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1Back to top Go down   Engine not firing Empty Engine not firing on Mon Aug 13, 2012 2:17 pm

twincarb

twincarb
Life time member
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Background: engine been stripped and rebuilt. back on bike bike won't fire...worked through electrical side no fault found.... onto mechanical...

Just checked the compression.... Bearing in mind that the engine is cold my reading are...

Cyl 1 100 psi
Cyl 2 120 psi
Cyl 3 0 psi
Cyl 4 0 psi

not
tried to put any oil in the cylinders to see if it will increase them,
as a reading that low says something major... top end strip down now
see if my valves are Foobarred....

I have stripped the top end down (engine still on the frame) and the only thing i can see is as per the pic below. cylinder 4 is the right most
[img]Engine not firing Imag0210 [/img]

As can be seen on one of the valves there is scoring, I am guessing this is where it's come into contact with the cylinder... suggesting it's not closing properly?
There is a similar mark on the same valve on Cylinder 1

The photo below is of the cylinders... which all look good...
[img]Engine not firing Imag0211 [/img]

Any idea's or suggestions? It also pose's the question of should I pull the pistons out and do a visual check of the piston rings and strip the bottom end all the way down as well...


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
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2Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 3:28 pm

twincarb

twincarb
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ok quick update... the Exhaust valve on Cyl 3 is bent.... how does that happen??
cyl 4 exhaust valve looks ok to me.... I have lapped it again and it appears to seat perfectly....

onto cyl 1 and 2 because cyl 1 has got a slight marking the same as cylinder 3 had...


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

3Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 4:33 pm

Avenger GT

Avenger GT
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The two ways valves usually get bent are;

1. Contact with the piston. Caused by either incorrect valve timing or a broken timing chain or belt. The latter usually wrecks the head.

2. Laying the cylinder head down on the gasket face with some valves open. It doesn't take much to slightly bend a valve if sideways pressure is applied to it.

Since you say that the engine has been rebuilt, then one would have to assume that either the valve timing was incorrect on re-assembly, or the head was laid down on the gasket face while it was off the engine.
If it was a valve timing issue then there should be marks on the pistons where they hit the valves.

    

4Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 4:38 pm

twincarb

twincarb
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Logic would also suggest that all 4 valves would show similar problems I would have thought, however the only marks are on the valve heads of cylinder 3 and 1 the valve in cylinder 3 being shot but the other is fine....

The pistons were spotless clean when I put it back together so no carbon build up to show any contact marks....

I cant find any problems with the top end side for cylinder 4 which also had 0 compression mind....


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

5Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 6:04 pm

kfilipow

kfilipow
Silver member
Silver member
Twincarb, Is it possible the shop put in wrong valve shims. They would not have fired the engine, maybe not even done a compression test. The difference may have caused contact between the vlave and piston....I think. Best of luck.

KF

    

6Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 6:13 pm

92KK 84WW Olaf

92KK 84WW Olaf
Life time member
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I am not the expert on this but I did see another post about timing chain wear, tensioner issues and possibilty of valve timing going slightly off.

I think looking at the photos I have done a few head jobs and love to to see everything nicely polished up, piston heads, valve cut outs, inside of the head and the valves themselves. If you havent done it I would have all the valves and springs out and clean out everything, check the valves for damage and being straight.

I havent checked on the seats/grinding in requirements but from what I see there were hardened seats used on later models to allow use of unleaded petrol. The other thing I have not checked is whether the pistons have a right/wrong way of being installed if the valves recesses are not the same on each side.

However if the engine was rebuilt none of this should be the case.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 103,800 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

7Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 6:19 pm

twincarb

twincarb
Life time member
Life time member
I wish I could point the finger at someone else! But alas it's my work!

The valve clearances were all identical when I put it back together as when I took it apart.

Still trying to work out what the problem is with Cylinder 4 I think it is going to be a bottom end strip next to check the rings...

The pistons fit one way.... well they will go in the "wrong" way but there are arrows that point in one direction so it's easy to get them right.... you can roughly see the arrows in the second photo at roughly the 9pm position and all point towards the cam chain...

