ENGINE TOP END ASSEMBLY: Yamaha TTR125 Part Six

[@evasantmier1953]

Hey man thank you i was having a problem putting mine back in thank u so much you're a great mechanic

[@TomsTinkeringandAdventures]

Just glad to hear that the video helped

[@greggthompson7]

Sorry for the late comment but I really appreciate your video.

[@TomsTinkeringandAdventures]

It’s always appreciated to hear that I’m appreciated!

[@Victor-tm2kl]

best clear video with a lot of detail, thank you good sir

[@TomsTinkeringandAdventures]

Uncook Stunts glad to help a bit, thanks for watching.

[@MrMjroach24]

Great video but just to help you with chain tensioner in the future, if you turn it all the way it locks into place. Once it’s installed you easily release it.

[@TomsTinkeringandAdventures]

Thanks, didn’t realize that!

[@ETvoice]

Great job and video! Thank you 🔥👍

[@TomsTinkeringandAdventures]

Thanks for watching!

[@mariuszpawlowski440]

I owe you a beer, actually probably the whole keg!

[@TomsTinkeringandAdventures]

Well, hopefully I run into you some day!

[@L8R-HP]

Nice video!

[@TomsTinkeringandAdventures]

#L8R-HP thank you, are you fixing a 125?

[@L8R-HP]

Tom's Tinkering and Adventures my kid and I just picked one up on Facebook market and it doesn’t run. Not even sure where to start, lol so I’m just watching a bunch of videos to get an idea. Never worked on dirt bike engines before.

[@TomsTinkeringandAdventures]

#L8R-HP these are usually really reliable bikes. I doubt that you will have to get this in depth. A carburetor cleaning and you’re probably good to go. Best of luck, have fun!

[@L8R-HP]

Tom's Tinkering and Adventures its missing a kick start and when I tried to roll start it I heard some noise inside the engine that I didn’t like. Haven’t had a chance to do a compression test yet. What are the most common fails on these? Thank you

[@TomsTinkeringandAdventures]

#L8R-HP I’ve worked on several of them, the one from this series of videos had a weird shifting issue but other than that they are really solid. Once in a while they burn a bit of oil, and when run low it will cause the cam to lose lubrication and burns up the head. If you were close (SoCal) I know of an engine available.

[@mariuszpawlowski440]

Great videos. Thanks!!!!!!

[@TomsTinkeringandAdventures]

Thank you!

[@derrickzimmers6557]

Where did you get your repair manual at? Thank you for the great video!

[@TomsTinkeringandAdventures]

You might have luck searching online forums to get a link. Sometimes free, sometimes a small fee.

[@ianbates7720]

Hi Tom, a question about tightening the camshaft sprocket nut. In the manual is says to put a wrench on the crankshaft nut (making sure your marks aligned for top dead centre). But when I try to tighten the camshaft sprocket nut, it moves - and I'm still holding the crankshaft nut just like in the manual. Suggestions?

[@TomsTinkeringandAdventures]

Are you saying that the camshaft is moving? Like it's skipping on the chain?

[@lauriviitala3978]

which way should the arrow on the piston be?

[@TomsTinkeringandAdventures]

It should point to the front or the exhaust side.

[@aarong8933]

How do you rotate the camshaft to align the marks before installing the cam chain?

[@TomsTinkeringandAdventures]

Just got to patiently install it, sometimes it takes a few tries to line it all up.

[@aarong8933]

Thanks Tom! I’m wondering what is happening as I will get it all installed and put the tensioner on then when I go to test it and rotate the flywheel the cam chain sprocket will turn about a 1/4 turn then it will stop rotating even as I’m rotating the flywheel. You think the cam chain is getting off the flywheel sprocket?

[@TomsTinkeringandAdventures]

@@aarong8933 hard to say, just make sure you have everything installed correctly including the cam chain guides. Ensure the cam chain tensioner is holding tension when you get everything lined up and then turn the engine over a few times. I'm sure it's something little that you're missing, it's all about taking your time and double checking it the first few times. Good luck.

[@notwhite4292]

Excellent video. Keep em coming!

[@TomsTinkeringandAdventures]

Not White thanks for watching.

[@Damianthelovetour2024]

Question. I have a 04 ttr 125le. Replaced carb. Started up but had hardly any power. Did a compression test and got only 70 psi. So I’m shopping for a top end. First time rebuilding but worked on medical equipment for years pretty straight forward Any recommendations on parts. Or a kit. I see $60 kits with new cylinder and then $200 for rings lol Oem. Idk 🤷‍♂️. Any help would be greatly appreciated

[@TomsTinkeringandAdventures]

You can try those cheap kits, but the quality is questionable. OEM is the best, but obviously more money.

