Valve Replacement on Lifan Pit Bike Motor - Part 2, Re-assembly

Part two of two videos showing replacing the valves in a Lifan 125cc clone of the Honda Z50 engine.
Replacing the valve seals, lapping and installing valves, attaching the head, the cam timing chain and test starting the engine.
I did not install the exhaust as I didn't need it to test the engine and its just more work if I had to take it of for some reason. I also just forgot to hit record when mounting the carb, but its just a spigot mount VM26-606 anyway.
I will add annotations at some point.

[@n1bpd]

Thanks for the feedback (especially more so because its positive), its appreciated.

[@tunturimies84]

I made that tool and installed both valves trouble-free, thanks bro!

[@ryushev2000]

Seeing quality metal being put together is truly sexy

[@n1bpd]

I've had the engine since 2010, has been fine. Starts up first or second kick even after being stored in winter. Only problems I've had I caused myself. I'm only changing the valves here because the spark plug got cross threaded, I nicked one of the valves when I re tapped the hole.

[@justian8910]

My nephew just done the same thing with the threads how and what did you use to re thread spark plug thanks

[@JayDee-bz2ge]

I always push a nylon hose over the valve stem and lap by pulling with a drill.... Did a Subaru boxer like that and it was awesome & sealed acetone without weeping...

[@andyshaw8334]

Just the vid I was looking for awsome really appreciated this video thanks mate 👊🏼

[@user-fd9wm9hv2y]

to grind the valve you can also use a tube like a carbs tube..you will put it a the back of the valve where the spring goes and you will turn it around to grind

[@mAdAsZaC]

i ended making a tool for it on my bench grinder... took freekin forever to put the collets back in, hope my bike goes harder with the new cam i just installed

[@mertti96]

14mm wrench was nice enough to fit inside the head, and then i pulled the wrench in the way that it pushed down the spring, and i could take off the 2 things holding the valve, its easier when you put something under the head so the valve will not move when the spring compresses

[@mAdAsZaC]

you can now get a big valve head from tbolt (30mm intake and larger exhaust) and the ports to match them all but for you you would need to bore out your cylinder or buy another one or do your own valve reliefs on your piston.

[@clockworkbike]

Wow! Great camera/lighting work.

[@n1bpd]

Tappet bolts meaning the 4 bolts that attach the tappet covers? They are M6 bolts, on my engine the lower two are 20mm long (M6-20) and the top two are 16mm long (M6-16). Make sure you see how deep they go into the head before attaching the cover plate to make sure they are not bottoming out in the hole instead of getting tight against the cover. If you mean the actual bolt and nut used to adjust the tappets then you'd have to use trial and error or call a company like T-Bolt USA.

[@mertti96]

yea, i had a small piece of cooling hose under the head, towel should work fine. but putting the valves back in is really hard, but after few tries you should come out with some technique that works :)

[@mAdAsZaC]

sweet, that will save me buying a valve spring compressor (what i used to use at my old job) if you put a towel underneath it will hold the valve w/o hurting it

[@afkgang5076]

Did you have low compression cause I do ?

[@n1bpd]

Did you do any work to it or is this all of a sudden and it used to work fine? If you did some work then I'd check to make sure the timing it set up properly. If it used to work then check your tappets. I've had popping and air coming from carb when the CDI wasnt connected properly also.

[@markunit72]

i just did this, great video. i made the piece with a few inches of pvc pipe and a hacksaw

[@n1bpd]

Best bet is If the person your buying it from bought it new, find out where they got it and call them. Failing that eBay generally has a good selection of aftermarket parts, at least for the type of Engine shown in this video - the TMS is completely different so that might not be the case for you though.

[@addy3dia]

What’s that sticking to the wood handle to the valve

[@n1bpd]

Sorry, I don't understand the question. Can you describe what you mean by probe?

[@bachforelle11]

would you say the quality of that lifan pitbike/engine is good or not ? i consider to buy one.

[@n1bpd]

The seals that go around the valve stems? I dont know what they are made from. The replacement valves I used came with new seals too.

[@craigoates1665]

great vid helped me out no end.

[@samsara965]

Hello、Thank you for a video and I am contacting via Japan. I have a question that you picked parts up on around 10:47-10:51 This plate is not locker arm and what kind of function does this plate have? I have a Lefan engine (150cc model) and this model has same parts. I would like to know a function of this parts. Please let me know!! Thank you Best regards, S.M

[@deegaw11]

Is that the tensioner that you took out before you bolted the timing gear down? Do I have to remove that part? I’m about to put my timing gear back on and don’t want to mess up the timing.

[@tp73717]

What springs do you use Honda's im looking for stronger spring for my 150

[@aussiematt3369]

I know this is 10 years old almost but you should have stuck the cam sprocket back on the cam and made sure the timing marks were aligned on the head and sprocket before setting the valve clearances other than that great job have been build E22 style motors for over 14 years now

[@g8trlvrjr]

That was exactly what I was thinking. Turning the crank and removing the tensioner too. Idk don't sound like a winning combination.

