If I had to guess. It was a chain reaction of events. First started by the lexx pipe and cdi box upgrade. More exhaust flow due to enlarged pipe and adjusted fuel map due to cdi upgrade Which in turn allowed to rev higher and floated a valve. In turn piston meets valve and boom bob's your uncle. The hole in the piston is from the valve stem giving it a little pokey pokey. Imo. I'd go back to stock. This particular machine is very robust right from factory. After market parts destroy machines at least in my experiences. For general all purpose riding, stock is the way to go. Just my opinion.
Do you think there's some of that piston in the bottom end still it would suck to go through all that trouble and have a piece of the piston get sucked up in the bottom end I think it should get a whole tear down and inspection
Watching this shows something important that I need to work on for myself: treating each task as a voyage of discovery instead of a major catastrophe. Total zen. No stress. Well done.
I have the same bike. The seller did the same thing to me…..said he was riding it and it just stopped. Told me it was the solenoid stopping it from turning over. Paid “$1,700”for it…..must be the scammers price for exploded 700’s. Hope you put out more tutorials so I know how to repair this thing. Up until your video no one has put anything online about the Honda 700xx.
Man I have quickly become addicted to your channel, this is rad ass content and the vlog style going to buy then fixing is making them all hits. Congrats 👏
Love your channel I’m a new subscriber, if I could make 1 suggestion I would bring some tools when you go look at these bikes on the get go and pull the plugs and bore scope them yourself:)
I've said it before I'll say it again. I love how calm and methodical you are. I wish I could be mire like this when I get into projects especially when unexpected problems arise. Looking forward to the 300 being finished as well. As for this I'd go big bore. You have more proof of work than almost any reseller. You should be able to get a premium for this when it's all said and done. Keep up the great work.
I like his calm too but I want to throw stuff when he repeats himself 5 different time. Roll forward back stuck on something. Starter stuck on something. Manual roll stater 3 times stuck on something. Choose top or bottom end to open up. Pull spark plug where is it hung up.
Get a boreascope and take it with you on your inspections. It's a great tool that will save you thousands and help the seller to remember what really happened to it. 🙂 It will also give you way more leverage on the amount you are willing to pay. You might have been able to get it for $900 - $1000. If they won't allow you to scope it just walk away you'll be doing yourself a favor. You will know they are hiding something!!!! Great teardown and assement back at your shop.
@@billhartsfield424 I was just going to say. Plus, if you have a hole in the piston, who knows what little bits of metal went through it and are wedged somewhere, just waiting to be dislodged by the vibrations of a running engine.
Awesome video man. Good luck with the rebuild. I'm not familiar with trx700 but I've seen that kinda damage from downshifting instead of upshifting. Engine spins to fast, valve springs can't keep up and piston makes contact with the valves. At least it's in good hands now.
No he can't figure out valve float He can't even figure out how it over revved And bent the valve breaking it off he's looking and saying stupid things like it didn't get enough oil.. every bent valve in history is from over-revving 94% of the time
Don’t forget to look in the bottom end for that little chunk that came from the hole in the piston. That could cause problems after a rebuild. Keep up the good work.
Since the valve broke, the bottom end is damaged. The connecting rod bearing for sure should get replaced. If I did this I would rebuild entire engine, probably all bearings and seals plus anything worn. The camshaft with a flat spot is beginning to fail, it should be replaced. My experience working on all different types of engines is that when there is broken metal in the engine, inside the oil it ends up in the bearings, gear teeth, anywhere oil goes. Those items likely should be replaced. Usually this guy's repairs are sound, his thoughts bottom end is ok are way off. The piston had a hole in it ... where did the metal go? The crank stopped turning ... the force or piston coming to abrupt stop .... what parts saw those extreme loads? Were they designed to take it?
When you're getting a good deal you have to assume the worst and not take seller info at face value. That usually works in your favor except for when it doesn't. When it doesn't, we get some great content and a real world idea of the risks associated with "needs work".
Dude if you're someone who knows what you're doing as you do, this is 100% worth the rebuild on one of these. Especially if you're getting any deals on parts.
Throw everything at it, big bore stage 3 , hot cams. New power commander. This is where you get your revenge on that dam turbo. Keep this quad Joe, now you have to room to run something that’s gonna be that fast.
