Help i'm new but old timer

GoldenMotor.com

bigrskip

New Member
Jul 1, 2012
19
0
0
Kansas
I have a roadmaster sx sport and a univega mountain bike. Just bought a 80cc kit waiting for it to be here tomorrow. Which bike would be the easiest to assemble with the least modifications?
 
Sep 4, 2009
980
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Texas
Unless you are very mechanically inclined I'd put it on the cheaper roadmaster get used to all the bugs these kits tend to breed then buy another kit for the nicer univega. Welcome to the MB site good to see another old timer here!
 

bigrskip

New Member
Jul 1, 2012
19
0
0
Kansas
thanks george n texas have plenty experience in (MAKING THINGS WORK) just don't have a lot of time anymore.......
 
Sep 4, 2009
980
4
18
62
Texas
Cool I'd put it on the older bike then it has more space and surely is a higher quality bike. In the MB world older is usually better.
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
Lets put it this way, that $60 wally bike will probably fail before you even get the motor broke in. Just a good front shock or rear wheel is that much.

I can't tell from the pic how good the old school bike is so I will just leave you this advice, don't start with a crap bike.

One other note is there are no real 80cc motor kits despite the claims, they are 66cc.
 
Last edited:
Sep 4, 2009
980
4
18
62
Texas
I think they are rated at 2.5 HP they do make a lot of vibrations so the welds need to be solid which is why I say old bikes are better. Aluminum frames are not recomended neither are fenders if a fender gets caught on your front wheel it will face plant you not catipult you. Take caution and give yourself plenty of braking room as bikes aren't designed for this speed adding disk brakes is a big plus.
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
thanks so that's around 4.5 hp is that correct?
Hehehe, you wish 4.5HP from a 66cc, ~3.75HP with a tuned expansion chamber and good ignition system.
The thing is that is usually plenty enough to go scary fast and still be able to stop.

Granted I build more shifter bikes than direct drives these days and that of course changes my perception but I just have to caution against trying to re-machine your head to gain a tad bit more compression.

Not only will that make it harder to start but an Iridium plug may not fit and it does more to boost performance than any head mods I've seen for only $8 and a plug wrench and pretty hard to screw up doing

Your bike, your call, just passing on my experience.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Welcome to the forum, Bigrskip. You've come to the right place for help and advice.
I'm not familiar with either bike you mentioned but the advice offered above is sound.

Typically the older cruiser style frames will provide a better foundation for a motorized bike but some will require a custom front engine mount. The so called 'V' frame bikes make for an easier engine installation but depending on frame material and other factors might be less desirable that the older cruiser.

The Google Custom Search feature will provide you with mountains of information that you might find beneficial. Simply use a keyword, such as 'chain tensioner' and you'll have plenty to read on that subject. If you need specific help that you can't find by searching we're always here to answer your questions.
Good luck, have fun and ride safe.
Tom
 

bigrskip

New Member
Jul 1, 2012
19
0
0
Kansas
thanx everybody I feel like i've already gained knowledge from you who have answered this post. Thank You Again
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
thanx everybody I feel like i've already gained knowledge from you who have answered this post. Thank You Again
It's always easier to catch a nOOb before they start a build than answer 'how to fix it?' questions later.

One thing you have to get used to is you will get all kinds of advice, some of it not so good so take it all with a grain of salt including mine.

That said my top 3 tips for a new build are simple.

Use a good bike.
Mount your motor so secure you can't move it even kicking it.
Get you rag mount sprocket right, by right I mean in line with the motor as well as no wobble in either direction on the wheel.

I have about 10 more 'must checks' I do on a build but if you start there you have a pretty good chance at a happy reliable ride.
 

edangel

New Member
Sep 7, 2010
50
0
0
seveirville tn
Unless you are very mechanically inclined I'd put it on the cheaper roadmaster get used to all the bugs these kits tend to breed then buy another kit for the nicer univega. Welcome to the MB site good to see another old timer here!
univega are good i got a univega alpina 503 had to change thing on her did u get a pull start with ur china girl dance1
 

bigrskip

New Member
Jul 1, 2012
19
0
0
Kansas
well after sitting the motor on the bikes i built the roadmaster took her for a few test rides today so far i'm impressed.......question is it common for the fuel line not to be full of gas? thought this is odd
 

edangel

New Member
Sep 7, 2010
50
0
0
seveirville tn
yes it dont look like it should ur fuel filter has gas in it now if its start like its runs that dies than if u let it sit it will start again witch i had that problum with mine take ur fuel cap off ur tank and drill a pin hole in it
 
Sep 4, 2009
980
4
18
62
Texas
Don't be drillin with the cap on the tank we don't want no bombs goin off! There's a drain plug on the carb you can open it till it bleeds off the air in the line if it seems to starve the engine. Be careful gas is dangerous/ The cap is already vented matter of fact a lot of people complain about them leaking.
 

bigrskip

New Member
Jul 1, 2012
19
0
0
Kansas
wouldn't even think of drilling with cap on tank, that would probably be one big bang....i'll try the drain plug........thanks for the info...