and Intake Cam's aren't swapped.
Remove the Tensioner.
Assure that No.-1 is TDC.
Work slowly and deliberately.
>>
Make sure that the Crank does not move when you pull-up the Slack.

 

Re: I need your brains (Stuttering, Elec. Issues)

aarrrrgggg i was so sure it was the pickup coils. Im leaning toward a crazy-ly broken wire somewhere.
also ive never set cam timing where the dots lined up perfect. theres a lot of debate on the internet as to whether or not you'd wanna be slightly advanced or retarded... cant remember... advanced for mid range power and retarded for low and high rpms?...
good luck.

man, i was so sure it was the pickups...

 

Re: I need your brains (Stuttering, Elec. Issues)

No no it was a good suggestion! I'll find the problem sooner or later. It's in there somewhere.

When it comes to this, I am slightly retarded. OH, you meant the timing.

I was going to try the timing one more time, but I got real curious what condition the inside of my cylinders were in.

Yikes!



All the piston tops were pretty much the same story. Carbonized out ye wazoo.





What a mess.



Not sure what to take from this.

 

Re: I need your brains (Stuttering, Elec. Issues)

Buy or Rent a 1/4-Inch Drill --> "Flex-Shaft".

http://www.amazon.com/Heavy-Duty-Shaft- ... B001PTSWJ6

Use the Flex-Shaft and a Wire Wheel to clean-off the Crowns.
Rag everyplace that crud could contaminate.

Having an Assistant hold a Vacuum Cleaner Hose and collect the Carbon Deposits coming right off the Wire Wheel is a huge plus.

 

Re: I need your brains (Stuttering, Elec. Issues)

Another option, if you have access to it, or can send it out, is to soda blast it. That's what I did for my GPz. Much easier and, IMO, better results, without scratching the aluminum.

 

Re: I need your brains (Stuttering, Elec. Issues)

Thanks for the suggestions!

It just so happens that I have a flex-shaft rotary tool and a slew of non-metal wire wheels. That will take care of the piston crowns since the bike is stationary in my garage at home.

For the head, I will indeed soda blast it. I've actually got a gun made, and a paint booth to use it in (here at work), just never got around to finding where I can get the soda.

Your results look great. I'm looking forward to blasting the crap (ha) out of this.

Finding a head gasket for this bike is my biggest challenge -- no luck. I should have looked into it before I took the head off, lol.

 

Re: I need your brains (Stuttering, Elec. Issues)

Harbor freight carries the soda and here is a link to manufacturer: http://www.armex.com/

 

Re: I need your brains (Stuttering, Elec. Issues)

I didn't find any aftermarket gaskets for it, but I would have thought it would still be available as a dealer part. P/N seems to be 4BR-11181-00-00 and MSRP about $73.

 

Re: I need your brains (Stuttering, Elec. Issues)

Google:

Seca 2 / 4BR-11181-00-00

http://www.boats.net/parts/detail/yamah ... 00-00.html

 

Re: I need your brains (Stuttering, Elec. Issues)

Thanks guys.

When I checked a couple days ago, no one had them available.

This morning, it seems that Yamaha has another batch of them. I was getting worried for a hot minute.

 

Re: I need your brains (Stuttering, Elec. Issues)

Hey guys,
I am the new guy here. I joined for the exact problem i just read in this thread. I have had a lot of different bikes over the years but this one 1986 XJ700 air cooled has a studdering problem also but slightly different. Mine misses when your cruising around 4000 to 5000 rpm when there is no pressure on the motor neither acceleration or deceleration.
When you jump on the throttle it studders and hesitates for 1 or 2 seconds then takes off with no problems. been through the carbs checked the diaphrams changed plugs but did not check the resistor cap or chop the wires yet. Did away with the vacuum lines for the emission canister and the fuel, running it on pri, air filter is clean, plugs seem to burn even with good color. Bike is all stock with 10k on it seems to run great otherwise. Any advice would be greatly apprciated.

 

Re: I need your brains (Stuttering, Elec. Issues)

Damn Andrew, i wish I had read this one sooner....

My bike has/had the same issue. really weird, I've done some of the same stuff you have in the previous 5 pages, though not as much as you have.....

Same idea, starts to bog like it's not getting gas, somewhere under 5k and above 3500 usually for me, 4th gear it seems.

Rev it up, smooths out a bit, but as soon as it goes back into gear it is boggy, checked spark, fuel, filter, lines, blah blah blah no clear indication.

And it was intermittent, unlike you I couldn't start it up in my garage and re-create the scenario, I had to ride it. It doesn't seem to be heat/cold related for me, hottest days, 2 hours of riding it's fine, coldest mornings, no prob. cold engine, running all day, no difference. just seems for me, to be on twistie roads ((not hard core, just windy)) that it will suddenly bog, especially if I am going uphill.

