Xj650 seca 1982 4k0 cranking but will not start

First of all - i would like to say hello to this forum that i have been stalking as a guest for a very long time (a long time before i got my bike). I must say that you guys are just awesome and super kind and i would love to join your community and contribute to it as much as i can

Next thing - the main reason why i'm here. To keep things short - i bought a bike i wanted to have since i was a kid and my uncle had one of these - Yamaha Xj seca. So i waited a long time (a cople of reasons why, one being that i live in Slovenia, a country with only 2mil people) Xj650 seca with 90k+ km of which i have no insight in her past. All i know is that she just won't start. She cranks but wont give that sound of a running engine.
I did the following things:
- checked the battery (it'dead), so i use a car battery for my test runs atm
- checked sparkplugs, all are sparking
- i took off the carbs and cleaned them (they were in bad shape) and i set the floats dry and wet (all 4 sre in the 3 +-1 mm range)
- changed the gassoline (it was light orange)

I made a video with her cranking and posted it on youtube so you guys (ones that made it this far intoo the poast and are willing to help) can check out and give your 0.02 on the issue.

I will be gratefull for any help that i get

 

Welcome to the camp!

Video won't play back?
Sounds like you did a lot of the correct things (stalking here and reading a lot always helps).

Have you checked the valve clearances?
Go through your electrical connections and make sure all (grounds!) are clean and tight.

 

Did you set the petcock to prime and confirm that the float bowls are filling?

 

have you tried spraying some starter fluid into the carbs?

 

This might be of help - when i'm cranking the engine, i can smell a mild odor of petrol coming
from the exaust on the right side, from the left side - nothing. It's a 4 in 2 exhaust.

EDIT: i read that you need +5 posts for antispam reasons so this is the link part on youtube:
/watch?v=DWuD8isO7gc

Is the video working now? I uploaded it from my phone and it's also the first vido i ever uploaded....
That is the next thing i have in mind but it's quite a task, especially because the gasket on the valve cover
might be bust after i take down the cover. But shouldn't she fire even if the shims are a bit out of spec?
Tomorrow morning i'll check the gronds.

I did, and gas is in the bowls, i even went so far as to check the hight of it with the carbs on the bike. As Stumplifter said,
could the valve clearences be the issue? Did the video work for you?

I sprayed some into the air box, but nothing happened. Not so much as even a burp.

 

Still getting an error when trying to play video . . . .

 

Did you copy the /w.... part onto youtube? Or even google - it should find it:
/watch?v=DWuD8isO7gc

Other than that i don't know what it could be :/

 

Video link fixed. There was a character missing.

 

Perform a compression test.
Have you checked the valve clearances and made sure that they are in spec?

Are the plug wires connected to the correct cylinders? Left coil goes to cyl. #1 and #4, right coil to cyl. #2 and #3.

 

I have checked the plug wires today - they are in the correct order. You got me scared there - how could i have missed such a
detail

I have not checked the compression yet (i did but only with my hands - not exactly the most accurate way) or the clearences,
those are the next 2 things i have in mind but if i take the valve cover off i'll have to get a new gasket for it and that will take
time since, where i come from, the demand for shuch specific items is scarse and the time it needs to get delivered from abroad
is roughly from 7 up to 30 days. So I left the clearences as last on the list.

Besides that i have a problem with them. I have a 1982 German 4k0 seca model and
in the Haynes manual it states that there are 2 different intake clearence specs - but then i read a thread here:
/forums/threads/valve-specs.15140/

Are the clearences, as stated by Chacal, wrong in the manual and all xj650's have the same spec:

Inlet: 0.11-0.15mm = (0.004-0.006")
Exhaust: 0.16-0.20mm = (0.006-0.008")

Or do i go with Haynes and if so which one is correct?

And thank you for the help so far! I have found new hope in making her run again.

 

These are correct the Haynes manual is wrong.

Also this may be nothing or it might help, did you check to see if all the vacuum caps are on the carbs, and the YICS plugs are in and tight? I know I tried to start mine once with the YICS port open and it wouldn't start.

