My awesome project! By homegrown (Read 1,088 times)

[homegrown]

OK, so I picked up a scooter for $50. Too good of a deal to pass up. They said it ran when it was parked... almost 2 years ago. It belonged to their son and he lost interest in it so they put it up for sale to get it out of the garage. I know that it's a 50cc gy6. It appears to have been put on its side pretty hard a couple of times being as the headlamp, ferrings, and floor plate is all out of whack. The kid did some home-engineering by rewiring an LED headlamp and used a lawnmower battery by placing it in the seat compartment. The spark plug cable has also been spliced.

So far, I have rebuilt the carb, replaced the battery, and adjusted the valves.... It runs! But there are a few problems. When I get into the upper RPM range, 7k+, the motor begins to sputter a bit and then starts to completely cut out. When I release the throttle just a little bit it will resume like nothing is wrong. It even begins to pick up speed on a flat plane.

Would anyone be interested in guiding me through my project of turning this into a keeper?

[homegrown]

[olivertwisted]

Hi there, homegrown !
I couldn't pass up a $75 scooter found it in terribly rusted and salt corroded shape, and have had massive amounts of help in here over the last 5 mos and have a near new scoot now! Right off the bat, I'd say you ought to post up all the pertinent info (Make, Model,engine etc;). I'm no expert at anything so, I'll let our local experts chime in. This should be an interesting project to watch, should the mission be accepted.

[czmdiver]

Apr 15, 2016 2:20:36 GMT -6 homegrown said:

OK, so I picked up a scooter for $50. Too good of a deal to pass up. They said it ran when it was parked... almost 2 years ago. It belonged to their son and he lost interest in it so they put it up for sale to get it out of the garage. I know that it's a 50cc gy6. It appears to have been put on its side pretty hard a couple of times being as the headlamp, ferrings, and floor plate is all out of whack. The kid did some home-engineering by rewiring an LED headlamp and used a lawnmower battery by placing it in the seat compartment. The spark plug cable has also been spliced.

So far, I have rebuilt the carb, replaced the battery, and adjusted the valves.... It runs! But there are a few problems. When I get into the upper RPM range, 7k+, the motor begins to sputter a bit and then starts to completely cut out. When I release the throttle just a little bit it will resume like nothing is wrong. It even begins to pick up speed on a flat plane.

Would anyone be interested in guiding me through my project of turning this into a keeper?

Welcome.
Your Definitely Lean on the Top end (rpm's).
Your description is spot on.
You may have a Air Leak. carefully inspect you vacuum hoses and intake manifold.
If no leak you'll need to up-jet (give it more gas), crack that carb open and post what size Main Jet it has, this will be stamped on the side or bottom of the Main jet.
What does your Scoot have for a air-box or air cleaner set up?
Is it a Stock or aftermarket Performance Exhaust Pipe?
        Good Luck.

[cyborg]

What he said

[Alleyoop]

Here you go print it out and follow the step by step procedures and tests:

scooterdoc.proboards.com/thread/1499/4ts-carb-tuning

Sounds and Tricks of the Trade that tell you what the motor wants and needs.

scooterdoc.proboards.com/thread/8628/motor-sounds-tells

Alleyoop

[homegrown]

Sweet, and thank you! I just got the air/fuel mix taken care of. The bike doesn't have any markings as to who made it... it's in really sad shape. I'll put up a YouTube video soon that will do as good of a detail as I can get. I'll try to do a good look-over and then start the engine and show a bit more. I have mechanical experience on cars, but it's been years since I've touched a carb and I'm a dummy on wiring.

I had it out and about today for a test ride. I headed home after dark and that's when a real problem hit. The headlight has be rigged on and the switch was never grounded. I'm assuming that it kept shorting out because he had bypassed an inline fuse. Big mistake. The wire burnt out, starting at the switch. It did as much as melt the connector from the plastic, allowing the wire to dangle freely. It has burnt the insulation off of it and caught the battery ground wire. I had smoke coming from under my seat and everything. The bare ground wire was in contact with a constant hot wire. I called a buddy of mine that runs a vape shop and is very skilled at fixing regulated devices... He has the most knowledge of electrical work of everyone in my phone book. He helped me get my lights back and rerun a few new wires. This bike is a mess but there is hope!

[homegrown]

Also, my front brakes were missing the bolt that connects the fluid line with the calipers. I pulled one off the front disc brake of a junked mustang and ground it down to length. The threads fit perfectly!

[cyborg]

I smell a FRANKENBIKE BUILD!!!!!!!!!!!

[homegrown]

So, I attempted to start it up and do a video of how it looks, runs, and everything. But it won't start. I checked the valve adjustment, checked the petcock, pulled the plug and checked it for spark while grounded to the motor. Everything looks good. The other day, I had readjusted the fuel/air ratio on the carb and it ran much better...I even ran it for a couple days after that. Is there anything that I am missing? This is the 4th full tank of gas, all at a 91 octane since the sticker at the opening says to use at least 90 octane. When it cranks over, I can hear the compression.

[Alleyoop]

Is it firing? meaning it fires but does not stat? Or does it just crank and crank WITHOUT it firing at least once. If it just cranks and cranks pull the plug out and see if it is WET or DRY. Are you sure it is getting sprak reason I ask is the short may have burnt the cdi out.
Alleyoop

[homegrown]

The plug fires outside the head when grounded to it and it's dry after I pull it out after some time off cranking. It doesn't even seem to want to start with a quick shot of ether...



Edit: I did get it to start earlier with a spray of ether, but it died before I got to the throttle. It ran for about 30 seconds that time.

[Alleyoop]

Plug looks good, so that tells me it is firing, so since it is dry and does not even attempt to fire I would say no gas is being sucked into the motor.

Have you tested for gas flow to the CARB? in other words take the fuel hose off the carbs inlet and stick it in a cup and crank the motor over.

If fuel flows good cranking then the PILOT JET and its passages may be clogged. Do you have a fuel filter on this thing?
1. Take the VACUUM hose off the carbs ACV valve hold it up nice and high and pour a little bit of gas STRAIGHT down into the intake connect the Vacuum hose back on and try to start it. IT should fire at least once with all that gas in the chamber.
Alleyoop

[homegrown]

I took the hose off of the filter to fill a cup straight from the tank. The cup was clear and I noticed small black specs in the bottom but I'm not seeing anything in the filter. I drained the carb bowl into another clear container and noticed the same specs. I'm thinking that the jets are clogged... I attempted to pull the bottom off the carb but I started to strip the screws. Do you happen to know the size of screws they are? I may just tap them out and replace.

[homegrown]

Could it be possible that the cdi is too week to pull a good fire?