Modern Vespa

My gt200 started stalling at stop signs a few weeks ago (I must admit, I haven't been riding it as frequently as I used to...) and it sounds like my carb is just gunked up from the occasions when I don't ride it for a few weeks at a time. AFAIK, it's never been cleaned.

I saw the incredibly helpful carb cleanout for the LX here and I figure I could do the same thing for the gt200.

Two questions though:
1) I got the clamps off the rear boot but that thing does NOT want to come off the carb. Any risk in just prying it off with a screwdriver? Is there some special way I can loosen it or pull it away from the carb?
2) Has anyone actually done this method where you don't fully disconnect the carb with a gt200? I've read the coolant runs into the carb and that sounds like a pain to drain/disconnect so I would love to just be able to flip the thing over and unscrew the bottom like in the LX instructions.

Thanks for the help!

First of all, yes, pry the boot off. As it's a bit older, I'm sure it's hardened quite a bit.

Secondly, the coolant hoses don't run directly into the carb body, but rather to a small passageway that bolts to the carb with a small Philips head bolt. If you remove the boots, you should be able to tip the carb towards the front of the bike enough to get a small screwdriver in there to remove it. If you do this, you don't have to worry about coolant spills. An alternate method is to use locking hemostats on the hoses, then you can remove them from the carb without spilling very much.

Excellent, I'll try some more force on the boot today and see if I can just flip it over. Thanks for the tips!

I started on this today and ran into one issue. Got the boot off OK (yeah, it's a bit stiff and just needed some gentle tugging, I suspected squeezing it a bit warmed it up too, it's not so old as to be brittle yet) but flipping the carb over without disconnecting the lines running into it seemed impossible. I took a shot and disconnected the line indicated on the left thinking it was vacuum and it was in fact coolant



I got it on there again quick enough to not loose too much all over the garage floor but yes, I've got to refill that and replace those single-use clips with some stainless clamps.

Point being: for those people who said that you can remove the bottom part of the carb without disconnecting the lines (the "just flip it over" method), how is that possible with these tiny coolant lines? The one indicated on the right is the *other coolant* line and runs to the opposite side of the carb, but has a similar amount of space to flex and move around (i.e. none).

My only suspicion is that it's possible on the other GT200 carb. This one is the Kehin variety, not the Walbro, so the lines could be different/longer on the other one.

It is possible on both types of carbs, while i can't say which is which, i can say with one you need either a 90* or a stubby screwdriver and the other you need a ridiculously long screwdriver (and attack it from outside the bodywork).

either way, once disconnected, there's no reason to reconnect. just leave it as a coolant bypass.

-g

Yeah, that makes sense. I could probably get a tiny right angle screwdriver in there given how far I can rotate it. I should probably get a mirror so I can see more of what's going on these tight spaces.

Thanks for everyone's help on this! I took the carb apart, verified the jets were all junked up, cleaned them out and reinstalled. Now it starts up like it used to, just the ignition and no throttle needed

I took some pictures along the way, I'll write it up soon so there's a step-by-step guide that any other GT200 owners can use.

Have you changed out the fuel line? If not i'd do it. The deteriorate overtime and can fail. Easy to do but the clamp on the one in the scooter is a one time use. You'll have to buy one. Mine at 5yrs crumbled when we took it off. Good luck.

Next time you open it up, put a 105 main jet in. You will be pleasantly surprised.

Hi greasey125, could you elaborate on 'once disconnected' 'leave it as a coolant bypass'? Are you saying to 'splice' these two coolant lines together as a coolant bypass"

I'm about to check the carb on my GT200 also, and that would be a key part of the effort.

Thanks for the help!

The piece with the two hose barbs in this photo is what you disconnect from the carb. Remove the single Phillips head screw that holds it to the carb body. Don't disconnect the coolant hoses. Simply reattach it when you are done cleaning the carb.

-Craig

I will definitely try that out! Do you know off the top of your head how much MPG changes going from the stock 090 to 105? I have not... my hoses seem to be in decent condition so far (always garaged, no cold weather in SF might have something to do with it) but I'll definitely take a closer look next time I'm poking around. Thanks! Ha. I realized this once I had the thing flipped over (after the coolant hose was disconnected) but I'll include this bit in my writeup. Considering the entrance into the carb points upwards, does most of the coolant stay in the lines if you disconnect the barb piece? I ended up draining mine.

I did the exact same thing the first time I removed a GT200 carb. I just grabbed a couple of bolts the right size and stuck them in the open ends of the hoses.

-Craig

Thanks Craig, that's what will happen then on mine.

Mine looked fine. Here's what they looked like when we took them out. Just broke in pieces in my hand. I'm horrible about preventative stuff. I hate being stranded on the side of the road. This was done at 5yrs.

Where are these bits located?

Fuel lines. Check the line going to the fuel tap. To be fair the guys did mine but you should be able to see them around your carb etc. Clear one's the worst. The clamps in there are a one time use. We got ours at Lowes. The lines at O'Reillys.

I don't get why Piaggio uses that clear line for the vacuum operated fuel tap. That stuff is total crap. When you replace your lines, make sure you use proper black fuel hose. And use the black rubber vacuum lines too. It all lasts much longer than the clear tubing.

-Craig

MotorSport sells a tyghon(sp) one that lasts forever. So true Casch.People really need to change them. You can't tell how bad they are just by looking at them,either.