Aero 125 NH125 Bystarter Pictures

[ClemSpree]

Having a bystarter issue on the Aero so I took some pics and measurements. Not 100% sure these are Aero bystarters but I have two of the same off of two different bikes. The reason I question their application is that they appear to work but both are too long and seal when installed.

OAL top to bottom is approx 2-3/4 plus a little, extended is +1/8". The important dimension is from the face of the black plastic to the bottom of the cap. 3/32 short of the carb mount to needle hole should do the trick.

Since I get extension but otherwise seem too long, I'm going to shorten(make new) the silver pin in the brass item as it is what extends when heated. It slides right out but I neglected to take a pic with it out, there is a small groove cut in it which I will probably not replicate for testing.

If it all goes well, I may cut the original pins to retain the groove.

This should apply to the spree as well, they have the same pin. Not sure yet what is going on but if I have the correct starters, it seems that they have become permanently longer.

[ClemSpree]

A 1/8" drill bit suitably cut and dressed worked perfectly, hot length is now 2-3/4 + a little. It might be slightly too short but pressure tested well, it may just be cooling down too quickly. There's a rubber boot on it now, I may add a bit of fiberglass covered with high temp electrical tape.

Started easily even after replacing all the fuel supply lines.

BTW, one scoot had what looked like an original 108 MJ with a TSB needle, clip on 3rd down and the other had a 105, FGY clip on 2nd down. Both had 40 pilots and 91B slides. Running the FGY on 2nd/105/1-3/4 out. Its very good now, will probably leave it accessible and move the needle/swap around a bit.

Also BTW, found that the gas cap wasn't venting correctly, anyone know if these come apart?

[mousewheels]

Thanks for the pic, I've wondered what a vacuum bystarter looked like.

I moved parts around (hopefully - moved correctly!) and in highlighted the part you modified. Please post back if there are issues, we'll get a pic (without mod) and your measurements added to the wiki bystarter topic.

Aero_125_bystarter_mod_sm.jpg (35.56 KiB) Viewed 2307 times

[ClemSpree]

Looks about right, but IIRC, the needle goes through the cylinder and can actually be shimmed like a carb needle. I should have another, all put together, I'll try to snap a pic.

Scoot starts super easily, as it should, but will stumble/burble from dead cold if you hammer it. Takes about a short block to clear itself, I'm guessing that its not closing off fast enough and leaving a slightly rich mixture. From dead cold, I let the bigger motors warm up slightly as I'm putting on gear, loading stuff so this is a non issue for me.

I'm working a Riva 180(four stroke sounds funny on a scooter, imho) that actually was much better than expected and a Spree that turned out to be much worse than expected. The Spree is requiring alot of soaking in atf and wire brushing.

I have a couple more Aeros and lots of parts, some of which I'm planning to put into a Spree or Razz so there may be more Aero info coming.