17 TC 125 cutting out

Paw Paw 271 wrote:

I would replace the reeds.
I would suspect that the power valves are fluttering.

Paw Paw

40acres wrote:

You could always flip the reeds as well to see if that doesn't help. Then slap the new ones in when they arrive.

BR8ES wrote:

are the F1 arms worth the money?

CarlinoJoeVideo wrote:

If your power valve arms aren't moving smooth, yes for sure. My bike was fine with stock arms and with F1, some people notice a night...

If your power valve arms aren't moving smooth, yes for sure.

My bike was fine with stock arms and with F1, some people notice a night and day difference if they are experiencing problems with OEM.

There's no performance gain besides them helping to make your PV work normal.

dtl210 wrote:

I recently purchased a used 2017 TC 125. The bike has 47 hours on it, 10 hours on a new piston and clutch. It runs great...

I recently purchased a used 2017 TC 125. The bike has 47 hours on it, 10 hours on a new piston and clutch.

It runs great everywhere, but right where it comes into the powerband. I'm not sure how to describe what it's doing, kind of cutting out or bogging. It runs great up to that point and after it. But it you keep the throttle right at that mid position it continues to get worse, add throttle and you're on the pipe and all is good. Replaced spark plug just to rule it out, plug is a light brown after a few laps.

Initially I thought it was the 45 pilot jet that was stock on the 2017. Switched to a 35 to match the 2018 spec, didn't make a difference. It has a 480 main, stock needle and I've been all over the place with the clip position, doesn't seem to cure the problem. With the 45 pilot it would load up in the mid-range, now it seems to run much cleaner but is still cutting out.

Powervalve seems to be functioning as it should and not sticking when revving it on the stand. The powervalve was adjusted to about 4 turns in from full out, changed it to 2 turns. This definitely made the power come on sooner and smoother, but it's still acting up.

Finally I pulled the reeds out. There are some pretty big gaps - could this be the issue? I would have thought reeds would affect the bottom or the top, not the middle but maybe I'm wrong. When I pulled the reed out there was quite a bit of gas in there that came out with them.

Pictures show the reeds sitting on a flashlight. The gaps are twice the thickness of the reed in places.

riv187 wrote:

I have a 18 TC125 model. Mine did same thing..half way accellerating it did a booowahh ...If I kept it screaming pinned it was fine...but accellerating...

I have a 18 TC125 model. Mine did same thing..half way accellerating it did a booowahh ...If I kept it screaming pinned it was fine...but accellerating it was horrible and difficult to ride. The problem is your slide cut-a-way is too rich.#4 You can source a 5.5-5.75 from other model bikes,,,75-130 bucks,,,get yours cut by rk for 30,,or grind the opening larger with a dremel tool and sand wheel as I did. The reeds ARE not the problem...everyone thinks this is the taduh moment when they see the gaps,,,I installed different reeds in my 17 TC250, after flat sanding stock cage,, and no real change..Grinding slide on that model gave the same solution..the 18 TC125 changed night and day in smooth excelleration after grinding the opening larger(leaning 1/4-1/2).

DynoDan22 wrote:

You mentioned the bike ran ok before you did a top end? The garbling I hear reminds me of when I had a customer put a...

You mentioned the bike ran ok before you did a top end? The garbling I hear reminds me of when I had a customer put a piston in backwards. Not saying you did our the previous owner did, but take the pipe off and shine a flashlight up the exhaust port and take some pics. The sound your bike is making in the video seems mechanically related (piston in backwards or powervalve not opening/closing etc.). I had a '17 with atrocious jetting from the factory and I don't recall mine making that muffled bog. Strange!!