A few questions from a new Builder...

Vendedda

Member
Joined
Jun 16, 2020
Messages
34
So I purchased an older used 2 stroke bike from a guy. First time ever riding one of these things, and sooo much fun 👍😁 Worked pretty good for a while, but now its having some issues.

So I decided to try to build one on my own for the first time brand new. Ordered an 80cc PK80 off Amazon. A little more work than I expected, but a good learning experience and look forward to getting this beast running.

I have not got it to run yet though, and have a few questions for you guys.....

So I installed everything a few days ago and I was getting a spark from the plug at first, and it sounded like the engine wanted to start. But I didn't try to start the bike yet because I still needed to make some more adjustments.

Well yesterday, I finished making all adjustments and tried to start the bike and...nothing. I checked the spark plug again holding it to the engine and rotating the back wheel for spark and...nothing. (it's the new spark plug that came with the kit). Also tried another spark plug on the bike and no spark. Did I somehow burn out the cdi? (it's possible I had the cut off switch wired incorrectly, not sure).

Second question: The back wheel spins freely.

With my used motor bike which I purchased from someone, I had to hold the clutch lever down to free up the back wheel. But with the new bike, I installed everything correctly (I think), yet the back wheel still moves freely regardless if I hold the lever or not.

I should mention I watched a video where the guy said with some kits you have to adjust the clutch plate because the manufacturer screws it down too tight. Such was the case with mine. So i checked and adjusted the clutch plate to make sure the gears rotate, and have proper 1/8 inch gap for the clutch plate(?) to move inside when the lever is pulled.

(Not sure if I'm using proper terminology)

So I think I did the clutch right, but the back wheel still moves freely. Should I be concerned, or will the clutch engage properly when I start the engine? Are these two things related, and possibly the reason for no spark?

Any help is appreciated 🙏

96906
 


Don_Parsons

Well-Known Member
Joined
May 6, 2020
Messages
909
Welcome to the forum...

Is there slack on the clutch cable,,, a bit of free play,,, you know,,, can you grab the chrome clutch arm and wiggle it freely...

I would start there if you haven't loosened the clutch cable off totally...

A simpler way to check is back your clutch cable off...

As for no spark,,, what's engine kit do you get,,, 4 wire or 5 on your cdi box,,, and how many wires coming out of the engine...

Lots of folks will help you out since their keen at this stuff...

Lets us know what happend when you back the clutch cable off totally... then we can help you out from there...

Dull Pencil Don 👍
 

Don_Parsons

Well-Known Member
Joined
May 6, 2020
Messages
909
Yes,,, I have 5/8 inch travel on the rod...

That is using the cable holding screw measurement to the castings on the gear side housing...
20200616_131538.jpg


5/8's allows for full engagement to disengagement... your engine clutch might measure more or less too enguage / disengage 🧐

The point where the back wheel will not spin when the clutch-lever is pulled in / disengaged.

If I rev my engine up,,, I dont see the back wheel revole at all,,, very little if anything...

Its wize to pay attention to our clutch adjustments if we want longevity...

Don
 

wan37

Active Member
Joined
Oct 12, 2011
Messages
613
The first thing is getting the clutch lined out. The crank shaft has to turn before you get spark.
 

Frogslayer

Well-Known Member
Joined
Jan 20, 2019
Messages
1,522
That's what i was wondering, how can you check for spark if you can't turn over the engine?
 

wan37

Active Member
Joined
Oct 12, 2011
Messages
613
Remember this cables can’t be bent . Now they can kind a curve a little . They won’t function right if sharp bends.Check that out.
 
Last edited:

Don_Parsons

Well-Known Member
Joined
May 6, 2020
Messages
909
Ill post the ft lbs of energy needed at the lever screw to disengage the clutch-pack pack with 5/8th travel...

I wont know until i get my scale hooked up tomorrow...

Its a hand full doing the lever by hand...

Ha

Don...

Dont loose the pin and 8mm ball ...
 
Top