Pocket Bike Engine Project

GoldenMotor.com

gera229

New Member
Sep 4, 2011
465
0
0
USA
How many teeth are your sprockets? I'm asking for both drive sprocket and driven sprocket teeth. Thanks.
 

lowracer

New Member
Oct 17, 2008
1,319
2
0
Charleston, SC
gera229,
I run v-belts (not chains) on both my pocketbike MB's so no teeth.
I have a 1.5" drive pulley & a 22.5" rim pulley with a 25" tire giving me a 15.6:1 final drive ratio (did rollout test to confirm this).
-Lowracer-
 

lowracer

New Member
Oct 17, 2008
1,319
2
0
Charleston, SC
The longer headbolts from McMaster Carr are part# 91303A168 (1 Pack Metric Blue Coated Socket Head Cap Screw, M6 Thread, 90mm Length, 1.00mm Pitch)...For those looking to get the longer bolts...I used a few lockwashers to take up some extra length since these are just a bit too long. Dont forget to use some red loctite on the threads...
-Lowracer-
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
What's the difference between a lockwasher and a normal washer?

Hey how do I order from McMaster? I tried to place an order, but it did not seem to lead me to a page to pay for my order. How much do they charge for shipping?

Low racing, zero on ebay does not ship out performance clutches with the cuts due to a lot of problems with them. Do you have the performance clutch? have you had any problems with it? Did your springs ever blow?
 

NEAT TIMES

New Member
May 28, 2008
1,964
1
0
PENSACOLA, FL
gera

Most of my orders are $5. sh and sometimes less. One time part of the shipment came from another warehouse and was around $8. for that part of order. Told Them I was not a happy camper!! lol.

I`m in Pensacola Fl and most orders come from Atlanta Georga in 1-2 days. Many of my orders have been fairly heavy for bolts and nuts = 3-4 box`s.

Ron
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
Hey lowracer, I wonder how the stage 2 kit increases horsepower from the original motor. You know how to cylinder is longer and so is the rod.
Is the diameter larger also? Diameter of the piston and cylinder?
 

lowracer

New Member
Oct 17, 2008
1,319
2
0
Charleston, SC
I believe the piston is the same 44mm for all these cag stage engines.
Compared to stock, the compression is higher, better piston & crank & connecting rod & the performance carb really works well.
The performance clutch works well too.
For the extra $50...its all worth it
-Lowracer-
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
So it's really not the extra cc that give it more horsepower, but the other mods right? What oil/ fuel ratio are you using? What number octane gas are you using?
 
Last edited:

lowracer

New Member
Oct 17, 2008
1,319
2
0
Charleston, SC
Gera,
Yeah, its not the cc's.
MB's in most States where MB's are legal need to be at or under 50cc's.
These pocket bike engines are so tiny they look low cc's but run out strong.
I run 32:1 Yamalube 2R mixed with 91 octane no-ethanol premium unleaded.
-Lowracer-
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
Ok,

If you put a stage 2 on a 49cc it will be 51cc, if you put it on a 47cc will it also be 51cc?
So engine is all the same everything is the same, but the cylinder is the only thing that makes the difference right?

I will order my engine today and buy longer head studs, no other bolts are needed right?

I asked dax about his GT50R and he says he uses 95mm head studs, I have no clue how, but as you said they will not fit so I won't get them. It's weird, is Dax's motor different or something? I said stage 2, maybe he mistakened for the stage 3 kit which I believe probably needs even longer head studs.

Thanks.
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
I wonder if you know answers to the other questions.

Also, how would a 95mm fit a stage 2 for Dax, but not for you when its all the same engine as the gt50r?
 

lowracer

New Member
Oct 17, 2008
1,319
2
0
Charleston, SC
Gera229,
The stock bolts are 80mm & I couldnt find 85mm, so I bought the 90mm & use a few split lock washers under each socket cap to eat up the few millimeters that make the 90mm's too long. 95's would be way too long (I'll bet Dax just made an error saying 95mm's).
Best thing for you to do is to get an engine & then do your own measuring. Then research the suppliers who sell hardware & pocket bike parts. That way you'll know that the info you receive is correct...
-Lowracer-
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
Hey I wanted to know do your clutch shoes look grey at the ends or brown in color? The friction part is what I'm talking about.
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
Hey what's the dome size on these? Is it 13:1 (91 premium unleaded fuel)? Or is it 15:1 (105 unleaded fuel)? Where can I get 105 fuel? What fuel do you use?
Is there any way to change the dome? Will I have to change the entire head?

Also to test your max speed did you use a GPS (very accurate)? 50mph is fast.
 
Last edited:

lowracer

New Member
Oct 17, 2008
1,319
2
0
Charleston, SC
Its not 105 octane.
I use 91 octane no-ethanol premium unleaded mixed @ 32:1 w/Yamalube 2R
Wife clocked me in her car, but then I bought an RPM meter to verify the speed doing the math. It is fast, but feels less fast on the DH full suspension MTB than it does on the no-suspension bike that I have the same engine on (on that bike it feels like 100...lol) These little engines are surprisingly powerful especially for a bicycle application.
-Lowracer-
 

gera229

New Member
Sep 4, 2011
465
0
0
USA
What's the dome size and ratio on these? Is it 13:1?
If it's 15:1 then you need 105 if it's 13:1 then 91 will work.