Cheers, I've been thinking of doing an updated one for a while now but I'm glad to hear that this one is still so helpful!

Good luck and have fun with it! I've got a couple other videos about this bike on my channel you may find useful.

And yet, there/here I was/am...! Nice looking bike you've got!

Cheers to that!

Im buying two of these bikes, glad that there is some visual help out there!

You got it! Glad to hear I could hold your attention for the whole vid. I tried not to fluff it up with too much bullshitting and somehow still ended up with nearly an hour long video anyway. Oh well, the information is all there, I hope.

Absolutely. I wouldn't be as far as I am without shared knowledge and the generosity of the more experienced. Hoping to pay it forward with vids like this one.

Also: if you do other, more niche maintenance jobs on your bike, it would be super cool if you documented that on video

Thank you! Glad I could be of help to you

Good luck with your bike, I hope this helps you get it to a reliable place. Nothing like confidence in your work to make the ride that much sweeter.

@@Gumaamug Any chance we could get a list of tools that you said you set aside to figure out what you needed for your trip?

Sure thing, here's what I ended up with, including a couple of extra things that I didn't use in the video: Ratchet Small socket extension (4 inches) Sockets (mm): 8, 10, 12, 13, 14, 17, 19 Hex head sockets (mm): 3, 5 (these are for my case bolts, which I replaced with SS hex head bolts) Spark plug socket (M18) Assorted dental picks Box head wrenches (mm): 8, 10, 12, 14 Two adjustable crescent wrenches (for axle) JIS head screwdriver (better than Philips, you can look up why) Flat head screwdriver Small flat head/Philips head screwdrivers Feeler gauge set Wire strippers Vice grips Needle nose pliers Zip ties Metric allen wrench set All of this I fit in a $15 tool roll with spaces to spare. Some of it is probably overkill; I would hope to not have to remove the axle on a road trip because it means something has gone seriously wrong. But because I had the space it seemed wise to grab the extra stuff like the vice grips and wire strippers. Just in case.

Thanks for the compliment! I'm glad to have helped

I'm glad to hear it, I hope they were able to help you in some way

Thanks stevie!

Better late than never. Glad you found this helpful.

Love the backstory! The memories are the reasons we keep these lovely machines around!

It's been more than a few years since I rebuilt that engine, but my memory is that the top bolt is only connected to the mounting bracket of the tensioner inside, and the bottom bolt is connected through the bracket to the spring assembly. It wouldn't certainly wouldn't hurt to do both.

Awesome video though man, helped me learn a ton

Thanks for watching. I believe I got both the sync tool and the vacuum gauges from vintagecb750.com. The driver is part no. 35-0084 and the gauges are part no. 35-0085

What do you want to learn about?

@@Gumaamug you should do videos whenever you do something on the bike, or other bikes if you have any.

That's the plan. My other bike is a fully restored '70 CL350, but there are plenty of 350 videos to go around. The next thing this bike will need is probably a carb clean a few months from now, and I will definitely be taping it.

Great technique! I'll add it to my repertoire.

Haha that's me alright. I've got a lot of little hustles trying to add up to one normal life.

An old 900 would be cool

Hey Jack, I'm glad you find this video helpful. The sound that you're referring to is just the transmission rolling around in neutral. There is a lot of force in these engines and the primary drive is capable of turning those gears even at idle speeds. You'll notice as soon as you put the bike in gear that the sound goes away. This is because putting it in gear meshes the drive gears with your front sprocket, and if the bike is standing still then the inertia from the back wheel, transferred to the back sprocket, through the chain, and to the front sprocket stops the transmission from turning around inside the case.

@@Gumaamug ah ok thanks for the detailed answer, I was kind of terrified I had spun a bearing or something as it's been sitting a while. I'll follow your tune up video before getting it on the road. Thanks again!

