4-Stroke Engine Mod Help Needed

[jakemnz]

I've been doing a lot of research on 4-stroke MABs, but no one has done a great job of explaining performance modifications in my opinion. BikeBerry made a pretty good article that explains what mods I can get and what they do, but as a novice I some more questions that I'd like answered. I ordered a 49cc HS engine and the two main things I'd like to upgrade are the exhaust and the carburetor. What kind of carbs should I be looking at? Can I put a 66/80cc carb on my 49cc engine; should I? What kind of mufflers should I be looking at for the most boost in performance? Can I put a muffler for a scooter on my bike?

What other parts should I replace for the best performance? I'll mainly be riding on flat roads with the occasional overpass or incline. I know I can get a jakcshaft kit, but I want to save that for later.

Bike
Kit

 

[skyash]

I got a 142f 49cc taking the muffler off or getting a different one does nothing at all no help goes the same even the sound doesn't get louder.the stock carby works great no need to change it .if you do you might get 1/2 mph more there's not much you can do its the same as a car with a camshaft so if it works on a cars cam it should work on the 142f .but like cars the muffler on your car restrict the air flow so when you change it it flows better your not adding nothing to your power your releasing what's already there .the shift kit is the best thing since sliced bread for any engine.my car would be slow to if not for gears ....

 

[skyash]

O one thing I did see is a 50cc 4 stroke super charger real one not electronic.its for yz50 peewees all them bikes it's on YouTube like double s your power funny video the man on a peewee and you can hear the supercharger working lol

 

[jakemnz]

I got a 142f 49cc taking the muffler off or getting a different one does nothing at all no help goes the same even the sound doesn't get louder.the stock carby works great no need to change it .if you do you might get 1/2 mph more there's not much you can do its the same as a car with a camshaft so if it works on a cars cam it should work on the 142f .but like cars the muffler on your car restrict the air flow so when you change it it flows better your not adding nothing to your power your releasing what's already there .the shift kit is the best thing since sliced bread for any engine.my car would be slow to if not for gears ....

Alright, all that being said, I'd still like to know where to get mufflers. Can I just grab any muffler with this, or do I need to look for other specifics? That's the part no one's explaining, I want to know what kind of muffler/carb I would need for my engine. I keep getting linked to products and no one is telling me why they work, they just say they do. I want to look around a little, make my own choice.

Like I said, I'm really new to this

 

[Deleted member 12676]

be aware that carbs are made for either 4 stroke or 2 stroke but not both. Don't ask ne what the difference is.
low RPM engines don't need less muffling for better flow.
best bet is to take the head off and lathe down the mating surface .8mm to increase compression

 

[jakemnz]

be aware that carbs are made for either 4 stroke or 2 stroke but not both. Don't ask ne what the difference is.
low RPM engines don't need less muffling for better flow.
best bet is to take the head off and lathe down the mating surface .8mm to increase compression

Alright, I have two more questions. What kind of carb would I need to get to consider it an upgrade (Do I buy a 66/80cc carb, a 49cc carb, somethine else)? Also, other than jackshafts, are there any ways to fully assemble my MAB kit on a bike with a rear disc brake? I'm running low on money for this project and this jackshaft kit is ridiculously expensive, and out of stock.

 

[Deleted member 12676]

well I'm no 4 stroke expert but I'd get the largest carb that still has the same mounting size (where it connects to the manifold)

the 48/69/80cc carbs you are referring to are all for 2 strokes

Find a distributor of parts for your engine and ask him. I can only speak in generalities