Connecting rod stretched? Overheated wicked bad at high r's. Multiple points of failure. My theory. Definitely big bore with stage 3 hot cams. My take. Excellent video thanks for taking us along
Also check your oil reservoir in the bottom there's two screens in the hoses that go in sometimes when you replace the o-rings in it you bend those screens and you don't get oil flow to your motor you restrict it and they clog up and everybody forgets about them so you might want to check those out too the black oil reservoir canister the screens are built into the hose on the bottom
He knew that it had catastrophic failure he just wanted to unload it and hope that he could get somebody to buy it and take it without too many questions he's not an idiot even if you're not mechanically inclined you know when something don't look right like a spark plug
I think you should do a complete engine rebuild. Why? Because I am doing that same thing on my 700xx and I could use all the help and advice. LOL! I had metal shavings in the bottom section.... My cam bearing(s) failed and caused huge damage. Can't wait for the followup videos on this. Great job!
WOW that is an insane amount of carnage. Usually you see that kind of damage in a multi cylinder engine that keeps running, but a single cylinder engine normally dies before they're damaged that badly. Crazy!!
Could someone have taken it way past red line to float a valve or two so when the piston came up it hit a valve which broke causing all the damage? I like the way you do your diagnostics,you’re easy to follow!
HIs diagnostic skills are a lot to be desired, it drives me nuts😂 and I've done this for many years I don't know how many times I can watch him except for the screw-ups. And comedy.
Bummer, I would have never drove so far to pick up a bike that didn't run. Especially one where the engine was locked up. Too bad, cause it's a good lookin' bike. I didn't even know Honda made one-cylinders that big... Reminds me of the legendary two-stroke 500cc "Quadzilla" that Suzuki used to make. They were simpler, and were a bit easier to work on though. Those were wicked awesome bikes! I wish you the best of success buddy, I know you'll be able to make this one into a runner. Who knows, maybe you'll find some cheap parts and you'll ultimately break even! I wish you well, and peace out from Quebec, Cheers! :P
I think I would take the entire engine out of the frame and rebuilt it the best proper way you can. Obviously new bearings, new cylinder, new piston and rings and I would even install a new cam. Costly...yes, but than you will have a near new engine you can rely on for a long time... JMHO Thumbs Up!
I'd definitely would install with the big bore kit, somehow I would feel more justified with the rebuild.. I would definitely call the original owner up letting him know what a great guy he is..
piston hitting valve.. is usually a good idea to replace rod / bottom end too... With the force of the impact, It has more than likely affected the rod / big end bearing... So basically your looking at a FULL rebuild... Bottom end, Piston, Barrel, Head etc... I'd never take my chances and keep that bottom end in there now...
I think this machine would be worth it to do a complete rebuild. They are somewhat rare and would be great to add to a collection. Value in my area is between $7K-$8K. Even if you put several thousand into it, it's worth it.
If you're getting $7k-$8k in your area let me know where you're at. I'll send them to you all day long for $6k, you can make a nice profit and so can I!
Yeah you can look up the OEM part and see that its heat treated on the top like that so I don't think the crank overheated, guessing broken woodruff key on the flywheel or something and skipped timing.
everyone holds the throttle open , and lets the motor run against the rev limiter , that may have caused the problem , or if that part of the cdi box was bad , just a thought. Great content👍
I believe it had to do with the mapping system he put on it with the pipe. It most likely increased fuel/air mixture beyond the specs. Just my thoughts.
Build it back to Oem, also loose the "tuning" box, together with bad maintenance (old and not enough oil!) probably the cause of failure! The seller was FOS anyhow, but you'll fix it like always!
I bought my red/black xx as a left over model in '10. After 12 years ownership, it now has 38 hrs. on it. I had it vinyl wrapped before I ever rode it because I knew what boots would do to the black plastic. Shortly after, I messed up a foot and parked it for several yrs. while trying to get my foot where I could put weight on it. In the meantime, I bought a Rhino and it became my play toy while waiting to heal. Started it regularly to circulate the oil and gears. Hopefully this spring I will be back on it. From the prices you are talking about, makes me wonder what my almost new one would be worth. Great video by the way!!!
