First build - the journey begins

Welcome to the forum. I can feel your enthusiasm, but don't rush thru your build. Get one thing right before moving onto the next.
The Dawes looks like a great bike but that fat down tube will probably require an over-sized front engine mount.
The other thing I suggest is that you get your engine installed and running smooth in stock trim before adding all those other goodies. We (non-experts) have to build these things in a methodical fashion or troubleshooting problems becomes very very complicated. Enjoy your build. As you said, the build is part of the journey.

Rudz said:

I bought a 19“ mtb with front suspension from bikes direct, I plan on building a decent mtb that happens to have an 80cc motor.

http://www.bikesdirect.com/products/dawes/hay1000xi.htm

Disc brakes, lock out forks and it was cheap.

Got it, put it together, rode it. Now I'm waiting on my motor.

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Quick tip, there is no such thing as 80cc, they are all 66cc.

I'm afraid you are going to be in for a horrible surprise, I don't a think a 2-stroke is gonna fit in that 19" frame even with a slant head rotated to face forward.

The engine will have to sit so high the top will hit the top bar.

Assuming it will fit you will find you have to jackshaft it if you have a rear disc brake, no place to mount a direct drive sprocket unless you sacrifice the rear disc which would be silly so figure $200 more the JS kit but you can return some of the silly stuff you ordered below

Parts ordered

Dual pull lever
Sram thumb shifter sans brake levers

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That makes no sense.
Let me help steer you in the right direction assuming your engine will even fit.

Regardless of it being a direct drive or a jackshafted shifter there is only room for 2 pull levers and 2 twist controls on the handlebars if you want it to be safe to operate not just for yourself, but anyone else you let ride it.

You ordered the sickbikeparts self adjusting dual pull, good, you'll need it as the clutch lever goes on the left.

This is how I do all my 2-stroke handlebars if it has pedal gears.



All the bikes brake and shift controls are removed including the whole front derailleur system and it's controller.

Just pay attention to the main control layout and not the extra stuff I do with grips and such.

Dual pull brake lever and throttle on the right.
ROTARY rear gear shifter and clutch on the left.

Just my advice, take it or leave it, but I've built a lot of bikes and this handlebar layout has proven to be the best you can get in many ways.

Bummer man.
I know what it's like to see it in your head but have it turn out to be mechanically impossible to do.

IF you can get the engine to fit I highly recommend you jackshaft.
Maybe there some direct sprocket that will mount with your disc rotor for a direct drive but why?

I have offered all the help I can and wish you the best of success on your build, I'll keep tabs on it and look forward to seeing how you deal with all the obstetricals in front of you.

Looks like you're getting past the obstacles pretty well, but you'll still have a few more to get past, getting that engine to fit into a 19" frame won't be easy, I know because I did mine in a 20" frame and there's not much room once everything is in place, especially at the seat post area... there's very little room for the carb and air filter so I have to remove the filter to get the carb on and off, then re install the filter after the carb is in place, not to mention custom filters won't work unless you get an offset air inlet duct. You can get an offset intake manifold that'll eliminate that problem by placing the carb next to the seat post instead of in front of it, and the longer intake will also give you better low end torque.

I had to modify the rear mount block by cutting off all but the cradle part of the block, so basically about 3/4". That let the engine go into place then up front I have an oversized front tube, and it's oval instead of round so I originally used some really long studs in the front mount, but after battling lots of engine vibration I decided to cut slots into my lower frame tube and welding a steel bar theu it to mount the engine directly to the tabs sticking out of the frame.
I'm using a Fred head because the slant plug head left me no room for the spark plug unless I took the head off and reversed it, but the Fred head is nice for performance and keeping the top end nice and cool, there's maybe about 1/4" clearance between the head and the top tube.
Once you get the engine mounted where it sits securely in the frame, the rest should be pretty easy.

The tank may give you some trouble but if you use some rubber pads made either from an old grip cut up or a section of inner tube between the tank and frame and fit it as far forward as possible you should be ok there, double sided tape works wonders here.

Main thing is just take your time and don't try to rush anything as you get things to fit, make sure the engine sits very solid and securely, and be sure the chain lines up really well and it should work just fine for you.

What looks really good on MTB frames if you want a bigger tank are those Honda clone pitbike tanks, they're plastic and have a cool shape to them and cost about $30... Here's one I got on my ebay watch list... http://www.ebay.com/itm/390669428393?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649 these look kinda plain as is, but you can get the cover panels in just about any color to finish the look and then they look cool... You will need to make up some brackets tho to get one of these to fit right.

The stock tank does look good on a MTB tho and will give you about a 60 mile range.

I'll eventually be switching to this type of tank but I'm still in the process of doing several improvements to mine so I won't really worry about getting the tank until I'm closer to ready to take it back apart and paint it.

Trying to dremel a sprocket to enlarge a center hole can be quite time consuming, I'd be looking to have somebody at a machine shop do that job for me too if I didn't have the machinery to do it. Luckily mine fit the first try. If you have a set of carbide rotary files for the dremel tho it'll speed up that job considerably.

Glad to hear you had a carbide bit to use, they're a real timesaver... IF you need to get more of these, don't spend $10 each for them at Home Depot or other places... I got this set on ebay for arouns $25 and these fit the dremel http://www.ebay.com/itm/171354864070?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT
They don't get used very much here because I usually use a bigger die grinder, but these are great for smaller jobs or when I don't want to run my compressor, no worries about dulling these...

For the tank, you can probably make some longer (and more durable) straps if your top tube is too big around, just be careful not to overtighten the nuts because the studs are spot welded on pretty weak, Most of us just use some rubber from a cut up grip or inner tube along with some double sided tape to keep the tank from moving around and so we can use less torque on the tank hardware which works really good.