T5 will not start

Please can anyone help whent to work on scooter started 1st kick both times .Left work about 4 miles down the road started to splutter then died would not fire plug has a good spark petrol getting to engine put old carb back on got it started in the end got home it died again. Cleaned 26mm carb with air line put it back on got it started in the end will not tick over or sta rt every time and it some times back fires out of the exhaust when you kick it and allso popping blowing noise coming out of the carb under air filter does not start when it makes this noise. The compression does not seem as good as it used to be could it be the piston rings have had it. the scooter is t5 with 172 kit scorpion and 26mm carb with 125 main Thanks Gary[:smile:] [:dance1:]

Hi plug is ok nice choc brown will the malossi piston rings fit any piston or do they have to come with the piston as i have spare set thanks

yes changed plug made no difference.What i should have said is are the piston rings graded like the pistons

Yes exhaust side. kit was about 3 years old head done by tafspeed

new kit in scoot now the running in starts been long 2 1/2 weeks with scoot off the road

I know what you mean and the piston rings are all the same. What he means is that the malossi has A,B,C grade pistons C being largest. Im sure the rings are all one size though. A common problem with Vespas is the wires coming from the stator plate breaking down within the insulation. If you look the insulation is rubbery and doesn’t support the copper core especially when you increase revs and therefore vibration. With ignition problems be methodical and work from the plug back. Do one thing at a time then you know for sure you have solved the problem. Check the wire as they go into the CDI box. They should be a tight fit. Pay special attention to the white wire as this often causes problems-it is the stator plate earth.
Usually if the rings are very worn(unusual with malossi) you will start it fine from cold but will struggle when its hot.

He he don’t you know it. Like I said mate think you may have just been unlucky.

Start simple have you changed the plug? They sometimes spark but will not ignite the fuel.

I am of the same opinion of slidingdog.
So woodruff key or moving stator plate.
Sorry gaz7 I didn’t understand in your last messagewhen you say
„piston rings graded like the pistons“.

Was this on the exhaust side? as mine seem to go thier, I put it down to worn bore/rings? [?[]
was the head modifed? and was it an old kit?

Just a bit unlucky there mate I think. Ive had a kit on one bike thats about 5 years old and done holland 4 times. The piston sounds like its trying to make a bid for freedom but I cant be bothered to do anything with it but thrash it! Glad to see you’d rather get your scoot done than go in a car to Cleethorpes- we’re a dying breed you know. Caravans at Skeggy- wtf that all about?

…like in most love stories.

Hi plug is ok nice choc brown will the malossi piston rings fit any piston or do they have to come with the piston as i have spare set thanks

hello,

Diablo I confirm that cables from stator plate after a certain time tend to give problems, especially the one that are in the position to be in contact with the stator itself or other part of the cranckcase, though the „telluric“ synthoms of Gaz7 engine seams to go toward a messing up of timing.
I would for any electric problem suggest Gaz7 the same approach one thing at the time as you Diablo suggested.

I hope Gaz7 you can solve this problem the soonest.

Hi thanks for your replys found the problem 1 broken piston ring a bit of the piston between the 2 rings about half a inch long also broken off barrell looks to scored to use new kit will be ordered in morning thats means no cleethorpes rally this weekend.what would cause this would it be to weak mixture or timing to advanced. 125 main jet used timing about 15 . 16 .the rest off the piston looks ok apart from the bottom . Plug a good colour to

Yes scooter rallys for scooters not in the car. any ideas why this has happened.All ways some thing happens when scooter seams to be going ok

new kit in scoot now the running in starts been long 2 1/2 weeks with scoot off the road

Might be the woodruff key? sends the timing right off, hence backfire.
If you have lost compresion, would check barrel next though [:(] What colour was the spark plug?

yes curare scooters like women to bloody true.