Yamaha YZ85 Top End Install

[@DYLLY0456]

I swear you put the base gasket on the wrong way the coolant port is on the left side and the hole in the gasket was on the right🤔

[@GarageAddiction]

Looking again, it does look like I did. That would actually explain a lot considering the overheat.

[@J2stroke-sherco46]

Definitely wrong way around

[@friendsinlowplaces619]

Your channel is going to save me a TON OF MECHANIC FEES lol THANK YOU in Advance brother!!!! 💯💯💯💯

[@GarageAddiction]

Cheers! good luck with your rebuild!

[@Molsen124]

Good video. I just did the same work on my sons yz85. I have the problem that coolant water runs out of the exhaust hole when I pump the kickstarter. Have you had the same experience? Cylinder, piston, gaskets are new. Top has been event out. It's still not tight. Any help is very welcome.

[@GarageAddiction]

Check the base gasket and the cylinder head orings. Those should really only be the two sources for that leak.

[@tejdz1337]

i got one of these a while back, my bike ran like absolute shit and i just put it in a shed for a year or two. today i found this video and saw u mention the oring problem, so i tried putting the stock orings back on my bike and it fucking ran again. im assuming the orings that came with it were so bad that not only did it leak compression into coolant, but also messed up combustion by leaving a gap between head and jug. thank you for showing me what the issue was. now its only a matter of how long these niche cylinders last for road racing XD i got a whole summer to torture it.

[@GarageAddiction]

Awesome! Let me know how it goes, I still have the cylinder kicking around somewhere haha

[@alexloto6120]

Hey whats up man can you do a video on what should be done if the kick on yz85 gets frozen

[@GarageAddiction]

Check out the bottom end rebuild, if it’s not something with the kickstart cluster, clutch, or crank spline it’s probably deeper in the transmission and you’ll have to split the cases.

[@manuelhacksteiner7560]

Hey, since i also bought this zylinder i wanted to know what size of main jet you use with the keihin carb? Thanks

[@GarageAddiction]

I have a 138 main in right now, I'm at roughly sea level with boysen reeds, and a uni pod filter. I run the clip at position 2 and have a 45 pilot as well. I believe those are the stock numbers for the bike.

[@jeffdelany2676]

Great help thanks.

[@mclovin_it8872]

I just did a top end rebuild on my yz85 i ran it for a day not going crazy but breaking in the cylinder and piston. However the following day my bike did not want to start at all. I made sure i had spark before I started doing anything els and I noticed coolant leaking right where the top meets the block above the exhaust port. I look in my spark hole and saw coolant on the piston. Any idea what i could of done wrong? Also i know when i was putting in the studs into the block 2 out of 4 were shorter. does it matter which orientation i place them? Dont want to sound confusing. I made sure my studs for the cylinder cap were the same length. If you have any suggestions I appreciate it.

[@GarageAddiction]

Probably what I ran into, I had flipped the base gasket and it blocked the coolant port and overheated melting the head orings. I had a pinned comment but I think I'll pull this video down as it's not super prominent. If you're sitting on the bike the left two studs, the side with the dowels, are longer than the right side.

[@mclovin_it8872]

@@GarageAddiction update!!! i took off my cylinder and noticed coolant got into my crank i turned over my bike and coolant started pouring right out. I tried my best to remove the exes liquid with a rag. Once I started to put everything back together i made sure gasket was set correctly. Made sure studs were in the right spot. I Torqued the nuts to spec. What I noticed were my orings both big and small they were how should i say not a snug fit in the grooves. They had play and what i think is because i left them in my garage for a while b4 i started the rebuild. Ill have to order new rings and i believe my CDI went out because after i put everything back together. Still my bike wouldn’t turn over. Even with spark, fuel and compression

[@GarageAddiction]

Good to hear! CDI is probably fine if you've got spark, might have just been lower compression with the head rings leaking.

[@mclovin_it8872]

@@GarageAddiction got some good news! I was able to start my bike after i drained the coolant. I added starter fluid in the spark hole by the second kick my bike turned over with a bunch of smoke coming out the exhaust but the bike didnt keep idle. So ill have to remove my carb to clean it out b4 i put it back together

[@albundy6804]

I need a new barrell n piston ring kit! Can u hook us up?

[@GarageAddiction]

I highly recommend replating your stock cylinder and going with a prox piston. I’ve been looking for top end kits and aside from the big bore Athena I haven’t found something I’d run.

[@albundy6804]

Does that work out cheaper?

[@GarageAddiction]

It tends to be as long as your cylinder is salvageable.

[@HaydenHowardH]

Do you think tusk o rings would work with this to make it not leak?

