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Messages - StealthDJ
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1
« on: August 30, 2022, 04:25:55 PM »
This may seem rather an odd question, but is anyone aware of an avid 750 collector who lives in Dundee?
To provide some background, I was stopped at a petrol station in Dundee while on my way up to Aberdeen a couple of months ago, and the gentleman in question, having spotted my F1 while in his car, turned round came back for a chat. Mentioned he had what sounded like an epic amount of 750 spares (including sandcast parts), gave me his number and said to give him a call if there were bits that I was after.
Typically, I managed to put his number into my phone incorrectly, so now all I have is an entry that reads 'CB750' and a mobile number that's one digit too few. Doh.
Given his enthusiasm, I figured if he was known anywhere, it'd be here, so thought it was worth a (very long) shot. Anyone got any ideas?
2
« on: July 11, 2022, 10:33:49 AM »
Sorry to raise this topic from the dead, but did you ever find a solution to this? I find myself in a similar situation on a number of points:
1. F1 750
2. Replacement plates from DS with angled slots on the 'standard' plates rather than perpendicular
3. No 'double' plain plate (that I recall seeing)
Where it differs is the the exact symptoms - the bike is rideable. And can even be held in gear with the clutch in and no need to hold the brake. However, the gear changes (downshifts especially) are so bad that false neutrals are a frequent occurrence because I can't get full throw on the gear lever. That on its own would suggest the clutch lifter needs adjusting, but a: it already is, and b: while the clutch still drags with the lever held fully in, it doesn't actually properly bite until the lever is almost completely released.
I'm fairly sure I'm going to have to take the whole lot apart again, but curious to see what I'll be wanting to look for when I do...
3
« on: July 05, 2022, 02:12:22 PM »
Thanks all.
re. the drain plugs - I guess that explains it. I left them in place in the sonic cleaner after a previous bad experience when one sheared and left me with a continuously draining float bowl until I could find a replacement. I tend to just remove the float bowl if I want to drain it.
Looks like there are some differences in the mounting plates - in mine below (throttle stop on the opposite side for a start) you can see two holes in the plate in direct line the with fuel unions. I had the idea to run both pipes through these and then link up behind the carbs before going to the fuel tap. My main concern was how close to the engine block it'd all be...
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4
« on: July 05, 2022, 09:30:12 AM »
Thanks - I'll start with the standard settings then and work from there.
And a couple of last stupid questions (they're back up on the bike, I'll stop soon, I promise!)
- How do you all route your fuel lines? To me it looks like there are two holes in the mounting plate perfectly positioned for the lines to go through and then run across the top of the inlet rubbers before linking up. Only other way I can see is to loop round underneath the carbs, or go round the end of the carbs and then underneath one inlet rubber to come up and join the fuel tap (as mine was, and it looked ugly). Main problem is that I can't find any pictures of existing setups.
- The carb rebuild kits I got (I'm not using the jets, just the needle, gaskets and float assemblies) contained a small rubber o-ring which I can't identify and I definitely haven't removed any similar ones from the carbs. Anyone hazard a guess as to where it should locate? Did wonder if it was related to the air mixture screw, but I'm not sure how that'd work, or ever be retrievable.
5
« on: July 04, 2022, 12:13:59 PM »
Good to know, thanks - I'll stick with the original F1 carbs and airbox.
On a related note, are most people running standard (105) main jets? Previous owner has told me that the reason for the 115s being fitted was because the originals ran too lean for EPA reasons and also because of the Dunstall exhaust. I've fitted a Delkevic exhaust which claims to use standard jetting and replaced all the intake rubbers which were either loose, hard as nails, or both and so feel like I should start from standard. But that said, I don't want to toast the engine, or waste time if no-one uses the 105s anyway...
(Yes, I know jetting is bike and situation specific, but a pointer to a sensible starting point would be good)
6
« on: July 01, 2022, 02:57:19 PM »
Your F2 had F1 carbs cos the F2 PD type are abysmal
Really that bad? What makes them so unpopular, out of interest? Irritatingly, I actually have *two* sets of F2 carbs - one built up, one in pieces. Guess that ruins my plan of trying to sell them... 
7
« on: July 01, 2022, 02:53:07 PM »
Plus the F2 has the godawful pd carbs that are an utter nightmare.
DO NOT fit new jets just ultrasonic all the old stuff, aftermarket brass is not always accurate
Unfortunately, I do need to replace the main jets at the very least - it's been fitted with 115s instead of the standard 105s. I'm not sure why (to compensate for an air leak, perhaps?) but I don't have the originals anymore, either way.
8
« on: July 01, 2022, 12:50:33 PM »
The F1/K carbs and F2 carbs are completely different, even the fitment is different. There is a way somewhere on the internet where you can swap F2 for K carbs but have never seen anything about the reverse. Put simply they don't fit.
Interesting - my old F2 had F1 carbs fitted (which is why I have the spare set). It did have pod filters fitted though, so that may have made the conversion easier...
9
« on: July 01, 2022, 09:52:48 AM »
So after my F1's 20 year sleep, I've decided to give the carbs some attention - new airbox and engine rubbers, new boots, new jets and seals, plus the whole lot going through the ultrasonic cleaner (multiple times - the previous owner was pretty liberal with WD40 as a 'protective agent', so they're caked in crud.)
But it occurs to me that I still have, from my previous ownership, a full set of F2 carbs and the accompanying airbox.
Is it worth me fitting the F2 setup instead? I figure its newer, and slightly more technologically advanced, not to mention not having all that exposed linkage that the F1 items do. Not sure if it'd give any power advantage, but I wouldn't complain if it did.
Or will I just end up chasing bizarre mixture problems?
10
« on: July 01, 2022, 09:44:13 AM »
Hi,
Just checked my F1 gearing for you.
Rear sprocket - 43t
Rear chain - 98 rollers (49 links)
Also I'm sure the front sprocket is still the standard size.
Hope this helps
Skoti
Thanks for checking - that's definitely quite a jump from the standard 48 rear sprocket and more than I'd have considered going otherwise. I'll have to get the calculator out and figure out the ratios... 
11
« on: June 27, 2022, 10:44:14 PM »
Previous owner fitted a smaller rear sprocket to my 1976 F1, it pulls 60mph @ 3500rpm.
It's nice and relaxed and pulls top gear fine when two up touring loaded with camping gear etc.
So yes I can recommend a smaller rear sprocket.
Hope this helps.
(Photo taken on route to Honda4Fest earlier this month)
Good to know, thanks - any idea what size sprockets / number of chain links are on it?
12
« on: June 27, 2022, 04:30:19 PM »
Hi all,
After a number of years since my last one (an F2), I’ve come into ownership of another SOHC 750, this one a 1976 F1 that had been dry stored for 20 years, but with a largely unknown history of modifications.
I’ve sorted the obvious issues - rotten exhaust, worn out clutch, seized brakes, plus a few others and last weekend did 240 miles over two days, mostly motorway work.
The thing that struck me, especially from what I remember of my F2, is that it feels very under-geared. The Delkevic exhaust isn’t exactly quiet, but 70mph (around 5k rpm) feels like I’m thrashing it, whereas my memory of the F2 is that it’d pass 100mph with relative ease. I’ve checked the drivetrain though and it’s running 18/48, which appears to be standard. Should I be taking a couple teeth off the rear sprocket, or is this normal?
Also, from the section of the trip where my wife was following me, it seems what shows as just over 60mph on the speedo is probably closer to 70. Wondering if I might have the wrong speedo/drive, or if it’s more likely that the internals are gummed and a refurb is required…
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