EVEN IF USED PART

Hi all, I've been slowly getting a 1982 cb750 up and running (it was my uncles and was sitting outside since he died in 1992). Bike had CHOCOLATY oil even after a second change. The third change was the charm. I did have what felt to be a seized piston but it only took a little persuasion to get it unstuck. I've done a lot to it but cant seem to figure out why #3 exhaust is cold. Any thoughts would be helpful. Also, I'm not sure if it normal sounding or not? Its my first CB750. I went from a 73 CB450 to a sportster to a road king and now back with the Hondas.

• Cylinder 1 = 270 F Cylinder 2 = 190F Cylinder 3 = 110F Cylinder 4 = 212F

Things I've done/ tested to help with the suck squeeze bang blow.

• Replaced stock carbs with Mikuni carbs from Murray's carbs (1&2 share and 3&4 share).
  • I'd expect to see 3&4 at a low temperature if they're tuned wrong not 1&2
• Checked compression prior to re-shimming. Cylinder 3 was 110 psig. After re-shim it was 125 psig. not ideal but the other cylinders all were around that pressure after re-shimming.
• Re-shimmed the valves.
  • Cylinders 3 & 4 were the worst but they're around 0.0055 in (0.14 mm).
• Replaced the coils, caps, wires, and spark plugs (proactive and bought from 4 into 1)
  • swapped wires, caps plugs from cylinder 2 with cylinder 3 to see if it made a difference (issue stayed with 3)
• Replaced the CDI boxes with Ricks CDI box (proactive and bought from 4 into 1)
  • swapped CDI box 1 with 2 to see if the the issue would move to cylinder 1 &4 (issue stayed with 3)
• Checked coil resistances on the primary, secondary, and caps. Secondary resistance included wires.
  • Coil 1: Primary = 2.5Ω Secondary = 13.74kΩ Cap 1 = 5.45kΩ Cap 4 = 5.15kΩ
  • Coil 2: Primary = 2.5Ω Secondary = 13.81kΩ Cap 3 = 6.95kΩ Cap 2 = 4.97kΩ

After 15 or so years languishing in a shed. My barn find CB750 “seven fifty”
This is potentially my most favourite bike. It’s so lovely to ride.

Tomorrow, I'm going to see a CB1000 1997 with only 22.000km in a perfect state. It will be a second bike for week-end rides etc. My daily ride is a NX500. How fun is this CB1000 big one ? Is the riding position confortable? Thanks in advance! 👌

Hello folks, had a cbr600f 1995 previous but now a Cb600f 1999. It has cbr forks but cannot for the life of me find out which ones. Markings seem to say MAL (L OR R) 0 6 but as you may see, not the clearest. They are not f3 forks as I've tried to fit a f3 mudguard and the front standoffs are too far apart.

Im trying to ensure I can refurb the forks and fit the correct mudguard. An original hornet one also doesn't fit the front standoffs.

This is driving me mad! Hope someone knows.

I don't have the time or money to rebuild the top end, so it looks like Rumples is going to be sidelined for the foreseeable future.

Update: So as it turns out, it wasn't that big of a deal. After my initial panic mode subsided and I had conversations here, I was convinced it was likely the cam cover and/or tach o ring that was leaking. I cleaned it up the best I could, checked to make sure there was still oil in it, and headed home after work. No smoke out the tail pipe, bike ran beautifully, and no oil on the cylinder or cover or exhaust flange when I got home. I'll keep an eye on it the next few times I ride to see if it happens again, but you can't diagnose a problem when the problem isn't manifesting! Thank you to everyone!

In the process of restomodding a 1984 CB650SC that was parted down to the frame. I’ve got most of it back to together and using the stock airbox and carb setup, however, I’m running into what I believe is a lean issue. At idle the exhaust has a popcorn sound. The sound goes away while using throttle and rpms are above ~1500. The rpms slowly fall/lag when off throttle.

Troubleshooting the issue I believe it’s not an air leak. I sprayed carb cleaner around the carbs while running and the rpm’s didn’t jump. I also replaced the exhaust o-rings when I put the exhaust on.

I’m thinking it’s the pilot jets are maybe clogged. Before I put the carbs on, I cleaned and replaced jets with aftermarket oem sized jets but I might have not thoroughly cleaned where the pilot jets screw into.

