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Old 01 August 2014, 01:57   #21
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Not a clue what you have just said

Move the piston back 1mm and the dial gauge shows wait for it........1mm WOW.

This thread was black magic as far as I'm concerned by the time it had got to post 3!
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Old 01 August 2014, 02:41   #22
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Not a clue what you have just said

Move the piston back 1mm and the dial gauge shows wait for it........1mm WOW.

I just meant that if you don't have access to a DTI it still is possible to get pretty darn close. I've used the first method and then had it measured with a DTI and it was pretty much bang-on.

Cheapy TDC finder:


"Out"
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Old 01 August 2014, 03:18   #23
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now my head hurts even more
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Old 01 August 2014, 03:52   #24
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Originally Posted by HughN View Post
Cheapy TDC finder:
"Out"
Even cheaper TDC finder



I understood Hugh's description, but will try explaining it in a different way.

Start by removing all spark plugs, in order to make the motor easy to turn over by hand. Get a socket and ratchet or a wrench to turn the motor over.

You shove the pen, plastic side in with the top removed, into the cylinder, thru the spark plug hole, then slowly turn the motor over until the pen quits coming out. Keep going until the pen just starts to drop, and mark the flywheel. We will call this point A. Now reverse the ratchet or wrench you are using and after it tops out again and starts falling, mark the flywheel (This is B). There should be around a 1.5cm gap between the A and B marks. The center of this is the actual TDC. You can rock the motor back and forth a few times to confirm your markings.
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Old 01 August 2014, 06:24   #25
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Even cheaper TDC finder



I understood Hugh's description, but will try explaining it in a different way.

Start by removing all spark plugs, in order to make the motor easy to turn over by hand. Get a socket and ratchet or a wrench to turn the motor over.

You shove the pen, plastic side in with the top removed, into the cylinder, thru the spark plug hole, then slowly turn the motor over until the pen quits coming out. Keep going until the pen just starts to drop, and mark the flywheel. We will call this point A. Now reverse the ratchet or wrench you are using and after it tops out again and starts falling, mark the flywheel (This is B). There should be around a 1.5cm gap between the A and B marks. The center of this is the actual TDC. You can rock the motor back and forth a few times to confirm your markings.
Yes all well and good if thats all the op needed (to find TDC) not rocket science is it?

But he needs to be able to set the timing at 3.35mm or 0.132in before TDC, how does he do that with a biro or owt else he sticks down the plug hole except of course a dial gauge.
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Old 01 August 2014, 11:19   #26
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after nearly all day of calling just about every used spares place in the uk i had a call back at 3pm from a guy who had spent 2 hrs going through his stock he phoned and said he only had the cdi type cm66-25 and the only other one he had was a cm66-23 which he said was not a cdi type --- eirlier in the day i spoke to a verry knowledgeable guy at sea cat marine in cornwall
who mentioned the cm66-23 is the only other one that will work but harder to find so with that info and for the price of 35 delivered within 24 - 48 hrs and fully returnable if it dosent do the job i was more than happy to order there and then t secure what seams like the only one left in the country

the one from usa wanted 25 for posting then noticed it was the cdi type and appart from that i cannot find any other ones arround anywhere

also ime going to contact the guy who i got the engine off see if he has the origional one in his workshop as he must of removed it to fit the cdi one see if i can secure this one as well
ile update as soon as it arrives
thanks again for all your help so far
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Old 01 August 2014, 11:39   #27
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But he needs to be able to set the timing at 3.35mm or 0.132in before TDC, how does he do that with a biro or owt else he sticks down the plug hole except of course a dial gauge.
Well here is specialty tool number 2 then Must be used with a digital or dial caliper.


I admit I hadn't read the directions. A cheap junky dial indicator would be the easiest way. I have a few dial indicators that mount in different ways with one pair working off of a pair of Vise Grip pliers. I do like the cut off spark plug though for its simple ingenuity
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Old 01 August 2014, 12:00   #28
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I'm a retired car mechanic but I did do quite a bit of work on 70s Yamaha bikes with points and as said above the timing is critical. I had (probably still do somewhere) a spark plug thread adaptor for the dial gauge. And you really do need to use a dial gauge to get it spot on. If you are stuck I'll find it and post it to you.

It's surprising how the most miniscule movement of the piston can be seen as a really large movement of the dial gauge.

Edit- Found it!

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Old 01 August 2014, 12:17   #29
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Originally Posted by stigoftd View Post
after nearly all day of calling just about every used spares place in the uk i had a call back at 3pm from a guy who had spent 2 hrs going through his stock he phoned and said he only had the cdi type cm66-25 and the only other one he had was a cm66-23 which he said was not a cdi type --- eirlier in the day i spoke to a verry knowledgeable guy at sea cat marine in cornwall
who mentioned the cm66-23 is the only other one that will work but harder to find so with that info and for the price of 35 delivered within 24 - 48 hrs and fully returnable if it dosent do the job i was more than happy to order there and then t secure what seams like the only one left in the country

the one from usa wanted 25 for posting then noticed it was the cdi type and appart from that i cannot find any other ones arround anywhere

also ime going to contact the guy who i got the engine off see if he has the origional one in his workshop as he must of removed it to fit the cdi one see if i can secure this one as well
ile update as soon as it arrives
thanks again for all your help so far
Bloomin heck best keep my eye out for a spare (just incase)

Well hopefully that will sort you out and you never have another problem
Did not think that they would be so hard to find, I still cant believe that there are no generic coils that fit, like I said one of my coils has no marking/numbers or owt on it
Anyway good luck with it, and if you need any more info out the manual just let me know
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Old 01 August 2014, 12:39   #30
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f you are stuck I'll find it and post it to you.

It's surprising how the most miniscule movement of the piston can be seen as a really large movement of the dial gauge.

Edit- Found it!

[/QUOTE]

Nice one beets my sparkplug conversion , wish I had yours a couple of months ago

Click image for larger version

Name:	dial gauge 002.jpg
Views:	52
Size:	49.8 KB
ID:	97460

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