[@GarageAddiction]

I'm not sure, I'd like to test out some yz85 parts but I'd rather test it on a stock frame that's easier to work on.

[@HaydenHowardH]

@@GarageAddiction i understand! Thank you for commenting back!!

[@bornamajor3224]

What are your oppinions on the actual cylinder and piston?

[@GarageAddiction]

The piston looked ok, the finish was a little rougher than some other aftermarket ones and it felt light. The cylinder seemed ok the ports were pretty rough and the playing inside had some poor finish near the ports and some voids at the edge. Overall I’d say it reflected the $100 ish bucks wasted on it haha

[@bornamajor3224]

@@GarageAddiction i know i have the same kit I havent installed it yet but did it like fail you or lock up or something?

[@GarageAddiction]

For me the head orings we’re too big and failed pressurizing coolant and filling the crankcase. Might be fine with some moose rings but I’m steering clear, this is a road bike for me so I don’t need to get stranded all the time haha. kzbin.info/www/bejne/Z5vGmayCatOcaa8

[@bornamajor3224]

@@GarageAddiction ok thanks

[@JaredMcelwain]

U put base gasket on wrong didn't line up coolant port!

[@remady5827]

What kind of flat slide carb is that I usually only see them on the 250s.

[@GarageAddiction]

It's the stock Carb for the YZ85, Keihin PWK 28mm

[@луцик-б9э]

Hi where did you buy this kit cpg

[@GarageAddiction]

The niche kit? I think I picked it up on ebay. I'd stick with replating the stock cylinder though.

[@jayroberts1297]

i’m looking to bore out my 2001 yz80 cylinder but can’t find a kit. is it possible to send my current cylinder out and have a shop bore it out to 100 or 105cc and port it and the head? if so would it be worth it ? and would how long do you think it will last? i street ride i’m never really going full throttle that much loll thanks.

[@GarageAddiction]

The only place I saw when looking for big bore kits that have yz80 stuff is www.kustom-kraft.com/yz80-big-bore-kit. Honestly I'd look for a bigger bike vs going big bore on these little guys.

[@jayroberts1297]

Garage Addiction thanks for the reply i’m just looking to build a beast yz80 that will keep up with 250 4 stroke and stuff but keep reliability and some longevity i’ve heard people say pistons won’t even last like 20 hours with the big bore do you know if that’s true?

[@GarageAddiction]

I don’t think going big bore will kill your hours. I run my stock bore race bikes for 40+ hours no problem. The big challenge will be getting the jetting dialed after that your clutch will probably need some attention like hd plates and springs

[@alanssnack1192]

what oil ratio do yamaha recmend?

[@GarageAddiction]

Yamaha recommends 30:1

[@300blkaac]

How did the cylinder slide on so easy

[@GarageAddiction]

lots of oil and compressing the rings as you set the cylinder on :)

[@Cabreratonn]

What happened to the dowel pins tho

[@GarageAddiction]

They got left in the last cylinder which I missed

[@gbikelife5727]

Can i use my old cylinder head that has small dents on it with a new piston?

[@GarageAddiction]

Dents? I’d opt for a new one or new to you used in good condition. Are the dents from rings slamming into it?

[@gbikelife5727]

@@GarageAddiction Not dents like little really small chips from little pieces of metal slamming in to it. They told me i can just sand them down but this is my first 2 stoke so am not sure..

[@GarageAddiction]

I’d see if you can get it to a machine shop and have them clean it up, it shouldn’t cost too much to take a small pass at the dome. Here is a pretty handy head damage guide from Millennium Tech www.millennium-tech.net/pdf/2_stroke_head_repair_when_is_it_needed.pdf

[@gbikelife5727]

@@GarageAddiction thanks for the help champ 🏆

[@1200s-e8n]

My 2003 YZ-85 piston wrist pin wont come out? Tips??

[@GarageAddiction]

Try a socket to push it through while holding the piston firmly.

[@1200s-e8n]

Appreciate that!

[@easydoz1]

I used a Dremel with a sanding wheel to get past my deep scoring.

[@dennis5879]

What carb size you use?

[@GarageAddiction]

Stock carb, 28mm.

[@mikecal516]

How hard is it to do a top end rebuild? Be my first time doing one on my 2014 yz85. What top end should I get and do I have to look for anything or have to do. Thanks!