Hi Edgar, you can find on my channel another video about testing the electrical system. It sounds like there's no power getting to your starter motor if the solenoid is clicking but the bike is not cranking. Definitely check your battery voltage with a meter while you have the starter button pressed. If the battery does not have over 12v with the bike off, it will not have enough juice to crank the motor. If the bike is new to you, I wouldn't be surprised if it needs a new battery. Otherwise you can check your ground connection from the battery (-) terminal, check your main 30A fuse in the solenoid. The electrical path to the starter motor is very direct from the battery through the solenoid. Good luck!

Ah damn Andre I'm sorry to hear that!! Yes like many things it seems obvious in retrospect, I'm sorry I didn't think to mention it in the vid

Hey Brad, it's the latter. You should also do this while the bike is warm-ish. Like, not after an hour long ride, but not when it's cold (because oil from the head collects back down in the crankcase). Ride it around the block a few times and then check. Cheers!

@@Gumaamug thank you!

Cheers! Make sure if you do take any shims out to swap them, do NOT rotate the cam while the shims are out. I did not mention this in the video and another commenter pointed out that he scratched up his cam doing so. It says it in the manual, it says it almost everywhere else, I just forgot to; always cross-reference info before trying something at home!

@@Gumaamug Thanks for the heads up on the shims. I will be be doing a lot of due diligence fore looking at the valves, where so far there are no overt issues. Except a leaky Valve cover where Ill check Vintage 750 for one My bike, 'Beauty' I bought new in 79. Stored her in 88 to raise my family. finally two years ago moved in retirement where having a garage to restore her. Last Summer was a great reawakening. I even got a M on my drivers license - I took a short 40 mile trip this morning. In Ct from Bridgeport area to Naugatuck and back. Earlier in the week, a trip was taken that was twice a long to Lime Rock Race Track. She holds together like a champion. Im running 10W30 but just got 10W40 to move to when learning that z70's are to have the latter. I have a Pizza Oven Gauge on my bike that read 220f once I stopped for a moment in Naugatuck . Back on the highway i got her down to 180f. I believe to 10W40 will prevent the excessive heating up. What is you opinion on that.

@@ClassicRider I know that part of the country well-- I think you'll be fine on 10W-40 and 180F sounds nice and cool to me. Leaky valve cover should be an easy fix. Congrats on getting back into it and enjoy the riding!

@@Gumaamug don't forget the gasket cement or you will have leaks around those camshaft covers -

Hey sorry I missed your question when you posted it. The engine does need to be running in order for the dynamic timing light to work. The bulb works by induction; it senses the pulse of electricity passing through the spark plug wire. If you're not seeing the hash marks while the bike is running with light attached, make sure your induction clamp is on the wire for cylinder 1 (or 4). If that is correct and you're still not seeing the hash marks, it's possible that your coils are swapped somewhere in the electric signal chain, and I imagine you would have a hard time starting the bike at all. I hope this helps. The alternative is a static timing light, but I have not used one on these bikes and cannot guide you there. Dynamic timing is always going to be better on these engines, because you do need to be able to check that the engine is advancing properly starting at ~1500 RPM and fully advanced by 3000, which you can't do statically.

Clyde, check the About page on my channel

Thanks! You can take off the circular timing plate cover while the engine is running but not the whole side cover as it does have oil behind it. By contrast, the stator on the opposite side (right hand) is a dry cover

Thank you , keep up the great content !

On the left side of the engine where the pulsers are, turn the engine so that the index marker is lined up with the line labeled "1.4 T" - this means "cylinder 1 and 4 piston is at top dead center" - with the valve cover off, both cam sprockets should have punch marks (small dots) on the actual sprockets. There are two marks per sprocket, and they should form a straight line that is even with the surface of the cylinder head. On cylinder One, the cam lobes on both cams will be pointing in, toward the spark plug for cylinder One. If they are pointing opposite directions, rotate the engine 360 degrees. If the chain is slightly loose, which is likely, these marks will be off by a little bit, which is OK. If the chain has skipped a tooth on one or the other sprocket, it should be very obvious. Boa sorte!

