Newport piston noise ???

so i have gotten this beat up and non running puch newport, 77', to run. it excelerates great and has a decent top speed. the only problem i am now having with it is that when i get to about 23-25 i get this high pitched banging sound coming from , what i think., the cylinder. i have never taken the cylinder apart on any ped so i am a bit leery about ripping it open. can anyone help me on this , any other opinions on what this sound could be?

like i said it runs fine, idles beautifully, and doesnt make any strange sounds untill i hit 23-25.

1977 puch newport 1.5HP

Re: Newport piston noise ???

hey bandit,

Never got your IRC working?

Anyway, it's hard to say without hearing it, but here are some comments:

If the engine has damage, normally you'll hear it at idle, or when you are running with little throttle, at low speeds. Piston slap is most obvious under low loads, and tends to go away when you gas it. If it were a rod or main bearing, you'd hear that almost all the time.

Pinging, preignition, detonation, etc tend to happen under heavy acceleration, or when the throttle is wide open - near top speed. If an air-cooled motor like a ped starts to ping, it can be very obvious. Sounds line someone hitting the cylinder head with a little hammer, and louder than you'd expect.

I'd pull the plug and look for any evidence of pinging or detonation. Also, make sure that (for some reason) the piston is not striking the plug - this will be obvious.

Since the bike is old, it wouldn't be a bad idea to pull the head & exhaust, and decarbonize it , just for drill. If you have any amount of carbon buildup, that could easily be causing the pinging.

Hope this helps,

MA Chat is online!

irc://irc.freenode.net/mopedarmy

Re: Newport piston noise ???

hey yeah i cant get the IRC working, everytime i tryt o download the program it tells me that the IRC somthing or other isnt available....

i got fire fox but cant get find the ma channel. i tried to put in the link but that didnt work

i will check the plug tomorrow. i decarbonized the exhaust but as i said before i am a bit leery about doing the head.

if you could send me an encouraging, "you cant screw that up" or "any monkey can do that" it may help.

i dont want to damage anything while im in there.

Re: Newport piston noise ???

Jason Luther /

its cake. unscrew the four 10mm nuts, and just pull the head off. you dont even have to take the cylinder off (unless you want to to make sure the rings are okay.) then you have to take the carb and exhaust off, and then slide the cylinder off. then you will know for sure if a bearing is bad, you can check for excess play in the connecting rod and inspect the cylinder and piston for damage. its only 4 nuts, you can do it. rah rah rah

Re: Newport piston noise ???

so thats it eh

ok well ill be doing that tomorrow. hopefuly it go's well

what should i be looking for in terms of a bearing being bad, what will it look like?

legendre

if the piston is hitting the spark plug, how do i stop it from doing that?

Re: Newport piston noise ???

Jason Luther /

unless the totally wrong plug is in there, it wont be hitting. if it _is_ then you have major problems. pull the connecting rod stright up and down, it shouldnt move a bit (up and down, itll wobble side to side a tiny bit) or try rotating the magneto by hand, there shouldnt be any play if you wiggle it back and forth (perhaps a tiny bit). but if you look into the crankcase with flash light and dont see any debris or anything, and your piston and cylinder isnt gouged, then i would say you are fine. like legendre said, if a bearing was bad you would hear it at idle or at full throttle. when you are tooling around at 30 mph you cant tell where any noise is coming from. my puch reflectors used to vibrate, the speedohousing vibrated, the choke knob vibrates. could be a million things. taking the engine apart if fun though, and you will learn a lot about the machine, plus you can clean it up.

Re: Newport piston noise ???

I have a 77 Newport too!

Puch Newports are noisy little buggers!

I wouldn't rush out and take the engine apart if it is running strong... they all make that noise at 25-30 and it can range from an elusive hissing sound that sounds like a bad headgasket to a weird clicking noise that comes and goes that I actually think is the speedo sending unit in the front hub echoing off the underside of the ped (the older ones are metal and the newer ones are plastic but they seat into the hub and spin internally and can make a racket! It could be that the hot weather is thinning out the grease in the hub and raising the noise level.

Also check the tension of the chain and make sure it isnt slapping the housing where it runs over the pedal shaft... there is supposed to be a little black plastic shroud on there that the chain runs over... but a too loose chain will make that noise at certain speeds especially when the chain stretches a bit....

I used to worry about it all the time lol... I think it's normal as long as it isn't clanging, vibrating, or kncking or something of that nature... after all it's a Puch and I found the more I beat it the better it runs...

I throw a capful of Marvel mystery oil in the tank from time to time and use synthetic oil... the synthetic oil made a huge improvement... and smoothed and quieted down the whole motor..

Hope this helps... :P

Having issues as well..

For me it's when I accelerate, I hear a high pitch sound almost a whistle, It'll happen on the stand as well. At first I thought it was something rubbing but then I realised that the sound stops as soon as I let go of the throttle?? Starting to think it's something to do with the air intake?

other wise I also get a big PUT PUT's at an idle, so much so that I feel the PUT knock the ped forward...I'm gong to make a leap of faith and say that this is piston slap?

