minarelli: help! spark plugs and performance

i have a 1979 safari moped with minarelli engine. i'm not sure what model engine it is, but it has a plastic blower housing.

i think this moped and i were meant to be. it was manufactured the same month and year i was born: 7/1979.

anyway, it has very little power at all and it eats gas. it runs ok in the high end though, which i expect is normal.

the thing with the low end is that it is sporadic. sometimes it would be able to go up my driveway, which is a bit of an incline, and sometimes not. i also tried to ride it on my yard, which is a hill, but it wouldn't go at all. not even ACROSS the hill with no incline.

i'll try cleaning the carb, but it seems that gas is getting in all too well. i put in 400cc of fuel in and most of it is used up in five minutes. my off road kart and car can get further on that! i did a conversion, and that's 0.1 gal. so a moped should go about 10 miles on that. maybe the jet is too big? are jets standard enough that i can get one at a motorcycle shop?

the ped has 700 miles on it, and compression seems good. don't think there's any problem there.

it doesn't have an airfilter. so i guess it's running lean. it doesn't smoke at all. is that normal for a good running engine? it used to smoke and backfire alot after i first brought it out of storage. no more of that though.

ahh, the spark plug. the spark plug on it is a bosch w8a (same as w8ac). didn't seem like the right plug, but apparently it is from internet research. i'll have to try a new plug. tried some other plugs, and, of those, the spark is much weaker than that of a champion j19lm. the latter has a really nice, wide, bright, and "loud" spark compared to the bosch. the j19lm looks too short, though, so i don't think it will reach far enough into the head. can't try it now since the engine is in pieces. i'll let you know if a new plug gets a nicer spark.

anyone experiment with other spark plug types? splitfires? someone said that bosch platinums didn't work as well in his machine.

finally, is it possible to get higher performance headers or exhaust for such an old minarelli? i've been looking at different places but no mention of such a part. have any of you tried making your own pipe from the design-a-tuned-pipe link on this site?

btw: the carb leaks because the bowl gasket is crap and the plastic piece that the fuel line attaches to is cracked. i'm trying epoxy to fix the plastic. dunno what to do with the bowl gasket. i'll follow up on how i fix it if ppl are interested.

sorry for writing so much.

thanks alot!

ped_small.jpg

Re: minarelli: help! spark plugs and performance

not sure exactly what the drop in performance is ... but many of us ride minarelli mopeds. they are a dream. first, go to the "resources" section of the site, and look under "articles" for "how to fix your moped" (aka fred's guide). but let's see if i can answer a few of your questions.

first, parts are easy and cheap to obtain. contact any moped parts store. you have a minarelli v1 engine and a dellorto carburetor. you should have a 14.12 carb, if not (if you have a 14.9), that's why you have poor performance. jets are not standard beyond dellorto (that i know of), and you want a #51 or #52 jet (the number is stamped on the jet itself).

second, make sure your seals are tight on the carb, since leaking and such may all affect your performance. also, don't run w/o an airfilter. that will damage your engine. get the airfilter and airbox and run them together. fuel line is easy to fix, and use an inline fuel filter.

third, check your points. your poor performance might be due to improperly aligned points. take the plastic fan cover off and check the magneto.

fourth, your muffler might be a problem. be sure it's clean and has no obstructions. two-stroke engines need a good muffler for the engine cycle.

fifth, actually, a bosch platinum is the best plug for a minarelli. the correct size is 4214 platinum. that's similar to the champion L86 series. that's the size plug you need.

sixth, be sure you run the right mix of oil and gas. minarelli runs at 2.8oz per gallon.

seventh, check your front sprocket. if you have an 11-tooth or larger sprocket, that explains your lack of low end performance. i have an 11-tooth sprocket (among many many modifications) and that means i lose acceleration and climbing ability. but ... i gain top end (reaching about 40mph) in exchange. you can get a smaller sprocket if you want to drop down, or a larger one if you want to go up.

ok, that's all i have so far. i hope all this works. the minarelli engine is great. parts and service manuals are easy to find. parts are cheap, and they are easy to work on. good luck!

