Yamaha YZ- F 450 - 5 valves cylinder head - Simply repair of tight camshaft bridge.

Repair of old motocross engine - Yamaha YZ- F 450 year 2004

[@tituskoreman1565]

Nice job! One way i found that also works pretty good is, apply some fine valve lapping compound to the camshaft, torq the cap down and 'lap' the camshaft in the head. I was amazed how nice and easy it worked out. Keep up the good work! Cheers

[@daviddanielstephenson2833]

A metalic compound is not recommended due to the carbon particles becoming embeded in the softer alloy, which remains there and is difficult to remove once embedded, scraping is the much better option.

[@yomin3mg]

I use lapping compound as well, worked amazing and very quick. I just ran 600 - 1500 grit after to smooth out.

[@5tr41ghtGuy]

This is the first fix I've watch that *I* might be able to do myself. Thanks for sharing!

[@PaulXchannel]

👍

[@NikilaMoo]

I had this problem on my yzf250. The cause was the bearing on the cam. It wouldn’t sit properly. Got a new bearing and hey presto it was fixed. Keep up the good work. Your projects are amazing 🤩

[@kylehorn09]

I knew exactly what you were going to do as soon as the bluing came out. I then kicked myself for not thinking of that before. I've done this same thing for scraping in my lathe bed and carriage ways.

[@PaulXchannel]

👍

[@thisnotmyrealname]

This series should be a 20+ minutes long. Excellent job!

[@craigguy5756]

I did that on a race bike a few years ago with Roger DeCoster and Goose looking over my shoulder and shaking thier heads. The bike went mint 👌 😁

[@blazeweaver7467]

Dude, thank you so much. I'm poor so i can't pay someone to do this crap in my 25 year old bike. It's still running because of videos like this...

[@MrTSOPKAS]

You are great teacher! Thanks that you shows us your experience !

[@dimashabunka2637]

О да, о ес , о геометрии можно забыть и никогда не вспоминать.

[@jonathonrogers9461]

You certainly know what you're doing well done 👍

[@cristianogomes5606]

Muito bom o trabalho,meus parabéns!!!!! Vc é dedicado ao que faz🧐🧐🧐

[@optimisticskeptic3126]

You are removing aluminum both from the journal and the cam. Where did this aluminum come from? Has it just been “redistributed” from one area of the journal to another? If so, are there now low spots where this aluminum came from? I’m not questioning the repair, I get that you are saving the head - not restoring it to original, I’m just curious.

[@PaulXchannel]

By reducing aluminum a new track will be created .These are minimum values.

[@U.F.O.Technology]

A good tool, sharp.

[@eatingplaydoh]

excellent as always

[@ThePurplePupUwU]

I've got a similar problem on my bike, except the cam cap is slightly warped with about 0.4mm lifted on one of the bolt locations when the 3 others are flat, do you believe that this method may be able to fix it? the intake cam is very tight and requires a bit of force with 2 fingers to spin, however if i slightly loosen the bolt in the hole that is warped up, it spins freely, i have checked the bearing which is fine, and the cam it'self doesn't seem to have damage, do you think that this method, or using lapping compound may work on my bike? for reference, its an 07' kx250f, and from what i can find, I cannot really just buy a new cam cap since it is machined attached to the head, pairing it to this specific head, could this method or lapping compound work on my bike or are there other methods you may suggest, do you think?

[@yinyangyin]

yep, brilliant clip, you understand. also like the comment below mine, i've also lapped in tight camshafts & housings. nice work. 🏴‍☠️

[@michaelgrubbs1618]

You don't like muriatic acid for that aluminum. On that cast iron?

[@arfansetyana9722]

good job mate, greetings from indonesia

[@BotjahDoesoen]

Sama dr Indonesia juga selalu menyimak

[@trialetcompagnie4481]

Nice job ❤🤙🔥🔥🔥🔥

[@user-om7gy2jm5b]

Странная технология - снимать слой алюминия в местах, где краска не стёрлась, а следовательно оставался зазор между крышкой и распредвалом... Я не понял идею этого ремонта.