 

+1 Electro Tech
Sounds like you have the main players working to fire it up - spark, fresh fuel, and timing. I have not viewed the video - but - 3 things I'd check - clogged air filter, dragging starter, and possibly intermittent fuse box connections. You need at least 10 volts going too the starter when cranking. Cams must be turning if you smell gas in the exhaust.

Just a thought. Good luck.

 

Did you check the resistance on the spark plug caps? I had one that showed spark, but was so weak, the cylinder misfired regularly. It turns out the resistance was infinity, completely open. Was apparently loosing enough spark energy it wouldn't ignite fuel properly, even though I saw a visible spark.

Just one more thing to check....

 

A quick update:

Valve shims:
- 7/8 were out of spec, one shim didn't even want to budge - good thing I can swear in multiple languages (i saw that priceless advice on this very forum)
-> now i need to find shims, which i hope to find in my city, if not - interwebs it is

Spark plugs:
- they were carbon folued, i guess because the last owner used colder NGK BP8ES instead the regular BP7ES
- altho they did make a spark, i guess it was not enough for ignition, i checked the resistance on them - but got nothing, even the current couldn't pass through

Spark plug caps:
- thank god, all are at 5k OHM - so yeah i got that going for me

YICS ports:
- if YICS ports are those 3 bolts (2 on the side and one in the middle), than all are closed tight, if not, i guess i don't know what to check

Next in line: checking the coils and the spark plug cables, if everything is ok i'll change my shims, plugs, i might trim the cables a cm or 2, check compression and try to run the old gal.

If she won't run: check the starter, possible bad connections and many more.

If you guys have any other suggestions - shoot, ideas are welcome.

And thank you for all the help so far!

 

Oh and this: The spark plugs that were on.

 

Welcome .... just dumb question have you turned on the fuel enrichment(choke) when trying to start? Sometimes only half setting is required. If your battery is dead using a car battery to jump start is not real condusive to your problem .

 

Carbon fouled, too cold. Those are non-resistor plugs (and should be) so you won't see much resistance on the electrode; not any more than you'd see on the ground strap. any resistance you measured would be due to the carbon deposits.

The shims are of a very common diameter, so should be easy to find. Just make sure to get shims that do not have beveled (chamfered) edges.

YICS ports. The actual ports are inside the head. The bolts you're looking for are at either end of the YICS manifold, which is part of the cylinder casting.
The below image is a bit mislabeled (the "extra" bolts actually help hold the head to the cylinders), and is not specific to your bike (the oil bolt isn't an oil bolt, nor do you have the oil line pictured). What it does show is the YICS manifold (round tube looking thing just above the "extra" bolts, and below the drilling plugs for the YICS passages (the middle YICS passage arrow points right at it)). You will find the bolts (screws really) at either end of that tube.

 

UPDATE NO.2:

Compression tests done:
I don't know should i be happy about the fact that they are all about the same or should i
be sad - since the compression is so damn low on all 4 cylinders.

- no. 1,2 and 3 are at 90 (+- 2) PSI
- no. 4 is at 86 PSI

Valve clearances:
OHHHH Boy was this funn... :
- 7 out of 8 valves out of spec

Clearance Shim New shim?
Intake 1 : 0,08 265 260
Exhaust 1: 0,15 265 260

Intake 2 : 0,15 (in spec)
Exhaust 2: 0,13 270 265

Intake 3 : 0,10 275 270
Exhaust 3: 0,15 270 265

Intake 4 : 0,10 275 270
Exhaust 4: 0,15 270 265

So the question is: could it be that the shims are the cause of my low compression (+ not so perfect valve cover gasket) or is it too low for a simple shim job to fix this issue??

PS:

I got my self some new spark plugs - BP7ES, which should work fine.

I took home both ignition coils with spark plug cables to test them out.

 

Since all cylinders are equally low, perhaps redoing the compression test with a second tester would be a good idea. You could find that it is the guage that is off as opposed to your compression. Out of spec valves don't help either, though! The valve cover gasket will not have any effect on compression.

 

Was the compression check done twice? First one is typically dry. If any (or all) are marginally low, I put a tablespoon of motor oil in the cylinder and test again. This rules out any leaking past the piston rings. I do this especially if the motor hasn't run in a while.

