I have a YZ400f that has quickly become my favorite bike of all time. I have had issues with the accelerator pump but I tracked down and bought another OEM carb so I can use one for parts. gonna get that tuned up and put on hopefully this week.
They are solid bikes! I feel the same. The AC pumped must be timed precisely for it to be optimal, along with proper jetting. Just wish the 400/426 had an adjustable leak jet in the bowl. Ive tried the BK mod and it made things worse
@@frankiemarchese2978 yeah I got mine from someone who lives in a 1000ft elevation difference from me so I’m gonna reset the whole thing to stock specs as well as replacing the ap parts that I need. I’ve come to realize these original carbs are hard to come by. It’s a 98 so it’s running the gen1 fcr carb where the whole mechanism that actuates the ap is all external
@@Dirt_SerpentThats right, I know what you’re talking about. I used to have a 99 yz400f. You can probably put a newer gen carb on it with some slight mods to the manifolds/cables
@@frankiemarchese2978 that’s my next step if I can’t make one of these first gen carbs work. I know you can use an 03 yz450f carb with the matching cables, I spoke to Lectron as well and they make a carb that fits the bike as well, we’ll see how much I wanna spend though haha. Either way this bike is a monster
@@frankiemarchese2978 I did a carburettor clean on my WR so busy putting it all back together for some riding this weekend hopefully. Is the carb on the 426 fairly easy to remove or is it a case of removing half the frame?
From the bike fully assembled to the carb in my hand I can do it in under 7 minutes. I’ve done it many times, you do not need to remove any of the subframe bolts. Just need to man handle the airbox a bit
UPDATE : The 426 is at 12 hours currently and running like an absolute beast! The only thing I want to mod on it is the leak jet. I remember when I adjusted my wr450f leak jet it made a big difference
Just a question what kinda carb do you got on that thing, I have a wr426f and my carb will rev up and down by its self I’m not sure what to do any tips will help.
Thank you! Nice those are great bikes, very similar to the 426. Supermoto is the way to go. Especially if you have the roads for it. My 426 is scary fast in the dirt, can’t imagine the fun on 17” sm wheels lol
Sweet build👍 sounds like the timing chain tension is a little loose though, I had to replace mine after the second top end 🤷🏼♂️ sounds great otherwise.
Thanks 👍 That’d be strange if the tension was loose. I installed a new chain, new tensioner, and both guides all oem. The only parts I didnt replace were the valves. I did do the valve seals though 👍
did you check guides too. Or how about lapping the valves? I'm about to do the head on my 426. I'm just wondering about the shims. When I got the bike it was in parts and was missing a few shims. It also has a hot cam for the exhaust, I'm not sure if the valves are going to be okay with it (which stage the cam is). I have the part number on the cam , but I can't find the reference number anywhere on google. Any advice on shimming? Great video! Cheers!
I replaced both cam chain guides 👍 I read that it is not good to lap titanium valves so I didnt touch them. I just removed the carbon. As far as shimming I would check the clearances before taking it apart just so you know the measurements. And then you can use vernier calipers to measure the shim size if its hard to read their #’s.
My yz426 probably has about 4 hours now and I just realized I forgot to put the cam clips on. Should I put them on? Or are the cams held sufficiently in place by the cam covers.
I would definitely put them back in. That’s similar to having a dowel pin missing. Eventually something will shift imo. That’s definitely a better safe than sorry scenario. Plus that’s a relatively easy job vs it blowing up potentially.
Nice work man. Great video. I just picked up a yz426f for cheap that had the auto decomp cam fail. So I am in the process of tearing the engine down to see the damage that was done. If you don't mind me asking where did you pick up the parts for your rebuild at?
@@frankiemarchese2978 ok great. Trying to decide if I need to rebuild from scratch or just fix the cam. I'll find out in the next few weeks once my manual comes in on how much damage was done. Why did you end up doing a full rebuild?
