5 replies to this topic

[samandkimberly]

I have a TY80 I bought for my son. It's in nice shape cosmetically, burns clean, starts great, and has *lots* of mid range power; ticks like a watch at idle too. But throttle response from idle/low RPM to maybe 2,000 RPM is lackluster at best; it feels like the idle jet is off a bit or the throttle slide cutout is too big. The jets are clean. But before I start messing with changing out carb parts I thought I should see what tuning advice this community has to offer. I'd love to hear any general TY80 tuning tips, but I'll start with some specific questions:

• Should I be expecting snappy off idle response out of a 80cc bike made in the 70s? I mean it works as is, but I wouldn't want to put my kid on it in a trial - it would take a lot of clutch work to keep it going in anything tight.
  
  
• How sensitive are these to jetting/carb wear?
  
  
• How much does ignition impact off idle response? Should I be redirecting my efforts there? Speaking of which, can anyone point me to an on line manual for a TY80?

That's a start anyway. Thanks in advance for any and all input.

Sam

Edited by samandkimberly, 04 April 2011 - 02:17 AM.

[thedktor]

I have had several and still got one tidy one. They are not very powerful I must say, but with a light rider they are very capable, and WILL pull from low revs. I am 11 stone and struggle to get up anything without lots of revs in 1st gear, while my younger son at around 6st has no problems and can use 2nd gear on quite steep stuff.

In my experience poor running is nearly always the pilot circuit blocked up, as the jets are so tiny it takes very little to block 'em, worth one more look I would suggest.

The points have never given any problem to us, but obviously if worn or not gapped correctly it won't help.

Also they will still run fine even when the piston/rings/bore are completely worn out, but low down power will suffer....

Oh, gearing too, 12/41 is standard (will check) but a 11t front will help lots.

- Steve

[jon v8]

I think you both have something wrong,my kids TY80 pulls rather too well,I have even thought about calming it down a bit.But the engine is pretty much as new with all genuine bits,so starts,runs and sounds like new.
Most Ty80's I see around are tired old dogs that people dont want to spend any money on.Totally agree about the carb though,they can be a pain to get fully clean.

[lineaway]

I seem to remember we ran 11t cs and 46 or 48 rear sprocket. That will change the need for any clutch work and that mighty little engine could pull my 190 lbs up some pretty nasty hills.

[samandkimberly]

Thanks everyone. It really does feel like a small pilot jet, so I'll go in there and make damn sure it's clean before I do anything else.

Sam

[insultaco]

 jon v8, on 04 April 2011 - 11:34 AM, said:

I think you both have something wrong,my kids TY80 pulls rather too well,I have even thought about calming it down a bit.But the engine is pretty much as new with all genuine bits,so starts,runs and sounds like new.
Most Ty80's I see around are tired old dogs that people dont want to spend any money on.Totally agree about the carb though,they can be a pain to get fully clean.

Im with Jon V8, my lads TY80 pulls me (5'7"/90kg (190lbs(ish)) around with no problem and is sharp on the throttle. Standard timing, but on electronic ignition.

The bikes been well used, but does have new piston and rings on used barrel and engine.

Timimg and/or jetting has to be favorite from what I know. I've got the haynes manual if you need the numbers for standard jets, timing etc, send me a PM.

Good luck!

Mick