CDI UNIT ??

Would it not make any sense to carry one of these as a spare?
And would I be right in saying there are 2 types one more reliable than the other?
And why out of all the parts off a T80 I broke have I ended up with very few parts left and a perfectly good CDI!

Admin drgaz wrote:Would it not make any sense to carry one of these as a spare?
And would I be right in saying there are 2 types one more reliable than the other?
And why out of all the parts off a T80 I broke have I ended up with very few parts left and a perfectly good CDI!

Worth keeping, the one with grey sheath to wires is rekoned to be the better/later one, but in reality I dont think it makes much difference. Vary rarely fail, but if they do you could be a few days finding another. Note the T50 one will not work on T80 & vice versa

I was going to ask if a T50 would work on T80 ,thanks for that John /Gaz  

JohnW wrote: Note the T50 one will not work on T80 & vice versa

Are you sure about that? Is there a difference in cables or connectors?
As there is no difference in the resistance of the coils.
As i know because i am a T50 owner, cdi unit for T50 has the N/R :2FM-85540-MO and for T80 is: 35T-85540-M1.
But there is a T80D and T80ED with cdi code the same as T50.
As there is no difference in the resistance of the coils.

You can see the codes at the yamaha online catalogue here:
http://www.yamaha-motor.eu/gr/services/yamaha-online-catalogue/index.aspx

Duckrider wrote:

JohnW wrote: Note the T50 one will not work on T80 & vice versa

Are you sure about that? Is there  a difference in cables or connectors?
As there is no difference in the resistance of the coils.
As i know because i am a T50 owner, cdi unit for T50 has the N/R :2FM-85540-MO and for T80 is: 35T-85540-M1.
But there is a T80D and T80ED with cdi code the same as T50.
As there is no difference in the resistance of the coils.

You can see the codes at the yamaha online catalogue here:
http://www.yamaha-motor.eu/gr/services/yamaha-online-catalogue/index.aspx

They look the same, & connectors are the same but they are not, believe me I have tried a T50 one on a T80 & it did not work. I sold it to someone who had a T50 & it worked OK. The flywheel mags are also different on the T50 & T80

Ok, thank you a lot, i will keep it in mind.

These days i am trying to put a T80 cylinder to my T50 engine, i will keep all the other items as they are, i will change only the main jet from 77.5 to 85 and if i will find the pilot jet from 12.5 to 15.
Now i am at this point:







I will try to open an new thread with my work, as my English are not so good.

I thought that the stroke was different on the 50 and fitting a 80 top end would not work?

Hi I see from the pictures which are very good you are using a car oil filter removal tool to hold the fly wheel did this idea work or did it slip wile undoing the center nut?

Admin drgaz wrote:I thought that the stroke was different on the 50 and fitting a 80 top end would not work?

Correct, the T80 has a stroke of 45.6mm (bore 47mm) the T50 has a stroke of 41.4mm (39mm bore)
so T80 cylinder will not fit the T50. In any case as has been said before, the T50 has the useless 3 speed gearbox, so better to find a good T80 engine & change the lot. A T80 cdi unit is required also.

And the T80 exhaust is slightly longer and will be needed I think I am right ?

Admin drgaz wrote:And the T80 exhaust is slightly longer and will be needed I think I am right ?

No the T80 & T50 exhausts are interchangeable there is sufficient adjustment in fixing slots. There is only around 5 mm difference.

Ho I see I thought that there were 2 different part numbers for the T50 & T80 pipes. that's ok then

Admin drgaz wrote:Ho I see I thought that there were 2 different part numbers for the T50 & T80 pipes. that's ok then

I think Yamaha had two different part numbers because the T50 had a restrictor baffle, but external dimensions were same. Motor Cycle Products quote same part number for T50 & T80 http://www.motorcycleproducts.co.uk/search_results.php?keywords=MCP23706

yes 10/4 that john cheers

JohnW wrote:

They look the same, & connectors are the same but they are not, believe me I have tried a T50 one on a T80 & it did not work. I sold it to someone who had a T50 & it worked OK. The flywheel mags are also different on the T50 & T80

John,

I was sure that I had a T80 engine running in a T50 townmate frame along with the electrics of the T50. This would include the CDI as I don't remember switching - i could be wrong.... it was 85 i think... would the bike not spark at all or would it just run badly?

laurpat wrote:

JohnW wrote:

They look the same, & connectors are the same but they are not, believe me I have tried a T50 one on a T80 & it did not work. I sold it to someone who had a T50 & it worked OK. The flywheel mags are also different on the T50 & T80

John,

I was sure that I had a T80 engine running in a T50 townmate frame along with the electrics of the T50. This would include the CDI as I don't remember switching - i could be wrong.... it was 85 i think... would the bike not spark at all or would it just run badly?

When I tried a T50 CDI unit on a T80 nothing happened would not start at all, changed back to the T80 one & it was OK. I suppose the T50 could have been faulty, I sold it some time ago & the buyer never complained so I assume it was OK.

I've been thinking about using pitbike stuff on my rebuild. The stator, pickup coil etc are almost identical as they're just a C90 copy. I built a mobility scooter with a Lifan pitbike engine in and it never failed to start.

If I mark up the original timing marks and turn up a plate to suit the new stator/flywheel setup I cant see why it wouldn't work. This way I could use the pitbike CDI box which are around £6 new and also gain 12v charging and ignition. Parts are also a lot easier to get hold of. Win win if it works, if not I might loose about £40. Got to be worth a shot?

I have a lathe so getting the flywheel to fit wouldn't be a problem.