I just got my 79 Newport up and running. I went through and cleaned the tank, fuel lines, carb, and changed the spark plug. and cleaned it all out. It ran pretty well but only got up to about 18 mph. I took the exhaust apart, cleaned it all out and now it won't break 15 mph. It sounds ok, but doesn't seem to wind up quite as high as it used to, any ideas on where to go from here?
There are lots of things you can check! Is it four-stroking? Check the clip setting on your carb needle. Check your jetting. Is your chain rusty or too tight on either side? Replace, or clean and lube your chain. What's your gearing? Maybe you have a shitty 14x45 ratio like I had, and you need to bump up to the 16x45 that came on all the other puchs. What is the status of your air filter? Is it present? Is it clogged? Have you checked compression? Maybe you've got a bad set of rings. Does the engine make a sort of grinding noise when it's running? Maybe your bearings or crank is shot. Sorry, didn't mean to overwhelm you.
Not four stroking, chain is good, air filter is good, compression is good. It ran better/faster before cleaning out the muffler and exhaust. When I take the air filer off, it doesn't throttle at all... too lean right? What do you mean by check your jetting? jet size? Sorry, I am very new to this and am feeling my way through. Also, I'll have to check the gear ratio, but it didn't change from before the exhaust cleaning so the ped shouldn't be slower right?
So...... I found my mistake. I used a rubber washer to hold the baffle to the exhaust pipe, effectively sealing off the end.... pulled that off and I am back to 20 mph. I have the 14 tooth front sprocket with a 1HP engine. What kind of reduction in torque is it going to cause going to a 16 or 18 tooth. Also will I need a different chain, and where can I get the chain? What would be the quickest/easiest way to boost the power on the engine. I don't feel like machining anything out. Are there stock fit upgrades?
think about what happened. If you opened up your exhaust by cleaning it out, to allow your engine to breath more, maybe something on the other side needs to be tuned now. Your engine is breathing out better,but maybe now you are running too rich (if this is the case, more air or less fuel) or you are running too lean (too much air, meaning you should upjet)
most things on a moped are seriously simple.
lol maybe all the crap in your pipe gave it the shape of a tuned pipe :P
I think I need to upjet. The air filter is clean, the exhuast is clean, which means I probbaly am getting too much air through. I need to tear it apart again to get a needle reading, but I'll post the results as soon as I can.
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