engine tweeks to increase hp

vcain

New Member
Joined
Mar 7, 2008
Messages
8
if anyone has anymore that they have done let me know and i will try them out too always up for making my bike go even faster lol

ok i know is said a month or two ago i would post this the next day but i had other things get in the way and i will admit i forgot (you memery is always the second thing to go with age)

ok the things i did to increase the speed to my motor are:
bored out the exost port on the cylender and the muffler
also in the baffle i cut the tube inside to about a half an inch long
bored out the intake tube that the carb mounts to to the same size as the whole in the cylinder to maximize gas/air also changed the stock filter to a sock filter it allows more airflow and it is so much easyer to take off and wash
went from a stock 44 tooth sprocket to a 38 tooth sprocket
this is on an 80 cc engine if you have a 40 or 45 cc i only recommend going to a 40 tooth anything lower than that will take away from your power band

top speed after breakin of a new motor is about 48 to 53 mph depending on the wind but 53 is a bit scarry on a bike lol
you loose a little on the take off so you have to peddle a little more from a dead stop but i think the top speed is worth it
 

Zev0

Member
Joined
Jan 6, 2008
Messages
695
Moved to 2 stroke section as that what the OP is talking about. It was found in the bicycle repair section where it does not belong.
 
B

BSA

Guest
It sounds like you've done most of the mods. The others would be rejetting the carb and expansion chamber. Look in wild in the streets for even more modifications.

BSA
 

badmoon

Member
Joined
Apr 20, 2008
Messages
75
First im french and dont understand all if you can explain me some tips i will be happy :)

when you say "bored out the intake" do you cut the intake put it out or just buff the inside ??? cause me i have a 27 tooth sprocket and have modified the muffler with some new hole and ive reduce the baffle inside so my speed on flat is arround 34 mph max and when i climb
i need to pedle so give me some help i want to reach 40 mph in flat road .
 
Last edited:

Maxx Ported

Member
Joined
Aug 2, 2008
Messages
57
Have you reduced the head chamber size, to increase compression and polished it?
 

Attachments

  • 7-28-08 002.jpg
    7-28-08 002.jpg
    17.8 KB · Views: 1,212
  • 7-28-08 011.jpg
    7-28-08 011.jpg
    15.3 KB · Views: 1,036

Bikeuser

Member
Joined
Jun 4, 2008
Messages
60
You can't reduce chamber size without affecting the integrity. You show me a guy who has a 9:1 compression HT and i'll buy you a harley davidson
 

Maxx Ported

Member
Joined
Aug 2, 2008
Messages
57
You can't reduce chamber size without affecting the integrity. You show me a guy who has a 9:1 compression HT and i'll buy you a harley davidson

I'll post the cc"s when I get the other engines, to compare stock to my Reduced Volume head,
 

Attachments

  • 7-28-08 004.jpg
    7-28-08 004.jpg
    17.3 KB · Views: 901

Maxx Ported

Member
Joined
Aug 2, 2008
Messages
57
rainy day today so I pulled the heads off three engines. comp on 2 stock engines is 55lbs. the moded engine is 100lbs.
stock head is 12.1 and the shaved head is 5.8. I cut .075 off:eek: have over 137 miles on the engine runs great will pull the front wheel about 2 inches off the ground if the throttle is open, when first started.
 

Attachments

  • aug 25-08 005.jpg
    aug 25-08 005.jpg
    95.6 KB · Views: 891
  • aug 25-08 003.jpg
    aug 25-08 003.jpg
    82 KB · Views: 835
  • aug 25-08 009.jpg
    aug 25-08 009.jpg
    55.4 KB · Views: 954
  • aug 25-08 012.jpg
    aug 25-08 012.jpg
    73.6 KB · Views: 830
  • aug 25-08 016.jpg
    aug 25-08 016.jpg
    58.5 KB · Views: 837
A

andyinchville1

Guest
HI,

SWEET!....So .075 is the "magic" number....good to know...Does it still run well with regular or at the higher compression did you have to step up to plus or premium fuel?

Thanks.....I can hardly wait to try it out on mine!

Andrew
 
Top