Most excellent. For no spark, start running through the ignition from the plugs back which means check the resistor caps. The F model I helped get running recently had just that problem after sitting since the 80s. The resistor caps showed infinity on the meter. A quick change with a new set of caps and it fired up. Your starter button issue could be the neutral switch. Did you have it in neutral with the clutch pulled in when you started it up?And as far as the frame/motor ID, they never matched on Hondas. That motor number (CB750E) tells you that is a facelift model. E for European because Honda added Euro features. By those carbs, that looks like a 77 or 78. I'm not going to lie. Those carbs are a bitch to get clean because of the accelerator pump circuit. Once they're right, they're awesome. Also airbox for that year is only for that year. It has a notch for the choke that other years don't have.I hope you guys have fun with this one. I still love the 750s, even though I turned mine into a chopper.
Thanks Irk for jumping right in!Had bad sparc too on my XS750 project,ended up switching out caps,cables and ignition box.Is there a way to measure the plug caps (you stated showing infinity) with a multimeter?if yes hwo doI need to set the mulitmeter up?thanks!
Pull the caps off the wires, put one lead in the wire end and the other lead in the spark plug end. Set the meter to 1k ohms. For a 76 or later, they should read 10k ohms or less than 11k. Any more than that and the caps are burned out. Pre-76 will be 7.5k ohms and are burned out at 9.5k ohms. You can get replacement NGK resistor caps at 5k ohms and improve spark. It's not a bad idea to do it regardless.
Just cleaning the main and idle jets doesn't usually work on these carbs. PD carbs are unique in a lot of ways. The biggest issue with these carbs is the accelerator pump circuit. It's prone to clogging when left stored for too long, and it's vital to the performance of this motor. You can try to spray through the circuit with carb cleaner, and if you're lucky, it will work. But you need to get full spray on all for carbs coming from the pump nozzles. The tendency is for #2, which is where the pump is located, to clear and the fluid just stream through that circuit. The pump circuit is the rubber tubes that run between each carb.
You can do it. It's more a pain in the ass then it is complicated. Check the pump circuit first. I may not be that bad. That said, paying someone $150 to rebuild these carbs for you might be worth it.
Is there someone in the forum that offers this service?Do you have recommendations?
Well, yes there is. With regards to no spark: clean the points and then follow the procedures. Checking plug caps, put the multimeter in resistance mode and set it to 20k. Caps should be around 5k. (Don't worry if they show 4000 or 6000, that's just down to the inaccuracy of cheap multimeters, as long as it shows some resistance, you're most likely fine.)'77 750 shouldn't have a clutch or neutral switch cut-out switch.Be aware that the exhaust, if polished up, might be quite sought after. If reasonably rust-free as only the early versions are available as replicas.
I don’t know the nuances of a police spec 7fitty, but you normally need to have the bike in neutral with the clutch engaged to get the starter to turn as der_ nanno said. You still get power to the coils, so that can be checked with a meter. I swapped out for a different solenoid to bypass my safety switches, but you can also install a jumper. I’m not sure how the police version would’ve done it.Sent from my iPhone using DO THE TON
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Topic: Honda "l'arancio dolce" CB 750 Resto-Mod Project (Read 2506 times)
