so I have this 80cc engine from bikeberry and today i tried to run it. I have run it multiple times, but today i didn't hear any compression, and wasnt able to run it. I removed the spark plug and checked for spark... and it sparked. I then checked for compression with the spark plug out and it sounded fine, like it should! I went to check the fuel from the spark plug whole and it was wet. I am very frustrated. all help is appreciated
I have a big problem!!!!!!!!!!!!
- Thread starter noodlecare
- Start date
Some more detail would help but off the cuff I wonder if your head bolts are torqued down properly. A leak at the head will make it very hard to start. If you are using the stock kit acorn head nuts, then cut the tops off or replace them as they often "top out" inside and give you a false sensation of being tightened. This can easily cause you to strip the head bolts in the engine case.
thank you for replying! I haven't messed with the head bolts ever. I have messed with the magneto and clutch before, which may or may not affect the situation. The weird thing is that my bike used to make it very apparent when it had good compression, but today, when I let out the clutch, i couldn't hear or feel anything
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Do what the chimpanzee says and check your head-nuts. Make sure they're torqued down properly. Not sure about your being able to "hear" compression; you can FEEL it though. You have a spark, you have fuel-delivery, and you have run the engine previously: your issue, with a high-probability, is lack of compression due to a loose head.
Then how come when I take out my spark plug, I hear and feel it just fine. By hearing it I mean I can hear it 2 stroke
I can tell you that I ride every day. When I start out to ride, before I fire up the engine, I set the engine by rolling the bike forward with the clutch engaged until I reach just before the downstroke, then I disengage the clutch. Then I pedal and release the clutch lever to engage and fire up the engine on the downstroke. Sometimes when I start in the morning it is much easier to roll with the clutch engaged than other times. It varies from morning to morning. I don't know why, but it would feel like less compression when it turns over easily. After she's fired up its all good and same compression as normal. Perhaps you are feeling a similar idiosyncrasy.
Does the clutch need to be tighter or looser? How should i diagnose this issue. Thanks for replying
Lucky you had a visit from Dr. crassius. I think he nailed your issue. Here's a link to the clutch adjusting procedure. Go through every step. Also check the pads for oil or grease.
http://motorbicycling.com/showthread.php?t=22726
http://motorbicycling.com/showthread.php?t=22726
I will try to adjust my clutch later today. But if it happens to be something else would it probably the head bolts??
Quite possibly yes. But I think crassius has diagnosed correctly. You can hear the engine turning over with the plug out because no compression is present since the plug hole is open. When you install the plug there is enough compression to make your clutch slip, so the engine does not turn over.
thanks for explaining! Once I have the chance I will try it and update y'all! This community is the greatest!
Usually a loose head will not cause a no start condition, I mean, usually it will still start but you will have no power because of the loss of compression, however if it's a big enough leak it might not start at all. It's recommended that you get rid of the short acorn nuts on the head because they will often times bottom out on the studs before they are torqued down properly. Just go to the hardware store and get quality nuts and use washers and lock washers and torque them to 120 - 140 inch pounds.