Looking to build the ultimate mountain Motorized Bicycle

Noxuz

Noxuz

New Member
Hello!! after lots of thinking and searching for upgrades for my motorized bike i came to some conclusions.

-Nice suspension forks only come in OVER size frames
-Over frames are mainly of aluminium and really rarely are big enough for a motor.
-Motor perfect frames are for standard forks and made from steel.
-Only mid and high end aluminium frames comes with rear disc brake mounts
-I need rear suspension really bad, i live in a town with lots of rock streets and i have like punctured 3 times my rear tire cuz of falling in medium speed in street holes.

soo only cheap bikes have the big space for a motor to fit..... cuz aluminum bikes comes in really weird dessings.

soo im stuck with cheap but worth bike parts....

Soo i recently decided to start designing my own bike frame, and maybe weld it myself or take it to a blacksmith.
here are the needs for my ultimate frame

- Over size fork tube for high end suspension forks
- 25mm of tube diameter for the 3 main tubes in the frame (for perfect tank and motor fitting) (im not sure wich is the ideal diameter)
- rear disc brake bracket
- made of steel, cuz is way cheaper and stronger.
-and a SBP jackshaft kit.
do u guys think it will be expensive?

Here are some examples of what i mean (NOT MY PICTURES)

GTLTS-5.jpg

FS-OBEAST-8-600x365.jpg

bicycle010gx6.jpg


But this one is the most fulls my design needs

4022086698318b89f7aco.jpg


i would just change the fork tube for an over and put a disc brake bracket, but the location of the rear shox is THE one i want.

i just love motorized bicycle better than motorcycles, i mean, motorized bikes have that more ''freedom'' and fun sensation than motorbikes.

What u guys think of the frame build? i will proceed to do the blueprints and show it to a blacksmith (meanwhile i get a welder)

THANKS FOR READING my second post guys!!dance1
 
Re: Looking to build the ultimate mountain MB

Here's an idea.....keep it simple.

-Nice suspension forks only come in OVER size frames.....
true, the reasonably priced ones.

-Over frames are mainly of aluminium and really rarely are big enough for a motor.....
false.

-Motor perfect frames are for standard forks and made from steel.....
false.

-Only mid & high end aluminium frames comes w/rear disc brake mounts.....
true. Then buy a used mid or high end frame reasonably.

-I need rear suspension really bad, i live in a town with lots of rock streets and i have like punctured 3 times my rear tire cuz of falling in medium speed in street holes.....

How much do you weigh? Are you lifting your butt off the seat and slowing down before you hit the pothole? Maybe you need fatter, softer tires with less tire pressure. Or maybe a front and rear suspension would work for you. Might be hard to find a f/r frame which an engine would fit midframe.

Try hard to avoid the potholes.

soo only cheap bikes have the big space for a motor to fit..... cuz aluminum bikes comes in really weird dessings (designs).....
false.

soo im stuck with cheap but worth bike parts....
false.

Soo i recently decided to start designing my own bike frame, and maybe weld it myself or take it to a blacksmith.
here are the needs for my ultimate frame

- Over size fork tube for high end suspension forks
- 25mm of tube diameter for the 3 main tubes in the frame (for perfect tank and motor fitting) (im not sure wich is the ideal diameter)
- rear disc brake bracket
- made of steel, cuz is way cheaper and stronger.
-and a SBP jackshaft kit.
do u guys think it will be expensive?

YES!

Here's my suggestion:

Find a used quality frame, either steel or aluminum, with front suspension and disc brakes front and rear for reasonable price. I'm thinking you want a Cheap China Girl midframe engine. If so, find the measurements needed to fit the engine to a bicycle frame. That information can be found on this forum.

Buy Schwalbe Big Apple 2.35 x 26" tires. Use 40lbs psi. Do not buy a bike which will not fit big tires. Know the roads you travel and slow down before you hit the potholes.

I have an SBP shift kit, and I love it.

In my opinion, this is much more reasonable and cheaper than having someone build your frame. You would still have to design the rear suspension and buy the parts for it. Search for the GT front/rear suspension frame on the internet. I believe there is room for a midframe engine.

Installing this engine and riding on bad roads has been done reasonably or cheaply, hundreds and hundreds of times,

Good luck. Building a motorized bicycle is a compromise. Unless you have the $$ and are very particular about how your bike handles, don't pay someone to build your own frame.
 
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Re: Looking to build the ultimate mountain MB

Thanks a lot for your answer!! and btw im a little curius about the jackshaft kit, about the traction being made by the weak bike chain, have u never broke a chain going uphill or in a ultra intense riding? im a little worry about it, and wich derrailliuer do you have?
 
Re: Looking to build the ultimate mountain MB

Regular chain and derailleurs will work well. You MUST keep your derailleur well adjusted. I have Tanaka 47R engine, maybe 3hp. My bike chains break when they jump off the front sprocket and jammed between the frame's bottom bracket.

Chains will not break going uphill or intense riding.
 
Re: Looking to build the ultimate mountain MB

Why don't look on Craiglsist? Many bikes from previous seasons have all the features your looking for.
 
Re: Looking to build the ultimate mountain MB

I am running a KTM clone (claimed to have 9hp) against an SBP shift kit and havent broken a chain or freewheel yet and I even have a day of racing at the Grange Motor Circut on it. And its on a full suspension GT LTS even.
 
Re: Looking to build the ultimate mountain MB

if you have a chain set up right, they are amazingly strong. I'm running 8 hp electric (TORQUE!!!!) through tiny 25H chain on my motard for efficiency and it stretches a lot but hasn't broke yet. *knocks wooden desk*

It's about the brand quality, for an affordable strong chain I'd go with KMC chain.
 
Re: Looking to build the ultimate mountain MB

I had a lot of troubles with pot holes and everything else in chicago streets tearing up my back tires. the easy fix I found was a HookWorm Tire and a down hill raceing tube. the tire was not cheap and for a tube neither was the tube but worth every penny. I weigh over 280lbs and can run the HookWorm as low as 30psi and not tell that its low looking at the tires profile when Im on the bike
 
mountain bike for potholes??? i was going to make a serious post but if seatpost suspension for 30 bucks cant help you......
 
Cool. The Specialized GTS would be my first choice for a motorized rear suspension mountain bike. Plenty of room for a motor in the front triangle and the four link rear suspension limits chain problems.
 
Here's a picture of the GT LTS in your picture. Now it's a track jumper that is collecting dust on my rack in the garage.
 

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I took off the rock shock and replaced it with a Risse Racing rear air shock. The front has triple crown forks. It's a really good frame.
Too bad you're not local or I'd be willing to sell you this bike.
 

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Easy Rider said:
Here's a picture of the GT LTS in your picture. Now it's a track jumper that is collecting dust on my rack in the garage.
Click to expand...

And it's also the same model BMX turned Mtn. Bike Racer Mike King won some big Downhill championship races on. Intense, GT, Schwinn and many others started build very exotic downhill specific race bikes about that time in the 90's.
 
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