Thanks

Re: Having issues as well..

Jason Luther /

i would say the put put is a misfire, unless you can feel the piston slap happening 25 time a second (1500 rpm idle speed). sounds pretty normal. all peds make a variety of noises, and unless a marked decrease in performance is seen, engine part failure is probably not the cause.

Re: Having issues as well..

My puch whistles too... all Puchs do... we are not talking a Lincoln Continental engine here lol

If that put put is like a popping kind of noise it is completely normal and healthy.. if it is pulling forward when it puts it's probably just idling a bit too high... take it for a hard ride at wide open throttle and get the engine nice and hot and adjust the idle down to the point that the rear tire barely spins when you lift it off the ground..

These Puchs love to be ridden hard.. the harder you beat them the better they run... I've often screamed down steep hills holding my breath waiting for the dngine to blow only to feel the thing pull away stronger and smoother than ever at the bottom of the hill begging for more... they love to ridden hard.. that's the way they are engineered!

I just took both my Newport and my Magnum out for a wide open throttle ride along the river between these posts and the higher the engine revs the better they scream... they are geared to scream happily along at full throtle all day!

PUCH is the toughest four letter word in the dictionary!

Re: Having issues as well..

i think that the piston hitting the spark plug may be my problem. i dont know why but the wrong plug was in there when i checked.... errrrr

i dont know what i was thinking, i specificaly bought a new plug just for the newport and ended up with the wrong one in the machine.

i guess thats what happens with 3 different brands of peds with 3 different spark plugs haha

so later today i try the new plug and see what happens and ill post the results

peace

Re: Having issues as well..

There you go!

Throw in the right size Bosch plug and you sould be fine!

Hey Bandit.. I was thinking about taking a ride up the coast to the beach today and will probably be riding through Salem... are you going to be around??

Re: Having issues as well..

ahh its hard to say. unfortunetly i may be at work untill 5 30 or so. my boss is out for the day and i have the weight of the printing because of it so i may not be able to even ride at all. i work in ipswich and live in salem which is about 45min. away by car in the afternoon so i am not sure if i could make a solid commitment sorry

maybe we could plan a ride sometime soon though. there is a guy that lives near me that is up for a ride anytime. he owns the front st. cafe if your in salem stop by there he may be up for it.

Re: Having issues as well..

I think I rode by that place last month if it has funky multi colored painting on the front.. I went by a place like that with a moped out front... it was on the main street :P

Either way..lets ride soon.. i love the roads around there and may take a ride to Wingaersheek beach later.. I usually swing by Woodmans in Essex for some fried clams and swing through ipswitch on the way home :P

Re: Having issues as well..

bandit,

The wrong plug in the hole could be a problem, for a couple reasons. If the plug is the wrong style (like a BP 'protruded' tip in an engine that is designed for a B) the piston could hit the plug at higher RPMs. It will be totally obvious - impact damage on the plug itself, and the top of the piston.

Assuming it's not an issue of plug style, it could be a heat range issue. If the installed plug is too hot (say, a B5HS instead of a B6HS), that could cause preignition, detonation and pinging. When a little engine like this starts to ping, it's a very unnerving clatter.

Anyway, straighten out the plug issues, and see if the trouble persists. The comments about chain slap, vibrating parts etc, are also good.

Re: Having issues as well..

haha rock, i think that that guy rides a red batavuse HS50 or something like that. yeah this area is nice

i work in ipswich and i like riding the back roads home they are kinda quiet and smooth

well definetly get together sometime soon i havent riden witth man people off of here so it would be cool to do that

peace

Re: Having issues as well..

ok thanx a ton everyone

Re: Newport piston noise ???

I had a noise I swore was preignition but it turne out to be the chain was too loose check and see if it's laying on the swingarm and adjust if nessasary.Jim

Re: Newport piston noise ???

also take off the magneto cover and look at the three stator plate screws and see where they are located in each of their slots?they should be near the middle for a stock engine one speed.

Re: Newport piston noise ???

i concur.I think my speedo either the cable ,speedo itself or the sending unit does make noise.like little rushed clicking noises.

my chain was steched and actully at stop lying on the swing arm that made noises which i thought were engin e noises but wern't.I also add syntheitic additive to my oil http://www.Militec.com to my chain lube, gas/oil and trans. fluid which does quiet the engine alot.Jim

Re: Newport piston noise ???

good advice ill give that a shot also

Re: Having issues as well..

hey all

i changed out the plug to the proper one and tightened up the chain to the proper tension, but i still get the metal slapping sound???

it isnt as bad, i can hit 25 hear the sound and let back a bit oon the throttle a couple mph and it goes away. i am kinda confused but it runs amazing untill that speed. i cant figure it out but i will work on it a bit more tomorrow

peace

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account