$150 FORGOTTEN Honda CB750 | Will it Run?

that's good this dragon break working on taking the plugs out we're gonna let that one soak what's up everybody i'm john i'm isaac today on cars and cameras we are out searching for a new engine for our cross cart so our original engine a dual overhead honda dual overhead cam honda cb750 engine i punched a hole in the bottom of the oil pan it's not stuck but it's just kind of tired and old so we found on facebook another dual overhead cam honda cb750 engine for sale on a bike doesn't run no title but the price is right he only wants 250 bucks for it so uh we're pulling up to his house now and uh we will back be back with you in a second yeah here we are nice shop and it looks like he's got plenty of uh bikes i see some some honda 750 wheels so we're here checking out the cb750 um we know it doesn't run doesn't have a title uh the tank is in fuel shape but the price is right so we check to see if it spins over freely and it seems to have a hard spot somewhere so i think we're going to pick it up just as a part spike maybe we can look into it when we get home and see if it's a stuck valve it could be something simple um or a mouse on the cylinder it could be yeah it could be an obstruction in the cylinder we don't know until we until we take it home uh but this is actually a really cool shop we are at uh the rebel spirit uh custom parts motorcycle shop it's owned by zach over here and he primarily builds all kinds of custom fabrication parts for vintage motorcycles we got the 1980 cv 750 in the trailer gonna grab some dinner on the way home and i think we're gonna see if it'll run what do you think bud i have my doubts but you know i don't know i just have you ever had that feeling like something ain't gonna work yeah gto man so i just have this feeling like it might be a little bit more serious uh because i you know when i rocked that engine it just it felt pretty solid yeah and i'm thinking of a valve hanging up or something and uh i don't know i'd like to be pleasantly surprised me too well we have your borescope we can use take the spark plugs out and check uh see if we have any damage in there we can drop some coils off of well the cross card 750 and see what it'll do but uh yeah we made a new friend our buddy zach you can follow him on instagram at the rebel spirit for all of your custom uh chopper fabrication needs he has some pretty cool stuff yep um and i think we're definitely going to be using him in the future for like steel intake manifold yeah he'll build steel intake manifolds i'd like to get one of those lights yeah that would be cool make some cool tail lights as well for choppers so be sure to check them out and we'll see you at home so you don't have a great feeling about it man but let's just see what happens let's see if we can make this old cb run man there's the coils but no plug wires so we're robbing stuff off our other cb750 kind of looks like it what are you gonna do buddy what you gonna do you know what i got we got those plug wires the yellow ones oh yeah we can uh shove those in the hole wherever they're at and uh yeah we'll we'll make it work wait shove them in the hole shove them in the hole oh that hole okay yeah hey what happens if you just shove a spark a plug wire in to a spark plug hole well the compression just usually pops it out but will it light it off it probably could interesting depending on the octane fuel and all that stuff and uh yeah i bet you it could probably ignite it it wouldn't do anything really yeah just kind of blow it out yeah blow the wire out cool well hey we need to grab your boroscope man cause i know we when we were barring this thing over it seemed like it had a pretty hard spot in it yeah it did and it could be the top end could be in the cylinder it could be in the bottom end yes so we can only look at the top end that's right so let's uh see what we got buddy all right working on taking the plugs out we're gonna let that one soak all right this one's good that looks all right hey doesn't this look exactly like what we put on the cross car yes indeed this is almost a little bit nostalgic i'm honest oh boy i'm gonna let this soak some more since i unscrewed it a little bit to try to get some of that in the threads blaster into the threads yeah and uh go from there sounds good that does not feel good it's not wanting to come out like smooth at all all right horoscope looks a little rusty bud not rusty it's a carbon got a lot of carbon but there's a shiny something right you see that shiny yeah i don't know what to think about that gotta wonder a little too shiny there valve whacked it i don't know doesn't really look like it i don't know the pistons look different really yeah doesn't this one look like a flat top okay yeah okay check this one out oh man it's got like valve reliefs in it it's got a raised portion uh okay you ever heard of that before you ever heard of two different types of pistons only when someone puts the wrong piston in it is it like can you do it is it really bad yeah you can do it is it really bad yeah it can cause vibrations you know out of balance oh it makes sense yeah you know one cylinder's got more compression than the other let's try rotating spinning the engine over yeah which cover did we remove to it was that one over there i think so so we're gonna move this uh cover over here spin it over with a wrench or something so we're barring this thing over and this is exactly what ike was doing when he found that there it is yep let's see which piston's at top what is hear that loud snap that was a funny one man yeah i don't want to believe that this honda is is not worth saving man this one's at top that one's at the top this one's at top so it looks like it's the two outer ones but i can't make out uh stuck valves so what we could do is we could take the valve cover off and we can inspect and see which valve is stuck in the down position if it's hitting a valve i think it is you think it's a valve and not bottom end yeah yeah all right man i think yeah yeah wait a minute do me a favor yeah well let me see you know i should i suppose i have to check and see every pistons going up and down oh wouldn't that be something yeah pistons don't come up and down then we got problem all right that one's moving down oh what is