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THE MOMENT OF TRUE. 7 months 2 days ago #31661

  • Ted
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...But the Porsches burned more clean which was better for the environment.
1981 KZ1300, '98 Suzuki GSF1200S, '80 Honda CT110, '11 Honda CBR250, '75 Honda CL360, '00 Honda XR100R
Speak softly and mount a fast bike.

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THE MOMENT OF TRUE. 6 months 3 weeks ago #31686

  • kawaBCN
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This is the needle seat o ring that most people miss when rebuilding the BSW32 carbs. It seals the needle seat in the carburetor body. If it leaks, fuel will bypass around the seal and carburetor flooding will occur.

this o ring is 7.5mm outside diameter and 1.5mm thick. My advice is to replace it with a Viton75  o ring of that dimension. Ethanol will not affect Viton75. The original o ring was Buna-N Nitrile and back in the 1980's, Ethanol was not a component of gasoline.

As an example of updates to fuel systems-
Back in the early 1980's gasoline was just gasoline and fuel components that were elastomers were typically made of Nitrile. Along came fuel injection and the early mechanical fuel injections systems ran with fuel pressures aroung 15 PSI. Then along came electronic fuel injection and most  ran with fuel pressures around 43 psi. Then there was the introduction of Ethanol in fuel as an octane booster. Ethanol will react with Buna-N Nitrile and typically will shrink and weaken the Buna-N.
Porsche came out with a service bulletin requiring all Buna-N Nitrile fuel lines be upgraded to fuel injection certified fuel line material which was a Viton material. When the bulletin came out in the early 1990's , most Porsche owners were not going back to Porsche for service and were not aware of the bulletin. Many engine fires of Porsches from the 1980's and earlier were reported because the Nitrile fuel lines were disintegrating and leaking fuel into the engine compartment and fires occurred.




 
After a few days of inactivity I dismantled and cleaned the carburetors again, everything seemed in its place.
I realized that the carburetor on the right had difficulty lowering the cylinders of the needles that did not go down completely, letting gasoline escape, I dismantled the upper part of the carburetor and the membrane rubber was incorrectly placed, once the fault was corrected it was solved the fuel spill problem.
I changed the fuel tank valve for a membrane-closing one, with an inside-drilled oiler housed in the intake manifold and a tube I built the vacuum system.
The bike started and ran great.
I went out to ride and on a straight line when I went over 6000 RPM I noticed a CRACK, now it seems like a cylinder is hitting the head with a valve.
When I have time I will remove the valve cover to verify the breakage.
RUN LIKE THE WIND¡¡¡
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THE MOMENT OF TRUE. 6 months 3 weeks ago #31687

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So after a few days thinking about removing the engine, today I decided to do it.
I removed the coils and valve cover.
The result has been the jumping of a tooth on the intake valve shaft.
As the user manual says, I counted the teeth from the first marking point with the crankshaft set to the T.
The count was 17.5 links to the dot mark on the valve stem.
(View photo)
I removed the timing chain tensioner, then loosened the screws that hold the shaft and moved the chain one tooth. I gave the crankshaft a couple of turns with the 14-inch wrench and checked that everything was still in place.
I reassembled the chain tensioner, then removed the spark plugs and activated the starter motor without noticing any strange noises.
I reassembled the valve cover, the coils and tried starting the bike.
At low revolutions the tensioner makes noise, only the tensioner, reaching 2000RPM the noise disappears by "balancing" the chain tension by inertia.

CONCLUSION

I have to change the chain tensioner. Which one do you recommend?
I also don't know if the inner nylon bearing is broken, in case I have to change the tensioner bearing...
Does the cylinder head have to be removed or can it be done through the tensioner hole?

I'll be waiting for your answers.


RUN LIKE THE WIND¡¡¡
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THE MOMENT OF TRUE. 6 months 3 weeks ago #31689

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Sorry to hear that the intake camshaft jumped a tooth. I tried to direct you to read the FAQ's before going any further because the tensioner can be a problem.
You stated that your count on the links was 17.5, so the intake jumped 1 tooth retarded which is 10 degrees camshaft or 20 degrees crankshaft retarded, so you may have got lucky and not bent a valve. You also said in a previous post that you thought you heard pistons hitting valves and that would happen if the intake jumped 1 tooth advanced or if the exhaust camshaft jumped 1 tooth retarded. In either case, you need to do a compression test to figure out if you have a bent valve.

Your question -  Does the cylinder head have to come off to access the nylon gear and  tensioner arm? Yes the cylinder head as to come off. The tensioner arm pivots on a pin ( item #12) that is the shaft for the nylon Cam Chain Sprocket (item #16) in the parts drawing and it sits in a slot in the cylinder block. When the cylinder head is installed, the head captures the pin between the cylinder block and the head.
The tensioner wheel is at the bottom of the tensioner guide item #15 in the parts diagram.  Replacement wheels are available from www.z1300.de  You have to go to the "Motor" tab and go down about half way to find the tensioner wheel.
The nylon gear can be replaced with a  steel idler gear from Liska

 
Parts diagram from Partzilla

 

Screen shot from www.z1300.de showing the tensioning wheel they sell.

 
This is a picture of what can happen to a bad tensioning wheel. We've seen this more than once.

 
This pic shows a damaged nylon gear. The teeth are all gone. the pic also shows the pin item #12 from the parts diagram that sits in the block and why the head as to come off.
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THE MOMENT OF TRUE. 6 months 3 weeks ago #31690

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Thanks for the help Kawboy.
I read everything regarding FACS in addition to the threads dealing with timing chain tensioners.
Before testing the bike I loosened the tensioner screw so that the spring could do its job, seriously, the engine sounded good, the failure occurred when the RPM increased which makes me think that the nylon gear or the rubber bearing They were already damaged.
Consider that the motorcycle only has 24,000km. The chain tensioner assembly should be in good use.
This week I will try to disassemble the cylinder head and look for the damaged parts.
Thanks again.
RUN LIKE THE WIND¡¡¡
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THE MOMENT OF TRUE. 6 months 2 weeks ago #31693

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Well, I was able to get an endoscopic camera.

With the valve cover and the timing chain tensioner removed, I was able to take photos to verify the condition of the guide sprocket and the rubber wheel of the tensioner.
ts condition is perfect, I am not going to remove the engine head.



I have also discovered how to correct the malfunction of the tensioner that loosens itself.

I have loosened the screws that hold the body of the tensioner two turns, I have tightened the central nut that fixes the position of the tensioner, then I have tightened the retaining screws and it has not loosened again.
 




I have started the engine and it sounds fine, without any noise.

I AM NOW WAITING FOR THE ARRIVAL OF A MANUAL SCREW TENSIONER BOUGHT ON EBAY.

It seems that I see the light at the end of the tunnel again. 
RUN LIKE THE WIND¡¡¡
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