@@mitchellferguson7098 awesome. Yeah open it up, do some surgery and figure out what it really needs. I rebuilt it basically just to freshen it up. I want to know it can go another 20+ years strong if i decide to keep it. These are great bikes so I wanted to fully revive it 💪🏼
@@mitchellferguson7098 oh yeah I played with the carb many times. Did the bk mod. Had a dsp air wing on it. Played with the needle. Factory ac pump cover r&d...none of them worked well for me. Stock carbie with a bigger pilot/main (usually 1 size) with a timed ac pump squirt is what worked best for me
I only have one written down because that was the tight one. I should have marked them all down. It was a 190 and I needed a 185. The others were around the same but I don’t remember.
Frankie what happened to the vid of you sweating in the bearings for this engine? I’m sure I watched one you did? I have mine to to I just wanted to watch easy you made it look before having a crack at it myself 🤞🏼
That was my wr450f heres the link at around 2 mins in. Keep the bearings in the oem bags in the freezer for a few hours while the cases heat up. You can obviously use a torch as well I just dont have one to heat up the cases. Let me know if you have any questions m.th-cam.com/video/r4_rhZw-e7U/w-d-xo.html
I may have made it look easy but some of the other bearings were pretty tough. The main bearings are the easiest ones to install imo. Definitely make a video of the first start too!
@@frankiemarchese2978 I am doing all the bearings in both casings I have had them anodised finished and hoping it shouldn’t cause too much of an issue 🤷🏻♂️ I cannot wait for the first start upp Frankie 🤞🏼 I will need to get the head finished after , it isn’t far away 🤗
@@frankiemarchese2978 I just bought it off A guy Yesterday, He started it on the second Kick and then First Kick every time after that. I only know it’s a 2000 Yz426f.
Ill try to describe the starting procedure the best i can through text. I had this same problem when I bought a 426 over 10 years ago when I was 15. So without the compression release lever kick the kickstart until max compression is found. You should be able to pretty much stand on the thing without it moving. From that position simultaneously pull the release lever and kick the kickstarter down ONLY a couple inches, NO more. Then let go of lever, bring the kickstarter back to the top of its position and then give it a good kick like you mean it! If it doesnt work repeat that process until it does. If it doesn’t start within 5 kicks something is off. Let me know if that helps.
If you look carefully at the video or my previous videos with this bike look carefully at the kickstarter. And of course NEVER pull that compression lever when its running
I did not have to re cut the valve seats. It costed me right around 1,100 for everything which isnt too bad for all genuine yamaha parts. I ordered from partzilla
If possible send the crank out to get rebuilt. You might need to buy an oem or hot rods connecting rod. If the cylinder needs to be replated or replaced you can send that out too or look on ebay. Try to find oem main bearings if using oem crank. Replace any bearing thats not smooth, replace all o rings in the engine and seals, clean up the combustion chamber, and seal up the cases with yamabond4
@@frankiemarchese2978 thanks this be so helpful. Also how i know i need new timing chain and guides? And do i need to rebuild the heads too where the valve are or leave them
I would get a new cam chain, guides, and even a new tensioner. Especially if you don’t know the exact hours on the bike, it can get expensive but you might as well do it right so it can last. I put new valve seals in my head just to be safe but that’s all I did because the valves were in spec. I didnt do anything with the valves or their seats I just took them out to replace the seals. If you’re clearances are way off you may need to rebuild the head im not sure on that
@@frankiemarchese2978 yeah i think i should get new cam chain and guides for it. I didnt even check the valve when i took it all apart, it could be way off. Think i will need to replace everything on this as it was in really rough condition, you think it be worth it? Was debating if i should of just part it out and buy a newer model instead of putting so much money on an old yz426 when its my first time rebuilding an engine. All the stuff i bought cost more then a good running yz426 already.
Nice job! Did you have any difficulty finding all those parts? I have a 426 I need to rebuild and I'm not sure it's worth putting the money into, it seems like it will cost quite a bit more to rebuild than a 450. Please correct me if I am wrong.
I didnt have any trouble finding the parts. 1 or 2 were back ordered but didnt take too long. I used ebay and partzilla. I did the same build on my 450 and it was about the same price
I didn’t have to do anything to my cylinder. The engine ran great before.I was just doing this for maintenance and so I can mentally know exactly how much life is on it. I just ran a flex hone through to get the cross hatch back into it.
