engine

Hi 😊 to all I own a cb750 k Dohc 1981, I have had this bike for two years and it is really a great ride when it runs. The latest fix was regulator stator and rotor to sort the charging system. Now poor spark number 4 but great on number one also number 3 intermittent. When bike warm #1&2...

'79 750 has a very small oil leak. Looks like pan gasket. Is it possible to drain the oil before storage WITHOUT re-filling with oil until Spring next year? Thanks

I'm posting here to see if anyone has tips in helping me figure out my issue. So my Cylinder 1 plug keeps fouling after a short period of time, I can hear my motor pinging then the plug will foul. No oil or wetness on the plug when I pull it, just a lot of black carbon build up preventing...

My 1979 750f dohc slipped the timing chain and I believe I have it correctly timed but it won't fire even though I know I have spark and I have sprayed starting fluid directly into the cylinder while cranking it. I saw the following advice in another thread and I would like someone to help me...

The timing chain on my 79 750f must have slipped. I have retimed it, but it won't start so I will do a compression test but I'm almost certain there must have been damaged to the valves. I have spark and fuel but it will not fire. So I am wanting to remove the head in order to do a valve job...

(I have only moderate repairing skills and limited tools) I was riding my 1979 CB750F when it suddenly shut down with some rattling noise toward the front of the engine indicating what I thought was a broken timing chain. The engine would crank and seemed to have similar compression as before...

My 82 supersport struggles to turnover, I have replaced the battery, battery cables, checked and double checked all connections. I hooked the battery straight to the starter all with the same results. The engine will turn over fast if the spark plugs are removed. I have checked the compression...

Good morning, on my 72 had to replace the clutch a couple years back and had no problem, everything worked fine bike has sat for a while started it off and on but not riding it, noticed my clutch was not working correctly and decided to investigate. I pulled the cover off and noticed little...

80 cb 750 C , do I have to take sidestand off to get pipes to line up...have 4 into 4

This post is important for owners that are not getting the best performance for their cb750. And the ignition system is a make or break system that will shorten engine life and increased parts and labor. One thing for sure is the replacement points and condenser for these older classics are or...

The other day I needed to change my oil for my 1978 Honda cb750k. So I headed to the local Walmart to get some Castrol GTX 20-50w, when taking my quarts of oil I noticed that ist had a new label that stated it was Castrol vintage 20-50w with added zinc for less friction. I ran this grade in...

Hello everyone, I need to replace the starter cover and alternator cover gaskets on my 76 cb750f and I was curious if I put the bike on the center stand and take the cover off, how much oil if any will come out? This isn't a job I need to drain the oil for is it? I tried my best to find the...

Hello everyone, I need to replace the alternator gasket on my 76 cb750f and I was curious if I put the bike on the center stand and take the cover off, how much oil if any will come out? This isn't a job I need to drain the oil for is it? I tried my best to find the answer myself, but no luck...

Hello everyone, I'm in the process of rebuilding the engine and I found that one of my pistons has a little scratch/edge on it. I can clearly feel it with my fingers and it pokes out a bit. I'm wondering if I need a new piston entirely. Weird thing is the cylinder/sleeve isn't damaged at all...

Hello everyone, I'm in the process of rebuilding my first engine and was wondering how you guys remove the carbon build up on/around the valves ( if its even necessary to remove all of it ). I don't want to be too rough as I know these parts are delicate for clearances, especially around the...

Hello I have a restored Honda CB 750 Custom from 1981. The motorcycle has undergone a major renovation. Chains with tensioners, pistone rings, valve seals, pans and bushings have been replaced in the engine. The problem is that when I start the motorcycle on the choke, even on warm days, for...

Pulled apart the bottom end of the engine due to the crank chain breaking inside the motor. Crankshaft is missing a tooth on the gear. Can this be seperated and replaced or am I better off buying a whole new crank? Any suggestions on cranks if so? Used vs. New?

I am doing a complete engine rebuild for a 1981 CB750 Custom. The original motor timing chain broke. I tore the original engine down to do a rebuild and bought another for parts in case. I noticed that under the gasket on the crank case around the pistons is some tooling or dent from the...

Hi all, I am new to this group, but not to the CB750C, or to Honda. I got my first bike about 30 years ago, and about 20 years ago my first CB750C, an '81. I've been riding an '84 V65 Magna now for the last 10 years and love it! Back to the 750 though. I gave it to my son, (who also rides an...

Hey Guys, Did a cold compression check on my 77 last night. The bike has been sitting for approx 3 years. Numbers for the cylinders were Cyl 1 -127 Cyl 2- 126 Cyl 3 -125 Cyl 4- 126 Im pretty happy with those numbers and expect them to go up after a couple riding sessions. Question I have...

Please help. I just got a 76 CB750E motor in a Ridged frame w/ springer front in the guy I bought it from clearly stated it runs. but runs like crap if the battery is low. but nothing else is wrong. well I bought it knowing it could possibly be a untrue. just needed something to help me get back...

I have a 1978 Honda CB750K. When I was idling the bike, the camshaft drive chain sounded like it was loose and hitting something. The Cam chain tensioner had already been completely tightened and the sound persisted. I pulled the engine and took a look at the Cam drive to find that that the...

Hi all, just aquired another rough cb 750 sohc .don't think the frame and engine are a factory pairing ? ENGINE No CB750E 1113550 FRAME No 2224478 . Was imported into the uk in mid 1990s ,not sure if it came from the usa or europe ?. any help on the id and origin of the bike would be...

Hello everyone! I am a long time lurker, and finally got around to joining. I have used these forums for help over the last couple of years, but needed a more specific answer this time. So, a few years back I decided that my back had finally decided that sport bikes were no longer an...

not alot of aftermarket exhaust options for the nighthawk dohc 650 ive done some research but some say its the same as the cb500 exhaust and some say the cb750 exhaust will fit will all DOHC models fit? Looking for a 4-1 exhaust

Hey Guys, I finally got around and started the valve clearance job. But here comes a vague situation. I got a micrometer and also a feeler gauge. When i measure the feeler gauge with the micrometer it gets to the appropriate measurement( so 0,05mm is 0,05mm+-0,01mm) I started measuring my...

Greetings! Just rescued this "beauty" from leaning against a shed for 21 years... My first DOHC. Just sold a 72 SOHC chopper. Anyway ... Looking at exhaust and would like to know if ~ 78 SOHC exhaust would flange up to this 79.... The "78" exhaust im looking at buying.... looks...

OK, after getting a grounding issue and buying a decent set of jumper cables, I was able to do the compression test on my newly acquired 79 CB750L. Figured I'd move this over to the engine forum since electrical issues are sorted. After seeing the compression test results, I'm wondering if I...

I have 2 broken fins on the cylinder block of my 1973 cb750. I don't have the pieces, otherwise I would weld them back on myself. Should I find a new cylinder or is it safe running it with 2 broken off corners?

Hello, just brought home a 79 CB750L project. Bike is partially together and was able to get it running with some jumper cables and starter fluid at the previous owners place before making the purchase. Once i got it home, i tried again as i wanted to do a compression test. Yeah, i know, should...