Roadmaster Mountain $75 & Walmart?

[GorillaTimeMachine]

I have bought the Roadmaster Mountain $75 at Walmart not realizing how small the frame actually is.. I have see post saying this bike will not fit the engine? Is this true?
I'm looking into buying a 2 stroke 80cc engine kit from Daemon bikes on eBay? Tell me what you think im just getting into this hobby so yea..laf

 

[KCvale]

Did you buy the one in the store, or the largest they have on-line?
The Large looks like a motor will fit to me, it may not be easy, but it is the next shifting bike I plan to build actually.

But why buy a motor off E-pay from who knows?
Just look at the linked ads here or go to gasbike.net and use the $35 coupon.
The 2010 motors have a 90 day warranty and the same price for either color and 48cc or 66cc size.

80cc motors are Chinese math. They are 66cc but more than enough and more than is legal in many states like mine, but they look like a legal 48cc with a simple decal change ;-}

It does look like a motor mounting issue but again, if you got the giggest one and do it right the motor should fit, I have fit them in smaller.

 

[spad4me]

If you get the angled plug head it will fit better.
I shoehorned a 66 cc happytime into a roadmaster mountain bike because they were offered at clearance prices for $39.00 at the time.
You will have to grind the front engine mount as wide as it will go. Think all the way to the boltholes and even then slightly massage the front tube with a hammer to make it slimmer.
Mount the engine at a slight angle if necessary.
Or just return the bike an get a larger one.
I ran the roadmaster into the ground.
Be sure to lube the wheel bearings on such a inexpensive bike.

 

[bluenosegoat]

I have built a roadmaster mtn bike- not the latest bike available but the size looks similar. Very difficult- had to drill a hole through the frame to get the throttle cable to the carb and I was using a 49cc engine that had no intake manifold- carb bolted right to the cylinder. My son destroyed the roadmaster and I would not encourage anyone to purchase one with the intent on motorizing- garage sales or craiglist and get a quality bike to start with.

 

[KCvale]

Thanks for the tip blue.
The last thing I want is a nightmare build.

 

[bluenosegoat]

here is a pic of the carb and how tight it was!

 

[KCvale]

Though with most things tight is good, that isn't one of them ;-}

 

[Cogswelln]

i currently am still using mt road master front suspension mt bike as a motor bike, the rims are junk and will eventually warp and even brake spokes, i broke on spoke in my rear rim out in thye trails. Depending if you want it for street or for off road purposes. I dont really use my motor bike on the road any more. mainly because i have been trying to blow my motor, and still havet been able to. With bikes you get what you pay for unless you find a nice bike at a steal of the price.


I can remember whose qoute it is but it explains it well. "good bikes aint cheap, and cheap bikes aint good." but dont get me wrong ive had my roadmaster about a year or so, and the frame is still solid, had to replace other parts, but than again i love screaming down the trails.

 

[dag_29307]

Dude I started with a 24" roadmaster from wally world I ran that thing for over two years and it still ran great when I sold it for $200.00. yeah the angleed head would have been great. I just went with a shorter plug, and tilted the carb alittle to the side and she ran like crazy.

 

[wyldstallions]

I put a 48cc in mine.

 

[solokumba]

Just look at the linked ads here or go to gasbike.net and use the $35 coupon.

Off topic... but... What $35 coupon?

 

[Russell]

here is a pic of the carb and how tight it was!

What non standard HT carb is that. Dosen't look like a standard carb and manifold would work. Also please post a full shot of thet bike.

 

[bluenosegoat]

I built this wal mart bike recently and I think this is the one most readily available at wal mart. In my earlier post I said I would not recomend this bike and I still dont and the bike was for someone else. The only thing I really had to do for the engine to fit was to use an offset intake and it worked just fine (the engine has the larger front mount- without that the engine would not fit). The front forks are incredibly soft- good for street riding but will bottom out very easily. The brake pads also had to be replaced with some decent ones. I sold this bike after putting about 10 miles on it ( I always test ride to find the bugs) and overall it seemed alright. Small but still rideable for me at 6' tall. Of course the seat will have to go but after selling this bike I havent heard back from the owner since. I assume he is happily motoring around town!
I would still recomend a better quality bike. With the cost of the offset intake, granted I had one laying around, you are back up to about 100$ and that 100$ will go along ways on craigs list! You can get treks for that! But if the money is that tight and you want a brand new bike and plan to upgrade, this one will do.

 

[bluenosegoat]

What non standard HT carb is that. Dosen't look like a standard carb and manifold would work. Also please post a full shot of thet bike.

I havent seen that carb in an engine kit in along time, in fact its the only one I've ever seen! I still have the 49cc engine and carb in my shed- the bike has long since been tossed in the garbage. I dont have a pic handy of the bike it was in but here is the engine and carb- no idea why i still have it! Started making a whinning sound that i never bothered to diagnose and my sons next bike was a 66 with a chamber on a rock solid Fuji bike so the 49 has sat for a couple years. Kind of neat though in that there is no intake- mounts right the cylinder!

 

[Russell]

I like the way that carb mounts. However engine mounting can be a little more flexable with the standard manifold mount, in that you can modify it to keep the carb level.

 

[bluenosegoat]

I've built at leat a dozen bikes and some had carbs mounted at pretty severe angles and I've never had problems with them surprisingly. I know some people have had float problems due to severe angles but I've never encountered this personally. Maybe its just me but my old CJ would run laying on its side! picture to come!

 

[Russell]

I also have not had any problems with carb angle. however I always attempt to get it as level as reasonable.

 

[wyldstallions]

I built mine to ride myself. So far it's been reliable. I got a few issues with how the retailer does business (you makes it harder for mom and pop places). There are not a whole lot bikes shops where I live. I wanted a new one.

The bike is good. Brakes are replaceable up on purchase. The tires will wear in 130 - 150 miles.

As far as the building, others here built it, I went for it. I'm glad I did.

http://motorbicycling.com/members/wyldstallions-albums-american-idle-picture178-2010-mosh-l.jpg

 

[Andyinchville1]

HI,

If the bike you got is the Road Master Mt. Fury from Walmart, it will work BUT you may have to shave the air filter a tad....there is a pic of mine in this thread:
http://motorbicycling.com/f51/great-quiet-exhaust-plans-25785.html
Hope this helps you.
Good luck
Andrew

 

[Goat Herder]

I havent seen that carb in an engine kit in along time, in fact its the only one I've ever seen! I still have the 49cc engine and carb in my shed- the bike has long since been tossed in the garbage. I dont have a pic handy of the bike it was in but here is the engine and carb- no idea why i still have it! Started making a whinning sound that i never bothered to diagnose and my sons next bike was a 66 with a chamber on a rock solid Fuji bike so the 49 has sat for a couple years. Kind of neat though in that there is no intake- mounts right the cylinder!

That's pretty cool have not seen that carb before! Musta ran pretty good then? Thanks for sharing that pict . Wounder now where one can find that carb? Still though I also question if it over heated much and boiled over on a hot July day?