Awsome job! 👌 The bike sounds great👏
Thank you!
I have a YZ400f that has quickly become my favorite bike of all time. I have had issues with the accelerator pump but I tracked down and bought another OEM carb so I can use one for parts. gonna get that tuned up and put on hopefully this week.
They are solid bikes! I feel the same. The AC pumped must be timed precisely for it to be optimal, along with proper jetting. Just wish the 400/426 had an adjustable leak jet in the bowl. Ive tried the BK mod and it made things worse
@@frankiemarchese2978 yeah I got mine from someone who lives in a 1000ft elevation difference from me so I’m gonna reset the whole thing to stock specs as well as replacing the ap parts that I need. I’ve come to realize these original carbs are hard to come by. It’s a 98 so it’s running the gen1 fcr carb where the whole mechanism that actuates the ap is all external
@@Dirt_SerpentThats right, I know what you’re talking about. I used to have a 99 yz400f. You can probably put a newer gen carb on it with some slight mods to the manifolds/cables
@@frankiemarchese2978 that’s my next step if I can’t make one of these first gen carbs work. I know you can use an 03 yz450f carb with the matching cables, I spoke to Lectron as well and they make a carb that fits the bike as well, we’ll see how much I wanna spend though haha. Either way this bike is a monster
That's a healthy 4 stroke. Nicely done
Thank you! In the process of wiring up the lights now
@@frankiemarchese2978 I did a carburettor clean on my WR so busy putting it all back together for some riding this weekend hopefully. Is the carb on the 426 fairly easy to remove or is it a case of removing half the frame?
From the bike fully assembled to the carb in my hand I can do it in under 7 minutes. I’ve done it many times, you do not need to remove any of the subframe bolts. Just need to man handle the airbox a bit
UPDATE : The 426 is at 12 hours currently and running like an absolute beast! The only thing I want to mod on it is the leak jet. I remember when I adjusted my wr450f leak jet it made a big difference
I just rebuilt my yz 426 from bottom up as well cheers they will be collectors Items pretty soon !
Congrats on the successful rebuild! Take care of that thing, they really are going to be known as one of the best dirt bikes ever made imo.
Bump…. Or should I say Thump!
She is still thumping strong!
Just a question what kinda carb do you got on that thing, I have a wr426f and my carb will rev up and down by its self I’m not sure what to do any tips will help.
Stock carb jetted to perfection. What jets do you have in it? Could be lean either from the jetting or possible air leak somewhere.
@@frankiemarchese2978I have an keihin fcr carburetor
Nice work bro, I have a wr400, thinking I might do a 426 suprrmoto conversion after I have some fun with it, awesome bike
Thank you! Nice those are great bikes, very similar to the 426. Supermoto is the way to go. Especially if you have the roads for it. My 426 is scary fast in the dirt, can’t imagine the fun on 17” sm wheels lol
I’m here for the 426
Sweet build👍 sounds like the timing chain tension is a little loose though, I had to replace mine after the second top end 🤷🏼♂️ sounds great otherwise.
Thanks 👍 That’d be strange if the tension was loose. I installed a new chain, new tensioner, and both guides all oem. The only parts I didnt replace were the valves. I did do the valve seals though 👍
Im going to re check the valve lash at 10 hours in
Just paid 85$ for a new oem tensioner for my 09 kx450f
@@frankiemarchese2978 right on 👍 who knows what I’m hearing 🤷🏼♂️ I watched it on my old IPhone so you know how that goes 😂
I hear ya, I actually upload all these videos from my old iphone 7 lol Its best under 720 of course. Gotta upgrade and get myself a gopro one day! Lol
Sounds awesome bro
Thank you!
did you check guides too. Or how about lapping the valves? I'm about to do the head on my 426. I'm just wondering about the shims. When I got the bike it was in parts and was missing a few shims. It also has a hot cam for the exhaust, I'm not sure if the valves are going to be okay with it (which stage the cam is). I have the part number on the cam , but I can't find the reference number anywhere on google. Any advice on shimming? Great video! Cheers!