That seems really unlikely to me. My guess is faulty oil pressure switch, bad wiring, or low oil

Idle speed is set with the black plastic knob underneath the carbs. This knob pushes against the rod connecting all carbs, so it is important to make sure the throttle butterflies are balanced as described in this video. It is true that the tachometers are not super precise, but they are more than good enough for setting the idle. You will also learn to interpret the idle by the way it sounds. There is a sweet spot below which the bike will sound irregular and/or die, and above which will sound obviously too high.

There are two cap nuts that hold it in place; the top one does not lock/unlock the spring mechanism that the tensioner uses and it is not necessary to loosen it in order to adjust tension. In fact, you probably don't want to loosen that nut at all unless you're removing the tensioner.

I'll make sure to do one the next time I have the carbs off the bike. I learned a lot of important things to look for when I rebuilt them, fortunately for me after three attempts they are clean as a whistle and I shouldn't need to take them off until next year.

Hey David, the good news is that there is plenty of information available for you. Start by Googling up a copy of the Factory Service Manual. If you can't find one, send me an email to the address in my About page. This will give you a step-by-step on how to dismantle the engine and provide you with tolerances so you can measure all the components and see if anything is worn out beyond its tolerance. Even just reading through will give you a great conceptual foundation for doing this work on your own. It's a good thing that the engine turns over. These bikes are built very well and there are probably very few things that you will need to replace. The first thing I would do is buy a compression gauge and measure the compression on each cylinder. If you are within the specifications that the manual gives, you probably don't need to rebuild it. However, it's a lot of fun and you will learn a lot if you decide to do so. Plan on buying a full engine gasket set; I recommend the brand Vesrah which is manufactured in Japan. You will also want to buy a set of engine seals. 4into1.com is a great resource for OEM and new seals. Seals can be replaced without dismantling, and in general it's a good idea to do so. Regardless of whether compression is low, if you take the cylinders off you will need to plan on honing them and replacing the piston rings. Piston rings need to "seat" in the cylinder wall in order to make good compression, and if you remove the cylinders you basically "unseat" them. If the cylinders are badly corroded, the next step would be having a machine shop bore them out by one size (the manual will have these specifications) and you will need to seek oversize piston rings. Again, this is all contingent on a failed compression test, so don't let it freak you out. Unless the bike was thrashed in its lifetime, the lower half of the engine (transmission, clutch) is probably fine. Remember that a bike needs three things to run: fuel, spark, and compression. The fuel system comprises the gas tank, gas lines, carburetors, and rubber intake boots. Pretty easy to make sure all of these parts are clean, and it's probably in your best interest to replace the old stiff boots with new ones to avoid potential air leaks into the fuel system. Make sure you buy OEM and not aftermarket; they are more expensive but for this specific part, necessary. The spark system comprises your electrics: battery, wiring harness, ignition coils, spark plugs, spark units, regulator/rectifier, stator, rotor, pulsers, starter solenoid, starter motor. A little more complex, but you can look up all of these terms to get a clearer picture of what they do. Know that the OEM spark units on these bikes tend to go bad and a recommended replacement is the Procom PE-C-MH900-A. You can get a set for about $79, and they bolt right in, no modifications necessary. New ignition coils are not a bad idea, and the combination of these two parts will actually produce a stronger spark than the stock configuration (Dynatek DC1-1 coils is what the community recommends; whatever you go with, make sure they are 3ohm coils, and you are using the spark plugs that are spec'd by the manual). Compression relates to the engine; start with a compression test and decide from there if you need a rebuild. You can google how to test compression correctly, but on this bike since there is no kickstart you will at least need to get the starter motor working to turn over and pump the pistons for you (back to electrics). Good luck, you are not alone and almost nothing is impossible to learn how to do on your own.

