Scorpa ty125 carb issues

[Belgian Waffles]

I put my trials riding on hiatus a couple years ago as i went off to uni and the scorpa (ty125 2006) started acting up a bit. When riding down the rocks pretty steep the idle would simply slow until it died very calmly.

Now the bike has been sitting for a while and i just recently put it all back together and gave it a go. With clean fuel and full choke it started right up. Rpm was obscenely high so i turned down the idle and seemed to be doing ok. Still full choke.

As it was getting warmer it didnt like the rich fuel anymore so i started easing off the choke but had to twist the throttle to keep the revs up so it wouldnt die. I tried to adjust the idle to get it to stay alive but now when i turned the idle screw it made no difference whatsoever. I turned the screw all the way in, all the way out and everywhere in between, but no change to the idle.

I remember trying this last year with the same results. Now i want to get back on the rocks so i really want this scorpa running properly, but i cant figure out why the idle screw seems to do nothing now (even though i got it to drop the idle down right when i first kicked it on with full choke). Carb is a mikuni ucal 3106.

Suggestions or similar experiences?

Thanks. BW.

[mung]

Your slow speed jet is clogged. Take the float bowl off and remove pilot jet and clean or replace. Then set air screw to about one and one half turns.It should run sweet.

[Sting32]

Originally Posted by Belgian Waffles

I put my trials riding on hiatus a couple years ago as i went off to uni and the scorpa (ty125 2006) started acting up a bit. When riding down the rocks pretty steep the idle would simply slow until it died very calmly.

Now the bike has been sitting for a while and i just recently put it all back together and gave it a go. With clean fuel and full choke it started right up. Rpm was obscenely high so i turned down the idle and seemed to be doing ok. Still full choke.

As it was getting warmer it didnt like the rich fuel anymore so i started easing off the choke but had to twist the throttle to keep the revs up so it wouldnt die. I tried to adjust the idle to get it to stay alive but now when i turned the idle screw it made no difference whatsoever. I turned the screw all the way in, all the way out and everywhere in between, but no change to the idle.

I remember trying this last year with the same results. Now i want to get back on the rocks so i really want this scorpa running properly, but i cant figure out why the idle screw seems to do nothing now (even though i got it to drop the idle down right when i first kicked it on with full choke). Carb is a mikuni ucal 3106.

Suggestions or similar experiences?

Thanks. BW.

99 times out of 100, if a bike sits for more than 3 months with today's gas, the carb is gunked up. alcohol in the fuel compounds this problem since the chemicals that have to be in the gas, to keep the alcohol (and water) suspended in the fuels, last about 29days, in small quantities.

SO you need to clean the carb carefully, there are usually 2 "jets" which are screw in, gas limiting devices, AKA special bolts with calibrated hole size in it. the hole is plugged or half plugged


Just FYI, IF you can find NON ethanol gas, and add stabil (there are other brands, and yep Ima havin a brain fart on which one I have) you can extend the storage.

Ramblings:
Dad and I started a small (antique) farmall tractor that we parked 12 years ago, or we think at least. there was 5 or more gallons of "old style" fuel in the tank. It still ran, the gas in anything lately smells like shit after a few months, this gas smelled fairly good.

ALSO, It has been a hot (drought) on the farm, I have lawnmowers that you have to re-clean the carbs between mowing (less than once a month), if you DON'T run with Stabil like products, and non ethanol fuels.

[Belgian Waffles]

Originally Posted by mung

Your slow speed jet is clogged. Take the float bowl off and remove pilot jet and clean or replace. Then set air screw to about one and one half turns.It should run sweet.

I looked at that a while ago, and even compared it with a spare, but I guess I was looking for physical damage rather than clogging. Ill check again when Im back at the garage next week.

Originally Posted by Sting32

99 times out of 100, if a bike sits for more than 3 months with today's gas, the carb is gunked up. alcohol in the fuel compounds this problem since the chemicals that have to be in the gas, to keep the alcohol (and water) suspended in the fuels, last about 29days, in small quantities.

SO you need to clean the carb carefully, there are usually 2 "jets" which are screw in, gas limiting devices, AKA special bolts with calibrated hole size in it. the hole is plugged or half plugged


Just FYI, IF you can find NON ethanol gas, and add stabil (there are other brands, and yep Ima havin a brain fart on which one I have) you can extend the storage.

Ramblings:
Dad and I started a small (antique) farmall tractor that we parked 12 years ago, or we think at least. there was 5 or more gallons of "old style" fuel in the tank. It still ran, the gas in anything lately smells like shit after a few months, this gas smelled fairly good.

ALSO, It has been a hot (drought) on the farm, I have lawnmowers that you have to re-clean the carbs between mowing (less than once a month), if you DON'T run with Stabil like products, and non ethanol fuels.

I've started using stabil (or something like that) when storing my Transalp or brothers Africa Twin, but those never sit long enough to leave enough crap in the carbs to notice it. I guess if this is the problem with the Scorpa I'll have learned the hard way and won't do again

Thanks for your help guys. I'll take a look and report my findings next week. As far as cleaning utensils.... careful use of toothbrush, needle and/or compressed air should do the trick?

I love ADV.

BW

[mung]

Take your pilot[slow speed] jet out and put it in a puddle of carb cleaner. Let it soak then blow out with compressed air. You might have to repeat sequence three or four times.Do not run wire or other metal through jet ! Hard metal rubbing on soft brass equals larger jet size.If you cannot get it clean it is best in the long run to just buy a new jet.Good luck.

[Belgian Waffles]

Originally Posted by mung

Your slow speed jet is clogged. Take the float bowl off and remove pilot jet and clean or replace. Then set air screw to about one and one half turns.It should run sweet.

One hand a half turns out? (ie. CCW from all the way in?)

Originally Posted by mung

Take your pilot[slow speed] jet out and put it in a puddle of carb cleaner. Let it soak then blow out with compressed air. You might have to repeat sequence three or four times.Do not run wire or other metal through jet ! Hard metal rubbing on soft brass equals larger jet size.If you cannot get it clean it is best in the long run to just buy a new jet.Good luck.

Noted.

[Belgian Waffles]

Soaked all the jets and definitely made an improvement. Only thing now is that when i snap the throttle the engine takes a while to go back down to idle. Almost like the choke is sticking. Throttle cables move freely and the choke seems fine, but i oiled all the cables and i'll see if that fixes it.

Otherwise, im happy to play around on the trials bike again. It's been a while.