e50 conundrum!?! please help :(

Elliott Giffisss /

alright so here is the break down:


polini(case matched)

15 bing

boss pipe

stock 2 shoe clutch PAZ springs


full advance on stator

gap is the thickness of a spark plug box

b7hs plug

here is the skinny on it.

this is my friends magnum by the way and im trying to be some assistance.

we started at mid90s in hopes of working down to mid 80s. nothingworked!

now when i say that i mean- it wouldnt start, and if it did start it would just idle super high and then as soon as gas was engaged it would quickly die. but when i slightly covered the airfilter with my hand it would blast.

so we tried the biggest which was 94 and put the clip on the bottom setting.

this made it ride able. shitty, but rideable.

Day 2

got more jets.. continued to upjet and as soon as the clip went towards a leaner position it would do the idling high and pull the bike. then we would drop the needle and it would be closer and it would hafta be on hte richest setting. enough for that day.

Last night..

im getting mad at this dumb ped and i figure to take everything off, well head, cylinder, exhaust, and intake.. check the gaskets and reseal everything with gasket sealer throw it all back on.

ehh fuck it why not throw a 110 jet on and mind you the needle is still on the richest setting..

anyways i start the bitch up and BOOM! like a dream come true, it rides amazingly.. it felt a tad lean so i for sure wanted to upjet the following day..

today.. i had no school so i was able to help my friend out. he grabbed some jets

and we decide to start at the highest 120 at the 2nd clip setting from lean and it didnt start.. anyways ive tried down jetting on the 2nd clip setting and nothing nothing nothing.. horrible.. hating life.. the only thing that seems to work is if its on the richest needle setting. 116 idling super high, 114 idling super high but runs deciently but i dont feel comfortable with number 1 being in such high jets for a bing?! 2 idling so damn high, and 3 having to be on the richest needle setting?!

OH and it runs SUPER hot.

any thoughts?! please advise.. should i just tell my friend to throw his magnum away?

Re: e50 conundrum!?! please help :(

It running so hot would scare the living bag out of me.

you checked everywhere for air leaks right? Everywhere?

Heat , idling high like that, and having it run better on 3 clip seems to indicate your running lean ( not the polini's best suit )

I dont know what the performance chart for stats has people running in bings for these, but you gotta kinda run with what you need, and thats sure sounds like a lean running bike.

Re: e50 conundrum!?! please help :(

ugh, this happened to me. sorta.

wouldn't start and all that goodness until i like threw gas in there.

turned out one of the seals was bad. the magneto side.

so the cylinder wasn't getting enough vacuum to pull the mixture in.

bummer. sucks splitting the case.

i dunno if thats what's goin on my mannnn, but a possibility fer sure.

Re: e50 conundrum!?! please help :(

Elliott Giffisss /

thanks for the input, i do agree with you.

for polinis from what ive seen and helped my friends out with in the past has been around 90s which has been the magic number..

but this is soooo freakin weird, i asked 1977 what they typically run in there bikes and they said the same thing between80s or 90s..

sigh.. ima grab some choke/carb cleaner and see what airleaks i can find.

Re: e50 conundrum!?! please help :(

Elliott Giffisss /


where you able to ride it at all? cause there are times where it rides super well.. feels amazing at that matter.. but i just dont feel comfortable with that damn 4th setting.

Re: e50 conundrum!?! please help :(

i think you are running lean because of air leaks. for real. next time you get it running spray carb cleaner anywhere there is a connection(intake, cylinder base, head, exhaust). if it dies you have leaks.

Re: e50 conundrum!?! please help :(

Don't weld anything to that cylinder. The heat it takes to weld aluminium will fuck up your cylinder, it will become and oval instead of a circle.

Re: e50 conundrum!?! please help :(

airleak 100% it runs hot because its lean as shit.

15 bing polinis are nearly dead on at 90 for break in, 88 for prime.

i've welded exhaust flanges on to 2 motobecane cylinders, expensive ones, and it hasnt warped a damn thing.

Re: e50 conundrum!?! please help :(

Elliott Giffisss /

thanks for the input guys-

update: sprayed around with some carb/choke cleaner.. i sprayed everything heavily in different increments and here was the findings:

sprayed the head to cylinder slightly died out- tightened slowly. eliminates die-age.

cylinder to case- perfectly fine.

intake to cylinder- sprayed. drop in idle but didnt die.

anyways saturday most likely ima take this apart again,

please any tips to what i should do to get GOOD solid connections. new gaskets? should i seal the gaskets with gasket sealer stuff as well?!

anyways i got it to perform a little better at 116 jet 2nd leanest clip. it gets going and its like a rocket mos def a champ in the making.

please advise..

thank you so kindly.

Re: e50 conundrum!?! please help :(

Tell him to throw it in the dumpster behind Louisiana Ave and Pestalozzi (area code 63118).

This may or may night be the dumpster next to my garage.

Re: e50 conundrum!?! please help :(

Elliott Giffisss /

tom- ill let him know, if he can find a car im sure itll be there in 2 days.. keep your eyes peeled.

until a car is found any suggestions?

Re: e50 conundrum!?! please help :(

Thanks man! Perfect solution.

Few Questions:

Was the case rebuilt for this build?

Was there are change from spraying carb cleaner where the Carb meets the intake?

Everything on the carb itself is tightened down / there? (primer pump?)

Gave the carb a good cleaning?

I know that last one sounds random and asinine, but we have had a 15mm missing the primer plunger and it run lean until fixed.

Re: e50 conundrum!?! please help :(

if people say 90 is right and your running that big i becha got a case or a seal leak

Re: e50 conundrum!?! please help :(

It says case matched, did you put in new seals? If not, you are putting the horse before the cart. You got to replace those things, they are only $13 bucks. Don't forget to lube them, too.

Re: e50 conundrum!?! please help :(

The seals was what I was going to say.

Re: e50 conundrum!?! please help :(

definitley an air leak. youre over compensating for one. check with carb cleaner/starter fluid around the case seam.

Re: e50 conundrum!?! please help :(

Case seam and carb clamp/intake junction (those bing clamps are the mayor of airleak city).

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