decrease in speed? why?

minibikin'

minibikin'

Sho-nuff
#21
#21
ant976boy said:
honestly I was hitting 40-45 stock re jetted but now I have other mods so I'm past that if you don't believe me then aw well we can race :scooter: and I'm not one of these brats I appreciate help but when shots are fired best believe I shoot back 2x
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I'd like to know how you are verifying your speed? I pass cars on the highway in my junk aircooled VW so it must go 150 mph...
Seriously, there is a lot of help here. It's not what you ask yes how you ask it. I'm not saying you aren't going 50, but to assume you are because "you passed cars on the street" doesn't hold any water.
 
Txpowdercoater

Txpowdercoater

New Member
#22
#22
redgokart said:
you hooked up a new throttle system? you need to check and make sure your throttle shaft is opening all the way.
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thats what I am thinking, along with more fuel for the additional air he has added via new filter set up. so a small re-drill of the jet and check to make sure the throttle blade /plate is opening all the way with no restrictions.
also while your at it, you mentioned the pushrod falling out, so that tells me you need to check and double check the valve lash, if you have done it, do it again :) that being set incorrectly could indeed reduce upper rpm performance and henceforth top speed.
 
graygoose420

graygoose420

New Member
#25
#25
I've hit 55 on a 196cc back in the days. Yes it Is possible. 50mph on a Gx 160 also.
10 tooth clutch , 33 rear on 41 chain, 12 tall tire. Ungoverned no billet. Yes I was young and stupid. Learned the hard way.
 
S

SAFETYpin

New Member
#27
#27
I've been trying to find the quote, but I believe Craig Vetter said, "It takes 8-9hp with good aerodynamics to run 50mph".

You can understand why alot of people with a considerable amount of experience are crying B.S.

Whats most likely occurring is you're getting used to the machine. Minibikes are incredibly crude machines, and its not uncommon for 35mph to feel pretty fast. As you gain some confidence it no longer feels the same, hence the slow down.

If I take your comment seriously the only explanation is a loss of power. Does the throttle open all the way? Does the engine sound like its turning faster?
 
ant976boy

ant976boy

Member
#28
#28
I'm not here to prove anything not brag I'm on this site to seek help and learn new things now I'm not a person to lie I'm just stating that I've been clocked in the low 40s when I had a governor still connected and a re jetted carb
 
Phil1958

Phil1958

#31
#31
ant976boy said:
I'm not here to prove anything not brag I'm on this site to seek help and learn new things now I'm not a person to lie I'm just stating that I've been clocked in the low 40s when I had a governor still connected and a re jetted carb
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guessing 12" tires?

a governed 3600 rpm gives you about 40 - 45 mph in a lossless
situation, i.e., no rolling friction loss, no drive train loss, perfect
aerodynamics while using a 10 tooth clutch and a 30 tooth rear
sprocket. it just seems like a tall order for a 6.5 hp engine.

what is your actual tire size, clutch and sprocket tooth count?
 
Phil1958

Phil1958

#33
#33
38 mph in a lossless system.

i'm no expert here but being a well seasoned engineer i do
know that lossless systems do not exist. i used the speed
calculator link to determine your speed. keep in mind that
this gives you an estimate and a generous one at that. to
give you a feel for the accuracy of this estimator if you
sit on your mini bike and the rear tire compresses down 1/2"
the speed estimator will be off by almost 6 percent. this is
because the radius of the tire from the center of your axle
to the ground is the effective tire dimension that determines
ground speed, not the diameter. your friends' speedometer
suffers the same errors.

i haven't been here very long but i have found a wealth of
knowledge and experience on this forum. my friendly advice
to you would be to listen to these guys.
 
ant976boy

ant976boy

Member
#34
#34
maybe I was wrong maybe I wasn't but it's not really a big deal it's not like I'm setting a world record for speed on minibikes the speed I'm saying has been doubled so why even argue about what I was hitting I do listen cause I know I don't know everything especially I'm something I'm new to, I can't tell a professional basketball player how to shoot a ball but he can give me pointers and I can tell him once I made a shot from the opposite side of the court on a windy day all im saying is t's not impossible to hit that speed and I only weigh like 150
 
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