[@JanASS1991]

Amazing craftmanship! Recently a mechanic damaged the cylinder head of my Husky FC 250 during changing of valve seals. Now intake shaft won’t turn. I guess a need a deburring tool now. Did You finish the surface of journals after using deburring tool? Greetings from Poland!

[@PaulXchannel]

Yes

[@JanASS1991]

@@PaulXchannel Thank You for reply. Could you please tell me what did you used for finishing? Is it possible to make with just hand tolls?

[@PaulXchannel]

Scotch Brite

[@JanASS1991]

@@PaulXchannel Thank you. I really appreciate this help.

[@jasinespinoza1026]

nice job.i have an 08 rmz250 that needs that done .how much $

[@saifuldarussalam3322]

Veri interest bro! Nice job!

[@daviddanielstephenson2833]

Hi Paul, love your videos and equipment, have you ever used a product called Plastigauge, with this tool you would be able to match the oil clearances between the good cam and the damaged cam to get the right clearance for the oil plane between the two halves of the caps?

[@dayossgarage]

Cooll..nice job

[@AC-uq5rh]

Шикарно .

[@dave_xc]

is the head aftermarket or does the yzf comes with dohc 5 valve

[@daviddanielstephenson2833]

Only on the older models, they reveted back to four valves made from titanium later on.

[@besas4513]

Well Lad, if I good see you have missing for both cam clip or half ring on bearings

[@DatBlueHusky]

hmm interesting, i thought you would need to hone out the bore

[@PaulXchannel]

This is an easy fix.

[@daviddanielstephenson2833]

Honing would not bring things back to the OEM clearances, doing it this way removes only the high spots and brings things back into balance, it is not perfect but brings back a serviceable result, otherwise it would be a new head.

[@yakman292]

Never seen such a quick method of properly fixing worn alumium how about honing a few thou then hard anodize or ceramic coat aluminum ?

[@richieschmidt6225]

What causes this camshaft to seize up, just lack of top end lubrication?

[@PaulXchannel]

Yes, not enough oil. But in this case the screws were too tight.

[@csiposmedvesajt]

God job! Why? Low oil?

[@PaulXchannel]

screws too tight

[@sociedadanonima5139]

Un capo!!!

[@giovannilocci5868]

Paul X...can i ask how much play you leave between the camshaft and the seat?

[@PaulXchannel]

Approx - 0.03mm

[@giovannilocci5868]

@@PaulXchannel thanks 👍

[@gerry343]

What caused the tight camshaft- poor machining by the manufacturer?

[@PaulXchannel]

Screws too tight

[@abdullahjan702]

Nice bro

[@barrbr8610]

We're can i get the tools that you use it...??? What the tools name that you use??

[@daviddanielstephenson2833]

Search for hand scrapers, Moore and Wright did a small set, this is the one I use from my kit, www.ebay.co.uk/itm/234471840279?hash=item36979c5a17:g:Ff4AAOSwieRiNF3P&amdata=enc%3AAQAHAAAAsCDo1m%2BhvmAmEimnY2%2Bl7MIM5Z762wQ91kJUkhEkpS%2BJBBdZtpOTyTEHX%2BSv8hGkYJp213xhtDdHWckY75o8VEk6BZryrZR%2BWTOQ31IP1prqG7qMs8sdkloLayFTQzdpbQVgKNaAGbzCS8Up7eguHR9YC7JPtTb4OCxw0IX%2BBRIRwnGbsF%2B6kNYwLNwvvTwV6ofyJc85j9H%2FvfF%2BuoMniBu4sXaqj2PH1%2Fmc5qsioTgb%7Ctkp%3ABk9SR9yz-aOKYQ

[@S3dINS]

In my opinion you used too much engineers blue. It only needs the smallest amount to find the transfer points.

[@PaulXchannel]

👀👍

[@than_vg]

too much blue actually leads to wrong conclusions...

[@PaulXchannel]

of course

[@fusemalaysia840]

this head can fitting to GY6 engine I think

[@georgbennings8540]

👏👍🤝💪

[@andreluis1850]

😃👏👏

[@buckrager4165]

Ok what caused it

[@daviddanielstephenson2833]

Cap bolts overtightened, lack of oil clearance because of this, the damage can be almost immediate.

