I'm finally taking delivery on a new Tomos ST A55 next week and was reading a review of that model at the Myron's moped site. The review, written by Shaun, says: "The jewel in the crown is the A55 engine. When first sold it went 28 mph, but now goes 37 with the intake restriction cut away and a smaller 28 to 22 tooth rear sprocket change."
My Q is WHAT INTAKE RESTRICTION? I thought the only way to soup up a Tomos was the sprocket change, biturbo exhaust and rejet the carb.
You can mod an a55 all sorts of ways, exhausts, porting, bore kits, ect. I dont know about the a55's but the stock airbox may be restricted.
OK. That sounds pretty easy. The guy's assertion that he went from 28 to 37 with a sprocket and increased air flow sounds kind of iffy, though.
I'm guessing that with a Biturbo pipe this kit would be just about everything a tyro could do. I'm not looking to turn the bike into a part-time job, just easy things to give it a little more oomph.
Thanks Saab and Maniac. I appreciate the tips.
I Just bought two new ST's from Sean. He swapped the cog, and opened up the air intake. He explained to me how to do the air box. If you look in the intake port on the frame side of the box, there is a "snorkle" or bit of hose that runs inside the box from there. Just remove that internal "snorkle". and yer done.
One of my ST's is right up there between 35 - 37 and runs like a champ. Everything else is stock.
The other is 32 - 34mph, but doesn't sound "right". I'm gonna need some professional help for her.
Thats all you did to get 35 out of it? Amazing. I guess it must be some sort of limiter to keep it under 30 for state moped regulations.
Thanks, Adam! Thats a hell of a lot easier than putting new jets in the carb.
mopeds in california must go 30mph at most, so there is a massive intake restrictor, with a gear change, and cutting the restrictor 37 is about right, but if you take that catalyzed pipe off there, they really start humming
Just so I'm completely clear...The snorkle Adam was talking about IS the intake restrictor, right? And you cut it out of the inside of the airbox?
If you cut that out you have to upjet too. Anything that allows more air will need more fuel to compensate. Changing a jet is very simple, unscrewing like 4 screws and putting it back, very very simple work.
What jet would you suggest?
Hey Colby, What pipe do you like on a ST. I'd like to keep the bore the same, and just do some carb/manifold/exhaust mods.
pipe on the st i like the tecno estoril, treatshq has em for tomos on ebay, its the best top end pipe, really takes advantage of tomos' low first gear
it will not "bolt on" it needs a little help, we can take care of that for ya with a trip to my house and a visit with shaw
and myron will actually purchase your clean stock pipe from you
Sweet.. I'm traveling on business, but when I get back to town I'll give you a hollar. Thanx
I'm not looking for a lot more speed but the best mileage I can get.
Does anyone know how the A55 is set up in other countries? Do they have the 30 mph restrictions? I wouldn't think so and I'd like to set up my ped as close to that as possible. Also I don't want to remove the pipe with the Cat. It's there for a reason and I'm an environmentalist. What i want is the best speed mileage combination.
I noticed that my A55 ST easily runs up to about 25 or 28 mph with my 150 lb. weight on it. I can tell the engine can pull more but is out of gear. I'm wondering if I can run a 22 or 24 rear and pick up the extra mph. I haven't checked the air cleaner for restrictions but I won't pull the Cat. For one thing two cycle pipes have specific back pressure and if you change that you can reduce engine life. I don't want the added noise of a second party pipe either even if it is designed for a specific engine.
So ideally I'd like to set it up the way Tomos does for other countires. This way the ped is within the engineering limits of Tomos and I bet I'll get better mileage.
Rob
dunno if it helps anyone or not buuut:
my lx with the a55 does about 44-45mph flat ground and maxes at 48mph (i think the a55 needs a bigger carb) but what i did was i put on a 22 tooth rear sprocket, removed the snorkle, cut the diameter of the rubber boot slightly larger than the venturi, also, on the box itself is a 12mm opening which i drilled out to 16mm. this got me running 39mph according to police radar with better acceleration than the a35 with a bi-turbo. i then installed a bi-turbo wich got me to around 45mm according to police radar.
It's totaly true. I bought two St's this year. The only modifications are the airbox de restrction, and a sprocket. 37 mph solid. 30mph on hills.
I didn't upjet, and I have a 1,000miles with the mods, and the expected performance.
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