I replaced both cam chain guides 👍 I read that it is not good to lap titanium valves so I didnt touch them. I just removed the carbon. As far as shimming I would check the clearances before taking it apart just so you know the measurements. And then you can use vernier calipers to measure the shim size if its hard to read their #’s.
My yz426 probably has about 4 hours now and I just realized I forgot to put the cam clips on. Should I put them on? Or are the cams held sufficiently in place by the cam covers.
I would definitely put them back in. That’s similar to having a dowel pin missing. Eventually something will shift imo. That’s definitely a better safe than sorry scenario. Plus that’s a relatively easy job vs it blowing up potentially.
Put more vídeos with the 426 ridding
I will be this coming spring season. Snow is all over the place here now, plus I have to buy a new gopro 👍
Nice work man. Great video. I just picked up a yz426f for cheap that had the auto decomp cam fail. So I am in the process of tearing the engine down to see the damage that was done. If you don't mind me asking where did you pick up the parts for your rebuild at?
Thanks Mitchell. I got around 95% of the parts on partzilla. I got a few on ebay as well that ended up being a bit cheaper for me.
@@frankiemarchese2978 ok great. Trying to decide if I need to rebuild from scratch or just fix the cam. I'll find out in the next few weeks once my manual comes in on how much damage was done. Why did you end up doing a full rebuild?
@@mitchellferguson7098 awesome. Yeah open it up, do some surgery and figure out what it really needs. I rebuilt it basically just to freshen it up. I want to know it can go another 20+ years strong if i decide to keep it. These are great bikes so I wanted to fully revive it 💪🏼
@@frankiemarchese2978 Great I will take it a part and take a look at it. I appreciate it man. Did you touch the carb at all?
@@mitchellferguson7098 oh yeah I played with the carb many times. Did the bk mod. Had a dsp air wing on it. Played with the needle. Factory ac pump cover r&d...none of them worked well for me. Stock carbie with a bigger pilot/main (usually 1 size) with a timed ac pump squirt is what worked best for me
Sick. How much did the rebuild cost you
About $1,200
Can you please give me the shim sizes that you got in your yz426 head exhaust and intake
I only have one written down because that was the tight one. I should have marked them all down. It was a 190 and I needed a 185. The others were around the same but I don’t remember.
Nevermind I have them written down. Both exhaust shims were 180. Intake (Left 190) (Mid 185) (Right192)
Frankie what happened to the vid of you sweating in the bearings for this engine? I’m sure I watched one you did? I have mine to to I just wanted to watch easy you made it look before having a crack at it myself 🤞🏼
That was my wr450f heres the link at around 2 mins in. Keep the bearings in the oem bags in the freezer for a few hours while the cases heat up. You can obviously use a torch as well I just dont have one to heat up the cases. Let me know if you have any questions m.th-cam.com/video/r4_rhZw-e7U/w-d-xo.html
@@frankiemarchese2978 spot on m8 thank you 👍🏻 that was the one . I might film it going together see if can make it look as easy as you did 😉
I may have made it look easy but some of the other bearings were pretty tough. The main bearings are the easiest ones to install imo. Definitely make a video of the first start too!
@@frankiemarchese2978 I am doing all the bearings in both casings I have had them anodised finished and hoping it shouldn’t cause too much of an issue 🤷🏻♂️ I cannot wait for the first start upp Frankie 🤞🏼 I will need to get the head finished after , it isn’t far away 🤗
Sweet! Have fun with the build 💪🏼
how much did all the new parts cost all together
Around 1,200. All genuine oem parts. I used ebay, partzilla, and bikebandit.
What exhaust is that? I have been looking for a period correct exhaust but can't find one.
Its a full big gun race series exhaust which was on the bike when I bought it. Sounds insane when on the pipe
@@frankiemarchese2978 cool af man
@@frankiemarchese2978 thanks
@@USER-pv2gj thanks. My advice would be to keep looking on ebay every now and then. Hopefully one day a nice system pops up on there
White brothers (e-series I think?) were very popular for this bike back in the day. The stock exhaust sounds great as well .
