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Cam noise . . . engine problems (cont)

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Recap: installed TT fly wheel and set the valves to the middle range of the stock specs. As I have the RHC cams Eddie suggested I tighten the clearances and the cams quieted down a bit. Take it out for a shake down ride, get about a mile from my house and life turns bad. Cruising in 4th gear and all of a sudden there is a CLUNK from the engine and the engine dies. Get my buddy to rescue me in my pickup and the bike is now in my garage.

Got around to opening up the engine this morning and my problems appear to be as follows. The right exhaust bucket appears to be much lower in the head than the other three valves. When I rotate the engine manually there is a grinding noise (which appears to be more from the bottom end) and I eventually get to a point where the engine does not want to turn any further. Have I dropped a valve?

I assume at this point I am going to have to take off the head and determine what's what. Is there some logic to disassembling the engine when it is not at TDC? Right now the cams are both pointing up and are not in contact with the valves so removing the cams shouldn't be too hard. Do I index every thing as usual and just make sure to reinstall the cams as they are?

I assume that if I have to take off the cylinder it won't really matter where every thing is as there will be enough stuff broken that I will have to start from the bottom end and line every thing up.

Let me know what the best way is to proceed from here. Thanks for the help in advance!

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Yup, sounds like a bent valve. Pull the head, inspect the piston. It probably is a good idea to pull the barrel too and check for any con rod and crank play. Becnt valve is bad, grinding from the lower end could be a real pain.

When reinstalling the cams, you want to follow the manual, having the lobes pointing away, marks lined up yadya yada.

When tearing a engine down, it does not have to be at tdc or any place in particular as you are going to line the stuff up upon reassembly.

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have you ever done the primary nut fix?

you need to put it TDC so you can see if the cam timing is off now.

Haven't done the primary nut yet. I think now would be a good time to do that :applause: How should I go about tightening it if I have the TT flywheel that does not have the 26mm slots to hold the crankshaft?

I will strip off the right side cover now, but I'm assuming that I want to do the primary nut before removing the head.

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At this point, the best thing would be to loosen the primary nut (if it is not already loose). Pull the head, pull the barrel, check for bottom end damage. You can apply the primary nut fix as you button things back up.

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OK, that's what I was thinking as well. The primary nut does not appear to be loose. Taking the head and cylinder off is not a problem for me, but is the best strategy to loosen and tighten the primary nut without having the hex head portion on the TT flywheel? I've got rubber strap things that act like an oil filter wrench, but the rubber stretches too much if you put any real pressure on them. Any other suggestions for attacking the primary nut?

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Well... Others may yell at me but... you can do the old "Rag In The Gears" trick. Simply get a heavish piece of cloth, put your socket on the nut, stuff the rag in the gears as you turn the nut. The rag will jam them up and enable you to loosen the nut. This is how we did in olden times.

A better way would be to simply use an impact air gun on it.

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Well... Others may yell at me but... you can do the old "Rag In The Gears" trick. Simply get a heavish piece of cloth, put your socket on the nut, stuff the rag in the gears as you turn the nut. The rag will jam them up and enable you to loosen the nut. This is how we did in olden times.

A better way would be to simply use an impact air gun on it.

You can also use a strap wrench on the flywheel, which is also the best way to tighten the flywheel nut, with this flywheel.

Neil. :applause::lol: :lol:

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You can also use a strap wrench on the flywheel, which is also the best way to tighten the flywheel nut, with this flywheel.

Neil. :applause::lol: :lol:

Hiya Neil,

He tried that with the one he has, but it was too 'stretchy'. He'll certainly need a good one to reassemble the P Nut properly, but I think he may have bigger problems now.

Mattys:

As Eddie suspects, the valve timing might be off. See if you can determine if it is. I understand this might be tough given the fact you cannot rotate the engin through complete revolutions. It is important to determine this as it might identify why you are having ther problem. This is nearly as important as resolving it.

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Right, when I took out the spark plug the tip was totally crushed from some part of the engine hitting it. I double checked the timing when I put the bike back together, but then again it still could have been off. My strategy is to take off head, remove bent valve, check for damage to head and cylinder, remove cylinder, check for bottom end and start lining every thing up from there.

At this point I'm not really sure what went wrong, but I assume I will have a better idea in a day or two when I have the engine completely apart.

Thanks for the help and I will keep every one updated.

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A strap wrench with a steel band is the type you need, often sold for oil filters.

Crushed plug is probably the bottom end bearing from the rod, assuming it is the correct pug. Would also explain the grinding sound.

Hopefully not, a valve bent or broken, will do that when the piston hits it :lol:

I found this the hard way in the mid 70's on Honda CB250 K series twins.

I had a collection of pistons, heads barrels and cranks that would have given a race team a headache.

I gave up on them after the 10th big bang in a year.

Neil. :applause::lol::eek:

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Right now I think it might just be as effective for me to send the engine to Eddie and sell off my FCR and RS3 pipe as ebay prices for these look to be pretty strong right now. The freewheelers crank, FCR41 and a bigger pipe would be a nice addition :applause:

That's only a thought for now, I'm still going try to figure out what went wrong with the engine when I have time. Life is too freak'n busy, I just want to ride the bike!

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