[@GarageAddiction]

It’s a pretty easy job, personally If your cylinder and head are in ok shape, send them off to get cleaned up and replated if they’re scored. I’ve had great experiences with proX and Wiseco pistons. Replace the wrist pin bearing while you’re in there. If you have a shop take care of the cylinder they can order up the right piston size for you at the same time. I wish the niche worked out for me since it was so cheap but it’s the only top end kit that’s ever screwed me. I also wish Athena made a stock bore kit :(

[@mikecal516]

Garage Addiction the guy before me that had it said it’s fully stock never been open and has 50 hours on full motor. I heard vertex is good and I usually run weisco in my 4 strokes but a lot of people said don’t run it in 2 strokes for some reason. The only thing that I’m worried about is the pins feel like they’re heard to take off and put on and the piston 😅 i just don’t wanna bring it to a shop and they charge top dollar. One shop told me it will be prob like 350$ tops for labor and parts but idk if that’s a good deal or not

[@GarageAddiction]

No pins to remove but there are a couple circlips that love to shoot across the shop. I may be getting my engines mixed at this point but there’s only one ring with the proX and a locating pin on the piston, way easier to get into the cylinder than a 4 stroke. Once the piston is in it’s all torquing bolts and reassembly from there. I paid about $190 for a shop to clean up my cylinder and head and get the piston, bearing, ring, circlip, and top end gasket kit. I didn’t need a replate but if I did I’d expect to be closer to $250 not installed.

[@mikecal516]

Garage Addiction hmm okay, I’ll deff look into it when my top end is basically fully done. It’s deff low on compression but still starts up first kick everytime no problem and has all the power still. But I wanna learn to do a top end on a 2 stroke so I can save a few hundred lol

[@GarageAddiction]

I wouldn’t wait too long, depending on how damaged the top end gets when it lets go you might be sourcing a new cylinder and head!

[@NelsonCreekCustoms]

Looks like you forgot the cylinder dial pins

[@GarageAddiction]

That is an excellent point. I didn’t see the dowels on a rewatch. They may have been on my stock cylinder at the time... luckily the stock top end is back on with dowels (although now I’m questioning that)

[@NelsonCreekCustoms]

Garage Addiction mistakes happen man just learn from them. Great helpful video other then that miss

[@wadesoutdoors1914]

So all you need to rebuild one is clutch holding tool , press , crank puller . And some sockets , pliers . Ext

[@GarageAddiction]

Pretty much, a case splitter, crank puller, flywheel puller, clutch holding tool, sockets, circlip pliars, and hand tools should do you. You can get away without a press, the dies and a hammer will get bearings in if you throw them in the freezer.

[@wufijs7507]

how did you fix the head gasket problem? the oem o rings are too thin and the keep blowing out, even with liquid gasket maker, ive already ran through like 6 kits of top end gaskets

[@GarageAddiction]

The oem rings never gave me any trouble, you may have a slightly warped head. a straight edge might show you if it's warped at all. A machine shop or old school bike shop can clean it up for you if it is. These aftermarket fat rings that came with the niche kit were garbage and made a huge mess of the engine.

[@maickoltejada3742]

Una nueva cuanto cuesta

[@GarageAddiction]

I think I bought the niche for $100 which was a red flag. For a shop to salvage a stock cylinder, head, order a new piston and gasket kit it's about $300-400 depending on the damage. I'd go that route over the cheap kit, I spent a good 2 days trying to track down the problems with this kit before finding all my coolant in the bottom end.

[@1200s-e8n]

100.00 de Amazon

[@chrisvandagriff]

What year??????

[@GarageAddiction]

2002 here, the majority of them are basically the same

[@chrisvandagriff]

@@GarageAddiction THATS THE PROBLEM!! NO THEY ARE NOT!!! 2019 HAS A POWER VALVE!!! THERE AINT 1 VIDEO HERE ON THIS!!!

[@GarageAddiction]

Send it to me and I’ll pull it apart haha

[@chrisvandagriff]

@@GarageAddiction that wasn't the point. There is not one single repair service manual for a 2019 yz85 anywhere to be found on the internet. There is a difference.

[@GarageAddiction]

@@chrisvandagriff could take a chance on this one www.ebay.com/itm/265143704043?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338722076&toolid=10001

[@sergioperez7577]

Ecselente

[@sinanerat4475]

Vous avez mis le joint d'enbase à l'envers, le liquide de refroidissement ne va pas pouvoir circuler, surchauffe moteur assuré puis serrage.

[@GarageAddiction]

Ah I do see it was flipped, excellent eye! This may explain the issues I had with the kit!

[@carlmatischok2469]

I didnt half cringe when you didnt stick any 2strokw oil on piston ring and slid the piston into the barrel dry 🤦‍♂️

[@GarageAddiction]

Haha that baby was fully wet, you can see the oil pool on the piston when the cylinder is set.