Supercycle XTI 21 skyhawk build

[impactblue]

Hello, fellow enthusiast here from Toronto, Canada. I've been on the forum for almost a year, lurking and gathering information, this site is a amazing tool for this hobby. once i learnt my way around these things, I started making my list for my own build, going over all the do's and don'ts of first time building, as well as all the precautions and preliminary checks that i've read about that go so easily missed during the build process. i began by tearing into my shed and saw my 9 year old supercycle mountain bike as the candidate. i tore the bike down fresh, cleaned up the frame and repainted her black.

all back together, now i have a good solid base to work with. new jagwire brake lines, tektro brake levers, new brake pads, new giant rubber grips, new rear rim, re trued front rim, regreased front and rear wheel bearings and crank.

 

[impactblue]

ordered my gt5 grubee skyhawk 66cc kit and started building. engine just fit in my frame. had to turn the head around 180, for the spark plug to clear. all engine bolts and mounting hardware replaced with proper fasteners, not the chinese junk it comes with.

engine mounted, gas tank mounted, clutch lever mounted, and front and rear brake levers moved together to right side of handlebar.

close up of my custom front motor mount. it uses 2"muffler clamp, and 2 pieces of 3/8" aluminum stock cut and triangulated towards each other for superior strength, it's not going anywhere.

 

[impactblue]

started wiring the ignition and kill sw.

wire loomed for neatness

 

[impactblue]

i made my own offset intake manifold to fit my carb, it would not fit in my frame without doing this. found a copper elbow that was the same dimensions as the opening of the carb opening from home depot, and soldered it onto the stock intake. ported the inlet and outlet of the intake aswell.

mounted with carb connected and wrapped in almost a whole roll of electrical tape.

i did away with the idea of using the stock tensioner so I made my own like this:

with chain on

 

[impactblue]

lastly, cut a piece of brass tubing the same diameter as the rear wheels hub, and enlarged the centre of the stock sprocket to fit it. this tubing allowed the sprocket to sit concentric with the wheel, no upand down movement.

i did my first run with this set up, and i was quickly back in the garage. i noticed although the sprocket was concentric, it was still not true. i devised a spring tensioner to compensate.

this chain set up was good for half the tank of break in period. when i went to start my bike the second time, the chain jammed in the front drive gear at the engine. the way my tensioner was set up towards the back caused the spring to over stretch which left too much slack in the chain, thus skipping a tooth at the engine drive gear.

 

[impactblue]

fast forward to today, i rode up to the local beach, and multiple trips before this update, revamped the spring tensioner by moving the swing arm forward opposed to rearward, added a piece of galvanized metal to act as a stop to limit the spring tensioner from over extending.

a couple better pictures of my front mount

 

[impactblue]

NGK b6hs plug

modified intake manifold and inline fuel filter

schwinn 20 function computer

SMD LED bright as f_ck headlight/flashlight, comparable to white HID

sitting at the beach

 

[impactblue]

some more photos

these bikes are never done, i think i still have things i can improve on it, but for now i am enjoying every bit of it!!! please let me know what you think. thanks.

 

[biknut]

Good work. The only thing I see that might be trouble is the intake manifold. The chain tensioner might need some work, but you got the right idea.

You can buy an offset manifold if you need to. I really like your brass spacer for the rear wheel idea.

 

[donphantasmo]

Looks great, but think about a shift kit. You'll love it.

 

[NormO]

Guess you learn something new everyday. I thought the XTI 21 was a full suspension bike, not a hardtail. Had one probably around 10 years ago. With a black frame and red forks. Doesn't matter i guess. Nice job on the bike. I would tidy up the chain tensioner area a bit by getting rid of extra material and smoothing off the sharp edges. Other than that nice job.

Sorry the XTI 21 was a full suspension bike but only if DS followed, forget i mentioned it.

 

[killercanuck]

Looking good impactblue, welcome btw! When you get sick of the tensioner, think about using mount spacers and run without (like these spacers)

 

[impactblue]

Thanks for all the comments/feedback everyone. I agree, my tensioner/chain set up is the ugly/weak point in my bike. Ideally, I would like to upgrade to a hub adapter rear sprocket set up to eliminate using the stock rag joint that for the life of me, I can never seem to get perfectly true. But, all the hub adapters I've seen for sale only cater to use with the larger cb100/110 hubs. I remember seeing manic mechanic website had a custom adapter program u measure your hub diameter input the measurements, and a custom hub adapter and sprocket could be had for almost any wheel application. Does anyone still offer this service? What would be my next step for getting a worry-free, true concentric rear sprocket?

 

[biknut]

All you need to do is buy a disk brake hub and have it laced onto your rear wheel. Then you can use a Kings top hat adapter. It's best of the best.

 

[impactblue]

I thought about that same idea, but didn't think that option was possible, but glad to know it is! How would I know what disk brake hub to get? Would my LBS know if I removed my rear wheel and showed them, or would I have to bring my entire bike there?

 

[biknut]

I thought about that same idea, but didn't think that option was possible, but glad to know it is! How would I know what disk brake hub to get? Would my LBS know if I removed my rear wheel and showed them, or would I have to bring my entire bike there?

Most of the disk brake hubs are the same size. If your wheel has 32 spokes, you'll have a lot of choices to choose from. Shimano has a disk brake hub with sealed bearings that's not very expensive.

 

[impactblue]

My rear wheel has standard 36 spokes. Does that pose a problem of finding a disk brake hub to suit, or do I need to switch to a 32 spoke wheel to accommodate the disk brake hub? Sorry for the noobish questions, I've just never come across this area during my research on this site.

 

[biknut]

My rear wheel has standard 36 spokes. Does that pose a problem of finding a disk brake hub to suit, or do I need to switch to a 32 spoke wheel to accommodate the disk brake hub? Sorry for the noobish questions, I've just never come across this area during my research on this site.

I don't think it's a problem, but the choices for a 36H hub are more limited is all. Most of the disk brake hubs are 32H.

 

[maniac57]

I think your best bet would be to watch craigslist or similar for a disc rear wheel and just swap it out. Lacing a wheel looks easy, but it's not. Trust me on this. If you can get an assembled setup, you avoid a LOT of potential trouble. You might find a local machine shop to measure your hub and make you an adapter to center the sprocket, but it's a lot of hassle.