[@anthonytyler7370]

I also did this to my wr 450 using 1200 grit sand paper and slowly polishing the surface I didn't want to use to method because I feel its a short term solution. cam shaft up and down play is only increased and valve clearance is never 100% please correct me if i am wrong paul ... also I have another way to repair this job but I am no machinist our aluminum welder again please correct me if I am wrong but is it possible to weld the aluminum and center bore

[@PaulXchannel]

this method is one of the most accurate in mechanical engineering

[@daviddanielstephenson2833]

@@PaulXchannel Spot on Paul, we used to hand scrape some our shells on the Merlin and other main Battle line engines to get the clearances perfect using Plastiguge for a level scrape across the whole bearing surface, there is no better way other than line boring.

[@redtobertshateshandles]

Someone just threw a 2nd hand cam in there.

[@matthiasschulze393]

really sketchy

[@giovannilocci5868]

hello, I'm writing from Italy, I've been following you for a while, you're very good. I want to ask you something. My kxf 450 has reworked the camshaft seats, the damage is not serious and can be repaired, according to you, brazing is better with hole restoration? or better to apply a bushing like in your video?

[@PaulXchannel]

Thanks. Busching.

[@giovannilocci5868]

@@PaulXchannel Busching??

[@PaulXchannel]

Yes

[@giovannilocci5868]

@@PaulXchannel thanks👍👍

[@varadivasile186]

Sorry but is not a professional job made here, you can use a reamer for this job and a fine grinding for the camshafts, don't forget the plastic gauge.

[@RANGOArts]

sorry, but this fix looks not professional.

[@daviddanielstephenson2833]

A good fix that will last the life of the engine thereafter.

[@rafaellastracom6411]

That´s because it is not a professional solution. It´s ridiculous really. Imagine that type of ´fix´ on a Yamaha R1. You would have to be an idiot to run it up to redline.

[@yinyangyin]

@@rafaellastracom6411 dirt bikes red line far more often than any R1 or any other sports bikes, that's a good fix & like another comment on here, it will last the bikes lifetime (providing regular oil changes are done, you'd be surprised at how many people don't), from a lifetime bike engineer. 🏴‍☠️

[@hanswurscht327]

nice botch

[@daviddanielstephenson2833]

Not a botch but an industry standard throughout history.

[@rafaellastracom6411]

@@daviddanielstephenson2833 Mr. Stephenson, with all due respect to you and the creator of this content, this technique of rectifying such damage is absolutely not acceptable. I am a mechanical engineer of over 25 years and I assure you this is not acceptable for high-speed machinery. The correct thing to do in this particular case would have been to simply replace the bridge with a new one. This type of ´repair´ will ensure failure in the not-to-distant future.

[@daviddanielstephenson2833]

@@rafaellastracom6411 It is good enough for the owner if they wanted to save money, it is a quick fix as the title mentions, this is all that matters, to repalce the bridge still would not rectify the lower half of the bearing, a new head is the best way but they come at great cost. If you are a seasoned engineer you should know that the cap and head are line bored and or matched when new and cannot be successfully swapped over, if you could buy a seperate cap you will be lucky as most are not available.

[@patersonrohan06]

No wonder they need over Hall... All the Time.... Very Badley engineering

[@beachboardfan9544]

Ehhh dont know about this one, this is definitely not best practice...

[@TheTrex600ESP]

I get you, not what i would done. But he said ,,this is a easy fix" Maybe an engine he do not care to much for, and its good enough for.

[@redtobertshateshandles]

There's more than one way to skin a cat. Scraping a bearing was the best practice at one time. Anyway , oil is great for taking up excess clearance. I love the Anally retentive repairers. Not.

[@stevendegreef93]

What happens when the engine heats up? The expanding metal could create new contactpoints where metal will transfer again, resulting in a lot of wasted time. Buy a new head. Stop wasting time.

[@PaulXchannel]

Don't worry - it works fine.

[@sircharlescv]

What a poor design. No cap bearings !

[@ilich444444]

Веду пьяных баб домой