Pocketbike Forum banner

61 - 80 of 92 Posts

·
Registered
Joined
·
82 Posts
Discussion Starter #61
ok i think i had a little victory, got up to 32 mph but only the first 10 minutes of riding with no weird bogging at top speed...until it warmed up, then it went 30, i tried to get the premix gas but couldn't find it so put lucas fuel treatment in and it does sound better
 

·
Banned
Joined
·
21,721 Posts
ok i think i had a little victory, got up to 32 mph but only the first 10 minutes of riding with no weird bogging at top speed...until it warmed up, then it went 30, i tried to get the premix gas but couldn't find it so put lucas fuel treatment in and it does sound better
Sounds like a descent start..It also sounds like it was running on the edge of the danger zone....

Hopefully you didn't scorch the rings and make them too rubbery to properly seal.

Have you tried to tune it in ?

A point n aim temp gun helps alot in getting a small engine tuned to proper operating temps...

Where do you live you can't find the high octane pre mixed fuel in a can anywhere?
 

·
Registered
Joined
·
82 Posts
Discussion Starter #63
in vegas, but i live in henderson about 15 min. and i havent done enough reserch to faithfully say that there isnt that gas anywhere, i will go online and call auto stores im going to dremel intake and exhaust ports again because i know i didnt open them to the amount that i was told in begening of thread
 

·
Banned
Joined
·
21,721 Posts
in vegas, but i live in henderson about 15 min. and i havent done enough reserch to faithfully say that there isnt that gas anywhere, i will go online and call auto stores im going to dremel intake and exhaust ports again because i know i didnt open them to the amount that i was told in begening of thread
I have a sister that lives in Las Vegas she has a VP gas station on Rancho Drive...

Be careful when widening the side that has the rings ride up n down in the cylinder or it will catch and bend a ring..
 

·
Registered
Joined
·
82 Posts
Discussion Starter #65
ive got after market carb and that dumb exhaust, getting ready to gasket delete i just need yamabond, is this not the aluminum air filter
If you want more power youre gonna have to do more than do the gasket delete.....


You must widen the exhaust port 1/8" on each side plus raise the exhaust port atleast 1/16"

For the intake side you want to widen the sides 1/8" each side and lower it 1/8"

For the transfer ports you want to open them up a lil so the flowmore fuel then also polish them ...

You want to reshape the skirt on the flow side of the cylinder so the cylinder skirt doesnt cause turbulence...

Turbulence is a power robber,,,,Velocity is what you need to make power.....

Seems to me this thing has been ridden hard with that exhaust leak hole and put away wet without very much love.....

What you really need to do is start off with a brand new fresh cylinder with brand new piston...……….

Good Luck
ok, ive been working on widening and deepening exhaust and intake ports, i dont know how to work on trasfer ports and reshaping piston skirts, thanks for the help
 

·
Banned
Joined
·
21,721 Posts
ok, ive been working on widening and deepening exhaust and intake ports, i dont know how to work on trasfer ports and reshaping piston skirts, thanks for the help
Those parts arent too pertinent unless youre doing an in-depth performance mod......



As far as the transferports they need to flow more fuel............


You dont have to go as extreme as this one



Stay more in this realm and youll be a lot better off...….

The extra flow that I grinded into the outer side with the Dremel more than doubles the flow to the cylinder aswell as adds velocity and reduces turbulence...

 

·
Registered
Joined
·
82 Posts
Discussion Starter #67
ok gets up to 32 steadily but feeling a little vibration, not much at all but still....i got to angle transfer ports downward? and what did you use for polishing, i got sand paper 200 grit, 400, 600, etc to 2500, have felt polishing wheels with rotary.
 

·
Banned
Joined
·
21,721 Posts
ok gets up to 32 steadily but feeling a little vibration, not much at all but still....i got to angle transfer ports downward? and what did you use for polishing, i got sand paper 200 grit, 400, 600, etc to 2500, have felt polishing wheels with rotary.
I use an array of things from sandpaper to steel wool to usig the rotary with wire wheels aswell as polishing felts...









