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Messages - flatfour
1
« on: November 07, 2024, 03:34:03 PM »
I changed the head gasket on the 400/4 that I am looking after in around four hours of spanner time, although this was divided into two sessions as the new gasket, when fitted, was left to settle overnight and then re- torqued in the morning before fitting the camshaft etc. The cylinder base gasket and everything below head level was left untouched and has not shown any issues since. When I lifted the head, I did, however ask the bike's owner to firmly hold the cylinder barrels down, to avoid moving the base gasket.
I often work on the "old" bikes and did the same work on my Benelli Sei a good few years ago, however my only real skills were learned in the 1970's and 80's when I was a "chalk and talk" technical trainer for Jaguar Cars.
In all honesty, providing that you can follow the manual and possess a few workshop tools including a good low - range torque wrench, I don't see the job as something that the average DIY mechanic would have trouble handling.
2
« on: November 05, 2024, 03:44:17 PM »
I lifted the cylinder head on a 400/4 belonging to a friend a few months ago for this same problem. A genuine gasket was bought from DS, together with the two short rubber tubes that seal the oil galleries on either side of the head. I understand that the 350 & 400/4's use these short rubber tubes instead of "O" rings, although as always, I might be wrong?
It has, incidentally stopped the leak!
3
« on: September 22, 2024, 08:41:17 AM »
Just back from the annual trip to Japan. Days between 36c and 40c, not a night (in almost three weeks for me, six for the wife) that dropped below 30c. Humidity 80 - 100%.
I've been travelling there most years since the 1980's when I worked out of Tokyo and have never known summers to be so hot and humid as now.
4
« on: August 17, 2024, 08:23:48 PM »
I'll be there with a Honda riding friend (I'll be on the Trident). We also have a 400/4 coming with us.
5
« on: August 03, 2024, 02:41:33 PM »
I can tell you that after the splines on my 500/4 gear lever became worn, I fitted one from a CB750 K2, which worked perfectly well in terms of bend angle and length. At the time, the item for a CB500/4 was unobtainable from any of the usual sources. I intended to find and fit an original, correct part when I could source it, however things looked fine and worked so well that I left it all alone.
6
« on: July 19, 2024, 05:18:48 PM »
I had something similar on my CB750 K6 a few years ago.
It turned out to be the final drive chain, where the original had been replaced with an "O" ring type and, being wider it was touching the engine case at times, presumably depending upon its exact position on the front sprocket as it rotated.
A replacement standard chain sorted things out.
7
« on: June 30, 2024, 08:55:07 AM »
Motobatt batteries all come with a set of terminal fixings that certainly work on Honda - I fitted them to both my CB500/4 and CB750/4. Both lasted for years, and were still in good shape when the bikes were sold. I will put the same make on the Trident soon - I am only delaying because it came with a new battery at time of purchase, July last year.
In addition, Motobatt have terminals on both sides of the battery, allowing connection in a multitude of ways.
8
« on: May 26, 2024, 08:58:30 AM »
My brother owned a CB250 G5 many years ago and, following some top - end work I remember the mechanic slackening one of the nuts above the cam box that, I think had a copper washer fitted under it. As I worked in a car workshop at the time I asked the purpose of this and he said that it was to confirm that oil was reaching the camshaft.
9
« on: April 27, 2024, 11:33:56 AM »
I've owned BMW airheads on and off since the 1970's when I had one of the last R90S's into the UK.
I think that Matt Hull (Classic Bike Guide) did say that the bottom - end problems on his bike came through low oil level. Most of the older boxer engines had a real thirst for oil and on touring trips with other owners, often at the end of a long day's ride on the continent, we would buy a gallon of 20/50 and share it between three or four bikes. There was never any left in the container!
My understanding is that both the gearbox and shaft drive is difficult to self - service though there are a few well - known businesses that offer overhaul if needed.
Perhaps it might be worth joining the BMW Club, which has lots of information available, as well as a tool hire service for DIY work that includes nearly all of the special tools ever offered by BMW?
10
« on: April 18, 2024, 05:43:35 PM »
I thought that I would offer a short update on life with the Trident as I've now ridden almost 2,000 miles on it, mostly during the better weather days through winter.
