My First Motorbike Project

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gera229

New Member
Sep 4, 2011
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Lowracer, can you tell me your idle RPM?
What tachometer are you using and how does it measure RPM?

Thanks.
 

lowracer

New Member
Oct 17, 2008
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Charleston, SC
Gera,
Here is a pic of my rpm meter & what the engine is idling at.
It can idle anywhere from ~2500 rpm's to ~3000 rpm's & never does the clutch grab at idle.
You can buy these on eBay for around $15 & they are very accurate.
There is a sensor wire that wraps around the spark plug wire to read the pulses (3-5 wraps around). I use some electrical tape to hold the sensor wire firmly to the spark plug wire.
-Lowracer-
 

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gera229

New Member
Sep 4, 2011
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What is the brand of your tach? I would like to get the same one if possible on ebay. Or you can give me a link. Maybe I'm idling too low on idle? My problem could as well be weak clutch springs.

Also what I have noticed is that when I revv and then go to a stop, my chain is still spinning and clutch is still engaged still (this can cause wear)? This might be the reason I snapped springs, but I am not sure?
This is either a carburetor problem or a normal operation that is actually supposed to happen.
 

lowracer

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Oct 17, 2008
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Charleston, SC
The tach is a Chinese no-name brand. Search for 'tach hour meter' & you will see many.
The chain will always turn as long as the rear wheel is turning.
The internal clutch shoes release at a given rpm & then the engine no longer provides engine braking. You may have messed up your clutch running the engine with no driver unit installed?
-Lowracer-
 

gera229

New Member
Sep 4, 2011
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Yes lowracer, I probably messed up my clutch. When I revved it the shoes rubbed against the engine casing and 1 spring flew out (unbroken, but greatly stretched out). The other springs were stretched out and loose, but I bent the tips of them to make them tighter, but I think they are still too loose. Maybe I will order new springs.
 
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cannonball2

Well-Known Member
Oct 28, 2010
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Colonial Coast USA.
They are very accurate. I have cross checked them with a very good quality hand held small engine tach made by Echo. They dont jump around randomly unless thats what the engine is doing.
 

gera229

New Member
Sep 4, 2011
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Ok thanks for the information. How responsive are they? What's the interval between number changes on the tachometer?
 

gera229

New Member
Sep 4, 2011
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USA
Lowracer, do you attach it to the spark plug or the spark plug wire?
What I noticed is that I see no wire on my spark plug wire that I got from autozone. All I see is white stuff inside it lol. How did you manage to attach it to yours? (Assuming you have the same wire since you got yours from autozone as well)

Pictures will help.
 

gera229

New Member
Sep 4, 2011
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Lowracer I know you did, but I still didn't understand it. So not on the spark plug, but on the spark plug wire. But how did you manage to stick it to the spark plug wire?
 

5-7HEAVEN

Well-Known Member
Aug 2, 2008
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Lowracer I know you did, but I still didn't understand it. So not on the spark plug, but on the spark plug wire. But how did you manage to stick it to the spark plug wire?
"There is no such thing as a stupid question".

gera, think or do before you ask questions. Get a piece of string. Wrap 2" of one end around the middle of a pencil. Tape the portion of coiled string onto the pencil, so that it does not unwind.

If you think the tape will unravel, ziptie the tape. That will keep the tape from unraveling, and the tape will keep the wire from uncoiling.

Sheesh!:-||
 

gera229

New Member
Sep 4, 2011
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5-7 Heaven that still didn't answer my question hahaha.

Where do I put the end of the wire (the metal part?)

Do I cut the spark plug wire housing or something?
 

5-7HEAVEN

Well-Known Member
Aug 2, 2008
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gera, you're kidding, right?

The tach wire picks up its signal by electromagnetic induction.

Electromagnetic induction is the production of an electric current across a conductor moving through a magnetic field. It underlies the operation of generators, transformers, induction motors, electric motors, synchronous motors, and solenoids.[Wikipedia]

No metal or direct connection.

I sense that you are a very intelligent young man, and you are sincere in your question.