[@freedomlover8525]

just wanna say thanks. great video

[@n1bpd]

The Service Manual for the Honda Z50 Engine says 7 to 9 ft/lbs, I use that value.

[@hankhamadi3410]

What size did u use to tightening the valves please?

[@bachforelle11]

i bought one today, lets see how it works :D

[@anglegrinder4630]

What are you grinding with?

[@MrBonesy84]

And Kayne that's usually tappets, valves or timing. Igniting at the wrong point firing gasses back through the inlet

[@dc_andrade]

What is the piece you put on after the cam shaft before the rockers like a plate of sort? And what is it’s function if you could please explain. I’m missing that piece and wondering if that’s my engine trouble. Thank you!

[@mattjacomos2795]

if it helps, it's the Rocker Arm Plate Set, I had to watch this video for the install as the item was missing from the workshop manual for the Madass 125 I'm rebuilding. I don't know what it does, but at least it shims the rockers on the shafts... TB has a kit with a plain plate to perform this function. Did you solve your issue?

[@mAdAsZaC]

same thing as this video, but instead of puttign the stock springs on put the double ones on and same with the cam new timing gear is the same as in the video also

[@jasoncapri5704]

Could I use tighting the headbolts or any bolts connected to the engine without using a torque standards ?.I have no special tools for it..

[@pyoson6914]

My tensioner is out but I still can't put the timing gear on

[@connorwilson8078]

Hi mate , last week adjuster tappet acre fell into cylinder , got running again but now when I rev there’s a mad slapping /cracking sounds when first rev throttle, could I have damaged something ? Close to selling bike as I’m fed up with it , am I best replacing

[@mtbridingog9083]

do you think that a lost of power will ce from the tappets not being properly treated or maintained because my bike womt even go on. full throttle at all not even half throttle it smokes like a 2 stroke and the spark plug is black so i changed out the oil and the plug and started her again and nothing changed

[@ekitten2]

its prolly the rings...requireing new rings an cylinder honing an new gaskets...(in my opion)

[@ergner]

10:46 what is the function of that part? Thanks

[@kowalvip123]

dzieki ziom najlepiej wykonany filmik jaki znalazlem

[@anglegrinder4630]

Does anybody here know the strategy of putting back a camshaft into its VERY TIGHT position?

[@cbrsixxer0169]

hey i have a 110cc mini bike with a similar engine, when i try to kick start it air blows from the carb and pops and has low compression any ideas ? please help

[@anthonyskorner4511]

I feel like I'm missing something. What holds the rocker pins from sliding out?

[@sethkrahn3155]

The long studs that hold the top end on

[@bertbuschbertbusch]

Hey what are your thoughts about milling the cylinder down a little to increase compression? and do you know it that would mess up your valve timing because of the tension of the timing chain?

[@n1bpd]

+Doitlikeidoit The cam timing tensioner should take up any slack in the timing chain, it will be different. I'd be too concerned about the piston hitting the head and/or the valves to consider trying it, way too much math and trial and error for me.

[@bertbuschbertbusch]

+n1bpd but you think only regarding the timing chain it should not be a problem?

[@n1bpd]

+Doitlikeidoit That should be fine yes.

[@XARHS007]

you had to wear exhaust before start the engine! :S what carb do you wear btw?

[@paulojorge8225]

23:38 whats does that bolt to the motor?

[@kaiserindustries5567]

I accidently opened this and i don't know what it is 19:47 please help. Is my pit bike now broken

[@j.lmarquez5110]

Hola me gustaría saber de cuantos milímetros es la chapa que has utilizado para el reglaje de valvulas?

[@Gear1993Head]

where did u get the bolt to pull out the rocker arm pins?

[@skatanafas5784]

How it;s called this part on 10.48??? help please

[@MohdFirdaus-vu2oj]

Skata na fas we called that thing rocker arm ..you got it 🤗🤗

[@vigneshbv8066]

How to diagnose damage valves? My bike vibration start just 40 kmph what solution?

[@n1bpd]

It's ok to put a little oil on the shaft with your finger just during assembly, but don't pour any oil on them - that would be too much. The outer part will get oiled by the lubrication system once the engine is running and inner part is in the combustion chamber and you don't want oil there.

[@keithflaro9257]

hey i was wondering what would happen if i lost my tappet bolts where do i get them?

[@dyllondunne4057]

i put the old head back on and got compression but wont start?

