new to this, hoped for some advice...

13013 · #1 07-04-2009, 08:49 AM

hey all, i've been looking at motor kits for a few months now but i'm finally getting ready to purchase one (or two, actually). before i did i had a few questions... i have a giant yukon mountain bike, and the seat tube is larger diameter (don't know the exact dia.) than normal... it's an aluminum frame, and i don't want to drill it... has anybody mounted a 2 stroke motor to this bike? i'm also interested in a shift kit from sick bike parts (or elsewhere if there are other options) to install at the same time... I understand the rear disk brakes require a shift kit or a new rear braking system. the bike has shimano deore deraleur, is this tough enough to handle the shift kit? dax seems to get no complaints on here, i'm assuming those who've owned the 2 strokes from dax like them? i'm going to be purchasing two sets of kits, for mine and my wife's bike, so i just wanted to straighten some things out first, thanks in advance and sorry for so many questions.
Robert.

Technocyclist · #2 07-04-2009, 09:33 AM

Welcome to the world motorized bicycles!!! Aluminum frames are not recommended because they tend to crack due to the vibrations from the engine, but I think it all depends on the type Aluminum alloy. For engine mounts, you can get it from Manic Mechanic. I got rid of my derailers and start using internal gear hub, so I can use BMX chain that are tough enough to handle the power and my weight. I'm using the shifter kit with rear disc brakes.

Also, you will still need to do a lot of things to the engine before installation. You need to a number of things on the engine. Most of us opens/ dismantles the engine before installation. Enjoy your build!!!

13013 · #3 07-04-2009, 09:43 AM

oh! the aluminum issue hadn't even occured to me, except that i'd been told never to drill my frame... well does anybody know if giant uses quality enough aluminum to handle this treatment? i really don't want to wreck these bikes.

Technocyclist · #4 07-04-2009, 09:56 AM

Aluminum might not last... Steel frames are still best... like the Surly Pugsly, and the Charge Duster... If you still plan to use the Giant Yukon, I think it would be better to install a rear mount engine. The in-frame 2 strokes have a clutch lever that can be really tough to squeeze which might not be suitable for your wife. Try to check your options...

and modifications that you will require...

13013 · #5 07-04-2009, 10:00 AM

yeah i saw the rear mounts, but i really want it to look good too, admittedly a secondary concern but the in frame two strokes look awesome... i saw an individual in here had converted a giant rincon, same frame, i wonder how it fared for him...

Technocyclist · #6 07-04-2009, 10:22 AM

In-frame with centrifugal clutch, lessen the vibration with rubber mounts or lead sheets, longer bottom brackets to fit the engine with centrifugal clutch... for the shifter kit... try using a 30 tooth or 24 tooth inner chain ring to reduce the stress on the frame... Hope this helps...

**2door** · #7 07-04-2009, 12:29 PM

Quote:

Originally Posted by Technocyclist

Also, you will still need to do a lot of things to the engine before installation. You need to a number of things on the engine. Most of us opens/ dismantles the engine before installation. Enjoy your build!!!

Do not disassemble a new engine unless you're not concerned with the warrantee. Most any kit supplier will not take back an engine that has been taken apart. Dax has this disclaimer clearly outlined to his purchasers. That being said there is some truth to the fact that if you do tear down a new motor you might find it contaminated with metal shavings, dirt and crud. The manufactures of these engines, especially the Chinese 2 stroke, do not put a lot of time into cleaning before assembly. The choice is yours. Retain the warrantee and run it like you received it or tear it apart and chance voiding any guarantee that came with the motor.
As for aluminum frames, there are many aluminum framed bikes owned and ridden by members here. Unless you plan to do some rough riding or will abuse the bike, a properly cared for and maintained aluminum frame will work as well as a steel one. Ride careful
Tom

13013 · #8 07-04-2009, 08:54 PM

cool thanks guys! i really wanted to hear that aluminum frames are used... i don't know what you mean about centrifugal clutch, technocyclist... as i said i'm totally new, but what kind of clutch do they come with?

**2door** · #9 07-04-2009, 09:47 PM

Quote:

Originally Posted by 13013

cool thanks guys! i really wanted to hear that aluminum frames are used... i don't know what you mean about centrifugal clutch, technocyclist... as i said i'm totally new, but what kind of clutch do they come with?

13013,
Most 2 stroke engine kits come with a manual clutch. That means you need to squeeze a handlebar mounted lever to disengage the clutch. There are some that can be ordered with a centrifugal clutch. This type engages as engine RPMs increase with no action from the rider. The jury is still out on the reliability of this type of clutch for the 2 stroke engines although they are in wide use with the 4 stroke motors. The notorious stiffness of the kit supplied clutch lever can be addressed in several ways. One of the simplest is to make sure the cable has no sharp bends or kinks. Also you can lubricate the cable so it slides more easily inside the sheath. There is a modification that can be done to the clutch actuator mechanism that will improve the mechanical action and there is at least one vendor who sells an upgraded clutch actuator that decreasese the force needed to disengage the clutch. My suggestion would be to do the two simplest things first and let your wife try her clutch. If she finds it too hard to pull then progress to the other options mentioned.
Tom

MikeJ · #10 07-04-2009, 11:02 PM

Hi 13013 -

Welcome! You will learn something new every day as you read more. MY input: I disassembled an 80/66 cc engine to its last components. It is my "experimental" engine. For its price (cheap), I have no complaint. The insides were clean, no loose metal shavings. The engine was not CNC machined as a really expensive engine is. "Close-fit" casting is the norm for these engines. Because the internal rotating crankshaft is not balanced, the engines shake/vibrate a lot. That vibration energy is absorbed by the bike frame and the rider. Aluminum frames hold up for time (months to years) which no one can predict. Steel frames tend to hold together much longer. The clutch plate engages and disengages just like a manual shift vehicle's clutch when the clutch lever is moved in and out. Not high tech, but it works. The engine maker assumes your fame tubes are about one inch in diameter. If your bike tubes are significantly larger, one way around that is to get a yard sale bike. Make your errors and learning curve on something inexpensive. I got hold of a bicycle maintenance manual and learned how to completely rebuild axles and the bottom bracket. A bike shop "tune-up" does not include this. Using "mainstream" bike frames will get you on the road faster. Then you can take everything apart and put it all on your next frame of choice. I am a strong advocate of using the best head helmet before you start your first ride. Your future income far outweighs the puny cost of the most expensive helmets; don't go cheap here. My lady friend crashed in her first mile. Her helmet saved her from serious injury.

Read and learn; there is a lot of experience here!
MikeJ