So I was puzzled, was out on a ride, it started acting up, and so I just started touching, feeling, pushing prodding while bent over the front of it at 40-45mph....

Put my hand on the #1 spark plug and turned the cap/wire 1/8 of a turn, and boom, went away.

Since then, twice I have had it come back, reach down, turn that wire and boom, instantly goes away...

Course, now that i see the last pics of the torn down engine I am not sure you want to hear my experience, but it sounds incredibly similar.

 

Re: I need your brains (Stuttering, Elec. Issues)

Welcome to the forums. Hopefully as I dig deeper into this problem, something will arise that helps you out. The problem is in there, we'll find it!

Sounds like you need to check your wires! Unscrew the caps and snip about a centimeter off the wires and screw the caps back on. Also if you look in the caps you can use a flat head screwdriver to tighten the assembly in there.

What you described was pretty much my problem. If yours is more random, I'd suspect a connector (like the spark plug caps). On mine, it is consistent across all the plugs, and I can replicate the problem exactly under the same condition. I can't tell if it's electrical or something like timing...I guess that's why I'm trying everything lol.

Ahh well anyway, yes as you can see I've got the head off. I spent a week or two rocking back and forth in a crazy drooling stupor because of bike withdrawls, but I am stable now. And being in such a stable mode, I figured it'd be time to overhaul some components while the bike isn't being ridden.

I've got a new head gasket and a valve spring compressor on the way. Really the two things halting any progress right now. Once I get the valves out, I can blast ye the head with soda, and then lap the valves.

This bike has 30k miles (10k of which are mine), so I suppose it's about time to give it a thorough cleaning anyways.

During this time I've gotten to develop a new love for one cylinder motorcycles. Fortunately for me, my lady has let me ride her LS650 while mine is out of commission. It's great and all, but...I miss mine. A lot.

[flash=425,355]http://www.youtube.com/v/awdqdUEvr_c.swf[/flash]

 

Re: I need your brains (Stuttering, Elec. Issues)

Take a break.

Go to the Dollar Store and get a few Ice Cube Trays and Muffin Tins.

Organize all the fasteners and parts.
Pick-'em-up off the floor.
Don't "Stack" any parts on something that can get knocked-over.

Looks like you are doing a real good job.
Take lots of pictures.

 

Re: I need your brains (Stuttering, Elec. Issues)

its crazy my 650 started doin this after tuning it from lean to where the plugs need to be. am gonna up my jets a size and see if it changes anything. it seemed this bike ran better being lean but I don't trust it. mine feels like it doesn't get enough hgas but its from 6000 to 9000 only going wide open.

 

Re: I need your brains (Stuttering, Elec. Issues)

Progress today. Valve spring compressor came and I went to town.

[flash=560,349]http://www.youtube.com/v/2i98TcNB1E0.swf[/flash]

Dirty dirty





Gonna bake some valve muffins. Yum!



Basically the story for all the valves



Left side, blasted. Right side, sans blasted.



Left side, heart warming. Right side, dilapidated.

 

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

PROGRESS

Finally got the head gasket, exhaust gaskets, and stem seals in.

So it begins. I'm very happy with the soda blasting results.


Stem seals installed.


Valves installed.


This type of cleanliness makes an OCD person happy.


Test fitting the head with the new gasket, making sure it sits right with the dowels.


It's so clean!


Buckets lubed and installed. Used some assembly lube on the head post threads and torqued it down.


Recorded which shims are going back in to make it easy.


A little dip.


Into the bucket it goes. The shim should snap in and rotate freely in the bucket. If it doesn't it's not in there correctly.


Cams installed, checking clearances. A couple posts ago I was having trouble getting the timing to line up. The crank would always end up 8-10 degrees off from the cams. But this time everything lined up perfectly.


So right now I am checking the chart to see if I need to swap some shims. After the shims and valves are taken care of, it's almost time to fire it up.

UPDATE: Checked my measurements vs. installed shims, and I only need one. Whew!

#1 IN .152
#1 EX .203

#2 IN .127
#2 EX .203

#3 IN .178 Just out of spec
#3 EX .203

#4 IN .152
#4 EX .203

 

Dude, I'm pumped just reading about this!

 

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

Thanks Len. I can't wait to get this thing on the road!

For the life of me I cannot find anyone in the ATL area with a 25mm shim. When I do get someone who knows what I'm talking about, they don't have that size.

Gahh why couldn't Yamaha just stick with 29mm! Looks like it will be next week before I can breathe life into the Seca.

 

Well, I can tell the work on my new freshly rebuilt head paid off -- it rides like the wind and sounds a ton better. No ticking noises from the valves, no knocking noises...

But I'm back to square one. Still stuttering on acceleration, progressively worse as the bike warms.

The only thing I haven't replaced or serviced is the CDI box and the battery.

 

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?