@@Gumaamug dude you are a legend hahaha. I feel like I know how to do everything I need just by reading this comment alone 😂 thanks so much, I can’t wait to get going. This was way more info than I was hoping to get so thank you so much

No prob, circle back with me in an hour or two, I'm currently posting another vid about the electrical system. And stay in touch!

If I understand you correctly, your carbs still have the vacuum-activated regulator sitting on top. This is the disc-shaped valve (I think it looks like the Millennium Falcon from Star Wars) that accepts the fuel line from the tank and then feeds it into the carbs... These are notorious for being finicky and causing issues just like you described, and the good news is that the bike works just fine without it. Its only function is to stop fuel flow to the carbs when there is no vacuum, i.e. when the bike is off. You can remove it and run fuel line directly from the tank to the brass carb inlet that sticks up between carbs 1 and 2. You can put a rubber cap on the vacuum nipple that comes from carb 2. If you remove this regulator, you MUST treat the bike like an older model and turn off the fuel from the petcock whenever you're not running it. Otherwise you risk flooding the engine or dumping all your gas out through the carb overflow depending on how well your carb floats/float valves seal. This is an easy habit to get into and a small price to pay for not having to deal with this poorly designed part of the carbs.

Thanks so much for your reply, your help and your suggestions - I will follow your suggestion after one more attempt on a repaired Millennium falcon. Last night after the failure of the Ebay swap, I took apart the original. Two theories were confirmed. A- Its a vacuum controlled fuel regulator ( try finding anything about it in repair books - best of luck ) , and B- that it had ruptured. The Rubber diaphragm has a factory hole , and then a small torn hole that I figure would cause it to fail. Eventually I chose a tiny dab of hot glue to seal the rupture. I rubbed gasoline on it after to see if it would breakdown. It appears to be doing its job, but just a littler stiffer diaphragm - If this fails then I go to your solution - Per your solution you noted to make sure not to over flow the carbs when parked by turning off the petcock valve. That to me is best practice - Question - is your concern that the floats in the fuel bowls are not reliable? I will follow best practice then - Again thanks for the informative help -

Floats and needle valves are as reliable as they can be, but you'd never want to find out the hard way that something had failed by waking up to five gallons of gasoline on the garage floor. Easier to just turn the petcock off every time you park the bike.

@@Gumaamug After lunch im going with your recommendation as 1- Im not Sisyphus, and 2- My wife ( its her new 750) learned from the MSF to always turn off the petcock valve when not in use - Thanks again !

@@Gumaamug Well Babe is running , but with dirt in the carbs - Ill vinegar the tank next week, and since I can get directly into the fuel line to the carbs now, ill use some carb cleaner to see about clearing the jets out ( I hope ) . I can get up to road speeds, but almost sounds like missing a cylinder - ( in power ) Wife wanted to know if ready yet? I explained besides dead stalls ( idle jets block) , that Babe could suddenly for a second or two be under full power and then run again in the dirty mode - She waited a month for me to get it road ready and she got to use it for a week until I refilled the tank - ((*&!^%)*@&^)$&) She rides well - kzfaq.info/get/bejne/oNenjax4ta2tdac.htmlsi=T5AdFoaKGXQpbDMs

It could be a timing issue. If the cams were re-installed incorrectly (i.e. 180 degrees off) or if they are not in the correct position relative to each other (i.e. the smaller cam chain is installed on the wrong tooth of one of the cams), it could produce this symptom when you try to start. It can also be an ignition issue: if you have the two pulsars swapped somewhere in the wiring harness (check the CDI ignition boxes under the seat), meaning all cylinders are firing at the incorrect time. Or maybe spark plug leads going to the wrong cylinders: left ignition coil goes to cylinder 1,4; right ignition coil goes to 2,3. Another possibility is low compression due to worn out rings or incorrectly shimmed valves. Lots of things to check on a full rebuild, but if you go system by system you'll weed out the issue.