[@TheFishyman1000]

how many foot lbs of torque should you put on those head bolts

[@robertkjotar1877]

Hello! I just changed my valves in my Honda Z50, (this head is a clone from the honda ones so it's the same thing). But i've got a problem now, when i try to kickstart it makes a squeaking noise and it won't start. It wasn't like that before i changed valves. Also, on 10:42 on your video i noticed that i don't have that part? Do i need it and what is it for? I can't remember if i disassembled it it was a while ago. Thanks for help

[@twiztedscythe4207]

Robert Kjötar sounds like you fucked up

[@christianlemonade5355]

I don’t get timing with these engines? How do you know where to set the cam gear with the cam?

[@guytypeperson]

It only goes on one way. The three bolt holes in the sprocket/cam are not evenly spaced (kind of like the holes in a bowling ball). There is really no adjusting them. You just have to line up the crank and the cam, and then get the chain on. The only way to mess it up it to jump a link on the chain.

[@allyhardie9818]

I have a z40 cam, valve springs and a new timing gear to fit to my yx140 is it pretty str8 forward?? I don't know where 2 start!!!

[@keithflaro9257]

no i mean the bolt to adjust the tappets on the rocker arm

[@MrKataters]

is it possible that your motor won't start if you forgot about the flywheel and camsprocket timing? i tried to change my motor but it won't start anymore i'm clueless :s

[@n1bpd]

That could cause the engine to not start. Does the notch on the cam sprocket line up with the mark on the case when the flywheel T mark is lined up with its case mark?

[@MrKataters]

n1bpd hey, thanks for your reaction, i already made some adjustments and its about right now ;) still got some problems though, i can only start my engine with the choke on and maximum gas, after about 5 seconds it turns itself off. you ever expierenced this and know what it could be? :) thanks

[@Lolofrikos]

help what valve filer sould i use for my lifan 125-29 moter

[@MrBonesy84]

When you set the valve clearances how did you know which point to set them to? I know when the engine is complete its TDC bit when apart? @Bachorfelle1 you will need to run it in first,then set valve clearances. I'm betting you haven't done any running in at all and just thrashed the bollocks off of it. I work for a company that sells lifans and the only problems we have are from people thrashing it out of the box, throwing away the running in guidelines as if to say"pfft I don't need that crap"

[@kevino2814]

Great bid buddy. What did you set the tappet valves to may I ask? As I'm not sure what they need setting to

[@n1bpd]

I think I used .002" intake and .003" exhaust.

[@danfrea8957]

is that a biycle wheel on the front of the pit bike

[@PancakeMan00]

is it ok to pour alittle oil in the valves

[@dyllondunne4057]

I dunno if I did the tensioner correct but I have to hold it on the T because it won't go on the normal it's like it falls off it

[@n1bpd]

I had to hold that on the T mark too, so thats fine. Does the mark on the cam sprocket line up with the mark on the case when the T is lined up with case on flywheel? If its 180 degree's thats fine too, just rotate the flywheel once and it should line up. There's also a roller for the cam chain (item 9 in the following link), not having that could make it rattle. www.partzilla.com/parts/search/Honda/Motorcycle/2007/CRF50F+A/CAM+CHAIN+%2B+TENSIONER/parts.html

[@dyllondunne4057]

n1bpd What do you mean 180 off when the t is lined up so is the mark on the line and it still doesnt get compression could it be got to do with the head and see the 3 holes in the cam sproket do them screws have to be tight to get compression?

[@marijnv.1845]

Very nice video, thanks for sharing! Does anyone know if this engine is technically the same as the YX160? I want to change the camshaft and looking for instructions. Can I follow the same procedure as shows on these 2 videos? Kind regards. Marijn

[@user-py2op7nv8r]

What gap in the valve? 0.05mm?

[@dany7025]

What is it exactly you're lining up with the flywheel? (on 19.18)

[@Stoney3K]

There's a mark on the flywheel and a mark inside the engine casing which denotes top dead center. And if you have the head off, you can just turn it until the piston is all the way up, the mark on the flywheel should then line up.

[@MrPigsdick]

Good job! Have you any more videos? Thanks in advance

[@16muhammet]

removing the valves without removing the spark plug

[@arturopastran6063]

As the gum that you use to support the valve is called,who is the mark

[@magicdevil1996]

hi, can someone please help me. I just rebuilt my 125cc pit bike and once i put it back together when i try to kick start it oil drips out of the bottom base gasket of the cylinder right were the oil pump is. I brought new gaskets and also tried gasket sealant but it still drips oil, can someone explain what the problem might be.

[@dabraapman5257]

+magicdevil1996 tighten the bolts down more and you might have a crack somewhere

[@jameslabranes6122]

would this video also work for a 140cc gio motor?

[@DimitrisHondaCr250]

nice work man i have a problem with my 125cc honda innova i replace the stock cam with a takegawa 5 stage cam and i don't know what filer sould i put to adjust the valves i mean 0.03 like yours or what else could you help me? Thank you

[@n1bpd]

Sorry, I couldnt give you the right answer to that - You'd probably get the best info from whoever sold you the cam.

