Tips for performance and smoothness of ride ??

flinttim

New Member
May 7, 2008
5
0
0
Hello to all, been a while since I joined up and left my introduction. I have a couple of questions maybe someone can help me with.
I built my bike about 4 years ago with a Grubee Roundhead. 48cc . All has been well with it, normal maintenance, new plug when needed, dab of grease on the clutch sprocket, that type of thing. The fastest I have had it up to was about 22mph. Above 20mph I start getting some minor vibration, likely from the wheels. Any tips for smoothing it out ? Do any of you balance the wheels ? Any tips are appreciated. Also, let's say I smooth it out. Is 22 mph about top end for this engine ? It's not that I'm looking for more, but would like what I have up to 22mph to be smooth and efficient. Can you lead me to a thread here on tuning the carb or any other part for that matter. This thing has been a lot of fun and now with gas prices what they are, it's now more a mode of transportaion rather than a toy.
I have been considering buying a moped for going to and from work (1 and 1/2 mile one way) but on the other hand maybe I should just spend a bit more money on this bike (wheel balancing, maybe new heavy duty front wheel with brake, exhaust etc) and end up with the same performance as a moped.
Any and all thoughts are appreciated. Thanks Tim
 

NunyaBidness

Active Member
Jun 29, 2008
1,062
2
38
memphis tn
a good brake system is very important on a motored bike
for a 1+1/2 mile ride to work I wouldn't do a thing to the bike. for a 3 mile round trip commute 20 mph seems plenty fast enough to me
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
241
63
up north now
I balance all builds with solder wrapped around the spokes...you can buy stick on lead weights where finer golf equipment is sold.

If you are riding 1 1/2 miles each way, I'd think a moped would be a waste of money.

Your bike should do 30mph or so with a 44T sprocket once it's got a few hundred miles of break in. The engine will run smoother too.
 

flinttim

New Member
May 7, 2008
5
0
0
I should add that I do ride it to work but would like to be able to ride out farther now and then too. I think the first day I rode it I put on about 70 miles so I know it is capable of longer rides. I have the 44tooth sprocket so it would seem my speed is below normal. Maybe it will go faster but I'm leery of trying until I smooth it out some. Along the same line of thought, are there any springer or shock type forks that will fit the mountain bike frames ?
 

Motoschwinn

Member
Jun 27, 2008
434
1
18
Independence MO
Hello to all, been a while since I joined up and left my introduction. I have a couple of questions maybe someone can help me with.
I built my bike about 4 years ago with a Grubee Roundhead. 48cc . All has been well with it, normal maintenance, new plug when needed, dab of grease on the clutch sprocket, that type of thing. The fastest I have had it up to was about 22mph. Above 20mph I start getting some minor vibration, likely from the wheels. Any tips for smoothing it out ? Do any of you balance the wheels ? Any tips are appreciated. Also, let's say I smooth it out. Is 22 mph about top end for this engine ? It's not that I'm looking for more, but would like what I have up to 22mph to be smooth and efficient. Can you lead me to a thread here on tuning the carb or any other part for that matter. This thing has been a lot of fun and now with gas prices what they are, it's now more a mode of transportaion rather than a toy.
I have been considering buying a moped for going to and from work (1 and 1/2 mile one way) but on the other hand maybe I should just spend a bit more money on this bike (wheel balancing, maybe new heavy duty front wheel with brake, exhaust etc) and end up with the same performance as a moped.
Any and all thoughts are appreciated. Thanks Tim
There's a guy offering a no vibration kit on eBay and at the 'evil empire'. Called sorbotane or something like that. I thought about ordering it just to do a review.

Might be worth a look.
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
3,666
6
38
Duvall, WA PNW
www.sickbikeparts.com
I just hit 36.2 mph effortlessly yesterday. That by no means is my top speed, it's within the confines of a test backstretch before I need to bring it to stop. Maybe 0.1 mile or so. Previous best was 34.8 mph. On longer stretches 40 mph, with no vibration issues. 20-25 mph is steep hill climbing speed, in 2nd or 3rd gear.

Here's some tips without details - I think you can find the "how to" if you search this and other sites.

1) You have to let the engine breath. Toss the stock muffler and air intake. Get a good larger filter and get and expansion pipe. Make the intake and and exhaust manifolds match the engine perfectly and throw the stock gaskets away and make your own.

2) Good NGK plug, new HT wire, and perfect electrical connections.

3) As mentioned perfectly balanced tires.

4) Good oil mix. 30:1 if it's a good oil.