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

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.