that mark what is that mark right there see that round spot yeah right at the bottom part of the screen yeah yep is that new what the round spot yeah i don't think so that looks oddly suspicious i see two valves on that one two valves on this side are open and i see one on this one so you're saying one of the values no there's two okay there's two let's see if they close as i'm see the valves oh yeah okay let me see if i can get the valves to start to go back in the in their place okay i see one valve open over here i'm ready man all right i've got all of the valve cover bolts out thank you and uh you got a gasket that's trying to stay behind yeah yeah oh man bringing it up with the head yeah it seems to be where it wants to go right yeah this is this one i'm having to do it with this one over here man this is high tech man look look look at this that is high tech it's got the chrome all right now we've got to figure out how to get this thing out oh boy all right well we can get a good look at the cam shafts now yep all the dirt that i put on them yeah all right so let us put it into the position where it locks up oh there it is uh number two cylinder as a stuck valve but the weird thing is it's uh stuck oh it's just stuck stuck all right so since we basically have one shot to get this last spark plug out we're breaking out the heavy artillery we went to the uh the welding supply store and we got an acetylene torch yep so one of the piece of equipment i wanted for quite some time and now we have it don't have much use for it but this is the perfect use for it right here so we're gonna give it a shot we're gonna heat up the spark plug use some pb blaster on it hit it with the impact let her sit overnight later sit down tonight come back i'll heat it up again hit it with pv blaster and hit the impact tool keep your fingers crossed [Music] good morning man um how we doing well a little worried about this spark plug but uh let's uh try to get it out do the best we can and uh fingers crossed man yeah fingers crossed we have to get it out without completely ruining the threads [Music] so guys i'm just going to go ahead and say that just to cover my butt don't do this at home uh get yourself a professional to do this because uh this can go bad quick this is just like a latch last ditch effort is all it is and uh you know aluminum doesn't give you any warning when it when it decides to go it can be solid solid solid solid it's gone so we are going to put some blaster to it try to get it to soak in and uh i'm gonna hit it with an impact moment of truth yeah it's not moving is it is that a good look or a bad look i can't see your eyes just give it a second that's a good look can i touch it can i touch it can i touch it it's a little warm it's not too bad so as you can see it's still steaming a little bit still a little hot uh it didn't remove any of the threads which is good uh i'm only guessing that maybe there's some rain got in there over the years and you know got a lot of corrosion going on but it looks good man i'm i'm uh i'm happy uh it looks like the heat the torch and the uh pb blaster did its job which is good so uh i'm ready to look inside that cylinder man and see if uh see what i see inside that piston looks fine i don't see any uh any debris make sure i'm not getting this tip too hot yeah we're good so the good news is that we managed to get the spark plug removed the bad news is that last night after we cut the cameras off we had another look in the cylinders with the borescope and in the rightmost cylinder on the top of the piston there's some debris like sticking out of the top of the piston and our engine still doesn't make full rotation so the conclusion we're drawing and we're going to give you guys another look here in a minute but the conclusion we're drawing is that either part of a valve or just metal trash made its way into the cylinder somehow and um it's sticking out of the piston so when the piston comes up and hits the head that is what is blocking it from making a full rotation yep ike's got it right here oh right there in the bottom left-hand corner of the screen right there right there in the center yeah that is a piece of steel poking up is stabbed into the piston and there's enough of it poking up that it won't let the piston come all the way up in the cylinder and that's causing the crankshaft to stop and there's actually another piece too there oh there it is oh look so you can see the shiny top where it's been whacking whacking the aluminum so yeah that i bet you that's a p that piece right there you can definitely you can see it good right there that right there is probably a half an inch of steel popping up out of the piston and what it is i have no idea don't know what it's coming from it could be a piece of valve uh or it could be something that got sucked up through the uh air filter when i when i say air filter i mean lack of lack of air filter because the intake yeah you could have had something just go whoop right into the intake now that we know this there's not really a clear path forward with this project we're probably going to put it to the side and use it as a part 750 and we're going to keep our eyes open for another 750 or a 900 ideally to repower the cross cart we have the 750 that came off the cross cart it needs an oil pan and it's just pretty worn out and we already have plans for that engine too so i'd really like to find a more fresh 750 or ideally a 900 because it'll drop right in to the cross cart so this is gonna get put to the side we could go through the effort of pulling the head off removing whatever's from the top of the piston and if the head doesn't look too bad throwing it back together with new gaskets but we don't have any gaskets and we also don't know the condition of the bottom end it could be trashed so [Music] it's looking like parts right now and we're going to keep our eyes open for like i mentioned another 750 or 900 and they are getting harder to find so if more time goes by and we can't find anything we might be revisiting this project but i'm just saying a long way to say we're done here how'd the carburetors look fine i didn't see an issue any issue uh nothing missing there so i'm a little worried you know those are some pretty big pieces like they had been like huge to