I'm new on here and barely know what I'm doing, so here is what came out of my upgrades to my '78 Puch from last night. I put on an Athena 60cc piston set and a BiTurbo exhaust, it runs, sounds decent except for a slight putter noise that I can't tell if it should be there. Also if I don't feed gas the engine just slows and dies. Do I need to do something with the timing? Cause I have no idea where to start with that. Anyway I can recover the low end speed that I lost? Would a new rear sprocket work?
New Athena 60cc, stalls
Re: New Athena 60cc, stalls
First question: What carb and jet are you running?
Re: New Athena 60cc, stalls
Everything until last night was stock
Re: New Athena 60cc, stalls
"Everything until last night was stock"
exactly what have u changed? if ur running the stock carb with the original jet the kit will not function well at all.
example of how to get better help from peeps on this forum:
here is the setup:
puch maxi e50
16x45 gearing
stock clutch
60cc athena piston port kit not port matched and un-modified
biturbo pipe
14mm bing with 80 jet
high flow uni filter
The bike as really bad lowend and if I don't rev the throttle at idle its dies, i haven't messed with the timing....
i don't know what ur actual problem is so i made one up cuz when u let off the gas all motorized vehicles in a sense slow and die. but if u give us all the info we can help u alot better.
o and sputtering sounds to me like 4 stroking aka the jets too big but i could be wrong cuz i don't know ur complete setup.
Re: New Athena 60cc, stalls
I'll definitaly start doing more research, make a list of what I have and what what does. I've never really looked at engines before much less try to modify anything.
Adjusting the flow of the carb may help though? I'll mess with the idle speed some when I get off work. I'm assuming a new carb would be better? A Dellorto 19mm?
I'm just now wondering if by starting this, the money I've spent so far, is it just the beginning, can't imagine it won't be worth it. It was 2 degrees when I rode to work today, all I could think about is what I need to do to my moped and how it was sounding.
Well, shit.
Re: New Athena 60cc, stalls
Do some reading, before you ruin the kit you just bought. You can run your kit with a stock carb, but you need to get the jetting right, or you will ruin your new kit. Please read up on tuning a carb. You will likely need to order some new bing jets. To get the most out of the kit you will need to case match the cylindar (Read about this.) and run a bigger carb
Re: New Athena 60cc, stalls
If it were me, I wouldn't ride that until I got some bigger jets for my carb (or until I at least verified very very carefully that it wasn't lean) -- especially not if it's 2 degrees outside. I think the best place you can start reading is here. That won't tell you everything or explain everything perfectly, but it's a good run-down to start with.
I'll copy and paste what someone very wise once said about bigger carbs and kits: The point of a higher displacement kit is to enable your engine to -- I'm pretty sure those only come in the PHBG style, not the SHA. The PHBG is a lot more complicated to jet and tune than the SHA or a Bing carb, so if you don't really know what you're doing with carb tuning just yet, it might be beneficial to stick with the stock carb until you understand it a little better.
I think it's hard to say whether you need to mess with gearing or clutch tuning (for low end recovery) or with your timing until you get it jetted correctly. Get that variable correct, and then if it still doesn't run right, you develop a new theory for why it still runs poorly, test that theory, and so on.
Re: New Athena 60cc, stalls
If it was a 1.5 hp (or less) it probably had a 12mm Bing and the restricted cylinder port (that's gone now).
The kit is only a 10cc jump, maybe it needs a 14mm Bing with 14mm intake and a handful of jets.
Upgrade the air filter so it can breathe easier and maintain good air flow and air velocity in the carb throat.
Too large of a carb jump and it'll loose the vacuum in the carb throat needed to atomize the fuel.
I'm running a 17mm Amal on my 70cc Athena. I could easily go to a 19mm but it runs great and good carbs aren't free.
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