So far, no real problems to report, I'm pleased to say. Since I last did a write - up, I've experienced two minor issues, the first being following a brisk run of around 30 miles, I suddenly found that there was no real power on twisting the throttle. A hurried glance at the oil pressure gauge showed over 75 p.s.i. so not a mechanical problem I thought, and pulled into a garage forecourt that I was anyway intending to visit for fuel. Looking down, I found that the twist - grip was simply sliding around on the throttle tube. A few sharp prods on its end tightened things sufficiently to ride the two miles home. The throttle tube is metal rather than plastic and, after removing the grip was found to be quite smooth, so emery cloth and glue sorted things out!
The second issue again involved a reduction in performance, although slight this time. The points controlling the left cylinder closed up due to sudden wear of the heel that operates them, retarding the timing on that cylinder. This prompted me to fit "Tri Spark" electronic ignition, not least because a feature in the owner's club magazine that happened to drop through the door the same day featured a bike exactly the same as mine, including its colour, that the owner had named "The Purple Piston Eater" following similar experiences!
Otherwise nothing to report out of the ordinary.
I have just changed the engine oil, primary drive oil and gearbox oil, once again cleaning or replacing all filters(3) as appropriate. There was no sign of debris anywhere and the oils were clean. Final drive chain adjustment has only been needed once in 2,000 miles, and the primary chain has not been adjusted at all as yet.
This is the first classic bike that I have not need to protect with ACF50 or similar as the finish is completely untarnished from winter, although I do pick my riding days carefully.
Overall I'm very satisfied with this, my first British classic!
11
« on: March 26, 2024, 06:02:04 PM »
For distance work in total comfort, I'd always go the BMW route. Both the twins and fours have low rear footrests, fitted luggage of the highest quality is almost universally standard, and heated grips (and seats) are normally found across the range. An R1200 or 1250 RT, or K1300 GT will offer frugal fuel consumption, the fours in particular also have huge power.
My current K1300 GT (July 2010) has 54,000 miles on it, has had one change of brake pads (no discs needed) and, except for an annual service, has wanted for nothing else of significance. In terms of running cost, both of my BMW's have needed far less spent on them than my Kawasaki 1400 GTR, Versys 1000 or Ducati ST, all of which were bought new. Tyres are lasting 10,000 miles or more on the BMW's and less than half of that on the Kawasaki's or Ducati.
As a further benefit, my GT still has a BMW warranty on it, including European - wide recovery and other benefits. This can be renewed annually or paid for on a rolling monthly basis.
12
« on: March 22, 2024, 04:10:31 PM »
I fitted the David Silver combined regulator/rectifier to my CB750 K2 around four years ago. Although I don't have the bike any longer it behaved perfectly in the three years that I ran with it.
Even for someone like me, who finds it hard to change a light bulb without causing another problem, it was simplicity itself to fit.
13
« on: February 17, 2024, 04:57:24 PM »
I worked (as a contractor) for quite a few years with Mike, Brigid (his wife) and Clive (their General Manager) and always enjoyed my visits to the company, they were very good to me.
14
« on: February 07, 2024, 04:34:35 PM »
My friend used his 1970 CB750 for many trips to France and Belgium until it was sold in around 2016. He was riding with myself, my daughter and my brother, all of whom were using modern bikes (me Kawasaki 1400 GTR, my daughter Honda NC700X and my brother a new Honda CB1100).
Each year we would head off to Dijon for the Coupe de Moto Legende and then Spa for the Biker Classic. To reach Dijon we always route via the A26 to Reims and then on to Dijon, on the return we would ride the backroads as time was unimportant.
During these trips, the CB750 never failed (neither did the other bikes, although perhaps failure on something relatively new would not really be expected.
Over some ten years of use, the CB750 covered around 30,000 miles in this manner. We modern bike riders did, however help with the luggage, as we all had top boxes and panniers!
15
« on: January 01, 2024, 04:38:33 PM »
Quite different here in Norfolk, totally dry, though only 7 - 8c.
I took the Trident out for a while and, whilst refueling, a large number of bikes came to the forecourt, mostly British classics from the 1970's, although there was a 400/4 amongst them. I think that it might have been a VMCC ride out, as they are very active around these parts.
In the past week, I've managed to ride eight times on various bikes, so weather generally fair, although there has been rain on occasions it has soon dried.
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