 

Clearances are tight, but not dreadfully so. Your shim size calculations are correct. The too-small clearances might be a cause of the lowered compression. Try the "oil in cylinders" compression test, you'll learn a lot from that (as wink1018 recommends above). If the compression goes up significantly...............bad rings or cylinder walls. If not, then the low compression is due to a valve issue......either clearance-related or burned (typically exhaust) valve faces and/or seats.

 

It would be cool if you had a leak down tester close by. This would do the same thing just with air and if you are leaking, you might be able to hear the location the air is going. The above mentioned wet test is a cheaper but safe way to pull of the same thing. Good luck.

 

UPDATE 3: (best one yet)

Coils:
- I took them off and checked the resistances - both are in spec on both tests.

Compression:
- After adding a bit of oil and a couple of cranks the compression went up to 120 (+- 5) PSI on all 4 cylinders.
So i guess i'll have to remove the head and check the walls and rings?

I'd use the tool if i had one, buuttt I'm a bit broke atm (typical student), and I'm not keen on buying cheap tools - grandpa taught me that. So i went with the
''oil in the cylinders'' test.

After I saw it go up to 120 I decided to place back the carbs and tried to start her.... AND GUESS WHAT - on the 3rd attempt with a small squirt of starting fluid
it went BRUUMMMM BRUMMMMM. The idle knob was set wwaaayyyyy too high because i tinkered with it while checking the butterfly valves after my bench
sync (4k RPM idle - i was baffled at start), but with a few turns it went to 1050RPM on idle. After that i left her to run for a min or 2, and tried to start the engine again -
it started without any problem.

Today i tried to start her again - same thing, cranks and she even gave a couple of thumps, but after adding a small squirt of starting fluid it started! But
when i turn the throtle it either: drops in RPM and dies or it gives the best roar i have ever heard (I am biased I know, but she is mine and SHE FREGING RUNS!!!!!).

My guess is that it tends to die because the compression is still a bit low and my carbs might be a bit off (tho i'm pretty sure i did everything as i should have).
It's worth noting that here, were i come from, is arround 5 °C sooooo it might be a cold start related issue.

Other known issues:
- A huge (corroded) hole on the exhaust (where it clamps/connects to the pipe).
- A leaking clutch clover (which also has a hole in the outer plate - that brake lever...)
- A leaking valve cover gasket
- A leaking head gasket (i suspect since there are oil stains under the engine head)
- A busted rear blinker

Is a complete gasket, seal and ring reneval the way to go? And if so, do you guys have any recommendations on
where to get them (i'm sorry to say this but $$ is a bit of an issue - I know....don't get a bike if you don't have
the $ to finance it, but i couldn't pass on the opportunity to get this bike since they are so rare here).


Thank you guys for all the support and help so far!

PS:
Here is a pic of the front fender after a couple of hours of aluminium foil and water (i have a before picture but it's bad).

 

When you cleaned the carbs, did you remove the idle mixture screws?

I suspect that you have enough compression to have a running engine, but that you do not have fully clean idle circuits.

The low compression sounds to me like stuck rings, that are now on their way to freeing up.

Your leaking head gasket probably is not leaking. There are drain passages that will let oil from a leaky valve cover gasket run down, and look like a leaky head gasket.

 

UPDATE:

Sorry, I wasn't active for a few days, was out of town- but I'm back on track.

k-moe - Thank you for the fast reply back then, I saw your answer but wasn't home to check on any of your ''hints''.
Idle mixture screw (i guess that's the one next to choke, ones you turn 2,5 turns out?) - i took them out yesterday, the were clean.


So I've been inspecting things on the bike and found a few ''issues'' and I have a few questions related to them:

1. I read somewhere that YAMAHA used to have matching VIN numbers and engine numbers is that true? Cause if it is - i might have a problem, mine do not match....
2. This one is strange to me and I might seem dumb (I think I saw this somewhere): is it true that YAMAHA med some bikes for Europe listed as xj 650 but the engine was 750?
2. I found that one of the valve cover bolts just turns and can not be tightened - when I took a better look the threads in the hole are well, how to put it, gone... - Is there an easy solution to this orrrr am i screwd?
3. K-MOE was right on the valve cover gasket part, it was not installed right the last time so it leaked, but I'm not sure if that's the only place of leakage, entire front part of the engine is oily. I guess cleaning and letting it run for some time would be the way to go (after i replace the valve cover gaket)?
4. The air filter was not installed right so when i checked the inside of the airbox (where the carb cups go in) i was full of dust and sand - i'd like to take the airbox
out and clean it, but i suspect that it won't go out without taking the engine out first - am i correct? Or will it wiggle out somehow? I saw a thread about abused airboxes - I wouldn't like mine to become a full time member of that comunity
5. My exhaust mufflers are in bad shape - the left one is coroded badly (on the down part close to the collector) but i think it can be welded back - but the collector is toast, it's just bust... it's a 4in2 system. Is there an analog to the collector or must i get an xj 650 specific collector? Because i found someone selling parts for xj 900 in my country, but as I read - nothing can be used (exhaust related) from that bike...

Plans i have for now:
1. Reshiming the bike valves.
2. Changing vlave cover gaskets, donuts and all (I sure hope Chacal ships to Europe )
3. Cleaning the front part of the engine - so i can spot any leaks
3. Oil change - 20w50, since summer is coming
4. Doing the carbs again.
5. Changing the collector? If i ever get one here that's in a deacent shape....

 

Oh and a vid of her running. If you can hear any anomalies please - shere your ideas with me, i'm more than willing to listen.

 

1. yes, they should be matching, in that your full 17 digit serial number should contain "4K0" after JYA, and the shorty VIN (on the engine case) would start with the 4K0, with both short and long ending with the same 6 digits.
2. from XJ4ever: NOTE: it has been suggested (but not fully verified) that some late-production 1982 XJ650RJ and RJC Seca model bikes came equipped from the factory with 750 engines (rather than 650 engines). All 750 engines are YICS engines, of course; so if your XJ650RJ/RJC bike has a YICS engine in it, it would be wise to check and make sure that it is indeed a 650 engine rather than a 750 engine......this can be easily determined by looking on the forward side of the cylinder "jugs" casting. Along the centerline of the cylinders, towards the top edge (at the mating surface between top of jugs and bottom of head) will be the engine cc displacement cast into the metal.

Soooo, maybe?
2.2 Not being able to tighten one of the valve cover bolts would be a very likely cause of the valve cover gasket leaking (issues with the valve cover can cause more leaking that you would think)
4. I believe you should be able to get the airbox out without removing the engine first. I believe I have heard of people unbolting the rear engine mounts to tip the engine forward, allowing for more room. Also, heating up the airbox to make it a little more pliable has been discussed. I have never done this though, I am sure a more experienced member can chime in.

 

VINS don't match, all my VINS are short (frame, metal plate, engime case and the bikes papers) so yeahhhh...

I've got some bad karma on me these past few days....
Was trying to get the airbox out (it's a tight fit), got it out buttttt cracked it with (what seemed) minimum force
+ broke the bottom hose on the airbox off with the plastic insert. - Haynes doesn't say what it is, it just says - hose. I think it's a drain for the oil that gets to the airbox from the transmision.

Good thing: I found out why the engine leaks oil at the valve cover.
Bad thing: There is a crack at the top wehere the valve cover sits on tthe gasket, so the gasket and valve cover can't get a perfect fot on the surface
. How bad is this? Could i just go with a new gasket and put a bit more gasket sealant in there and thighten the bolts to spec?

 

A larger picture.

 

Hard to tell from your pictures.
Is the crack next to a threaded hole? The protuberance on the side would say yes but the bolt head looks further back?
You need to check valve clearances (and get a new gasket), so go ahead and pop the top and see if that crack goes all the way through.

A shop vac would have cleaned your airbox out really nice, without having to remove it . . . just sayin'.

 

I'll go dismantle everything again and i'll take some better pics. That's just a protuberance, it has a couple of those - for an unknown reason to me.

 

The text is a bit unclear. Is the crack in the cover or the head itself? The only crack I see in the pictures is in the head.

 

I see the crack in the head. If it goes all the way through your best bet is to get a different head. Repairing that so it dosen't leak can be done, but it will require that the head be stripped, the oil baked out, and then the crack welded. Epoxy might work, for a while, but it'll be ugly. The issue is the amount of oil that has been baked into the casing.