[@DimitrisHondaCr250]

no problem.! Thanx

[@Sketch1994]

Dimitris Honda synh8ws einai 0.10-0.15...den briskw logo oi takegawa na einai e3airesh.isws na xreiasteis sklhrotera elathria

[@enoxosr1]

the tool for the valve adjustment is every neat, where did you get it from? thanks

[@n1bpd]

It's a tappet wrench, I'm not sure where I got it from but T-Bolt USA sell the Kitaco version which looks closest to what I have tboltusa.com/store/tappet-adjuster-wrench-p-226.html Or you can get a set of three for not much more from Amazon www.amazon.com/gp/product/B000JP31T8/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B000JP31T8&linkCode=as2&tag=n0841-20 I'm sure there must be cheaper alternatives on eBay too.

[@enoxosr1]

n1bpd thank you buddy, ebay maybe the way to go.

[@dyllondunne4057]

i changed my head gasket and dunno if i done the timing correct but now my bike has no compression and wont start and sound like a rattling noise from timing chain

[@n1bpd]

Did you tighten the cam tensioner? That's probably why the chain is rattling 22:42 You can check timing by removing flywheel cover and the cam sprocket cover on the head. Turn flywheel so that the cam sprocket's mark is lined up with the mark on the head - the T mark on the flywheel should be lined up with the mark on the case.

[@dyllondunne4057]

See the 3 screws that hold the cam sproket do they have to be tight to get compression

[@n1bpd]

That shouldn't affect the compression. If they are loose it will cause damage when they fall out. Make sure the dowel is in the middle which keeps it perfectly centered. Otherwise the tension on the timing chain will change and also cause problems. Did you only change the head gasket? Or did you switch out anything else too, like valves. If they are not sealing properly (from not being lapped) that will cause no compression and so will worn valve seals.

[@dyllondunne4057]

no just changed it but i loosened a screw where the cam chain is its black like a cam roller but i put it back tight and would having no exhaust on loose the compression and i just hand thightened them 3 screws would i have to tighten them to get compression and see when you take the head of and the gasket seal that was abit loose could that have anything got to do with it

[@alyloverforever]

why didn't u use a valve lapper

[@niceone3091]

Hey man hopefully youre still here, my atv has a pretty much same engine and for some reason it blows air into the carb what could i do? Maby a bad valve? Or something else , plz help

[@jasonmerrill6510]

Bent valve

[@kylelc17]

Timing could be off 180°. Having the same problem with my 125cc lifan. Redid timing and now it's sucking air through the carb instead of the exhaust. So it's all good now. Before was backwards

[@mertti96]

just replaced my valveseals and cleaned my valves, taking off the valves was a fucking pain the ass without valve spring comressor:D

[@zesthraxGaming]

23:08 what is the purpose of that that your putting into the bottom of the engine

[@mpp23]

I love Motoz those parts with the spring keeps the pressure on the timing chain

[@Kristo99]

so thats why i had trouble getting the chain on the gear

[@mAdAsZaC]

how did you manage that?

[@UsmanMalik-ev4zo]

Hy bro i am from pakistan i want to bring this head srlander please tell me

[@n1bpd]

Yup, its a Motoped.

[@migaraabeykoon762]

pls add demonstration with lessons in next one !!!

[@FASTBOOBS]

10:47 what's that?

[@michaelbennett6550]

Very good video👍

[@Fabroooman]

Does anybody know which seals i need for this engine?

[@user-py2op7nv8r]

what size should probe?

[@garysmart1]

hey man can you give the link where i can buy a repair book or videos.... i need to learn this. we have a lot of diffrent brand of moped in Philippines I tell you they all the same kind of engine except only the name and brand different. i was originally fromm there

[@JoshHopkinsYT]

Great video thank you so much :)

[@n1bpd]

I dont know how mechanically inclined you are so it may be easy, or it may be a huge pain. I found it relativly simple. Just watch as many videos as you can, have a nice clean work area set aside just for this with plenty of space to lay out your tools/parts and take it easy. Check out "thealexmanvideos" for some more indeph videos of taking these apart.

[@n1bpd]

I use 0.003" for the Intake and 0.005" for the Exhaust.

[@dimitrismitsaras3976]

What size is the instake valve? And what the exhaust. I have 32mm 28 mm

[@bachforelle11]

thanks for the information, but i bought one and it runs horrible...

[@logansportpilotrp8174]

Valve lapping with playdough? Well now ive seen everythng.

[@zsoltsvelta]

Nagyon esetlenűl fogod a szerszámokat.

[@n1bpd]

If its based on the Honda Z50 engine then it should be similar.

[@dineshswami3486]

how a assamble clutch of pulsar ( bajaj ) bike

[@Tixoxod102]

Thanks a lot, man!