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HELP NEEDED 1981 CB750F Supersport Bobber

mayushuo

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Hi CB750 Fam!

Been reading posts on the forum for quite some time, slowly learning and getting to know these beauties. Not until recently where I jumped on a purchase did I find the need to post this. So here goes my story...

Found this 1980 CB750 up for sale in my area and snatched it up since I really loved the look. Luckily, when I re-posted this for sale (just to see what kind of offers/interest I can get), the original builder reached out and provided some more info about the bike.

So it's a

- 1980 CB750 Custom Frame (~13,000 km)
- 1981 CB750 F Engine (less than 10,000 km)
- Marlin Hardtail Conversion
- Lowbrow Customs peanut tank

However, when I picked up the bike, the previous owner had lowsided it, scuffing up the engine covers on the left. One of the UNI Pods is completed torn and broken apart. Now onto some things I am currently experiencing with the bike, given that the previous owner had it safetied and on the road in Feb 2019.

- torn, sticky, gooey UNI Pods that need replacing (There's REALLY STICKY Yellowish stuff on the pods, no idea what it is)
- the bike starter sounds really weird, and wheezes to try to start the engine
- takes a while to be able to start it, playing with the choke seems to make no difference
- when starting from cold, it only runs on 2 cylinders (the 2 on the right, so cylinders 1,and 2?), but after a while, if revved a bit, warmed a bit, or ridden for a little (1-2 kilometers), and if I restart the bike a few times, cylinders 3 and 4 pop back online.
- when starting cold, it just chugs back to silence until I keep the revs up a bit for a while
- throttle is sticky, rev it and it doesn't return, I have to manually turn it back most times.
- There's no throttle response at all, sometimes the revs match my hands actions. Sometimes when I rev the engine dies, sometimes when I rev the engine just stays put, doenst react.
- front left fork is leaking oil
- For me, I feel the front is a little twisted (most likely due to the drop), just don't know which point is the twist and which part I need to be replacing
- Battery: the battery seems to die in the bike. I took it out to recharge it, and it holds a full charge outside of the bike. But once I put it in and hook it up, after some time (a few hours - half a day), it looses charge and doesn't have enough juice to start the bike anymore. Even when I go out to ride, if I turn off a bike a few times, and try to start it on the 9-10th time near the end of the ride, I can hear the starter pulling less juice. The only reason I was able to start the bike was cause the engine was warm and didnt need too much coaxing to start.


BUT....., all things aside, this thing still roars and pulls like a train when the trottle/fuel/air mix gets right. The warmer the engine, the better she runs.

Based on the original bike builder, he had the bike running on pods fine with the stock jets (he said he didn't touch the jets). And the motor should be in amazing state, so I'm hoping 90% of my troubles above are to do with the pods and carbs not being cleaned.

So I'm a little stuck here, and here in Toronto, I have no contacts as to who's a good mechanic or guy that I should be bringing this to for a full cleanup/tuneup. I am not too mechanically inclined, but can learn if I need to from Youtube and articles. Note that my garage has VERY LIMITED tools, so sometimes the cost of getting the tools I need to work on the bike might be double that of just having someone work on some parts of it?

Here's a video link I shot of the bike after she's warm and I went out for a quick 10km ride.

https://youtu.be/IRAGZlMGVXk

And some pics for those of you wanting to see the state she's in.

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The pods wreck the performance of the engine, nobody ever gets that part. The guy doing it not realizing the power difference says much. The slides then begin to open wonky, the throttle is NOT tied to the slides at all, they open when they want to. If nobody has ever run the valves (they simply DON'T) the engine is likely burning valves right now.

The starter drive clutch has 3 bolts holding it together and they commonly come loose to drag the starter.

You've got something running the battery down.
 
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