Metra 65 puch kit questions

Hello, bear with me for a bit I am new to mopeds and 2 strokes in general. A little more than a month ago I bought a puch magnum with an e50 motor under it. It had a metra 65 kit on it, a dellorto sha 16:16 carb and a performance exhaust. It had no air filter either. Well at the time it wouldn't start easy but would start and run rather well. It progressively got harder and harder to start until it wouldn't. I did a compression test on it the othèr day and the readings were very low at 75psi, so I figured the rings were done for. They are and the piston and cylinder, so much scoring on bottom side of piston and the cylinder. So today I ordered the same kit to install. Does anyone have an idea what might have gone wrong? Play in connecting arm? To rich or lean? I know the lack of an air filter contributed to it as well if not for all of it. Piston installed upside down? Anyways I was curious about jetting as well. What jet would for a 16 16 would you all run on this moped and what spark plug as Well? It has a ngk b7hs on it currently. I want to apologize as well as I am uncertain as to whether i should post this in performance or the repair sections. Thanks allot

Re: Metra 65 puch kit questions

Brandon Weiss (Detective brandon to you) /

How old was the kit (miles)? Sounds like you may have already answered your own question hahah

Maybe indeed some particulate matter got in and caused damage which ruined the rings over time?

I think it'll do fine in this forum, its sorta better to contain the matters of your single moped to one thread if you can, so i've learned.

Oh, and A picture's worth a thousand words:)

Re: Metra 65 puch kit questions

Probably Fred /

Ya a 16.16 carb has a small range so if you lean it enough for a good idle it will be lean on top so puchs with performance piston port kits/cylinders and pipe hate them.

Every puch I got or worked on that had a 16.16 sha on a pp kit had cylinder damage.

On a puch Reed kit a sha (15.15 or smaller is better/has better air/fuel mix) is not so bad you can richen them up for enough gas on top and because of the reeds they still may still idle but not on a performance build PP kit.

Use a highly tunable carb on your metra kit like a phva (a 17.5 phva just rips) or phbg that has starter, idle, progressive, mid and full throttle systems so your cylinder is not starved for fuel (and oil) see link:

Set timing low or use a retarding ignition and protect with a head temp gauge

http://www.mypage.tsn.cc/rdd/TT/contents/CARB/dellorto/index.html

Re: Metra 65 puch kit questions

Thanks for the replies. I have no idea how old or many miles is on the kit. It's alluminum not cast iron. On the 17.5 phva carb what intake does it require im,only seeing intakes,for sha's, Bing or phbg carbureators.

Re: Metra 65 puch kit questions

Probably Fred /

David Conn Wrote:

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> Thanks for the replies. I have no idea how old or

> many miles is on the kit. It's alluminum not cast

> iron. On the 17.5 phva carb what intake does it

> require im,only seeing intakes,for sha's, Bing or

> phbg carbureators.

Any phbg Spigot mount should work for phva

Re: Metra 65 puch kit questions

Thanks!

Re: Metra 65 puch kit questions

If you take the cylinder off, you'll see that the actual bore of the cylinder is cast-iron, but it it surrounded by all the cooling fins, which are aluminum. You can't really tell that it's cast iron from the outside.

Re: Metra 65 puch kit questions

the new ones they are selling are plated aluminum.

whoever built it probably just did a crappy job. lots of people kit their bikes, they never get them running right or seize them, so they sell them and say 'it just needs tuning' to some poor schmuck.

i'd start over, take the cases apart, check all the bearings, seals, gaskets, etc. make sure you don't have an air leak. set your timing, etc. you'll spend way more time in the long run (and maybe smear another kit) over just starting over and doing it right.

phbg is easy to work with because there is a little shorty cast manifold, and 10000 people have built it so you know exactly what tuning parts to change to make it run. i prefer a VM 20 mikuni but you're going to pay more for intake.

Re: Metra 65 puch kit questions

Graham Motzing Wrote:

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> the new ones they are selling are plated aluminum.

Right. My assumption was that it was an older kit, since he got it on a previously kitted bike, and the new ones have only been out for like, a year or so? But yes, it really could be either one, but the OP won't know without pulling it off and looking.

Re: Metra 65 puch kit questions

The old ones are very distinct, cast in intake and exhaust studs, poor quality finish, black. New ones are super nice, silver in color. and say Airsal on the side so there's that.

Re: Metra 65 puch kit questions

The old kit indead had a cast iron cylinder. It had on the back where it slides into the engine case something unrecognizable and 96. Possibly made in 96? Anyways I've decided to go on and rebuild the bottom end as well. the crank had some side play.

Re: Metra 65 puch kit questions

How,much easier is the mikuni to tune. The dellorto suggested at least to me seem like a bearing? Does anyone have any suggestions on jet sizes I should get, i understand they're so many variables I just don't really want to buy a dozen I won't ever need. Thanks again

Re: Metra 65 puch kit questions

Jets are cheap compared to not tuning the bike right and smearing you piston all over the cylinder. It's definitely worth it to buy a good range of jets. Nobody can really give you a definite jet size. Ballpark sure, but you'll have to tune it to what you need to get it running right.

Re: Metra 65 puch kit questions

I decided to go with a mikuni vm18. It looks much easier to tune! Thanks

Re: Metra 65 puch kit questions

What would a ballpark range for main jets,idle keys and so forth ?

Re: Metra 65 puch kit questions

Oh and sorry again I ordered one of those trail tech cylinder head temperature guages. What would an overheating temperature be at? I think I read somewhere here which I can't find now 400*f. Is there a general rule how many degrees the ignition should be retarded or will I have to play around with it? Thanks again

Re: Metra 65 puch kit questions

Brandon Weiss (Detective brandon to you) /

David Conn Wrote:

-------------------------------------------------------

> Oh and sorry again I ordered one of those trail

> tech cylinder head temperature guages. What would

> an overheating temperature be at? I think I read

> somewhere here which I can't find now 400*f. Is

> there a general rule how many degrees the ignition

> should be retarded or will I have to play around

> with it? Thanks again

400 is the danger zone, yes.

(edited)

Re: Metra 65 puch kit questions

vm 18's are super easy to tune, on a mk65 it will probably be a 25 pilot and an 80 or 85 main. needle ought to come out roughly in the middle

(two from bottom, or 3) and start at two turns out on the screw and adjust from there.

i've never tuned one on a MK65 but that is what they come out to on tccd or kstar 70's and they are very very repeatable. just about every 70 cc ish piston port comes out the same with that carb.

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