Thanks for the quick reply. The motor was not rebuilt, just the bike itself. I did the carburetor service. I did change the coils as the stock ones were cracked, the firing order may actually be the issue. What’s the best way to test continuity between the phasers and the coil connections?

@@tblackwell1 The old-school test would be to just pop the spark plugs out of the head and ground them against the outside of the engine block one at a time while you crank the starter. You should be able to see the spark with your naked eye.

You could try to find the brackets themselves on eBay, or yeah put a helicoil in and retap the threads. I would absolutely take the brackets OFF your cams and do this on the bench. No metal shavings in the top end allowed!!

@@Gumaamug yeah. new bracket would probably be better. thanks.

Usually every 50000 km it's time to replace them

That's pretty high mileage and I would probably replace them to be safe. Usually the best indicator is looseness in the position of the cam relative to the crank; the factory service manual has instructions on how to check that the cam and the crank are in the correct position relative to each other using a punch mark on the side of the cam and the timing hash marks on the crank. If you turn the motor with a wrench to the position indicated by the manual (usually 1+4 TDC), the punch marks on the cams may be off by a couple degrees, and that's a good indicator of cam chain looseness. The chain from cam to cam is pretty easy, you would just slide the new one on over the ends of the cams after freeing them from their brackets. The longer vertical chain from cam to crankshaft is a little more complicated and requires some special tools. You'd need to break the old chain, attach one end of the new chain to the old one with a piece of wire or something, and pull it through, down the bottom and around the crankshaft. Then use a master link and a chain tool to connect the two ends. Make sure you have the correct number of links on the new chain and that the motor doesn't turn while you do this, or your timing will be off and you could end up damaging a piston or valve. Use the same section of the FSM to double check that the cam and crank are in the correct positions relative to each other.

Can you describe it more specifically? Did the RPMs increase but the bike did not go faster? Could be as simple as clutch cable needing to be adjusted, or could be more serious like a worn out clutch. Or could be as you say a clumsy foot. Hard to tell based on your description.

@@Gumaamug I don't feel it was the clutch slipping, as was not a variable RPM like experience, and as I would need to re-shift up to the higher gear as it felt literally had shifted down as if i had done it - . Ill take her on a morning test drive for the near area tomorrow. _ The Clutch Cable Adjustment - were you suggesting more play ? Clutch seems to be quite fine as can handle low end torque from higher gears. .I have enough Horsepower and Torque that I can idle along in 5th gear in 25 mph zones quietly - Ill continue to see how she is doing tomorrow, as was hoping for a nice two or three hour trip in the county - Ill let you know what info I gather - thanks

I took her out yesterday for a two hour run with my dearest on back. No issues. Once Clutch Slipped. Only Once but under normal acceleration. I am able to drive low rpm in High gears at low speeds such as 25-30 with out slippage when adding demand in the throttle - This weekend Im going from 10W40 to 10W50 Motul Synthetic as my Pizza Oven Temp Gauge indicates a case temp of 200+ f on hot days - I figure this could affect the parts.

@@ClassicRider For what it's worth, I have always been told that synthetic motor oil will cause these types of wet clutches to slip. People on the internet have gotten outraged (surprise) when I've suggested that you should stay away from synthetic oil completely, but that's what I have done and I have never had slippage issues. Your mileage may vary. Keep me posted.

​ @Guma Ill let you know, thanks - if she slips, then Ill go old style and even try a 10W60 . I looked for issues like the after effects of additives etc. Only thing made clear is that it wont break down, and right now I can afford to hit 240f in a traffic jam in New England - Meantime I also hear how great it is. But I welcome your experience which should be accounted for. If my clutch starts to radially slip suddenly while under average demand, I will confirm it with you. And you are welcome to reference my cluster F'. I'm more concerned right now if I have to move the Long engine bolt to rotate the engine guard out of the way to look at the front left housing and possible lose parts which you have helped me with -

It's too real :(