yamaha 25 1980s ignition fault

[Barrowboy]

Originally Posted by bartiny

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!

[HughN]

Originally Posted by bartiny

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"

[stigoftd]

now my head hurts even more

[Peter_C]

Originally Posted by HughN

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.

[bartiny]

Originally Posted by Peter_C

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.

[stigoftd]

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

[Peter_C]

Originally Posted by bartiny

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

[Transporterman99]

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!

[bartiny]

Originally Posted by stigoftd

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

[bartiny]

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

[bartiny]

Originally Posted by Barrowboy

This thread was black magic as far as I'm concerned by the time it had got to post 3!

I hope you are still keeping up, multiple choice questions at the end

[stigoftd]

Originally Posted by Transporterman99

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!

wow many thanks for the great offer but hope i dont need it but if i do ile take you up on that
you wouldnt believe how many people i have asked for a coil or messaged all over the world - usa - canada - australia - germany - ireland - etc and just about every one i could find in the uk all have come back with no or havent seen one of them in years but then some are just a aste of time speaking to unless you want to spend 300 - 400 quid they aint interested in helping you how things have changed from when i was in the industry and that was only 10 odd years ago

[Transporterman99]

Anytime.. Anyone in the future is also welcome to borrow the adaptor for the cost of the postage.

[bartiny]

Originally Posted by Transporterman99

Anytime.. Anyone in the future is also welcome to borrow the adaptor for the cost of the postage.

Yes please, would not mind borrowing it to double check my heath robinson set up.
I will pm you

[Transporterman99]

Got your pm. Sent reply..

[Transporterman99]

Parcel sent..

One tip for when you use it. Leave the grub screw on the adaptor loose until you are sure you have the right length of rod fitted to the plunger. That way you can't accidentally clonk the dial gauge with the piston when the dial gauge plunger is already fully home.

Sounds more complicated than it is!!

[bartiny]

Originally Posted by Transporterman99

Parcel sent..

One tip for when you use it. Leave the grub screw on the adaptor loose until you are sure you have the right length of rod fitted to the plunger. That way you can't accidentally clonk the dial gauge with the piston when the dial gauge plunger is already fully home.

Sounds more complicated than it is!!

Yep will do, I will PM you when it arrives.

Top man

[stigoftd]

well that cm66-23 coil arrived today i spent 3 min fitting it and it has a proper spark so does the other so in the test tank and first pull off she went i had to set the carp up a tiny ammount and think the timing may be a little out of time but other wise she is running sweet as
still trying to get hold of the other engine

and if anyone needs any outboard spares i can totaly recomend
outboard spares unlimited - 01622817073 realy couldnt be anymore helpfull and arrived in 2 working days [could of been 24hrs if i orderd it in the morning]
otherwise i couldnt be more happy

[bartiny]

Originally Posted by stigoftd

well that cm66-23 coil arrived today i spent 3 min fitting it and it has a proper spark so does the other so in the test tank and first pull off she went i had to set the carp up a tiny ammount and think the timing may be a little out of time but other wise she is running sweet as
still trying to get hold of the other engine

and if anyone needs any outboard spares i can totaly recomend
outboard spares unlimited - 01622817073 realy couldnt be anymore helpfull and arrived in 2 working days [could of been 24hrs if i orderd it in the morning]
otherwise i couldnt be more happy

Great news (I will put that ignition stuff away now then ) lets hope mine is the right 1, been posted today UPS tracked hoping for the end of the week, but like I said its only a spare

[stigoftd]

your coil you say hasnt got any no's on if you take it off look at the reverse is should be on there as it seams that if it is on the tiller side of the engine they go on upside down the other side it is on show
hopefully ile be givving her a run down the river sometime this week nd report back