Glad to see this on your channel. I bought one in March and it's a beast. I bet it ran low on oil. I gotta add oil every few hours on mine. Fun watching you fix just about anything.
you shouldnt have to might wanna get that checked out before it ends up like his or atleast make it easier on yourself i have to fill my ltz 400 because the case it cracked so i know how it feel
@@mattsloop2736 Kerosene is probably great for carbon build up, sludge, oil, whatever soft thing you wanna erase, but I don't think it will work great on any metal pieces that might have already ended up at the bottom end.
@@mattsloop2736 Well sometimes the old ways are still the best. Sometimes the car/motorcycle isn't worth spending too much money on it until you're sure it can be saved. Look at the cool channel NoNonsenseKnewsHow, the dude often use diesel to clean or unseaze old rusty cylinder in rusted old cars he's trying to start up after decades.
I have decided that the next dirt bike or quad that I buy, I will take Joe with me, because he gets these good deals everyday. I don't know how he does it. Great Video as always Joe.
Great video Joe go for a big bore it should elevate the valve issue as common problem on this model investing in a big bore is the route I would go but get feedback of others aswell and see what works best for you have a great week mate look forward to the rebuild video 📹
People upgrade pipes and compression and all kinds of things on four-wheelers and every other kind of moter I just think they were ripping on it riding the wheels off of it and not maintaining it and maintenancing it the way you're supposed to and checking it out when you hear noises and making sure everything's okay that's why it failed you can't ride the wheels off of it and not maintenance it I know this video is old but great video and God bless
met a guy on the trail with one of these, he caught up to us asking to join in then it died on the spot and same issue with no idea why it broke. these quads just kill themselves man. total rebuild coming your way buddy. story sounds the exact same but once its running one of the coolest and meanest quads out there
If it were me, I would be splitting those cases and looking for any metal chunks. Clearly there is atleast one decent sized one in there somewhere cause of the hole in the piston. The crank rod looked like it had too much side to side movement as others have said so I would do a closer inspection of that. At a minimum given the money your going to put into it with a new head, cylinder, piston, rings, cam and chain, I would think you would atleast want to spend the little extra money for bottom end gaskets to ensure there are no metal chunks floating around down there. It would also allow you to do an inspection of the transmission while you have it split. It would really suck to put all that money into it just to discover something else was messed up that you could have taken care of cheap.
Awesome video. I always enjoy the work you do on quads. This particular one...well, it sucks how bad it is. As for me, if I'm keeping it, I go big bore kit no doubt. It sounds like you're wanting to sell it after its fixed so knowing these machines are beasts in stock form, why pay the extra money into an already expensive project?? Can't wait for part 2 and see it all come together.
Got a 3 year old Polaris 1000 xp v twin in right now, dropped valve in cylinder 2, guy kept riding. To limp it back to his trailer by then it was toast. Gonna be about a $2500 rebuild if I find everything it it needs. Even roasted fuel injection. Polaris wouldn't touch it, would slap in new engine that's it. Would be around $5500 for that. Keep up the good work. Love the dog, mine don't like the shop she just chills out front all day. Unless it's freezing.
this answer is correct. And with the after market mods grenadeing this machine, it was also run extremely hard, beat up from the street up. It's one thing riding fast, but they were raw dogging it, that's why they were modding it, so they can beat it harder.
Judging from cam and broken valve. My guess would be over tightened valves causing valve to kiss piston and wear out cam. Can't wait to see this one run. I didn't know they made a 700cc. Nice find. 👍
You would think the ride in the back of the truck would have stirred up the oil and coolant. I bet the put that crank bolt cover on with an impact. Those things don’t have to be very tight. Can’t wait to see the inside!
Loving your channel!! Watching your shows everyday lately. I’ve grown up with motorbikes so it’s great to be learning so much about the inner workings!! Thanks for sharing . Keep doing what your doing 👌Reuben from Queensland Australia
I have an 08'. I was thinking about messaging you to see if you were interested, but I live in Illinois mid state. These quads are beasts! The independent rear end definitely makes a difference in getting over stuff and uneven terrain. You fix it you're probably gonna wanna keep it!