go through the carburetor and make it in there i mean they might have probably wrecked the vowels on the way in yeah could be if that's the case or it is valve yep i've seen the head of a valve just snap off and get jammed in there so do you want to do like a leak test we can blow into the cylinder and uh and see if it comes directly out of one of the either intake or the exhaust we could do that on track yeah we can do that i've got some compressed air here i've got the both sets of valves the intakes and the exhaust closed supposedly and i'm going to put some air in the cylinders if the valves are indeed closed this engine is going to turn over it's going to send that piston all the way down valves aren't there it's not going to move exactly so if there's a valve missing and that's what's jammed in there it's just going to blow out either the intake or the exhaust it's a good test start off slow oh it moved it moved so uh it moved to the point where the intake started to open so that's why it stopped so so something gotten sucked into the cylinder it's not a valve it's not a valve that's good right i mean yeah if we want to save the head of course there could be all kinds of other problems with the head that piece hammering on the head those pieces could have been bouncing around in the cylinder multiple times before it finally got like hammered into the piston and then wham to the head so appear something got sucked in which is crazy or it and it'd be weird it fell in while they were challenging the spark plug fell in with the spark plug because when we got this bike that spark plug was missing so what could have happened is fell in the cylinder somebody went to go crank it over and that's it that's why you don't leave holes open if only we had the teeniest tiny pair of needle nose pliers get it out get it out is there any way to do it through a spark plug hole no you're taking the head off it's taking the head off dude those are those spark plug holes are way too small to put any kind of tool in there to try to retrieve what's in there all right so the 750 passed our compression test on the one cylinder i guess we didn't do the other three so no all we did was test to make sure that the valve head was still there yeah uh and since it is then i'm thinking something either got dropped down in the cylinder because the spark plug was out and when we spun it over not us but someone else spun it over and it uh wedged or while it was doing 9 500 rpm it sucked in a piece of metal from the street doing a wheelie going down the road and locked up don't know we don't know so i guess the thing to do is to pull the engine off the frame and pull the head on this thing yep so we know we need to pull the engine off this thing just for storage purposes um so we might as well yank the head while we're at it right let's do it [Music] so we just pulled the head off and my mind is a little bit blown man so it wasn't anything in there what we saw was some carbon pieces yeah and of course now it's gone and uh what we've got is stuck valves and the pistons were coming in contact with the valves crazy man yeah i mean i'm glad we did this and just didn't put it of course we're not out of the woods yet no no we're not far from it um but i mean look how much junk is on there guys it's pretty disgusting disgusting i wouldn't have wanted to crank this thing up so what's next man are we looking at unsticking some valves let me see i want to get a rotation out of this thing that's it so it's no longer stuck it's no longer stuck i mean that's a wind right that's that's a win 30k on the old gal man yeah so uh now we need to uh service the head uh put on a new head gasket and put the thing back together yeah we might have ourselves a new cross cart engine i don't know all right guys well hey today's video is ending on a much higher note than i thought it would i'm a little bit happier now yeah we got that we got the head soaking uh we only have one valve that's like really really stuck and and it's really stuck but thyme and pb blaster and massaging is gonna take care of it right it should cool so uh we went online over lunch and ordered a gasket set so when that comes in our head should be ready to put back on and we can reassemble this engine with the intention of using it on the cross cart kind of sounds good unless we find a 900 out there yeah we're still looking for a cb-900 but this 750 i love how this is the fresh 750 compared to the other one but this 750 is likely gonna be bringing the cross cart back i can't believe that both of our big uh our big builds are down right now it's kind of sad oh it is yeah yeah anyway they both should be coming back we're still waiting on transmission for the trophy cart and uh yeah as soon as we get this gasket set in we're gonna be slapping this thing together and getting it back on the or not back but on the cross cart again so thanks for tuning in guys if you enjoyed today's episode leave it a thumbs up subscribe to cars and cameras so you can tune in for when this engine i don't need to jinx it if this engine goes on the crosscart if it fires up and stuff um yeah subscribe so you uh stay tuned on that front as well if you are enjoying what we're doing uh consider joining the cars and cameras pit crew it's our membership program and also go to our website cars cameras.com and pick up a t-shirt or a hat or a sticker pack again to help support us and our future projects you can find ike at isaac it'll be fine on youtube and instagram you can find me on instagram at john underscore cars and cameras and facebook at cars and cameras reviews for sneak peeks on what we're up to behind the scenes uh subscribe to our podcast channel at the wheel with cars and cameras uh about once every other week ike and i are going live here on youtube and just kind of talking you know about builds about go-karts mini bikes about cars in general and car news as well so subscribe to the podcast channel as well anyway thanks again for watching we'll catch you next time trying to play chopsticks [Music]

Channel: CarsandCameras

Views: 146,150

Rating: 4.9435058 out of 5

Keywords: honda cb750, will it run, honda 750 will it run, 750cc cross kart, carsandcameras 750, honda cb

Id: zQ73T219MCI

Length: 28min 42sec (1722 seconds)

Published: Mon May 03 2021