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1987 SE50 naked scooter project

Posted: Sat Apr 23, 2011 6:02 pm
by TiffanySpree
I scored an SE50 parts bike without plastics. So, I've decided to build a naked scooter. Sort of a Ruckus styled Elite.

The build progress is here:
http://www.flickr.com/photos/eyuzon/set ... 350214757/

Basically, it will have a stock motor with mild mods. I've put a Unifilter, 90 jet, removed variator speed limiter plate, 90/90-10 tires. I only have the 11:1 gears but theoretically I should be good for 45mph if I hit close to 8k. I based it on calculations. Cosmetically, it will have Metro graphite rims, front fork, diamond plate floorboard, MTB stem and straight bars. At the moment the motor is done (honed stock cylinder, mild exhaust porting, new stock piston & rings). After getting it all on the frame, it wouldn't fire due to a bad exciter coil (open). I tore it all down while looking for a replacement stator. Today, I blasted the frame and will have it painted by tonight. I also painted the Metro fork clamp lower, the centerstand, rear handle, stock exhaust, heatshield and the front lower bracket. I've also cut up the harness to clean it up since it will be exposed. Electrically, I removed the turn signals, high beam, oil level & kill switch. Also, I moved the bystarter resistor towards the rear. There was a lot of redundant splices that could be relocated. I'll re-tape it all when it's on the frame and cleaned up. I'll also cut down the big fat stock seat. Maybe something thinner and smaller like the Ruckus. I have yet to pick a headlight and taillight.

Re: 1987 SE50 naked scooter project

Posted: Sun Apr 24, 2011 10:51 pm
by mousewheels
That's pretty good :thumbwink:
Also, I moved the bystarter resistor towards the rear. There was a lot of redundant splices that could be relocated. I'll re-tape it all when it's on the frame and cleaned up
I don't know of many who undo all the tape for re-splicing and to move a resistor. Yet on a bare bones, I can see how wire routing is part of a 100% project.

BTW - Post some pics of the Mrs NQ50D sometime too.

Re: 1987 SE50 naked scooter project

Posted: Sun Apr 24, 2011 10:59 pm
by TiffanySpree
Yeah, that's a bit picky of me. But being an electrical engineer, it's an easy task and having an efficient electrical system is part of my job. As a hobby, I like taking things apart and (hopefully) re-engineer it better.

I'll be heading back to Cali to pick up the Spree in May. Pics will come soon.

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 9:02 am
by TiffanySpree
Ok, here are some pics of my naked SE50. I already have progress pics on my Flickr page (in my sig). But I figure most people won't click there. So, I'll post some directly. I still need to cover the cut down seat. It will have red stitching! It came out pretty cool looking! I recently changed the belt and gained about 4mph. I'm still breaking in the new piston and rings (honed original cylinder). So, it has about 80 miles since. Not completely WOT but it hit 38mph at about 7000 rpm. The only mods are slight exhaust port grinding, UNI filter partially closed, 88 main jet, removed speed limiter plate and 90-90-10 tires on Metro rims. The suspension is front Metro forks and rear Ruckus shock. I'm running 40:1 premix on Honda GN2 with the oil pump connected.

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One question I had about break-in. When the rings seat after break-in, does it rev it higher due to better sealing? Everyone talks about not applying WOT during break-in but no one explains why. What really happens during break-in with the rings and cylinder? I think that the rings become precisely matched to the cylinder. How do you know that the motor is broken in? Does it rev higher, have more power, or what? I think that it will due to the rings sealing better. Before that, is the compression down because there are micro gaps between the rings and cylinder? Can't you tell I'm an engineer? :smile: :urban:

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 2:27 pm
by e-Pirate
Looks cool! I was thinking recently about getting panels for my naked Spree, but I like the way you pulled this off!

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 2:32 pm
by TiffanySpree
Thanks! I would have kept panels had it come with them. They are hard to find as it is. But, yes, it came out pretty cool. Ruckus like...

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 3:15 pm
by caferacer
I'm glad I came across this thread, I am doing something similar with a bare se50.
This winter I found a 1987 se50 not-running "parts" scooter with no body and decided it was worth the $50 the guy wanted.
So far I have done some of the same things you have though I am limited in my workspace/tools/time/motivation and probably won't put as much work into mine as you have.
I'll post in the technical help forum since I'm still having ignition issues (I'm starting to think its the ignition coil I just need to test it)

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 7:56 pm
by Wheelman-111
Greetings:

Nice work T.S. I dig the bare-bones look.

Since you went to the trouble of swapping forks, why not a disc front? Maybe it's better, surely cheaper to use what's handy.

Also you might want to thin that premix ratio a tad. That much oil can make for a tricky-to-jet lean mixture.

Don't axt me to Show My Work or even repeat the calculations, but several of us got together a while back and figured out that the right Premix ratio with a working pump was around 70:1. Thankfully some of the Concensus Cognisenti had actual Math Skills. Maybe The Mouse can chime in with an elegant and eloquent representation of the formula, but the total ends up being 30:1 with the pump adding its max contribution at WOT.

I've used between 65 and 80:1 wthout issues when I ran a pump on my 65cc SE/05 builds.

Nice work, Dawg!

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 8:22 pm
by TiffanySpree
Thanks, Wheelman! And thanks for the carb and other advice. Actually, I mis-spoke. For the pre-mix, I meant the total would be 32:1. I mixed 2 oz oil in a one gallon jug (64:1). I just guestimated that the pump provided the other 64:1. At the beginning, I had 32:1 premix and it smoked heavy and eventually stalled. I pulled the plug and it was oily. That's when I cut the pre-mix in half. 70:1 works out to 1.8 oz, so it's pretty close. Thanks for the confirmation. So do I change it after break-in or just stick to it? I thought I needed more oil during break-in?

Yeah, for the front, I used what was easiest. I like to mod bikes, but if it was going to be too involved, I'd rather ride it now and maybe consider it later. For 40mph, the front drum is good enough.

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 8:32 pm
by Wheelman-111
Greetings:

At 50cc even ported you shouldn't need to add oil at all. The added premix is supposed to compensate for the BB-kitted 65cc. May not hurt to break it in a little sweeter, but maybe start adding straight gas after the first tank or 2.

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 16, 2011 8:45 pm
by TiffanySpree
Ok, will do.

Re: 1987 SE50 naked scooter project

Posted: Sat Jun 18, 2011 11:37 am
by PimpinSpree
I think the stock oiler is 50:1.

Re: 1987 SE50 naked scooter project

Posted: Sat Jun 18, 2011 11:59 am
by TiffanySpree
Good info! I also heard one drop every 5 seconds (at idle?).

Re: 1987 SE50 naked scooter project

Posted: Thu Jun 23, 2011 10:47 am
by TiffanySpree
I just got the seat back from a local upholsterer! Awesome job!

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Re: 1987 SE50 naked scooter project

Posted: Thu Jun 23, 2011 12:07 pm
by MopedMark
Make sure that you put the rest of your cooling shroud on. If you run it without the top end shroud you will fry the piston and rings.