Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: Spitfire on September 23, 2014, 09:04:00 AM
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Just spent the day cruising around North Wales, did about 146 miles of mainly A and B class roads, generally keeping to the speed limits (mainly 60 mph), the bike ended up doing 48 mpg, is this a normal figure for these bikes, in the olden days I just filled the thing up with no thought to fuel economy so I have no idea of what it used to do.
Cheers
Dennis
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It depends on the gearing.
Honda geared the F down for better acceleration, and the one I ran in the very early 1980s was a tad thirsty, like around 40-42mpg.
If you fitted a gearbox sprocket off a K6, it made a hell of a difference: more relaxed cruising and consumption of 45+mpg, depending on throttle hand. I also acquired a five-gallon alloy tank for long journeys (like down to the Bol), because the fuel range on the standard tank was poor.
So 48mpg sounds realistic if it's been geared up.
I really disliked that bike, and only kept it for a year...... I twinned the front discs, fitted Girling rear shocks, decent tyres, and in the end sold it and went through a Moto Guzzi phase....
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The bike is bog standard, just as I bought it in 1976, I must confess that it is not my favourite CB750, that title must go to my 1970 CB750, or my 1971 CB750K1 with a 900cc conversion, but it's the one that I have got and I've had it that long that I will be keeping it.
Cheers
Den
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Well if you ever decide to sell, I'm looking for an F1. My project bike has no registration, so I need one to use as the base, for registration in Spain :)
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Well I suppose you could get 48mpg out of one on stock gearing. I never had the self-restraint!
And if I'd had a bike that long I wouldn't sell it either....
I remmeber taking mine to the Bol in 1982, with a mate on the pillion. That silly knicker-elastic chain had worn slack at some point in the run down there, to the extent that it was rattling on the chainguard, and when we stopped for petrol I decided I'd adjust it. And lube it. As I spun the back wheel, I saw the spring clip had popped off, and the sideplate had fallen off as well. Eek. Amazingly, I had a spare spring link with me.
Other memories were how it didn't stop in the rain, until somebody invented sintered brake pads.... Nice engine, though.
Got an F2 now - they should have built the F1 like the F2 right from the start.
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Yes I remember the standard chains in them days, some bright spark amongst us decided that it would be a great idea to go down to Brands Hatch to watch the racing for the day (from the Wirral), I was on my K1 and on the way there we stopped for petrol and the chain looked all rusty and was kinked. I had to buy some oil and soak the chain with a rag. When we got back I bought a Reynolds 3/4" chain conversion which solved that one, I swapped the sprockets and chain to the F1 when I bought it but had to swop back when I couldn't get the chain anymore.
At the moment I am re starting my F2 project, so I will see how that one gets on.
Cheers
Den
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I was unlucky to have the chain break on my F1 in 1978. I had fitted an Izumi, I think it was called, and it was supposed to be self lube! It broke on the A47 not long after I had fitted it, it did the usual thing and wrapped itself around the front sprocket punching into the upper and lower crankcases. I used doublebond and araldite to repair the damage, after draining the sump. I fitted an o-ring endless chain after that. The bike was stolen in 1980 along with the marzochi shocks, Tomasselli clip-ons and Raask rear sets. I bought an F2 after that. But I also just filled these bikes up with no idea what miles per gallon I was getting, other than the tank range was not good on trips to the continent.
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I never went anywhere on my 500 without a spare chain link. I still have it!
Mid-40's on the 500/4 if I remember correctly.
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Maybe my bikes due a service I only get around 35mpg :o
Its returning less than my ranger
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I never went anywhere on my 500 without a spare chain link. I still have it!
Mid-40's on the 500/4 if I remember correctly.
must remember to get a spare link,get around 10 miles per litre,so about 45 Mpg,thats cruising around 5k-6k all the time,on my
M plate 500-4
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About 70mpg in perfect conditions from my 550 k3 was the best I ever saw on a sohc honda. No traffic, no towns. The 500/4 N reg could chew through a tankfull in 100miles or make it last 140+. The 500/4 had a sidecar so one has to expect any hill to cause a rapid drop in mpg. Both did really well if a motorway was involved, at various times the 500/4 may have had a smaller rear sprockett.
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My CB550F2 was ludicrously thirsty. About 40mpg, and on one memorable thrash in France (trying to get to the hotel before the restaurant closed, after a delayed ferry crossing), it ran onto reserve at 76 miles.....
My 550 FourK was much better.
The 400 Four returns high 40s - low fifties if used gently, and low 40s if thrashed. Haven't actually run a tankful through my 750F2 yet, so dunno about that.
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Steer clear of xjr1300's chaps!😃
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OK, before giving you my figures I must fully confess to being a 'Careful' rider, my wife calls me 'Field Marshall Slow' on the basis that James May would no doubt pass me with ease! I only 'Open her up' occasionally to, er, 'Burn the carbon off the valve seats officer'.
My bike is in totally standard trim in every way except the inevitable MOTAD exhaust and unbelievably I get 48 mpg around town and on a gentle 50 mph cruise up the A1 I got 57 mpg! The gearing is believed to be standard F1 as I bought new sprockets with the chain in a set for the F1 and the revs seem similar to what I remember back in the day ( around 4600 rpm at 70mph )
I think 48 mpg for a more normal individual would be a very good average
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Blimey. Never, ever rode mine at a steady 50.....
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Been out on mine again and still returning around 35mpg.But it doesn't see much below 60.
It's developed a slight miss at around 4000rpm due to crappy HT leads so that probably doesn't help.
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Bike Pusher, I don't recommend 50mph on anything but quiet roads it wasn't fun on the A1 to be honest but I wanted to see what it would do, and also it was the first open road jaunt since I got it on the road ( and the motor being low mileage hasn't been rebuilt ) I was nervous!
Green 35mpg does seem very low I reckon somethings amiss ( or you have a fuel leak / overflow? )
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Mpg on both my Honda ntv an rebel 125 can be nearly doubled by riding steady as opposed to thraping them. Cane the ntv and do a ton getting there fast, a tankfull is a megre 200 miles or so, I have seen 400 out of a tankfull doing a steady ride and nursing it. The rebel even noticed a headwind quite a bit when it came to mpg. I regularly rode the rebel at a steady 50mph to keep the costs down, especially in winter what with the ice anc fog. On most of the roads around here it aint too bad cruising along at 50.
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No fuel leaks and the bike runs really well apart from a slight miss around 4000rpm when it damp out and I'v just realized the front brake sticks when hot.
My dad used it this morning and its used a lot less then I would on the same trip and the brake didn't stick neither.
So I'v come to the conclusion its down to me giving it a dam good thrashing.
Next time I go out I will take it easy and see what I get.
Mick