You forgot about 4 new tires.....there goes your "break even" tally..... Bummer dude, it might end up being a keep and enjoy type thing. Ill bet it is a RIPPER though. Keep up the great work brother. I really do enjoy watching you work on these. Take care, ~Jonny5🥁
It’s so good for you to know your way around these machines and for you to be able to give it a look over and then go with your instincts on what you believe is wrong with it. It’s too bad that you can’t trust anyone when it comes to people selling stuff because when it comes to money, you can’t trust a god damn thing that comes out of a person’s mouth. People will just beat on their stuff and break it,then they’ll have the nerve to tell you that it only needs the carb cleaned or something like that. Once you get into tearing down the engine, you come across something that’s one step away from catastrophic failure!
Do you think Vinny can smell trouble? He always seems to stay away from the bad ones. That engine might be bad news for Joe, but it was amazing to see. So interesting to see the damage that a valve can do when it's bouncing around on a piston. Cool as......
Cant trust everyone especially people that dont know anything like him if my bike did that to me id be shitting bricks this guy probably did even notice until he went to go start it again
You should try to have this guy come and take this thing back and give you your money. How he could lie with such sincerity Love your videos. Love your dog.
I remember back in 2008 when the economy tanked, my local dealer had one of these in the murdered out black spec for like $3999.99...the thing was like half price. My dad almost got it he loved the independent rear suspension.
After watching the teardown, I'd say the seller drained the milkshake out of the engine and radiator. Replaced with clean fluids, to get more $. The engine probably ran low on oil, the chain tensioner is oil driven. Loss of oil pressure made the chain go loose. Jumping time a tooth, they were probably riding it hard at full throttle piston broke the valve that popped a hole in the piston. Cracked the cylinder wall. That's my guess.
Brocken valve and dropped into the sylinder causing it to not turn completely over would definitely be my guess!! Definitely a top end problem!! And yes I had a buddy of mine that blew up a 385 stroker motor that I had built and I was out of town working!! I told him to get it back to the shop!!! The first thing I did when I got off the interstate and home I went straight for the drain plug!!! Well there was definitely over a gallon of straight antifreeze come out first thing and then I new it was junk!!!
Ouch, that sucks. Hindsight, it looks like if you pulled the spark plug, you would have noticed it was mechanically re-gapped Edit: Clearly I posted this before getting to the end of the video, sorry lol
You should really invest in your own borescope and bring it along with you while checking over these ATVs. Especially if the listing says the engine is locked up or not rotating. Simple enough to pull the spark plug and see for yourself what happened internally. Even just pulling the spark plug would have been a huge red flag, and from there, you could negotiate the price down even further. Probably wouldn't hurt to do your homework before purchasing on the price of replacement parts, based on what you know from the ad. Even if it didn't need everything listed, once you found the damage you could do some quick calculations and go from there. If the seller isn't willing to let you do at least that, walk away. He definitely knew something internal had let go, why else would he mention that someone else had borescoped it before you came along? As someone else mentioned further down in the comments, I would definitely check the flywheel key during the rebuild. If it sheared, it could have very easily skipped timing.
That’s a really good thing that I’m sure not many people would think about. And super useful in his situation with buying stuff that needs work weather it’s running or not.
Check the magneti in the bottom of the engine and it work to collect all the small pieces of metal befor the oil bomb bomb the oil to the valves, other wise the dirty oil will stuck in the holes by the way to oil the valves. So the values will not be oiled. Hope that you understand the small problem my friend .😊
I myself own 2 of these monsters and absolutely love them so I would recommend go ahead and rebuild it as far as stock or big bore really that choice I would think would come from if your going to keep or flip in my area they go between 4 to 6 depending on condition
Here is what I think happened, the small coolant hose you seen at first that was leaking caused the owner to add coolant from time to time. He neglected to put coolant in on a regular basis and the head cracked causing the coolant to leak into the crank case. Due to that happening, caused the oil to lose it's lubricity and not keep the valves running smooth and lubed, in turn heating up the components in the head, also visible by the discoloration, and eventually dropping the valve causing the carnage you know see.
The good thing is you have the knowledge to repair it .The block isn't damaged and he said he wasn't going that fast when it stopped running. So I don't think your looking at major damage. Wish you the best git er done.