The polish finish I get is mostly from doing milling machine type passes with the dremel and 3/16" carbide barrel cutter and carbide tapered tip cutter attachments.........…

Do you have a compression tester..?

I very interested in knowing what pressure the cylinder is compressing the mix at....

Sometimes with those small engines you need a lil kicker in the fuel like 1 oz of trans fluid added to 1 gallon mix at 50:1 or a pre-mix ratio of like 36-40:1 to keep the rings optimally sealed...

Also try an Autolite #24 sparkplug..add the crushwasher from the NGK to it for a tight seal...That sparkplug will have that engine screaming to death on the topend after you tune-in the carb….

If youre doing this on an old cylinder and piston I wouldn't expect much more out of what youre getting...….

Im pretty sure you mentioned you were getting a new cylinder....That would be the place to restart from aswell as look into gearing to enhance the topend…....

Good Luck
 

·
Registered
Joined
·
82 Posts
Discussion Starter #69
ok getting sparkplug now, everything going good but small vibration, and at top speed its maybe held back by gear or something because when i let off gas the rpm still maxed out and it feels like it mechanically slows down?
 

·
Banned
Joined
·
21,721 Posts
ok getting sparkplug now, everything going good but small vibration, and at top speed its maybe held back by gear or something because when i let off gas the rpm still maxed out and it feels like it mechanically slows down?
Sounds like the clutch spring being stretched or broke or the bearings in the transmission aren't liking the extra power and may need to be changed....

You also may need to richen the LSN/HSN needle so the rpms drop fast so the clutch disengages.......

https://www.flickr.com/photos/[email protected]/shares/9dPg16
 

·
Registered
Joined
·
82 Posts
Discussion Starter #71
what is blockoff plate with crank stuffer in-place? and are offroad wheels slower than street wheels?
 

·
Banned
Joined
·
21,721 Posts
what is blockoff plate with crank stuffer in-place? and are offroad wheels slower than street wheels?
Yes a lot of offroad wheels are slower than street wheels..most tires absorb a lot of surface friction...

It takes loads of torque and some extra horsepower to turn bigger offroad tires...………

As far as the "blockoff plate with crank stuffer in-place" question only sounds like something referenced by me in rcfish's bigblock thread when giving him advice on his build-up....

Heres what that means in the picture as the crankcase had two different ways to mount a reedblock and carb....I used his picture to illustrate my idea for blocking off the rear carb mount hole aswell as diminish internal crankcase volume..

 

·
Banned
Joined
·
21,721 Posts

·
Registered
Joined
·
82 Posts
Discussion Starter #76
ok i dont see uberscoot slick tires but the ones on the link u posted will fit? and i was going to get bearings but they have a lot for the uberscoot and dont have the details listed on existing bearings with the evo parts diagram, i know they need to be sealed
 

·
Super Moderator
Joined
·
2,140 Posts
you need to take the bearings out and take them to a bearing shop tell them you need skf bearings put ceramic bearings in the transmishon if you can afford it. you might as well replace the belts well your in there at least second gear belt...
 

·
Registered
Joined
·
24,101 Posts
Most scooter has 4" rims, What are yours? I found nice tires for my scooter Kenda or something like that, there not slick but they handle great. They look like real motorcycle tires but smaller. Can post photos later, on my new laptop, no photos yet.
 

·
Registered
Joined
·
82 Posts
Discussion Starter #79
ok i measure mine when i get off work thanks for the help, i googled 6904RZ but will take off bearings and measure them too, found a couple of bearing shops here
 

·
Super Moderator
Joined
·
2,140 Posts
the bearing shop is 100% the way to go they might even have them in stock then you can feal eatch one and if you have any problems or need any help in the future you have somebody right there face-to-face that knows about bearings.
 
61 - 80 of 92 Posts
Top