SquidHunter
Been Around the Block
My name is Brad, and I’m not afraid to admit: I don’t know squat about motorcycles. I’ve always loved them though. A few years ago the opportunity to scoop up a 1980 Cb750f came up, and I jumped on it. It was cheap. It only had 10,000 miles on it, it ran, and it was all there.
The exhaust was rotted out, so I swapped for 4 into 1. The bike was running lean, so I rejet the carbs and tuned it up to the point I thought it was good or at least the idle was good, and it pulled through the rpms. Still has the stock airbox, so it wasn’t a big deal. I went from 68/98 to 75/102, and swapped the worn rubber bits: the air cutoffs etc. It ran good, so I rode it ALOT. I’ve put 20,000 more miles on it over the past few years.
Since then I’ve learned a lot. I’m not even close to an expert, but I’ve been fortunate enough to meet a couple people who would actually hand down some real knowledge. Not much but some.
I’ve kept the bike stock the whole time, but I’ve been through it. Especially in preparation for my last trip. All this time I’ve kept the jets the same on the carbs, even though I’ve cleaned them a few times. The bike has been through some charging issues (typical). I’ve had to clean and seal the tank. I’ve changed the tires and shocks, and fork seals. All the typical maintenance items I’ve learned: checking the valves and compression, and using a multimeter to check the charging system.
On my trip the electrical system finally showed its true colors. I got caught in heavy rain and broke down about 30 miles from home.
Since then I’ve learned more. I’ve decided on doing a bit of a resto-mod, or more of a sleeper. Since the bike was down, and money had to be spent anyway, I went with upgrades instead of replacements. I started with the charging system, then the ignition system, and with some help I wired the bike up myself (until I can afford a m-unit replacement).
I’ve now rebuilt the carbs on a level that I haven’t before. I used a heated ultra sonic and the whole deal. Put the carbs on and the bike fired right up. When dialing them in, I realized they weren’t right. I pulled them and cleaned them again (this time adjusted everything right). When I put them back on the bike I can’t get it to run (I know).
Everything checks out, and I’ve narrowed it down to two possibilities (in my mind): either the plugs magically fowled or now the bike is way to rich due to my previous tuning attempt. Maybe now that the carbs have been properly cleaned 75/102 is too big? I’ve been told that simply adding 4 into 1 exhaust doesn’t justify a rejet by someone extremely knowledgeable about cb750s. But I also know each bike has its own personality. Either way, it ran when the carbs were wrong and it won’t when they are right (excluding the jetting).
The whole purpose, for this excruciating long post, is I’m hoping to meet some guys or girls who are willing to help me out. I know newbies may annoy some, and some are here just to show off. I get that, and most have earned it. But the internet and shop manual will only take me so far. I’ve posted some phots of my bike, and I’m absolutely in love with it and want to make the most out of it. Any help and information would be greatly appreciated
Sent from my iPhone using DO THE TON
The exhaust was rotted out, so I swapped for 4 into 1. The bike was running lean, so I rejet the carbs and tuned it up to the point I thought it was good or at least the idle was good, and it pulled through the rpms. Still has the stock airbox, so it wasn’t a big deal. I went from 68/98 to 75/102, and swapped the worn rubber bits: the air cutoffs etc. It ran good, so I rode it ALOT. I’ve put 20,000 more miles on it over the past few years.
Since then I’ve learned a lot. I’m not even close to an expert, but I’ve been fortunate enough to meet a couple people who would actually hand down some real knowledge. Not much but some.
I’ve kept the bike stock the whole time, but I’ve been through it. Especially in preparation for my last trip. All this time I’ve kept the jets the same on the carbs, even though I’ve cleaned them a few times. The bike has been through some charging issues (typical). I’ve had to clean and seal the tank. I’ve changed the tires and shocks, and fork seals. All the typical maintenance items I’ve learned: checking the valves and compression, and using a multimeter to check the charging system.
On my trip the electrical system finally showed its true colors. I got caught in heavy rain and broke down about 30 miles from home.
Since then I’ve learned more. I’ve decided on doing a bit of a resto-mod, or more of a sleeper. Since the bike was down, and money had to be spent anyway, I went with upgrades instead of replacements. I started with the charging system, then the ignition system, and with some help I wired the bike up myself (until I can afford a m-unit replacement).
I’ve now rebuilt the carbs on a level that I haven’t before. I used a heated ultra sonic and the whole deal. Put the carbs on and the bike fired right up. When dialing them in, I realized they weren’t right. I pulled them and cleaned them again (this time adjusted everything right). When I put them back on the bike I can’t get it to run (I know).
Everything checks out, and I’ve narrowed it down to two possibilities (in my mind): either the plugs magically fowled or now the bike is way to rich due to my previous tuning attempt. Maybe now that the carbs have been properly cleaned 75/102 is too big? I’ve been told that simply adding 4 into 1 exhaust doesn’t justify a rejet by someone extremely knowledgeable about cb750s. But I also know each bike has its own personality. Either way, it ran when the carbs were wrong and it won’t when they are right (excluding the jetting).
The whole purpose, for this excruciating long post, is I’m hoping to meet some guys or girls who are willing to help me out. I know newbies may annoy some, and some are here just to show off. I get that, and most have earned it. But the internet and shop manual will only take me so far. I’ve posted some phots of my bike, and I’m absolutely in love with it and want to make the most out of it. Any help and information would be greatly appreciated
Sent from my iPhone using DO THE TON
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