[@ninjaspy2708]

Hey Tom I can’t figure out the year model on my ttr 125 and it looks to be the exact same one as yours do happen to know the spark plug size because I am in need of one

[@TomsTinkeringandAdventures]

The engines are all almost exactly the same no matter what year. CR7HSA should work for you I believe

[@tgreean]

What is the manual you went by. I see there is a couple different versions but your seems to be the most visual. Just can't figure out what one you have

[@TomsTinkeringandAdventures]

It’s the Yamaha manual. You might find it online if you search.

[@maxlukey3731]

Ok fo you remember me I'm the one doing this right now

[@TomsTinkeringandAdventures]

Keep the press on, you got this!

[@maxlukey3731]

How did you fix the timing when it went down

[@TomsTinkeringandAdventures]

@@maxlukey3731 I show a bit of how to do it, but I can’t stress it enough...follow the instructions in the manual!

[@maxlukey3731]

Ok

[@Johnsonmotors69]

How do you know if it’s TDC compression or intake

[@TomsTinkeringandAdventures]

When you turn it over, you can watch the valves open and close. After the intake opens, the piston should be going up to the compression stroke.

[@waylundludlow248]

Tom. These videos are awesome. On the four long bolts on your cylinder head did you put Yamaha quick gasket on those?

[@TomsTinkeringandAdventures]

I don’t believe so, best to check the manual though... I don’t always get it right!

[@waylundludlow248]

@@TomsTinkeringandAdventures I did quite a bit of RTFM. I did put a new piston and I’m getting oil blow by and I don’t know why. Cam chain is aligned I’m wondering if I pinched that O-ring on the bottom of the cylinder head any thoughts? I thought maybe those long head bolts needed sealant. But the manual said to put it on the smaller two M6 size only

[@TomsTinkeringandAdventures]

@@waylundludlow248 I guess it’s possible that the o-ring could get pinched. Always frustrating when you are trying to fix something and create another issue.

[@TheCrazyR1]

Ey how do I get that chain up over onto the sprocket, I played the motor down and tried everything, the sprocket chain just gets stuck on the inside timing cover

[@TomsTinkeringandAdventures]

Joshua Loughry it’s a little bit tricky, just have to be patient.

[@TheCrazyR1]

@@TomsTinkeringandAdventures I've got it now, I watched u do it, start at the top, use a flat blade and brought it up over, motor is back together, my kick wont spring back up like it should, how come?

[@TomsTinkeringandAdventures]

Joshua Loughry likely need to look at how you assembled it, it’s very specific.

[@MrBajabug65]

Nice thumbnail!

[@TomsTinkeringandAdventures]

Aaron’s Adventures and Tinkering I’ve seen better. Did you watch the last ten seconds?

[@MrBajabug65]

@@TomsTinkeringandAdventures Indeed...what a clown

[@TomsTinkeringandAdventures]

Aaron’s Adventures and Tinkering I sort of forgot I put it in there. Easter egged myself!

[@tremontweaver8845]

Where did you buy the choke cable

[@TomsTinkeringandAdventures]

Tremont Weaver I get a lot of parts online, usually Rocky Mountain ATV/MC

[@tremontweaver8845]

Thankyou this video was very helpful...just completed a top end rebuild on my ttr125

[@TomsTinkeringandAdventures]

Tremont Weaver glad it helped. Hope your bike runs great!

[@tremontweaver8845]

So it runs well all except i hear clicking or ticking in the top end when running....is that normal?

[@TomsTinkeringandAdventures]

Tremont Weaver hmmm, sometimes the automatic decompression cams make a bit of ticking. I can’t even remember if that bike has one. Double check your valve clearance.

[@joeowsley2183]

How to keep my ttr 125 in time

[@TomsTinkeringandAdventures]

Are you asking how to set the cam timing? First step is to get a manual. I covered most of it in the TTR videos I made, but always have a manual if you're doing this work.

[@joeowsley2183]

I got in time back together but the bike won’t stay in time and I don’t have a manual

[@TomsTinkeringandAdventures]

@@joeowsley2183 if you have it set and have the cam chain tensioner installed, then it should stay correctly timed. Your chain could be worn out, tensioner could be bad, or something isn’t installed correctly. Get a manual.

[@joeowsley2183]

Does chain tensioner keep in time

[@TomsTinkeringandAdventures]

@@joeowsley2183 it keeps tension on the chain so that it doesn’t skip and get out of time. Get a manual!