That port on the side you couldn't get off try using your hand impact on the jar from the hammer most times will get it loose. same with the smaller screws holding the covers on. When i take a cover off I go around and hit them with the hand impact first and loosen them to avoid marring them up. It only takes a little bit of time but saves having rounded off screws out in the open.
Sorry about not seeing this video earlier, but this happens when the rider gears down too much from high speed or too low a gear going down a hill. In any case, the valve spring can not return the valve/s fast enough for the piston and colision happens.
The big end has definitely got very hot looking at the colour of the crankshaft, they probably ran it without oil till it started to knock, put oil in it, and then the valve broke shortly after. You should really strip the bottom end, too, as there will be a chunk of piston in there somewhere. Mustie1 had a similar failure on a smaller Honda ATV, but his was the oil filter fitted the wrong way round. Hope you get it sorted.
TRX 700s need the after-market tuner, they've got a problem going lean at the high end and sharp turns. My TRX 700 was by far my favorite quad I've ever owned.
New Subscriber here! If I had to take a wild guess, there might be a deficiency in the spring tension with the factory valves. They might not have enough spring tension to place on the valve, causing them to float, especially after it's heated up. Maybe there is an aftermarket valve train assembly you can get for it.
Ive never needed to add oil to mine but i known mine since the dealer first had it and besides changing fluids and filters I have only changed from thumb throttle to twist throttle. I like bikes without after market parts on them better in my opinion they have more protective measure then trying to get more speed or power in my mind. Wish he would been more honest and dropped price to 900 for you
The amount of force it takes for a piston to break a valve like that it don't matter how it feels or how straight it looks that Rod is always going to be a little bit compromised even if you can't tell by looking at it almost never trust that rod when something like that happens because of the amount of force it takes to do that to that valve takes quite a bit that engine was definitely not at idle when that happened it was definitely at least half throttle or more most of the time when that happens specially judging by that hole in the Piston too
No valve adjustment was probable ever done in my opinion was cause for failure. I would stay with stick bore and stick cam. It’s a monster stick. No need to feed the monster. Love watching your work. I’ve learned a lot. Keep up good work. Let me know when it’s up and running might have to buy it. Butch
Love you videos. Thanks for raising the value of my 700xx I swear no one knows about these gems. I just snapped the crank in mine last night so it’s funny this just popped up on my feed. Please let us know if you find cause I’ll be searching for mine!
if you do end up going big bore, you will need to remap, so if you go that route, then you know it will be done correctly. I would weigh the cost of big vs standard bore and then check your fuel map. I think this thing was ran wide open lean for too long and damaged the valve which stated the chain reaction of doom.
I noticed the head nut next to the bad valve was really hard to release. I'm thinking, since this seems to be a common problem, I would inspect the water jacket in that area. I have seen manufacture errors like this in the past. Incomplete water passage heats up that part of the head.also check the valve breaks for porosity in the metal., I don't know how deep you want to dive but you could see if other failures are in the same production year. Could have been a bad "lot" of valves, or heads. Well it seems the law of odds caught up with ya. You have had a few easy ones lately.. 👍
Honestly, when he said he paid $2200.00? I would have said $14-1500. New tires w/removal there is $400.00 + The plastic crack shouldn't be hard to fix/epoxy. Black covers up well with paint. $1700.00 + say $1100.00 in parts= $2800.00. You can still profit $2200.00. A bike stopping after a rattle/slapping timing chain but why borascope it. It had to have been really banging. Can't wait to see the rest of the video. :)
I agree with your thought. I also came to that conclusion based on how much dirt was around the motor, and the oil color (although hard to judge based on the coolant contamination) was very black, and dirty, especially when he pulled off the oil filter cover. I’m sure that poor machine never saw an oil change or even had the level checked. Glad to see he’s rebuilding it, the machine is totally worth it. Super rare, unique, and that motor is based off the ultra reliable and powerful XR650R dirt bike.
You know if you ever get real stumped on something you can call me and I can walk you through most of that stuff, I'm a master Tech n Honda, Yamaha, Kawasaki, Suzuki, Polaris and Can AM. I like watching your vids, they are great training tools for my young apprentice mechanic/s. Gives us some down time and I can quiz them on what your doing. Great job by the way.
