Winter 18-19 project rat bike "the Rocket"

Sounds like you had a Great time, Biker meet and greets are always a hoot .

As for the choke, I assume you verified the choke plate is Actually there and is moving Freely thru the entire range of motion from stop to stop?

Assuming the choke plate and linkage is correct The next thing would be a vacuum leak and considering the bikes history i would suspect ALL of the Rubber vacuum connections and hoses especially where they interact with the carb/'s.

In the past when cash was tight Ive used a pure silicon plumbers grease to lightly coat the rubber lines and O-rings. This grease permeates the rubber which helps revive the material and temporarily "plugs" any small leaks good enough to diagnose the problem section plus it leaves the treated surfaces looking much better then they were. Its cheap and has saved me a bit of time more then once when hunting down the source of the problem.
You could also lightly spary some water on the vacuum system, lines and around the carb mounts with the bike running and choke on to diagnose a vacuum leak if you prefer that route. Either way you go I wish you luck and will be waiting to read what the problem was.
 
A real fine group with all sorts of old bikes. Also an obvious assembly of characters.

Already have Dow Corning High Vacuum Grease on the isolators. I'll be checking with propane or MAP soon for a leak. The choke plates move through full range - the problem is more likely that I wasn't able to get the choke operation to provide "fast idle" on any of the three times that I had the carbs off. May have to make it four times off and perform some surgery. The arm on the choke mechanism is suppised to contact one on the throttle to give fast idle at 1/4 choke and up. Mine just doesn't do it.
 
I would have a hard time leaving the tank like that.
These bikes weren’t known for their handling characteristics.
I had a 1977 and a 1979 CB 750. I loved the sound!
My 1980 Yamaha XS1100 Special was a beauty.
From what I understand, you can get all the parts you need from Honda. Just need a wheel barrow full of money.
Is this still true?
Looks like you have enjoyed the project.
Thanks for sharing your journey.
 
I was fortunate to have a '72 CB 750, in great shape, from my girlfriend's brother for a grand. Lots o fun.
Also had a '67 Kawi A1SS and a '75 H1
And I can't forget the '59 Vespa! Used to sieze it up regularly LOL
 
markba633csi said:
I was fortunate to have a '72 CB 750, in great shape, from my girlfriend's brother for a grand. Lots o fun.
Also had a '67 Kawi A1SS and a '75 H1
And I can't forget the '59 Vespa! Used to sieze it up regularly LOL
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I think i had a bike built from all of those bikes at one point in my life, lol, a real Frankenstein!
 
Many of that era Japanese bikes had that optimistic speedometers. Most guys in my area would live with it or go up or down (depending on the error) 1 size on the front tire to get the reading a little closer to real. The CB 750F DOHC are excellent engines!
 
I like the dual CB 750 graft creations they used to make. I think someone even did a quad for racing- four engines, one bike, several pall-bearers
 
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I have a cheap digital tach coming in today. That should give me a better idea of RPM than the old mechanical. I guess I could also try it with an old GL1000 mechanical tach that I have, but with the digital I can have both at the same time and do a calibration comparison. I have the numbers for RPM to speed for this bike, but need accurate RPM. I know that Honda regularly had (even on my 2006 GL1800) 5 - 7% optomistic speedometers, but this may be as bad as 20%. This week I'll pace the wife in her Equinox (speedometer matches with the GPS) and check at 45, 55, and 65 mph.

Meanwhile, it's running great, but I need to pull the carbs one more time to adjust the fast idle lever because I'm not getting any fast idle with choke. It's a problem that I recognised when they were off, but just didn't address. Not a big problem, but without the fast idle requires idle stop adjustment as it warms up each time.

With three bikes in a small garage along with workbench full of tools (and crap) on two walls, furnace, washer and dryer, storage shelves - requires a lot of shuffling to get things accessable. Have had nine inquiries on the 750 last week as the weather is getting nice. When I sell it, I will have a lot better access to my mini lathe, mini mill, drill press, grinder, welder, etc.
 
Well, it sold last week for what I had invested in it. So, that paid the cost of my winter entertainment. Showing the GL1000 this season and enjoying thst. Planning to do a '79 GL1000 restore next.
 
Last week I picked up a parts donor for the '79 GL1000 project. Don't have the primary restore candidate yet, but I've learned patience for that.
 
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