Re: minarelli: help! spark plugs and performance

Miguel is totally on top of the minarelli. wow, that pretty much says it all, except you that you can get all those parts you need from www.handybikes.com or www.akronmoped.com either place is top notch, you need a fuel banjo, filter for it, and an airbox, and an air filter. Run a light sand paper gently between your points to remove any rust or junk. do so very gently, you are not trying to remove metal just filth. you probably do not have to reset them, do that as a last resort.

so get to it.

dan

moped army

swarm and destroy

Re: minarelli: help! spark plugs and performance

First,Greg,make sure you don't have a front or rear brake hanging up on you.Also make sure you have the correct level of 20W or 30W oil in the tranny(level to the side plug.)If there's too much it'll bog you down badly. Then get rid of that spark plug and install what Miguel said to.Your jet size should be 52 or up to 56.

Re: minarelli: help! spark plugs and performance

wow, thanks everyone. the carb is a 14 12 with a 52 jet. i just cleaned it out, so i hope that helps.

but what about sealing it? the bowl gasket doesn't seem like it's doing so well. the epoxy job i did on the plastic fuel nozzle looks good. is that the banjo? maybe i just need a new one. so, akron and other places have these parts available? wow.

i'll have to count the front sprocket teeth, but this thing should be able to go up hills regardless of speed, right?

any ideas on why it's eating so much fuel?

i'll have to drain the oil from the clutch box. i think there's too much, before i thought there wasn't enough :)

finally, 2.8oz/gal for oil/gas mix. is that the "modern" ratio with synth oil? the label next to the gas cap says 5%. so i've been mixing 5% with a metric measuring cup (20cc/400cc). i'll have to get one of those 2 cycle mixing and measuring containers.

i'll write back with the results after i put it back together.

thanks

Re: minarelli: help! spark plugs and performance

i'm a bit curious as to the use of epoxy on a carburetor. don't permanetly seal things that are meant to be taken apart and put back together. you can probably get a cheap float gasket or try to repair the one you have. flipping it upside down seems to help.

you won't go up hills easily if you're not geared for it. my bike does ok on hills, but it loses about 10mph on a slight hill (20 degrees or so) and al but dies on a steep hill. on a 45 degree hill, i can go up a block, but i'm down to about 5mph by the time i hit the crest (which is the end of that block).

try just doing some thorough maintenance. keep in mind that this bike has probably sat god knows where in god knows what condition for 20 plus years. that will take time to work itself out.

good luck.

Re: minarelli: help! spark plugs and performance

miguel wrote:

>

> i'm a bit curious as to the use of epoxy on a carburetor.

> don't permanetly seal things that are meant to be taken apart

> and put back together. you can probably get a cheap float

heh. no, i wasn't planning on that. well, i was thinking of gluing the banjo(?) to the disc fuel filter for a better seal, but not to the carb. i only epoxied the banjo itself. it had cracks. i think the epoxy sealed those, but i don't know how well it'll seal by itself to the filter and the carb.

the banjo and i think the bowl leak. it also appears to have some sort of internal leaking... dunno.

> gasket or try to repair the one you have. flipping it upside

> down seems to help.

really? i'll have to try that. i was going to put some of the "liquid gasket" crap in there before putting the gasket back in. but i don't like that stuff.

> you won't go up hills easily if you're not geared for it. my

> bike does ok on hills, but it loses about 10mph on a slight

> hill (20 degrees or so) and al but dies on a steep hill. on a

> 45 degree hill, i can go up a block, but i'm down to about

> 5mph by the time i hit the crest (which is the end of that

> block).

doh. maybe i'll get a 9-tooth sprocket. i think i have an 11 toother, but i haven't taken it off yet to count. or maybe just a bigger rear sprocket...

> try just doing some thorough maintenance. keep in mind that

> this bike has probably sat god knows where in god knows what

> condition for 20 plus years. that will take time to work

> itself out.

yeah, i've got alot of maintenance to do. i have the engine partially apart and still considering taking off and cleaning it up better. gotta clean the muffler too.

who knows what kind of abuse this thing saw before. my friend bought a pair of these (one good the other siezed) from someone for $50 and some magic cards. he wanted to use it for transport, but he couldn't get it working. i offered to fix it for free, but he wouldn't have it. then he bought a $50 car for $700. his father was a nag and made him get rid of the moped he had at his house. so i got it for free :) i didn't have the foresight or parental permission at the time to russle up the second one.

well, that was five or six years ago and it's been sitting in my shed for most of that time. now it's time to work off 20 years of inactivity and crud (only has 700 miles).

thanks for the help

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