Everything was spotless inside the head when it went back together all be it everything was given a light coating of oil.

The Valves can and should be reseated when they have been removed...

The biggist pain is that cause I have a bent valve I should/need to replace the valve stem as well hmmmmm


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

8Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 6:37 pm

twincarb

twincarb
Life time member
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Do I need to remove the Output shaft before I remove the Crankshaft? is it possible with the engine still mounted on the bike?!


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

9Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 6:38 pm

92KK 84WW Olaf

92KK 84WW Olaf
Life time member
Life time member
I would not be quite as quick to pull it all apart.

The low readings between two cylinders in car engines usually points to a leakage between two adjacent cylinders, probably at the narrow neck in the head gasket or the head just above it. The fact that the readings are so low suggests something 'big' and simple at the top end or holes in pistons which we clearly dont have.

I would have a relook at the head gasket itself too as I have seen different types of gasket materials cause problems here.

The bent valves have been commented on and are not difficult to resolve. Was the head checked for any cracks or skimmed?


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 103,800 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

10Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 6:44 pm

twincarb

twincarb
Life time member
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The logic being that I would only see a reduced compression if the rings were shot?

The head hasn't been checked for flatness, I don't think replacing the valve stem is a job I want to do so will take it to my local engine rebuilder He will be able to check the head to ensure it's not warped...

The gasket certainly looked as if it had a good seal I used one from motobins which has got a blue silicon seal around the gasket which was compressed in an even way all the way around.


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

11Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 6:51 pm

92KK 84WW Olaf

92KK 84WW Olaf
Life time member
Life time member
A lot of engines allow the removal of a big end cap and con rod/piston assembly if you remove the sump, without dismantling the engine. not sure if the K does. Do you have Clymer manual? I have a feeling one broken piston ring would not result in a zero reading but a low reading. 120psi gives you about 8:1 but for sure I would always get a second opinion as in try another gauge. Also, how are all the injectors/ injector seals? If you get the top end completely sorted and with good gasket I would like to feel it would solve your problem.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 103,800 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

12Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 7:00 pm

twincarb

twincarb
Life time member
Life time member
I am happy with the 120 reading as the engine was cold and I didn't open the throttle, in my mind the 2 good readings I got would be a fair chunk higher if the engine was hot and the throttle was wide open.

I have had a quick look at the Haynes manual and it would appear that the bottom end can be stripped from the position I am in now no need to remove the sump which is a blessing... I guess some purists would suggest stripping the bottom end down just to confirm the condition of the rings...

I read the Clymer for replacing the valve stems, and the thing that's put me off is the "special" tools for removing and then installing the valve guide....


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

13Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 7:26 pm

92KK 84WW Olaf

92KK 84WW Olaf
Life time member
Life time member
As you say you may well have two good readings and I suspect the cause of the low readings may be simple. Bent valves being one and relatively simple for any engine shop to do for you.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 103,800 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

14Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 7:57 pm

Toto_jp

avatar
Platinum member
Platinum member
Just looking at the picture of the head appears it h.as not torrqued down evenly
hence the blueing\blowback or may may be bowed (between 2 cylinders). the valve may not be bent but worn in a oval shape. I would be inclined to check the water passages prior to assembly to confirm a decent flow throughthe head that a blockage/air lock is not causing over heading insures remember to check the fan too else you will only have thermo syphon effect

hope this helps Tony

ps I ran OMO (washing powder )through my motor cleaned it like new but make sure you remove any residue else it suds up well

    

15Back to top Go down   Engine not firing Empty Re: Engine not firing on Mon Aug 13, 2012 8:37 pm

RicK G

RicK G
VIP
VIP
Put some petrol in the ports and see what happenns.
1 petrol stays--- Valves are OK
2 petrol runs past the valve---Valves are shagged i.e. bent from incorrect valve timing.
The #3 exhaust has hit the piston big time I can see that from the picture.
Remedy:- new valves.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

16Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 1:21 am

charlie99

charlie99
VIP
VIP
um you didnt inadvertantly put the exhaust cam in the inlet cam place ? wonder what the valve timing would be like then ?

dry run perhaps ?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OEngine not firing Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

17Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 3:44 am

twincarb

twincarb
Life time member
Life time member
Rick,
I had completely forgotten about the simple technique of using petrol and seeing if it runs past the valves! Will be doing that shortly now.... am i right in thinking bent valve also means replace the valve stem?

