Topic: Has anyone here done any moped modifications on a Chinese gy6 engine

[jamesb]

I picked up a baja 49cc for a friend who isn't fortunate enough to have his drivers license. And traffic can be hectic sometimes especially when your driving something that has a top speed of 35mph downhill. His saving his money to invest in a 150cc engine To slap in this thing. But was wondering if any of you guys have done some modding on something like this. To boost up the mph.

[flatlander]

i'm not familiar with the baja (more with vintage honda mopeds) but the little engine should be able to go faster. not sure about the US but over here they are artificially restricted to meet the legal requirements of the "moped" category driving license.

if it's a modern moped it's probably restricted on the CDI. you can replace it with an unrestricted one - ask your local scooter kids where to get one from, or search online
other things that may hold it back are the carburetor and exhaust but the CDI is the main thing and where i would start.

don't know your parts but 150cc would raise one or two eyebrows with the cops over here. it's noticeably bigger and the sound is very clearly heavier. it's more inconspicuous to change the cylinder to 80cc which already gives you better acceleration than 49. but here the legal limit for mopeds is 50cc - may be different over there.

i've got a honda ss50 from 1979 that goes 80kph out of the original 50cc cylinder. takes ages to get there, though. it's pretty much the original setup, with an unrestricted advancing flywheel (they used retarding ones over here) and original carb that matches the intake instead of the 4mm smaller ones that the bikes were sold with.

[grcamna2]

Is that gy6 a four stroke ?

[flatlander]

should be. on google it looks like a derivate of the honda moped engine with the lying cylinder.

[grcamna2]

I looked on google a little also & I see the upgraded 80cc cylinder,they also have a cyl. head that they say will work for either the 50 or 80cc... There's no way I can tell whether it has larger ports than the stock 50,they only want $40+ shipping for the complete head.
If it was my little scooter/moped I would get the 80cc cyl. and then find a person who will possibly open up the intake port a little; straighten out the intake tract if possible... so the incoming charge wouldn't have to bend around the corner so much when it flows through.I'd try to look online for someone who does performance work to those little honda type engines.I'd also check to see what type of air filter media it has & if paper, I'd remove that & install some Uni foam in the air filter that would flow more than a paper filter(if he cared more about performance than longevity..),I'd also have someone cut open a a little door along the length of his OE muffler and possibly drill some holes(be careful not to drill too many  ) into the inner plumbing of the muffler for more flow and then weld the "door" shut again and rejet the stock carburetor.
I think that he may also be able to do all the same things except for getting the 80cc cylinder and it'll probably give him another 10+ mph;if it was my scooter and I was going w/ this,I'd get the 80cc cyl. and find that little honda single performance guru to straighten out the curve of the intake port.
It's a LOT of work.  What would it cost him to get his license back ?

[jamesb]

I was doing some research on the kits. A lot of people said to go with the 150cc. His engine is the gy6 short case and they make a 150 short case. I didnt know if any body on here has messed with one. I did modify the muffler and that helped and the Cdi has been messed with already which that helps. But it's still not enough to get him up hills without pissing people off. It's going to cost him $1000 to even think about getting his DL back and I have to take him to Las Vegas New Mexico to do that. The guy was dealt a bad hand in life and he's trying to get it straight, and I'm trying to help him when ever I can. The cops around here are to stupid and lazy to check if it has a bigger engine. They go as far as running the tag to make sure it's a 49cc. I've done a pagsta chopper for him before and we put in a 125cc it bolted right up. But then somebody stole it from him.

[grcamna2]

jamesb,
     When you posted and said the cops weren't even bothering to check about the size of the engine...,well if it was me,I'd save for the 150cc engine,intake & exh. systems to match.
I'd look for a wrecked 150cc model scooter as a donor and then swap everything over into the 50cc frame.That will also be a lot of work but once your done tell him to drive easy when he's near town  .
I'd look online for a few MC salvage yards in KS. not far from you.

[jamesb]

We have one mc salvage yard close by and the guy is a total d!ck. the guy has the nerve to ask $50 for a used throttle cable on older bikes. He doesn't get much business. I found a brand new gy6 150cc short case for $300 shipped. My son is going to paint it with some sooted (acetylene torch) stripes. A friend of ours works for a chrome plating company so he's getting the rims done. We are going to do a full custom job on this. I gave him a parts list with prices and he's gonna have about $750 wrapped up in this when it said and done. I'm amazed at the aftermarket stuff you can get for these scooters

[grcamna2]

That was a hard thing to hear that the local salvage guy was like that,I'm glad he doesn't get much business. It's good to hear you can get that 150cc eng,can you get the intake & exhaust also ? I think if you keep looking you may find a Good/Fair salvage yard;I've dealt w/ a few(it takes a little extra time to locate one but they're worth the search)good ones in the past.

I took another look at your last post,you mean you're getting the entire scooter for $300 ? a new one ?
I wonder if you'll be able to register it as a 50cc "moped" ?....

Do you think he might be able to go for a little more $(1000)to get his license back ?

[jamesb]

The 150cc is a complete engine ready to start, minus exhuast. His problem with getting his license back is that he has to go to New Mexico and possibly stay a night in jail. Plus coming back to Topeka kansas And have  to take our test here.  Which I'm the only one he knows that would have a car that would pass to even take the test. And I'm the one who would have to take him to New Mexico. He's basically just like Lenny from "Of mice and men". He's kind of slow in the thinking department. Plus he thinks it would be cool to jump out of the hole quick around the bigger bikes. And the salvage yard guy is a very horrible rich brat. He's sells totaled out bikes for more than you can buy a nice for. On Craigslist this weekend He had a 1999 shadow 750 out of state salvage title for $4000 Harley's are even 3x the price.  It's oz powersports in Ottawa kansas.

[grcamna2]

Okay
Well,when you get that 150cc engine,will it install right into the 50cc frame ? if so then maybe that'd be the best thing for him right now considering it's getting warmer.

[flatlander]

yes considering everything, 150cc seems to be the way to go if he wants to get going quickly. it should be possible to find one of those that bolts right into the frame, such upgrades are pretty common. make sure you budget for a matching carb/intake and exhaust.

trying to get his license back sounds like a pain but i think long term he'd benefit from it. would save him from having a scooter do things it's not really meant for.

[jamesb]

I'm hoping the 150 will bolt right in  rings both engines are short cases. The engines only come in long or short. I've read that you might need to make a mount witch is no problem. I have a welder and torch set so it should be a simple fix. The carb upgrades are cheap also a person can get new clutch variators and belt pulleys for more speed. It seems like the most exspensive assesory  is the muffler. It's actually pretty exciting trying to hot rod this thing up. I'll keep this updated on the build. What sucks is everyone else's bike is getting done and ready for summer but my is just sitting there. I had to do electrical work on my sons 550 last night.

[grcamna2]

I would recommend the stock 150 muffler so they don't "hear him coming".