This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.
Messages - honda-san
1
« on: July 30, 2026, 09:55:34 PM »
I've ridden close to 750,000 miles now over the last 50 years and mostly on un-faired bikes. For the last 30 years I have always worn earplugs. In spite of this I now have Tinnitus (ringing in the ears). All day, every day - no treatment or cure for it. I'm not saying that wearing earplugs was pointless rather that the risk of hearing damage should never be under-estimated.
I use both the disposable foam type plugs and the yellow with blue cord silicon re-useable type mentioned previously, and find these days that the increased noise if I forget to fit the earplugs is such that I have to immediately stop and fit them.
2
« on: July 16, 2026, 09:24:04 PM »
Tighter coils against the cylinder head, definitely.
3
« on: June 20, 2026, 07:30:52 PM »
I have a quantity of new, original Honda, plastic head keys for the above. Limited quantity available as per the below list. Also fit GL1000.
£10 each, inc. UK 2nd class post
Number Quantity
506 1
00897 2
00978 3
09789 1
20809 9
20879 2
27890 2
27980 6
28097 2
29087 2
29870 1
29980 1
30709 1
30790 5
30797 1
37900 1
40708 2
48707 2
48709 4
50897 4
50978 4
70809 1
70890 2
77809 2
77890 3
78907 5
79870 2
79980 1
80797 3
90787 1
90780 1
90787 2
90807 4
97008 1
97089 3
98707 2
98709 1
4
« on: June 12, 2026, 07:54:48 PM »
Same width tyre on 500 and 750. I did measure using a digital caliper - no difference dimensionally.
5
« on: June 11, 2026, 05:26:37 PM »
Yes, 500 and 750 both have the same 19" front wheel and drive plate, so hard to imagine why their drive gearboxes have different part numbers. Having checked via both Fowlers and DSS web site, none of the part numbers supersede to any of the others - suggesting there must be a difference.
I too had pondered setting a wheel up, and attaching a degree disc to the square cable tang and making measurements. Just wondered if I had missed something obvious that would enable easy visual identification.
6
« on: June 10, 2026, 06:30:17 PM »
So, anyone know how to tell what model a front wheel drive unit is correct for?
Specifically the drive gearbox for the 350-4, 500-4, 750-4 all look the same and can be fitted to any of these bikes. BUT, there are three different part numbers - 350-4 and 400-4 use the same "317" middle part number item. 500-4 uses a "323" middle number item, and CB750 uses a "300" middle number item. That I can see there are no features / markings on these that enable easy model identification. Most likely the difference will be the internal gear ratio, which is not much help when trying to identify which bike a particular unit came from.
I have at least half a a dozen of these, not all of which are identified as the bike they originated from. It would be possible to to work out the gear ratios by spinning a front wheel an exact number of turns and measuring the corresponding number of rotations of the output tang (that the cable connects to), but actually not so easy to do with the necessary accuracy given the likely subtle differences between ratios.
Any good ideas appreciated!
7
« on: April 06, 2026, 06:55:37 PM »
I seem to recall that internally the K6 fuel tap is very similar to that used on the 400/4 - ie a plastic cone shaped bit which can indeed wear and therefore not fully shut off the fuel supply to the carbs when tap is in the off position.
IF the tap is leaking to the outside world, as happened with one of my 400/4's, that can be cured by replacing the o-ring between the plastic cone and outer plate. Wish I could remember the o ring size, but way back when I did not tend to make a note of such things. That particular 400/4 tap is still in use more than 20 years after changing the o-ring, and still with no external fuel leak; it does however not shut off fully, allowing a VERY slow feed of fuel into the float bowls - barely a thimble full over a 4 month lay up this past winter.
8
« on: March 15, 2026, 06:42:55 PM »
There is an advert in the VJMC Tansha magazine for supply of original Honda keys. Also a listing on eBay (item number 157299118185) for original 400/4 style plastic head keys.
9
« on: February 20, 2026, 06:55:26 PM »
I've done a few over the years, both 350/4 and 400/4 (re-built one of these last week). 350-4 and 400-4 are identical in terms of the primary chain / sprocket / starter clutch arrangement.
Whilst you can remove the primary shaft from the engine with it in situ, the primary gear, etc, is still "inside" the primary chain itself. Only way to get this out is with the lower crankcase removed - which of course means removing the engine itself.
No real problems (Haynes manual is pretty good for these), other than maybe previous owner bodges / poor maintenance, and the fact that these things are approx. 50 years old.
IF maintained properly, the 400/4 in particular is an exceptional bike. My current hack (only used in the winter these days) now has over 125,000 miles showing - and still on original pistons / rings yet does not burn oil. The cam chain and primary chains in it have now done over 95,000 miles since being replaced - and do not rattle. 350/4 is a slug in comparison and needs to be worked hard to maintain A-road speeds.
Only persistent problem has been oil weeps from the camshaft oil feed through the head gasket (every 25,000 miles or so), due to the use of crap (and expensive!) sleeve type seals around the oil jets. I am trialling a modification here to see if things can be improved.
10
« on: January 14, 2026, 07:07:07 PM »
I suspect they could be CD175 - I seem to recall there were some CD175 parts amongst the stuff you had when I collected the C72 chassis a while back?
11
« on: December 20, 2025, 05:49:02 PM »
I think I heard somewhere that these are made by Busso in Italy. Certainly cheap, but no idea of the quality.
12
« on: November 30, 2025, 06:56:56 PM »
Just spotted a genuine Honda shop manual for the CB750 K8 and F3 on eBay - might be of interest?
Ebay item number is 406419338743
13
« on: November 18, 2025, 07:11:59 PM »
400/4 breather covers were not painted (nor even clear coat / lacquered that I can tell from the ten or so examples owned over the years).
I believe the original finish was therefore "as-cast", similar to sump / carbs on the same
Chris R.
14
« on: October 02, 2025, 08:59:38 PM »
Whether or not asking prices are reasonable or otherwise is always subjective. Very often the asking price is set as a starting point for negotiations between seller and buyer.
However, as to the un-informed comment that HM300 stamped exhausts are not genuine and must be reproduction because genuine would be stamped HMCB750 HM300, REALLY!!- You would do well to do some research and get your facts straight (or try a different brand of dope!).......
The very first exhausts fitted to CB750 Hondas back in 1969 did not carry ANY stampings whatsoever.
Then factory fitted exhausts as fitted to UK and US market bikes built in 1970 and up to the end of K1 production were stamped simply with HM300. These will have a baffle fitted with a vertical bar in the outlet.
I believe that exhausts stamped HMCB750 HM300 were fitted to some European markets during 1970 – 1971, and did NOT have the vertical bar at the outlet. These European exhausts are possible the least common type encountered on bikes these days.
Hopefully others will offer further comment.
15
« on: September 11, 2025, 06:04:40 PM »
Still using my Morgan Carbtune mercury gauges, 30 or so years on. I believe Morgan still sell "vacuum" gauges just not with Mercury in them.
|
Show Posts