Charlie,
I don't think it's possible to put the cams in the wrong place because everything is offset, it was one of the things that we had discussed in work, but kinda concluded that everything would be 180 degrees out... and if everything was still spot on but out it would have fired when swapping the low voltage i/p to the coils.... (i tried that!)


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

18Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 3:57 am

RicK G

RicK G
VIP
VIP
If the valve is bent the whole lot goes to the garbage the stems are all one part.
Because the valves are at about 45deg to the bore the cams would work out with one being 90 deg and the other 270 deg out.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

19Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 3:59 am

twincarb

twincarb
Life time member
Life time member
sorry I meant guide not stem!


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

20Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 4:04 am

RicK G

RicK G
VIP
VIP
The valves usually bend just under the head and often there is a narrow part on the stem to let it happen there. The guides will probably be untouched but when the springs come off make sure they dont stick in the guide. If they are free then all will be OK.
I would advise to put new stem seals on when its apart.
And you are right they don't go in reversed.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

21Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 4:10 am

twincarb

twincarb
Life time member
Life time member
Thanks Rick, that has made it a whole lot simpler then, there was no sticking of the spring in cyl 3 when I took it out.

With any luck I can order the parts today and they should be here tomorrow with any luck. Just got to rule out any other problems with the head and cyl 4.


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

22Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 4:56 am

RicK G

RicK G
VIP
VIP
If you are worried about a warp get an engine rebuilding shop to check it and/or do a surface grind but that blueing is from the coolant.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

23Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 4:58 am

RicK G

RicK G
VIP
VIP
One thing to do before putting the head back on is do the shims before it makes it a heap easier and don't forget to use an antisieze on the bolt threads and under the head of the bolts


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

24Back to top Go down   Engine not firing Empty Re: Engine not firing on Tue Aug 14, 2012 5:07 am

twincarb

twincarb
Life time member
Life time member
I seem to recall reading that you can put the head back on with the camshaft in place, but I am sure when I looked at it the head bolts were to close to the cams to get a proper grip on them!

Makes sense rechecking the shims on the bench mind.... I followed the Haynes manual last time and it just said to use a light coating of oil on the Head bolts i guess that anitsieze would be better mind


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

25Back to top Go down   Engine not firing Empty Re: Engine not firing on Fri Aug 17, 2012 2:25 pm

twincarb

twincarb
Life time member
Life time member
Right on with the adventure....

I have fitted the new valve and when cold all 4 cylinders are now showing 120 Psi which I am happy with being cold.

Engine starts and idles a treat Very Happy

Onto the noise that I got from the rear end... essentially as soon as I increased the rev's I had a grinding noise and the engine stalled.

I have now stripped the bike back down... all the way with gearbox off, clutch off, bell housing off...

Quick peek inside and I can see where the problem is.... The Aux drive shaft is forced out onto the retainer plate and then it's coming to a stop.... It looks like I have everything in place that should be there but I can't see what the cause is.....

Any ideas as always welcome while I cook some dinner and look for info on here Very Happy


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

26Back to top Go down   Engine not firing Empty Re: Engine not firing on Fri Aug 17, 2012 4:50 pm

twincarb

twincarb
Life time member
Life time member
BINGO.... sussed it... Just had a read of Albys Sprag clutch cleaning.... looks like I am missing the Shim which would stop the clutch moving forward.... Time to have a hunt in the garage/workbench....

Does anyone have the size of it??

Engine not firing 25_sea10


__________________________________________________
BMW K100LT 1988 Matt Black Peugeot Electra Blue (ELX) Colour is now confirmed...
Yamaha Thundercat
Triumph Spitfire (not a bike but hell it's British chaps)
Engine not firing 169042 Engine not firing 169034
    

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