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1Back to top Go down   Engine compatibility Empty Engine compatibility on Sat Nov 17, 2012 8:49 pm

Rabidchiwawa007

Rabidchiwawa007
Platinum member
Platinum member
Hello all,

My 1992 k100rs engine with 91k miles is pretty much dead. There is 0 psi compression on the 1st cylinder. The others are: cylinder 2 = 140 psi, cylinder 3 = 140 psi, cylinder 4 = 130 psi. In order to fix that 1st cylinder, regardless of what it is, I'm looking at around $1,500 - $2,500 USD, whether I do it myself or take it to a shop.

So, I found a 1991 K100RS 16v engine with only 29k miles. It has 200 psi on each cylinder, and is up for sale for $500. This seems to be my best option at the moment.

The question is: Can I replace my 1992 engine with that 1991 engine? Aka, are they interchangeable?

Thank you!


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

2Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 12:49 am

RicK G

RicK G
VIP
VIP
In a word Yes.
200psi in each cyl I would be checking my compression gauge 165psi is all you could expect.
At $500 it would be the best bet, I did that with my K100 when I reserected it from a near death experience.


__________________________________________________
"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
    

3Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 1:26 am

Rabidchiwawa007

Rabidchiwawa007
Platinum member
Platinum member
Agreed, regarding the expected psi. That is, unless, the engine was modified with different pistons to have a compression ratio of ~13.6:1, which would make me concerned as to whether it would run on 91 octane (US) gasoline.


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

4Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 1:43 am

klompy the grey brick

klompy the grey brick
VIP
VIP
K75 pistons perhaps.....98 octane should be ok with that....


__________________________________________________
KKlompy Engine compatibility 2854237993
"Grace" 1984 K100RS Silver VIN 0019026 Mitt eine Staintune Zorst.
"Olivia" 1997 K1100LT Dark Grey VIN WB1052600W0237453.









Chassis number0019026
Vehicle code0503
SeriesK589
ModelK 100 RS 83 (0502 ( 0503 )
Body typeK 100 RS 83 (0502
Catalog modelECE
Production date1984 / 07
Engine0513)

Engine compatibility Au-log10


    

5Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 1:49 am

Rabidchiwawa007

Rabidchiwawa007
Platinum member
Platinum member
The only issue with that is: the highest octane gas you can get now-a-days, from a regular gas station, is 91.

Now, I know that ratings in other countries are different, and that, for example, Germany's 98 octane ~= US 91 octane. Is this possibly what you are referring to?


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

6Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 2:00 am

RicK G

RicK G
VIP
VIP
You wont get K75 pistons into a 16V engine


__________________________________________________
"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
    

7Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 4:53 am

twincarb

twincarb
Life time member
Life time member
Just out of curiosity.... How come your looking at $1500 dollars for the cost of repairing your engine? Do you know what the cause of the the 0 psi in the first cylinder is? I would have thought the worst case scenario is either a bent valve or a broken ring... getting that one cylinder back to 140 psi would give you a working engine again your engine would be able to idle smoothly...


__________________________________________________
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 compatibility 169042 Engine compatibility 169034
    

8Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 4:59 am

charlie99

charlie99
VIP
VIP
true enough twincarb ...even perhaps clearances on the shims ...but in any case a valve job by the sound of it


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OEngine compatibility 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 ..
    

9Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 5:03 am

Rabidchiwawa007

Rabidchiwawa007
Platinum member
Platinum member
Because regardless of what it is, the valve cover needs to come off, the head needs to come off, and then, depending on what it is (most likely a burnt valve), but a new valve, clean everything out, take the head and valve to get fit to one another, get it back, put it all back together. And that's only if its a burnt valve. If its a compression ring, then the barrels have to come off, rings replaced, etc etc. If I were to take it to a shop to get this done, there is tons of labor involved. If I did it myself, just the parts and machine work would cost quite a bit.

I do see where you're coming from, and I agree, but it's just more cost and time effective for me to replace the whole thing with a motor in seemingly much better shape.


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

10Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 5:18 am

twincarb

twincarb
Life time member
Life time member
I would take it one step at a time first off to work out what the problem is. I used the following process to figure mine out...
1. Compression test (engine cold not a problem) inject some oil into cylinder 1 only about a teaspoon using a tube on a syringe is a good way.
2. If the compression go's up it shows that the oil is sealing the piston and most likely the rings. If it shows no change then its a closer look at the head.

now it depends on what the oil in the cylinder test shows.

If it is a valve taking the head off at this stage is still no cost, at the moment all you need to do is replace the gasket. once you have your head on the bench put the spark plugs back in (and with the cam-shafts removed) you can pour a small amount of petrol into the top and if there is a problem petrol will leak down the valve. You would then be looking at getting a new or second hand valve and all you need to do is lap in it. The tool for this is very cheap it's just a wooden stick with a sucker on the end and you just grind it in.

If it is a ring again it's head off but also the crankcase cover remove the 2 bolts on the piston bottom end and out it will slide. The nicosil coating on our cylinder's is incredibly strong and resistant to major scratching to prepare the cylinder there is are many cheap honing tools on the market that will allow the new rings to bed in. it's now the cost of rings, 2 new bolts for the bottom end and also a head gasket....

I know I have over simplified the tasks above but they are both achievable with the advice that's available on here and the manuals that are available for our bikes. The head can be removed from the engine with the engine still on the bike! It's a tad awkward but is achievable... Had you been on this side of the pond I would have offered to assist

There is no real machining that is possible for our engines. The heads can't be skimmed (not to the best of my knowledge) and the cylinders can't be rebored and relined (unless you have more money than the cost of several new bikes!)


__________________________________________________
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 compatibility 169042 Engine compatibility 169034
    

11Back to top Go down   Engine compatibility Empty Re: Engine compatibility on Sun Nov 18, 2012 5:37 am

RicK G

RicK G
VIP
VIP
One important thing is don't throw the old engine out they don't make them any more and one day repairing it will be the most economical thing for someone to do.


__________________________________________________
"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
    

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