Reply To: Bike died but restarted. – GT125
Hello,
You have the situation called the infamous high speed fuel starvation, this is how it happens:
– Carb bowls are full
– Bike is running normally (under 20-30mph)
– The road opens up to split lanes (dualways etc, 70mph section)
– The revs rise as the carb slides rise up
– It starts to drink the fuel inside the float bowls faster than the fuel pump and tap can keep up.
– Once bike feels like its running out of puff, it coasts to a dead stop
– The engine is hot and fumming (no pun intended!)
– It waits for the carb bowls to fill again whilst cranking and cranking to start it.
Fortunately there is a remedy for this, so try these and every last thing you tick off below the bike will be grateful.
– Replace the lines (OEM Carb lines rot) and a monster filter is big enough to fill the carb bowls fast, or acts as little reserve for 1 mile to petrol station if you ride slowly and steady to maintain high MPG
See this (link here) and (this tutorial here)
– Better lines can hold more air in for the vacuum system to hold open the tap and pump under high revs and don’t swell near the hot rear engine.
So see this (link here) and the tutorial here
– Get “JIS” screwdriver (it is a must) before even thinking about stripping the carbs to upgrade their jets or just to check the previous owner hasn’t messed around.
Then see ( this link here )
– Do a “SLIDE MOD” while still at the carbs, look here -> (this link) , this will enrich the mid-range a little bit (around the 4-7k mark), so the bike is less flat.
– Get carb cleaner at halfords = Buy 4x cans (Yes you must go through 4 cans it is a must) then do the following
- Blow the jets clean
- Blow every hole inside the carb clean (every last of it)
- Clean the exterior hard
- Get a fat stubby screwdriver (JIS type!) and then remove the fuel pump, do not open it, as there is no need. Blow carb cleaner inside the “GOLD PORTS” only! (DO NOT SPRAY the silver port of the fuel pump)
Consider replace the fuel tap from the tank (it is too common to digress as Korea taps haven’t been great on the hyosung 125cc motors) , plus you probably want something that flows a little better (like this one)
Last not least, always (i mean always use “E5” fuel)
Let us know how you get on. I hope i wrote everything correct 🙂
Only if you do every last word above ^ with the fuel system and bike still persists , then we will discuss the air system and electric system but i hope it doesn’t come to that , as we still have some few warm days left of summer to enjoy
Regards