Strange noise on a de-restricted '07 people 50 2t

[blufx]

Almost everyone with a modern scoot with a nearly horizontal cylinder has noted how smooth the idle is if no brakes are squeezed and how they vibrate when the rear brake is squeezed. I am guessing the rear brake is squeezed and wildly guessing it has something to do with a bad bearing "getting better" from the subsequent vibration. My vote is still one or both main bearings and the only way to start the verification is to get to each end of the crank and wiggle the exposed end up and down, forward and rearward: there should be NO movement.

Karl

Except I'm not squeezing the brake. I'm barely moving the lever enough to light the brake light. It's not nearly enough to engage the brake shoes. If you read what I posted, I explained I suggested the same and removed the brake shoes. The noise remained. If it had anything to do with brake shoes engaging, it wouldn't happen without brake shoes installed, would it? The same applies to the "subsequent vibration". Without brake shoes or the bike even the bike moving there's no subsequent vibration. I'm gonna check the crank shaft end play just to eliminate the possibility, but I seriously doubt I'm gonna find anything. I believe, whatever the hell it is, is electrical. I don't understand how, but I do. A short circuit causing misfires maybe? I've been through all the mechanical stuff stuff that could produce a noise like this. Remember, the scooter only has 3300 miles on it. How can it have so much crankshaft endplay to produce that noise with no miles on it? I'm a tool and die maker with 40 years experience. I know worn parts when I see them. I wouldn't be in this forum right now if it was just a worn out part.           

[blufx]

Have you pulled the stator and variator to expose the crankshaft on both ends and tested it for end play, the way CROSSBOLT has suggested?

No, but I'm going to I'm gonna tear everything down and give you an accurate answer just to eliminate the possibility so that you and anyone else will stop guessing this bike with only 3300 miles is completely worn out. I'm hear for answers, not guesswork. You haven't read and understood what I've posted prior yet.

[chaz35]

Sorry not more helpful, we are trying to understand you.  Please report back, very curious what's giving you trouble.  Seems like you had trouble with CDI, maybe cut the wrong wire and replaced, maybe that's what's causing your trouble?  As I recall, your scooter has never run well.  My 1st Kymco scooter didn't even run, after a lot of work, runs like a top, good luck on yours, they are great scooters IMO.  Cheers

[CROSSBOLT]

Sorry I missed the part about the brake shoes. That blows my theory all to pieces, doesn't it? How about voltage checks, smooth and rough? I don't have a foggy idea but that might be a start. Yeah, 3300 miles is just close to being broken in.

Karl

[CROSSBOLT]

Been thinking and not thinking about this set of symptoms. It has taken me to grounds. Since it is related to the brake light filament which is pretty high current, I'm suspecting your ignition is somehow grounding through that bulb. Far fetched for certain.

Do the voltage checks while smooth and rough. Maybe that will give a logical start point.
Karl
 

[blufx]

Do the voltage checks while smooth and rough.

Oh, that sounds easy. If I knew how to, I wouldn't be here. Do you think you could elaborate just a little?

[CROSSBOLT]

Sure. I would start at the battery terminals. just hook the multimeter leads red to positive (+) and black (-) to negative, record the volts when smooth, then make it run rough and record the volts. Then I recommend you hook to the ignition coil primary and do the same thing, write it all down. Usually there are two skinny wires that are the primary and one fat one that is the plug wire. Meanwhile, someone on here may have a wiring diagram so we can see if there is some kind of regulator that may be malfunctioning.

You are the best one for this job since it is your bike. This is regardless of your electrical experience. First, we all here wanna help you back in the saddle. Second is to help round out anyone's knowledge from the pool of old guys on this forum. Lastly is to improve everyone's trouble shooting skills which includes reading carefully what the symptoms are!

We will wait for both what you find and any question you may have.

Karl

[blufx]

We will wait for both what you find and any question you may have.

Karl

Thank you Karl.
I have some things to do today, but will do this and report back. Sorry if I sounded like a smartass. I'm just getting very frustrated with this scooter and some of the advice I get from members that don't take time to read what I've already done and quickly assume the scooter is worn out.

[CROSSBOLT]

Believe me when I say I understand the frustration. Good weather is upon us and the ride won't work! Also our little "miss" on your original post! We go from here, "To infinity and beyond" as Buzz Lightyear might say....

Karl

[chaz35]

I think you replaced the CDI, didn't you?  Did you replace with OEM Kymco part?  Did the strange noise start after you replaced CDI, or did the scooter always have the strange noise since your have owned it?

[chaz35]

Have you pulled the exhaust and looked up the exhaust port?  If the piston and cylinder looks good, probably crank bearings OK IMO.  Also, could do a compression test, but requires a tool.  3000 miles is a long way, if scooter was run without oil/ or defective oil before you got it.  Cheers

[blufx]

I think you replaced the CDI, didn't you?  Did you replace with OEM Kymco part?  Did the strange noise start after you replaced CDI, or did the scooter always have the strange noise since your have owned it?

Yes, I replaced the CDI after inadvertently destroying it attempting to de-restrict it. No, it's not OEM, but it works fine. I followed another members advice on the one to buy. Here's the link:  http://www.partsforscooters.com/169-158-Honda-Dio-CDI?sc=34&category=132416  Yes, the noise was present before I replaced it.

Thanks for your time

[blufx]

Have you pulled the exhaust and looked up the exhaust port?  If the piston and cylinder looks good, probably crank bearings OK IMO.  Also, could do a compression test, but requires a tool.  3000 miles is a long way, if scooter was run without oil/ or defective oil before you got it.  Cheers

Again, I mentioned in the first post I've installed a Mallosi 70cc BBK. It has 344 miles on it. The noise was p[resent before I did this also.

[blufx]

Usually there are two skinny wires that are the primary and one fat one that is the plug wire. Meanwhile, someone on here may have a wiring diagram so we can see if there is some kind of regulator that may be malfunctioning.

Karl

I admit I'm lacking in the electrical department, but I can follow a diagram. I've wired a few Harley's from scratch, but my wiring harnesses were simplistic, to say the least. They didn't short out and when you pushed the button, it cranked. I have a wiring diagram in the PDF service manual I downloaded. I'm thinking about the regulator you mentioned. I'll look into that also.

[CROSSBOLT]

I'd say you are way ahead of the game with that experience and this project should be a mere challenge. The toughest thing will be the connections to the system you want to test. Reliable connections that remain connected while you duplicate the symptom. You will figure that out.

Karl