[@JCproduction0]

Trying to teach my self kinda scared to try it

[@TomsTinkeringandAdventures]

I’m not a professional, just got over being scared. You can do it too! Take your time and RTFM. 😃

[@JCproduction0]

@@TomsTinkeringandAdventures just got done rebuilding my first bike and you were right just taking it slow makes it so easier tanks this video helped me a lot

[@TomsTinkeringandAdventures]

@@JCproduction0 that’s what I like to hear, great job!

[@travisquintanilla2574]

Where did you buy your parts? I need to change out the piston and need gaskets. What is the best place to get them from?

[@TomsTinkeringandAdventures]

Travis Quintanilla I was helping a buddy, he got the parts. I buy OEM from Rocky Mountain MC/ATV. I also shop eBay a lot.

[@travisquintanilla2574]

Tom's Tinkering and Adventures I have the same exact bike. The serial number is rusted off so I’m not sure what type of bike it is. Is it a TTR125 or a YZ125. Also, when I go online for the parts, which category I choose. TTR125E, TTR125L, TTR125LE, or YZ125? How do I know which category to pick for my bike? And just to be curious, what year is your bike? I’m asking because I want to see if part are the same for certain years so I make sure I get the right parts

[@TomsTinkeringandAdventures]

Travis Quintanilla this is a TTR125, can’t remember the year because it’s not mine. Most TTR125 parts interchange across the models, some had electric start and some didn’t. That’s the biggest difference between the models.

[@travisquintanilla2574]

Tom's Tinkering and Adventures thank you for the replies. That sums up my questions. Thank you again.

[@TomsTinkeringandAdventures]

Travis Quintanilla good luck on your repairs.

[@wanted_450r]

Did your bike have a lot of compression after this build I’m not sure if my bike needs a new piston it still has decent compression using the hand trick to push down the kickstart

[@TomsTinkeringandAdventures]

It didn’t seem like a lot, but sometimes these smaller bikes are difficult to judge. Compression gauge is the only way to be sure.

[@joet6990]

Yea bikes like this ttr125 barely have any compression. You can probably go to a dealership and start one of the brand new ones up with your hand lol

[@kairynsaechao2364]

Hey Tom! I want to thank you for these video’s they have really helped me out in my rebuild. I do have a question about the piston rings though. I ordered everything new in the top end and put everything together, when I try using the kickstart if I slowly press it down the air starts leaking from the cylinder into the crankcase. No leaking from top end or valves. Wondering if I have the top 2 rings correct on the piston. I had trouble telling them apart. It says the bottom ring is the wiper ring but I don’t have a ring with a slant in it. All I know is that I have a chrome and a black ring, the chrome ring has a 1, the black ring has a 2 on it. These marks face up. They are 180 degrees apart and shouldn’t be leaking air into the crank. The black ring also has a slightly bigger end gap when inside the cylinder. If you could help me out I would appreciate it!

[@TomsTinkeringandAdventures]

KaiRyn Saechao some of the ring sets are difficult to tell what goes where, especially if there are no instructions. I would guess the 1 is top and 2 is middle.

[@kairynsaechao2364]

With brand new cylinder, rings, and piston, I think it has enough compression to start, it’s a really slow leak. Do you think the leak would be fixed after breaking it in? When the rings wear into the hone set from factory? Wondering if that’s possible too.

[@TomsTinkeringandAdventures]

It sounds to me like you've done everything you can with it. The rings do break in while running. Have you run a compression check on it? Anyway, you have it all there so I guess getting it going and seeing what happens is the next step. Good luck, let me know how it turns out.

[@kairynsaechao2364]

Tom's Tinkering and Adventures Thank you. Hope your doing ok out there and thanks for the help. I’ll update you soon!

[@TomsTinkeringandAdventures]

KaiRyn Saechao all good here, hoping for the best on your bike rebuild.

[@damianlakes3463]

Hi tom! Now on the flywheel mark for the timing there is a single line and then a couple with a line running across the middle of them . Kind of looks like an H .. it is the single line I need to line up on for my timing?

[@TomsTinkeringandAdventures]

The single line is the correct one.

[@landonking9632]

What manual is that?

[@TomsTinkeringandAdventures]

Landon king Yamaha service manual.

[@smokingcongojoe]

Put a v m 24 on it

[@TomsTinkeringandAdventures]

Is that a different carburetor?

[@smokingcongojoe]

Yes it is 26 Buck's from Amazon vm 24 will be all you need.. extra power and speed..I can send you a picture of it .cool...my phone is 202 945 ,0577 name joe joe..

[@TomsTinkeringandAdventures]

@@smokingcongojoe cool, yeah I looked it up after thinking about it. A few of my friends have these bikes so I might recommend it. Thanks!