It's not always the carbs :o)

[newmaac]

I have a 1980 Special that I have been working on (off and on) for 2 years. After doing the infamous "tripple clean" (several times), replacing the octipus, kreeming the tank,and hundreds of dollars of other things, I almost gave up on the bike beacuse it never really ran as it should have.
It always acted as if it were running WAY too rich, and was proved to be so, using the Color Tune.
Last week I was playing with the bike and double checked the timing. I found that it was way off. Enough so, that the gasses were not getting burned properly and the plugs were fouling.

I know that on these old bikes the carbs are often the culpret when things are not as they should be, but this has reminded me that it doesn't always have to be a MAJOR bummer to get back in good running condition.

I am having a BLAST. I only wish that I had double checked the simple stuff LAST year. )

[strom]

Hahahahaha

and again...

HAhahahaha...

and again....

Hahahahahahahahahehehehahahaoiahaoahahaa....

OK...

I just took off the valve cover (midnight here... now)... and the...
...OK, the symptoms 1st.

The bike runs OK at standstill, revs OK. When I try to ride it, the rpm drops to 500-1000 at full throttle and thats it... I wait half an hour and it revs OK. But that's it.

I figure its runnin way too rich.

I find out gas squirts out the air jet instead of air being sucked in.

I take off the valve cover

The intake cam is 1-2 teeth off... dunno how, but it is.

BTW: I had the carbs off at least 6 times... so I guess u're a genious with only triple-cleaning behind u...

Too bad it's like 30-40 cm of snow and -12 centigrade.... or at least if the road was dry... Id go for a ride... (got me a commie cop leather jumper and I wanna test it).

LP

[Ken Talbot]

Congratulations! I stand (well, sit actually) humbly corrected for all the times I tried to point you away from valve timing as the source of your problems. Here's hoping the weather smartens up early this spring so you can finally see what your XS is like in full, proper operating condition. You've certainly be patient enough....

[TopCatGr58]

Like a kick in the TEETH.

Hey there Strom,
Well, glad to see that you "may" have finally found your culprit, and it makes sense to me, if the intake valves were not closing soon enough, then as the pistons are coming up for the compression stroke, you would be pushing air back out of the carb throats, hence your fuel spray symptom, not to mention the poor performance. I just hope that it was somehow setup that way by the P.O. before you got it, due to some bad wrenching skills, and not because it actually jumped a couple of teeth, which could mean worn sprockets, stretched chain, or just poorly adjusted slack in the cam chain?? Good luck, keep us posted, and PLEASE, be careful out there, once that thing kicks in with full power we don't want you doing a ZIP-SPLAT on those icy roads!!!!!

T.C.

[strom]

Thanks guys...

OK, one fact is, I put a new chain in there, while the engine was apart... once it's apart, no point in not replacing all the stuff. The old chain was OK, so I kept it, but since everything else was new...
So, I have no idea how I could have miss THAT much... teeth look fine, chain is new...
OK, the good thing is... there's plenty of oil there (had a problem with that on kawa... they seem to have been holding back on the oil pressure).
The bad thing... well... I'll have to adjust the sprocket... and it's a pain... and I'll have to put the valvecover back on... lotsa nuts there... waaaay too many, but wuttahell...

Icy roads and my 6-16 years old tires should skid well togetger LOL... gotta get me a new set anyway.

Weather still sux... -15 centigrade or so... I hate winter. Gotta move to Oz... or Cuba.

LP

[newmaac]

Strom, no need to go to OZ, Just try California.
We had a Beautiful riding day today!! Now who's laughing??

Hahahahahahahahah )

Get yourself some tires. I am sure (I think), that you are kidding about skidding on the snowy roads. Man that sounds like no fun at all!

[strom]

Originally posted by newmaac
Strom, no need to go to OZ, Just try California.
We had a Beautiful riding day today!! Now who's laughing??

Hahahahahahahahah )

Get yourself some tires. I am sure (I think), that you are kidding about skidding on the snowy roads. Man that sounds like no fun at all!

I do most of my riding in winter... usually under better conditions.
I don't like california...

LP

[uk1.1s]

Cam timing

Hey Strom and Newmacc - good news

Strom - I know the feeling - set the cam chain onto the top sprockets - check - double check, and the whole thing still goes horribly wrong.

Had a similar problem with my '77 Z1000, which would NOT accept the cam chain without slipping somewhere / somehow. Bent the valves one time when the slip left the valves open as the piston came up -

If the darn thing does it to you again just be diligent and keep some sort of upward pressure on the cam chain before you bring it over the sprocket so that it can't slip on the crank down below. This was fundamentally my problem on the Zed.