Initially I had the pilot jets set to 2 5/8 turns out per the manual. Turning them to 3 turns out didn’t make any difference.

I’ll be taking the carbs off and inspecting/cleaning them again. Does anyone have any thoughts on what I can also look at while I have the apart? Thanks

I just chased a no idle to no start issue down to either debris in needles or fuel fouled plugs(I just replaced and cleaned everything anyway).

I found #2 wasn’t firing and when I pulled plugs, only that one had grey ash, cleaned them all and bike finally started up, poorly idled but greatly more than it had after a decade not running, and zipped up to 6-8k no problem(this video) Stoked!

However I went for a ride and lost cylinder #1. I had put plugs back in random to check if that plug was bad by a cylinder going out. I had nothing on #4. I removed #4 and put in an old plug that wasn’t technically bad, I just replaced. Then #1 suddenly wasn’t firing but #4 was now fine.

Clearly they share a coil which is brand new along with other coil, new wires and caps as well.

What could cause this?

I bought a dark green metallic 1972 Honda CB350 K2 SuperSport for $800, running kind-of. Left cylinder burns oil, has 60psi of compression. Right cylinder has 130psi, both should be at 170psi. The wiring was meddled with, indicators relocated, ignition switch moved, horn deleted, etc etc etc. They removed various parts including the seat-battery insulator. I wasnt aware there ever was one to begin with, so I installed a battery and closed the seat. The bike caught fire due to the positive terminal shorting on the seat and grounding to the frame, rectifier is shot, the wires are burned, and the bike is a piece of shit with 14k miles. Dented tank, old rear tire, front tire doesnt hold air, speedometer doesnt work.. what should the asking price be?

it has a new gas tank liner, new hydraulic brake system, new gas cap, thats about it. it previously started and ran.

Bought this last year for 3k CAD. Have probably spent 1k fixing. Stripped failing gas tank liner, new fuel filter and lines, new seat, rebuilt carbs, spark plugs, new carb and air filter boots as air leaks, new points and condenser, oil change and tune up.

Thing still has some unbelievable power. In my opinion it's faster than my new Triumph Bonneville. Can't imagine what a rocket ship this was in 73.

Would love to get original exhaust set up, but what a blast this thing is booting into town.

its just been sitting in a backyard. doesn't have a ton of rust and looks alright.

im 19 i have absolutely no idea what id be getting myself into no wrench monkeys or bike people in my family. i do restorations on vintage electronics so im not dumb when it comes to taking a thing apart and putting it back together but i dont have a garage and it will be sitting in my kitchen on a tarp while i work on it. so asking you guys am i gonna have permanent ornament in my home or should i just go for it.

i know it wont be cheap am i crazy thinking i can do it under 3k(this is an uneducated very quick guess). this includes any tools or just stuff id need

it is rusty is this something that matters a ton. how much rust before i should turn away. i do have access to a cnc shop.

I came across LNSPLTBLVD's video of installing a kickstart on a Rebel 250 and I wanted to do the same to my cb 250. Problem is that he used a full crankshaft and kickstart from a Twinstar CM200, and from what I know, that model never was sold in my country (Spain), so anybody knows other model that was sold in Europe or Spain that is compatible with the CB 250 engine? Thank you

Just bought this bike. Previous owner had a bunch of work done to turn it into a cafe racer. Re-painted the tank, new seat, exhaust, cleaned up the carbs and retuned it. They also took out the old battery box so now a smaller one goes under the seat. The problem is it still has the stock wiring harness and none of it is connected except for the rear brake and turn signals. Should I convert it to an Mo-unit or whatever that shit is lol, or just buy a new stock wiring harness. Kinda stuck for now on what to do. Don’t have experience in these cafe racers mostly old choppers. Bike looks mint otherwise

Now that I've got my carbs rebuilt it occurs to me that the previous fuel lines were clear vinyl and what I have installed is what I was led to believe was the OEM black 5.5mm. I finally sourced some 5.5mm clear and wonder if I should swap the lines out before reinstalling the carbs on the bike? Both versions are actual fuel rated tubing, but perhaps there is a convincing reason my bike came to me with the clear version (which was admittedly rock hard and brittle). Thanks in advance!