murp
Drag-strip hero
Posts: 239
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Post by murp on Apr 8, 2019 22:44:37 GMT 1
hi all
just going through dustys excellent engine rebuild thread.....
when i removed the nuts on either end of the crank, i DID NOT use a rotor holding tool..... i just locked up the primary drive with a 2p coin
would this have done any crank damage.....am i being paranoid..... what do the experts think..... how would i know.... i'm only dismantling engine to fix a leak between crankcase joint..the crank was ok..... hope i haven't f**ck it
cheers all
hears hoping
dave
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Post by steeley on Apr 8, 2019 23:00:26 GMT 1
Hmmm , its ok to lock the clutch side up through the primary drive with a piece of copper to undo the nut that side . Coins are steel with a copper plate on them . To undo the ignition rotor nut use the rotor holding tool or use a con rod holding fork on that side . Or an impact wrench on the nut to spin it off .
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Post by steven on Apr 8, 2019 23:12:52 GMT 1
Hi Murp,
What year was your 2p coin ? only the old ones are copper.
Worst case senario is you have twisted the crank, and the two journals wont be 180 deg out any more, best case is, its ok.
To check the crank in place you need to remove the spark plugs and put two DTI,s (clock gauges) down the spark plug holes, to check one piston is at TDC when the other one is at BDC (top/bottom dead center)
Anything other than 180 deg out, and the crank is twisted.
Do you know the history of the crank ? has it been rebuilt before ?
Paul at PJME told me that its the cranks that have been stripped and built once or twice, that are more liable to twisting, as the interferance fit between the parts gets less, once they have been pressed appart/together a few times.
Fingers crossed all is well,
Steven.
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Post by bare on Apr 9, 2019 3:55:13 GMT 1
Buy /use a cheap electric Impact gun it's an essential tool on our Yamas :-)
OEM yama cranks are repressable ~ 3 times... usually
Aftermarket / Cheap Ass SE asian ones rarely tolerate a single repressing
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murp
Drag-strip hero
Posts: 239
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Post by murp on Apr 9, 2019 6:58:13 GMT 1
don't know history.... I do happen to have 2 dial guages, which is strange for me and my limited tool itinerary..... but don't think probe is long enough to detect bdc....... knowing my luck I bet I've twisted it..... I'm 60 and have never seen a crankshaft before and stupidly thought nothing of loosening rotor nut that way...... on top of that it was a new 2p piece...... grrrrrrrrr
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Post by dusty350 on Apr 9, 2019 7:19:46 GMT 1
Hi Think it's a pre 1992 2p piece you should use. It's in the build thread - one of them anyway . I use a flattened piece of 15mm copper tubing instead - definitely soft enough, and have used rag in the past too with good results. I've rebuilt them with no rotor holding tool in the past, with no problems at all, but it's not best practice really, and the first engine build thread I put on here pointed me towards better/safer ways of doing it. Nowadays I always do a leak down test, use a rotor tool, and now lap rotors onto cranks which I've never done before. That's the beauty of the forum - always advice and new ideas to make life easier  If you are unsure about your crank, get PJME to check it for you. I was getting a rebore done there last year, and asked Paul to check and true my Pv crank at the same time. Did it for free for me - spent a few quid with them - but I think it was around the £15 mark otherwise. They will check all the tolerances for you, and then you will know for sure just how good/bad the crank condition is. Banish those negative thoughts that lurk in the back of your mind as much as possible by checking everything. A well built Lc with good parts should be a reliable engine  Dusty |
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murp
Drag-strip hero
Posts: 239
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Post by murp on Apr 9, 2019 7:26:39 GMT 1
thanks dusty..... I should have checked your thread before I started, but as usual I just jumped straight in, not knowing the pitfalls..... but in my defence your thread is a rebuild and I am taking it apart lol
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murp
Drag-strip hero
Posts: 239
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Post by murp on Apr 9, 2019 7:30:00 GMT 1
oh and thanks for other replys as well..... really appreciate it 👍
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murp
Drag-strip hero
Posts: 239
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Post by murp on Apr 9, 2019 8:10:39 GMT 1
the 2p I used was a new magnetic one..... I've got a jar full and this is the first one that came out grrrrr  |
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Post by oldelsieboy on Apr 9, 2019 9:28:38 GMT 1
Hi Murp, What year was your 2p coin ? only the old ones are copper. Pre 92 2p coins are actually made from bronze not copper. OEB |
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Post by cb250g5 on Apr 9, 2019 11:07:14 GMT 1
I use an old paperback book.
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Post by bazzer5115 on Apr 9, 2019 12:12:40 GMT 1
Ive always used a rag.
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Post by midlifecrisisrd on Apr 9, 2019 12:32:06 GMT 1
Check 1998 2p's
They were pressed in both copper plated steel AND bronze so both exist for that year🤓
Bronze is usually 88% copper 🧐
Steve
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Post by zedixe13 on Apr 9, 2019 15:45:47 GMT 1
I used a rag at one moment and I bent a teeth on the pinion , I could hear it every time the teeth engaged on the clutch gear , now I use a simple Y made of a straight bar with a moving arm both ending with allen's head
screws , just the right size for the flywheel holes .
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Post by tacky1 on Apr 9, 2019 21:01:47 GMT 1
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Post by wangwang on Apr 11, 2019 21:43:13 GMT 1
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Post by tacky1 on Apr 11, 2019 23:32:38 GMT 1
Yep, I have this for holding the clutch baskets, It sometimes grips the flywheels, I find that the stubs are a little short and they slip, |
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murp
Drag-strip hero
Posts: 239
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Post by murp on Apr 11, 2019 23:40:20 GMT 1
I set up my 2 dial gauges and they both transition bdc/tdc at the same time....so should I assume all is ok ?
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Post by steven on Apr 11, 2019 23:45:29 GMT 1
I set up my 2 dial gauges and they both transition bdc/tdc at the same time....so should I assume all is ok ? Hi Murp, Yes, I would say so. I do like a happy ending. :-) Steven. |
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Post by steeley on Apr 12, 2019 11:15:51 GMT 1
Nice .
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