As a good point though, I've put my XS11 engine together a couple of times now (long story) - and found the top end to be OK in getting the cams in and chain on. Do turn it over a few times with a 19 mm spanner (Wrench) on the end of the crank and check that after a few revolutions all timing marks line up still.

Have fun

[strom]

it's 22mm...
Adjusted the cams... checked compression... in that order

no. 4: 10.5
no. 3: 10.0
no. 2: 00.0
no. 1: 09.8ish

OK... the no. 2 is weird... checked again... no compression. And again... nothing... placed a thumb over the plug hole... nada...
I checked the intake valve clearancies, they were good, but I didn't check the exhaust ones... no. 2 is bout 0.75mm... OK, I got me a stuck valve... gonna keep u updated. I was too tired today to take the cam off, but I'll do it... in the next couple days...

LP

[TopCatGr58]

Stuck Valve

Hey there Strom,

Your stuck valve may be because it is slightly bent!?!? 0.75mm clearance is quite a bit, but not as bad as the 3.0 mm one I had when mine was bent!!!! The exhaust one might just have a bunch of carbon around the shaft, keeping it from sliding up into the guide?? Not sure if you will be able to clean/clear off the carbon by depressing it and trying to get at it from the Exhaust port side of the head?? You may have to pull the head after all, and if you do that, you might as well do ALL of the valve seats, Lapping them to get them all sealing nicely!!! The excessive carbon might also be from a leaky valve seal, so you may have to replace them as well?!

Good Luck, let us know!! At least now you know why it wouldn't idle or run very well!!!

[ACE]

Hey Strom,
Your getting alot of good advice here.
I must chime in here.
Patiance and some good cuss words get me through alot.
nothing tech from me today.
Just had a bad week and a few beers!
Oh !! Don't forget beer!
Good luck. Your in the right direction.
ACE

[uk1.1s]

compression depression

Strom

Top Cat may have something there. Check the exhaust valve pretty carefully. I was in denial when I bent the valves on my Zed engine ... surely I was really gentle when I hand-turned the engine over and the piston stopped (contacting the valves just before TDC).

No mater how gentle, if there was contact I'll bet a valve or two get bent, as valve stems can be pretty fragile to that sort of impact.

If that's the problem - then your compression readings look like you got away with one bend.

Alternatively, it could just be stuck under a heavy carbon build-up on the stem. Any clues when you last had the head off?

Don't know what spares availability is like out there, but I may have some valve stem seals kicking around in my supplies in the garage - if you need them just shout

Is that light at the end of the tunnel...? Lets hope so - good luck

[strom]

Heya ace... I was tired from the XSive quantities of beer the previous night... So no worries in that aspect.

Since I got the bike in boxes, I pulled and reinstalled the head. But I didn't check the valves more closely since the bike had new seals installed previous to being taken apart by the ex owner.

I'll pull the cam and see what happens. If there's no way I can get that valve to work, I'll pull the head again.

Don't worry bout the valve seals... I can get new ones delivered to the comfort of my garage. I must do some yelling at the supplier anyway since he sent me a wrong crank seal and the old one is leaking... gonna strip the engine anyways... again.

The only problem is, I'm broke and I'm buying a car... doh! I passed on a real good deal for a stupid reason... a 78 (same as my XS... and me) citroen CX 2500 Pallas Diesel. It had air condition, power steering, power windows, central locking, leather interior, power seats and the works... for bout 400 US$. Doh! And it had a cool sticker thingie on the back... same plastic writing as the original... on one side CX 2500 D and on the other NOT TURBO. LOL. I loved that.

Thanks for all the ideas... apretiate it.
What do I do if the valve is bent? Bend it back or get a new one? I prefer a safer option.

LP

[uk1.1s]

Get a bigger hammer

Strom - sorry the bigger hammer won't work as those suckers need to be V. straight and NOT work hardened!

The solution is a new valve - no way around it

I work for a consulting civil engineer company and gave the same advice to the site engineers the other day. Contractors managed to drive over all the reinforcement bars for the new Heathrow(London) Terminal 5 building, bending them lots. Question was "Can we bend back these critical High Strength Steel Reinforcement Bars?"....... Errrr Nope.

Bugger - so the crank seal is u/s. Hard luck mate - it'll be worth it in the long run - meet you half way across Europe sometime once we both get the beasties running.

Graham

[ACE]

Strom,
No way to bend a valve back! get a new one!
That, a few cuss words, and while the head is off i'd check the rest and anything else. It sounds like you found the problem.
I's alot more fun to ride them than wrenching on to only find the problem is still there.
Like T.C. said, lap the valve so it seats well.
ACE