Can you help ? I’ve been trying to start my 426 and I just can’t get it to start.
Yeah give me a little info on it. What year? Have you opened the carb? If so what are the jet #’s? Ever check the valve clearance?
@@frankiemarchese2978 I just bought it off A guy Yesterday, He started it on the second Kick and then First Kick every time after that. I only know it’s a 2000 Yz426f.
Ill try to describe the starting procedure the best i can through text. I had this same problem when I bought a 426 over 10 years ago when I was 15.
So without the compression release lever kick the kickstart until max compression is found. You should be able to pretty much stand on the thing without it moving. From that position simultaneously pull the release lever and kick the kickstarter down ONLY a couple inches, NO more. Then let go of lever, bring the kickstarter back to the top of its position and then give it a good kick like you mean it! If it doesnt work repeat that process until it does. If it doesn’t start within 5 kicks something is off. Let me know if that helps.
If you look carefully at the video or my previous videos with this bike look carefully at the kickstarter. And of course NEVER pull that compression lever when its running
@@frankiemarchese2978 I’ve been trying and I just can’t I know the Bike Is in good Conditions cause the guy I bought it off Started it like nothing.
thats dope im thinking about rebuilding mines how much was all the oem parts ? did you have to recut the valve seats ?
I did not have to re cut the valve seats. It costed me right around 1,100 for everything which isnt too bad for all genuine yamaha parts. I ordered from partzilla
Hey mate I have a 426 as well just wondering how much did it cost for all the parts for a complete rebuild cheers
Around $1,100. All oem yamaha parts. Crank, piston, valve guides, cam chain, cam tensioner, cam chain guides, all bearings/orings/seals, many bolts & lock washers, rebuilt water pump also.
Going to attemp my first ever dirtbike rebuild and it happens to be a 426. I need new cranks and pistons. Any advice ?
If possible send the crank out to get rebuilt. You might need to buy an oem or hot rods connecting rod. If the cylinder needs to be replated or replaced you can send that out too or look on ebay. Try to find oem main bearings if using oem crank. Replace any bearing thats not smooth, replace all o rings in the engine and seals, clean up the combustion chamber, and seal up the cases with yamabond4
@@frankiemarchese2978 thanks this be so helpful. Also how i know i need new timing chain and guides? And do i need to rebuild the heads too where the valve are or leave them
I would get a new cam chain, guides, and even a new tensioner. Especially if you don’t know the exact hours on the bike, it can get expensive but you might as well do it right so it can last. I put new valve seals in my head just to be safe but that’s all I did because the valves were in spec. I didnt do anything with the valves or their seats I just took them out to replace the seals. If you’re clearances are way off you may need to rebuild the head im not sure on that
I did the valve seals in this video so hopefully that helps
@@frankiemarchese2978 yeah i think i should get new cam chain and guides for it. I didnt even check the valve when i took it all apart, it could be way off. Think i will need to replace everything on this as it was in really rough condition, you think it be worth it? Was debating if i should of just part it out and buy a newer model instead of putting so much money on an old yz426 when its my first time rebuilding an engine. All the stuff i bought cost more then a good running yz426 already.
Nice job! Did you have any difficulty finding all those parts? I have a 426 I need to rebuild and I'm not sure it's worth putting the money into, it seems like it will cost quite a bit more to rebuild than a 450. Please correct me if I am wrong.
I didnt have any trouble finding the parts. 1 or 2 were back ordered but didnt take too long. I used ebay and partzilla. I did the same build on my 450 and it was about the same price
@@frankiemarchese2978 awesome. Great to hear. If you don't mind me asking, how much did the full rebuild cost?
Around $1,200. I did all labor myself. That’s including oem crank, piston, all bearings/o-rings/seals/guides/top end minus the valves.
I didn’t have to do anything to my cylinder. The engine ran great before.I was just doing this for maintenance and so I can mentally know exactly how much life is on it. I just ran a flex hone through to get the cross hatch back into it.
@@frankiemarchese2978 thanks!
Not how you put the head on the rings 🤦♂️
That’s how i’ve always done them. I don’t have a ring compressor and don’t see the need if this works. How do you do it?