Whats up with my ST

[Ghinwha]

Hope you all can help me again. The little 84 ST I bought has been going well but while we were away today she slowed right down to 50 max. Felt like fuel starvation but she seems to be getting juice. Drove her on and she was gutless, the left hand head is considerably cooler than the right but seemed to be sparking. Tried switching plug sides but the left was still cooler after 25miles flat out at fifty. The new HT leads I fitted are well in the coil and am wondering is the coil failing and what else can I check. Thanks in advance and you haven't let me down yet. Any ideas?

 

[England-Kev]

As there is only one coil it is unlikely to be that if only one side is being affected, so three things to check...

make sure the choke is returning all the way when off. (push it down with your finger)

Valve clearences

Spark Plugs (pull the plugs and check the colour)

are you sure it is not fuel related?

 

[Rob Farmer]

Diaphragm has split in the left carb.

 

[DrFarkoff]

wot rob says methinks

if its been sitting around a while it may be prudent to order two

 

[Ghinwha]

Thanks

Thanks again lads! Am working away this week but I'll give MOTORWORKS a ring and order two! Fantastic to know there is good reliable advice so close at hand. Will post some photos of the ST soon.

 

[Ghinwha]

Thanks lads! Got a couple of diaphragms from MOTORWORKS and have just replaced the left one and it seems to have cured the problem. Will replace both and am putting new springs on the choke returns as the right one is stretched out and not reseating properly without pushing it down with the finger. Will take her up the North West Causeway coast tomorrow and see if alls well. Fingers crossed. Have really fallen for this wee bike!