My first scooter: restoring an '87 SE50P

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Meatball
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Re: My first scooter: restoring an '87 SE50P

Post by Meatball »

Thats lean if I ever saw it. Needs more fuel. They call that color “Death White” for a reason. Lol
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keeif
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Re: My first scooter: restoring an '87 SE50P

Post by keeif »

Yeah, that didn't seem right. Good call on getting new plugs. :shock:

I'm surprised it's still rich with a 90 jet though. From what I saw, most people are running 85-87 with just an exhaust. I did replace the air filter and may need to put more oil in it, but I don't think it'd make that much of a difference.

Also, I don't see jets bigger than 90, so looks like I'll have to start doing some drilling. :cry:
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Re: My first scooter: restoring an '87 SE50P

Post by Meatball »

Taz had some big jets awhile back. Not sure what he’s up to these days on them. Just be aware that if you go too fat on the main for a happy top end, you’ll get mad bog at launch until it cleans up. Total dog from 0 to 10mph. Thats the downside of trying to tune a stock carb to do what it wasnt designed for. Good luck finding a needle kit for it. HeII…the pilot circuit is just a hole. Not much you can do with that. Lol
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Re: My first scooter: restoring an '87 SE50P

Post by keeif »

Yep, I'm really concerned about that cause I'm already having those issues with partial throttle and low speed flooding/bogging. Didn't think I'd have to get into aftermarket carbs with just an exhaust, but that may be what I have to do. Or maybe I could just run it on race gas :ndance:

Also, on the motor side of the stock carb there's a vacuum line. Is this supposed to be vented to atmosphere? It was when I pulled it off, so that's how I've been running it but thought I should double check.
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Re: My first scooter: restoring an '87 SE50P

Post by Meatball »

Its just a vent or an overflow. In the 80’s it was acceptable to purge excess fuel onto the ground. Would never fly these days. Yay 80’s!

These tuning issues are precisely why us scooter nerds preach about leaving a stock motor stock. The oem components were designed to function well at every circuit (idle, mid, wot). The carb, exhaust, air box, etc..were tuned to compliment the bore. As soon as a foreign part is introduced into the mix, the remaining oem pieces typically cannot adapt and operate effectively outside of their intended design parameters. They get close, almost, and danm near but will never be as smooth as 100% stock.

That being said, pandora’s box begins to open when modifications begin. This story started with an exhaust. Then need a carb with better tuning capabilities for said exhaust. Then need a high flow air filter since the stocker one is now a choke point. Then get taller gears so it doesnt revv to the moon and you can get more mph. Then a big bore kit gets added and you need a bigger exhaust/carb…see where this is going?
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Re: My first scooter: restoring an '87 SE50P

Post by keeif »

Ok glad to hear on the overflow.

Yep, I use to do some tuning and racing with subarus and evos, and if there's one thing I learned from that, it's that things get messy when you start doing anything with engines. Engineers of multi-billion dollar companies tend to know what they're doing :lol: My goal was to just derestrict this which seemed like a simple thing to do but here we are :roll:

With the ruckus variator, it does 45mph now which is plenty for me cause this little thing starts getting a bit sketchy at those speeds. So if I can add a carb to get a good air/fuel mixture, I'll be happy. It's something I'll have to look more into though. How complicated is putting a carb on and tuning it?
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Re: My first scooter: restoring an '87 SE50P

Post by keeif »

So I've been doing some more reading around on reading plugs today. Lots of different opinions, but the general consensus I saw was that 1: unleaded fuel doesn't produce as much color as leaded and it can be difficult to read air/fuel ratio based on plug with unleaded. And 2: You have to read the bottom of the insulator (by cutting it the plug or getting an eye piece with a light and magnifying glass) to get a correct reading for WOT as the top/tip gets hotter and will burn carbon off of it. So tip color = idle afr; middle of insulator = partial throttle; bottom = WOT. So if you've only done WOT pulls on a plug, then it would seem there shouldn't be much color on the tip or middle, like in my case. Thoughts on this?

So I'm now curious to see what the bottom of my insulator is like. I ordered this cheap eye piece off amazon: https://www.amazon.com/gp/product/B077P ... UTF8&psc=1

Or I'll just cut my plug.

Thinking of grabbing the trailtech CHT kit too.
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Re: My first scooter: restoring an '87 SE50P

Post by Meatball »

I wouldnt get too concerned about heat so much with the stock bore. Only swapping in an exhaust wont make it spin past the stock limit of about 8000-8500k. You changed the flow and back pressure so adjusting the jets a few clicks for runability is all to worry about. You can play with the airbox a bit by opening up the inlet hole to allow more flow. This might help clean up the launch bog or maybe even some wot but dont go too crazy with a massive hole. Less is more on that since the stock system is sensitive to even subtle changes.

My motors are fire breathing dragons that spin 11-12k so as you can imagine, heat is a issue. They need to be tuned more precise to find the tiny sweet spot between ripping and melting. Your range is much more broad and getting it “pretty close” should be your goal. Expect it to never be perfect at all circuits and accept it’s new personality with a few quirky throttle positions.
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Re: My first scooter: restoring an '87 SE50P

Post by keeif »

Still running strong :coolcruise:

I got a 94+ brake panel (shout out to bonesv for hooking it up), metro front wheel, and pirelli sl26 and it feels so much more stable and looks a lot better. Glad I did that. Other than that just been enjoying riding it around town!

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Also picked up an '85 Aero 50 for my next project 8)

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