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#16 | |
Join Date: May 2024
Location: Belgium
Posts: 15
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Quote:
Sorry, it looks like the manual is wrong. The engine states: 139FMB. (the engine you showed is a 125cc, my engine is a 50cc) |
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#17 |
Join Date: May 2024
Location: Belgium
Posts: 15
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That is possible. It could also be based upon the Honda 50cc four-stroke. regards |
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#18 | |
Join Date: Aug 2009
Posts: 549
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Quote:
You might want to try a valve adjustment of 0.05mm - intake and 0.08mm - exhaust, for starters, and see if the compression improves. |
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#19 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,554
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Since the manual indicates the larger engine, I am sure you can swap in that 150, if you can get away with it. It's not an expensive engine. Displacement is the most effective mod possible, and it would be stealthy. Do they inspect it that closely? You could just do it during Winter.
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it |
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#20 | |
Join Date: May 2024
Location: Belgium
Posts: 15
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Quote:
It is an option. But the ECU will need to be reprogrammed. There are also 70 and 85cc kits available. But these also need reprogramming of ECU. |
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#21 | |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,554
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Quote:
If so, I guess it would need an ECU flash. If it's a CDI system, it might be simpler. Maybe the 150cc engine comes with a carb and peripherals like CDI/coil.
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it |
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#22 | |
Join Date: May 2024
Location: Belgium
Posts: 15
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Quote:
Yep, EFI with ECU. That didn't do much for the power though, and still a low compression of 86 PSI. I agree a carb & CDI would be easier to tweak. (up to MY 2019 or 2020 it was a CDI that was easily derestriced. Alas, EU regulations (EURO 5) made an ECU and EFI a requirement. I am looking around to see if I can find a trustworthy source for reflashing te ECU. |
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#23 |
Join Date: Feb 2007
Posts: 1,357
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"A 139fmb big bore kit is available for the 139FMB OHC Cub Engine. A big bore kit can be used to increase the performance of an ATV or dirt bike by replacing the stock cylinder bore and piston with a larger version. This provides more displacement, increased combustion flow, and more torque."
Google "139fmb big bore kit" or "k157fmi big bore kit" or "A big bore kit for a 139fmb engine requires a cylinder, piston, crankshaft, head, and gaskets. Some recommend replacing the engine instead of trying to modify the existing one. A 125 cc pit bike engine can be purchased for around $300, and there are also many inexpensive and reliable drop-in replacement engines available." I don't know if it would work but I would prefer the engine swap if it can be fitted. |
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#24 |
Join Date: Nov 2019
Location: KY
Posts: 273
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In both the U.S. and the rest of the world a 50cc scooter with CV transmission is considered a moped, in spite of the prejudices exposed here.
All states specifically have exemptions and laws directed at these bikes and specifically refer to them as "mopeds". It is doubtful that your bike makes more then 2 hp since that is about the limit the law allows for them. My state limits them to 1.8hp. They are also legally limited to not over 30mph in most U.S. states. Since you have a full license you are exempt from this restriction and can modify your bike. You will also need to register it as a full motorbike at that point, or so they say. From my experience there are no rolling dynos or such in my area. Most of the restrictions on Mopeds are mechanical rather than electronic, as so many think. There is no electronic rev limiter. There are several mechanical restrictions on your 50cc engine. First thing to do is tune the bike properly. Rejet the carb to an 80-90 jet and install a good quality spark plug. Second, get rid of the stock exhaust. Replace it with a high performance glass pack and eliminate the CAT. Just those two actions took my 50cc from 25mph top speed to around 40mph and increased pulling power substantially. And I am an adult, 5'10" tall and weighing 230 pounds. With just that tuning action I nearly doubled the top speed. There are tricks that one can do with the weights in the variator and the clutch springs but I have found them of marginal benefit. The one thing that is a benefit is the installation of a "big bore kit". The normal ones will increase your engine capacity to 80cc and it will increase your HP by a proportional amount. Over here they cost less than $50 and can be installed by a competent wrench turner in half a day. Less if it is your second or third go. No modifications to the crankcase are required for the 80cc kit. Carb rejetted, engine tuned, exhaust replaced and "big bore kit" in place and you have an 80cc scooter capable of 50-55 cruising speed. Most of the people here consider scooters a waste and improving them more of a waste but I feel the same way about pouring $2000 of high tech mods on a 250cc Chinese bike that is worth $1500, just to get 75 mph out of it instead of 65mph.
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%90 of the Chinese motorbikes ever made are still on the road. The other %10 made it back home. |
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#26 | |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,554
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Quote:
Here are a few classics! Who cares what governments classify them as ![]() ELECTRIC mopeds are back in spades ![]() NO, they are not scooters, they are electric mopeds. You can pedal them with, or without electric assist.
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it Last edited by Thumper; 05-16-2024 at 10:07 AM. |
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#27 | |
Join Date: May 2024
Location: Belgium
Posts: 15
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Quote:
It looks as though various regions have differing definitions of "Moped". In my neck o' the woods (Belgium) scooters can be moped's or motorcycles. Depends on the displacement. Anything below 50CC is a moped, anything above is a motorbike. A scooter is defined as a two-wheeled vehicle with the engine attached to rear wheel. The engine is thus part of the unsprung weight of the system. Could be 50CC or more. A moped is also any other two-wheeled vehicle with a displacement of less than 50CC, whether this has pedals or not. I am not claiming this is wrong or right. It is just the way things work over here. That it may be confusing to others is without doubt. What I have at hand is a fuel-injected motorbike of less than 50CC (49.5CC). ![]() |
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#28 | |
Join Date: May 2024
Location: Belgium
Posts: 15
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Quote:
I am surprised as a honda 50CC engine is stated for approx 5HP. There is no technical limit imposed on the power over here, only on the max speed of the moped. The engine is fuel-injected (no carb, no cdi). regards |
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#29 |
Join Date: Jul 2024
Posts: 2
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Hi. anyone on here got a bin file for a Delphi MT05 running a 50cc euro 5 EFI.
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#30 | |
Join Date: May 2024
Location: Belgium
Posts: 15
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Quote:
beware, you will need additional tools to connect to the ECU. If you don't know what you are doing you may end up with a non-functional ECU. regards |
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