Compression low

Jrad831 · 08-16-2023, 03:10 PM

So I was riding my 125cc tao tao and I got close to home and all of a sudden my bike lost a bunch of power , I had to downshift to second gear and keep the throttle pinned in order to maintain my speed. When I went to kick it over the next Day I noticed that Irs super easy to kick over. Also I haven't tried to start it yet because I got a new mikuni carb and I started putting that on and haven't finished that job yet. So I've read that it could be my valves are out of adjustment, I'm just wondering if it's more likely my rings got fried. I did have a bottle of injector cleaner in the fuel tank because my previous carb was having problems. I cleaned the jets out numerous times but I kept having a hesitation at cruising speed where it would act like it's not getting fuel.... anyways I'm just wondering if anyone has had this happen to them before? And what was the fix. Was the engine toast or the rings outta adjustment.

herbie · 08-16-2023, 03:16 PM

I’d say more than likely it’s a valve issue?

Jrad831 · 08-16-2023, 05:02 PM

I just took off the exhaust valve adjuster cover and a couple big chunks of metal came out with it, also the intake valve adjuster is really loose and floppy, it like sorta floats around I think this engine is toast. So I'm wondering if I get a 140cc or 150cc lifan engine from ebay , what all do I need to swap it in ? Will I need a cdi or any electronics for it??

TominMO · 08-16-2023, 08:22 PM

Maybe you could get by with just a new head. Try these guys. Call them if it's not on their cylinder head page.

https://www.vmcchineseparts.com/coll.../cylinder-head

krat · 08-17-2023, 12:46 AM

These things usually happen in sequence.

Valve sticks
piston hits valve
valve breaks and falls into cylinder while stem shoots through top
valve chunks punch through piston, scar cylinder walls
rod bends trying to push chunks out top of engine

As you tear the engine down what part of all that happened to you, if not all of it, will be obvious. You will also see the reason there really is a difference between a clone and a Honda. Hondas last 50 years and go on trips around the world.

Ease of engine swaps is controlled by dimensions of the cradle with very little electronics being involved. Motocheez has done several on his channel.

08-16-2023, 03:10 PM	#1
Jrad831 Join Date: Aug 2023 Posts: 3	Compression low So I was riding my 125cc tao tao and I got close to home and all of a sudden my bike lost a bunch of power , I had to downshift to second gear and keep the throttle pinned in order to maintain my speed. When I went to kick it over the next Day I noticed that Irs super easy to kick over. Also I haven't tried to start it yet because I got a new mikuni carb and I started putting that on and haven't finished that job yet. So I've read that it could be my valves are out of adjustment, I'm just wondering if it's more likely my rings got fried. I did have a bottle of injector cleaner in the fuel tank because my previous carb was having problems. I cleaned the jets out numerous times but I kept having a hesitation at cruising speed where it would act like it's not getting fuel.... anyways I'm just wondering if anyone has had this happen to them before? And what was the fix. Was the engine toast or the rings outta adjustment.
	0

08-16-2023, 03:16 PM	#2
herbie Join Date: May 2019 Location: Illinois Posts: 864	I’d say more than likely it’s a valve issue? __________________ 2022 Venom KPR 200 Red- the fastest color 16t and 46t sprockets, NGK Iridium CPR8EAIX-9, aftermarket full exhaust system. Top speed 81GPS 2023 Venom SS3 KP mini 150– Nibbi carb, Nibbi air filter, aftermarket muffler, decat 2022 Venom Ghost chopper 250 1997 Honda GL1500 Goldwing 1978 Kawasaki KL250 https://youtube.com/@herbiesgarage681
	0

08-16-2023, 08:22 PM	#4
TominMO Join Date: Sep 2021 Location: De Soto, MO Posts: 1,868	Maybe you could get by with just a new head. Try these guys. Call them if it's not on their cylinder head page. https://www.vmcchineseparts.com/coll.../cylinder-head __________________ 2021 Lifan Xpect--sold 2022 Lifan KPX 1972 Honda CT90--The Carrot 1969 Honda CT90--The Tomahto Cheesy is the WDK (workplace drama king). Now retired. Nope, back in the saddle. Climate: The Movie https://www.youtube.com/watch?v=A24fWmNA6lM How our government really works https://www.youtube.com/watch?v=QjadCd0VRBw Question all authority.....think for yourself
	1

08-17-2023, 12:46 AM	#5
krat Join Date: Nov 2019 Location: KY Posts: 257	These things usually happen in sequence. Valve sticks piston hits valve valve breaks and falls into cylinder while stem shoots through top valve chunks punch through piston, scar cylinder walls rod bends trying to push chunks out top of engine As you tear the engine down what part of all that happened to you, if not all of it, will be obvious. You will also see the reason there really is a difference between a clone and a Honda. Hondas last 50 years and go on trips around the world. Ease of engine swaps is controlled by dimensions of the cradle with very little electronics being involved. Motocheez has done several on his channel. __________________ %90 of the Chinese motorbikes ever made are still on the road. The other %10 made it back home.
	0

08-16-2023, 05:02 PM	#3
Jrad831 Join Date: Aug 2023 Posts: 3	I just took off the exhaust valve adjuster cover and a couple big chunks of metal came out with it, also the intake valve adjuster is really loose and floppy, it like sorta floats around I think this engine is toast. So I'm wondering if I get a 140cc or 150cc lifan engine from ebay , what all do I need to swap it in ? Will I need a cdi or any electronics for it??
	0