My goal is 60mph need tips

#2
My suggestion would be first make sure you are going to have adequate brakes to stop from 60 mph. Second suggestion is to buy a lot of protective gear.

Then after that, I would look into modifying the engine. What kind of engine are you going to be modifying?
 
#5
Sparky,
Safe operation at that speed requires motorcycle engineering. Probably the easiest way to reach your goal is to mount your Pinto seat on a motorcycle of your choice.
I wish you success.
 
#7
Sparky,
If you search miniature motorcycles, you see some examples of the engineering you will need. Vintage go-fast bikes used Hodaka and Zundapp engines and transmissions.
Engray-Maico Spitfire
Steen’s T-102
Steen’s F-85 Matterhorn
And a bunch more that I’ve forgotten.
I wouldn’t use your vintage frame for this project. There is a chance that rust on the inner surfaces of the frame tubing has weakened some areas dramatically. Especially right next to a weld.
Good luck going forward.
 
#8
Ok yes I may be crazy I'm not dumb I'm not keeping the scrub brake and I'm willing to modify the frame with gussets and other structureal reinforcements I've seen people that push these minibikes even further than I want to and 60 at Max downhill with a tail wind is something I think I can manage but safety is my priority I have full riding gear and experience on a street bike and I was looking at engine options I think a predator 301 or 420 may be able to push that speed with a cvt but i don't think I can get the 420cc in the frame
 
#10
I know this is gonna take time effort and alot and I mean ALOT of modification but i think I can make it safe and make it a insane little minibike
 

bruces

Active Member
#11
I have been 60 mph on Honda z50 and ct70 bikes ,the 8” wheels on the 50 are very twitchy ,like veeery twitchy at that speed ,the 70 with the 10” wheels is much better ,but if you don’t have nice roads it is crazy to even try .
 
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#14
Aside from the legitimate safety concerns previously raised the top speed of the mini bike is based on the gearing, maximum RPM of the engine, and tire diameter. These are the factors that you should plug in to a top speed calculator to determine how to configure to reach your desired top speed. Using a 6" wheel your variables are maximum rpm and gearing.

P.S. The drag race guys run 6 inch wheeled bikes to 60 mph and more, but their bikes have purpose built chassis with appropriate rake and trail.

PPS. I have a golden pinto with a 3.5hp tek and its squirrelly as heck at 25 mph. Not much rake or trail I guess?
 
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SAS289

Well-Known Member
#15
I'm still wondering why anyone would want more than 40 on any mini bike? Especially if you know that you will not be drag racing.

I have seen a few comments where people have installed a TAV and said the ride felt scary at top speed. (38-42mph) But I guess it just depends on the bike you are using?
 
#16
Going 60 mph with tires that aren't meant for that speed is very, very dangerous.
Also IF you do this, you "should" modify the rake and trail to keep it going straight at that speed. Having death wobble at 35-40 is bad enough, at 60... could be a violent crash. Wear a helmet and leathers...

Danford1
 
#17
Michelin has 8" S83 scooter tires that are rated to 60mph. and I would recommend an adjustable steering damper as well. I think 60mph is very achievable with with a small block clone, there are speed calculators that can help you determine tire size, gearing and engine RPM's. For example: a 16" tall tire with an engine RPM of 6,000 and a 12 tooth clutch sprocket and 60 tooth wheel sprocket will give you a theoretical speed of 57mph, Good luck and be safe!.
 
#18
Michelin has 8" S83 scooter tires that are rated to 60mph. and I would recommend an adjustable steering damper as well. I think 60mph is very achievable with with a small block clone, there are speed calculators that can help you determine tire size, gearing and engine RPM's. For example: a 16" tall tire with an engine RPM of 6,000 and a 12 tooth clutch sprocket and 60 tooth wheel sprocket will give you a theoretical speed of 57mph, Good luck and be safe!.
8 inch wheels are not mini bike wheels. Of course sixty is "doable" with them. There are already plenty of scooters doing it.
 
#19
Might want to add a steering damper too. Death wobble at 60 is going to get ugly real fast.

At least from my experience on a bike that will do 60, a scrub brake is worthless. I even have a clutch brake on Tweety Bird and I have to say stopping is an adventure when you know you have to stop and it's a no go if you would have to do it quickly. Tweety is now just for use in the pits at the track, where speed is not a factor.

You know, I've been over 200 mph in a car, and 100+ in a boat and on a motorcycle, but 40+ on a mini bike scares the bejesus out of me.
 
#20
Michelin has 8" S83 scooter tires that are rated to 60mph. and I would recommend an adjustable steering damper as well. I think 60mph is very achievable with with a small block clone, there are speed calculators that can help you determine tire size, gearing and engine RPM's. For example: a 16" tall tire with an engine RPM of 6,000 and a 12 tooth clutch sprocket and 60 tooth wheel sprocket will give you a theoretical speed of 57mph, Good luck and be safe!.
Thank you and I will I like that I may be able to do this without building a 9000rpm 212 I didn't want to do that
 
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