Saturday 24 December 2016

Looking Back, Looking Forward

Firstly, seasons greeting to you all.

Christmas eve. The sun shines from a pure blue sky. The snow lies thick & crisp & even. Rosy-cheeked children make snowmen and I have the neighbours round for some mince pies and eggnog….no, not really. This is Scotland, it's blowing a gale and the rain is lashing down.

Anyway, as we head towards the end of another year I'm looking back at 2016 and forward to 2017.

It was a pretty good year for riding for me. I'll have done about 16,000 miles between my three bikes. This is about average for me these days. I don't commute or anything so these miles are mostly for pleasure rather than necessity.

The big event this year was getting the Suzuki SV650 having had a hankering for a middleweight bike for some time. As I've explained previously I use my Honda CBF250 for winter use, around town and runs when I stick to the back roads. The Yamaha FJ1200 is used for touring and longer trips. The runs that I was doing were generally 200-300 miles and a mixture of main & back roads. I felt that there was a place for something with more go than the CBF and less weight than the FJ. The SV has filled this gap perfectly. So well that I could run it as my only bike. In real world riding it is as fast as the FJ up to 90 mph but as nibble as the CBF round town. The FJ is better for long distance high speed riding with its big effortless engine, comfortable riding position and wind protection. But this isn't something I do that often these days.

Another good thing was fixing the CBF. It had a niggling engine noise problem that turned out to be a worn clutch basket gear. Things weren't that simple but after spending some money and time on the bike I think it's back to health.

A pleasure this year had been exploring Southern Scotland. This is the regions of the Scottish Borders and Dumfries & Galloway. These are a comfortable distance away and give access to beautiful rural scenery, picturesque towns & villages and a network of great biking roads. From there I can cross the border to Northern England.

Another series of good runs was searching out the minor roads of the Argyll coast in the West Highlands.

My plans for next year are more of the same really. I intend to run three bikes. The CBF as the runabout, and the SV & FJ for runs. There will be a nice contrast between the light sporty nature of the SV and the brute power and comfort of the FJ.

2017 will be my 44th year of motorcycling and I'm enjoying it as much as I did when I was a teenager.  

The bikes out on the road in 2016

"The Fleet" for 2017

Thursday 22 December 2016

Tenerife Sunsets

For those in winter's icy grip here's taste of summer. Sunsets from the Spanish Canary Island of Tenerife taken during our trip there last week.

Saturday 10 December 2016

CBF250 Clutch Fix - Part#4 - Conclusion

All this hacking about with engines is good and well but will the thing actually go?

I might as well check the valve clearances while the engine's on the bench. The camshafts are in good condition. These guys have opened the valves about 250 million times!

Also I repainted the frame in areas inaccessible with the motor in place

After that it's bolt everything together. I hit the starter and it fired up fine. A quick run confirmed that the whine was gone and the engine was running much quieter. 

Friday 9 December 2016

CBF250 Clutch Fix - Part#3 - Spark Plug Thread Repair

After the spark plug thread in the cylinder head stripped I staggered about holding my head and moaned NOOOOOOOOOO!!!! for a while then started to think about how to fix it.

the threads have completely gone
I could sort things by installing an insert. This means cutting a new, bigger, thread and then installing an insert with a 10mm x 1.0mm internal thread. There was no way of doing this with the engine in place, the frame is in the way, so out came the engine. It seems possible to do the work without removing the cylinder head.

Removing the engine is pretty easy on a small bike like this. I made this timber frame to hold the engine. I clamped it in my "wallmate" to hold it steady.

I bought a thread repair kit consisting of a tap and inserts of various lengths by German company BGS Technic.

I connected the tap to a 3/8" drive socket, extension & tommy bar.

The insert

An NGK CR8E spark plug  and a tube of Loctite 272 high strength, high temperature thread lock fluid.

A problem is the type of spark plug the CBF uses. It's a CR8EHS - the means that it is 10mm in diameter and had a 19mm reach. But the reach is only partially threaded. The top 6mm is unthreaded. This means that it won't fit into a 10mm insert that is threaded all the way. My solution is to use a CR8E plug that is the same size & heat rating but threaded full length. The unthreaded part of the original plug is tapered to provide an additional gas seal. In the new arrangement the seal will be by the gasket only.

Yes, I know that the old plug looks really rough. But, in my defence, its only been in the bike two years. This shows what the ravages of the Scottish winter can do.

When cutting the new thread it is very important to have the tap exactly in line with the hole. It is difficult by hand. I've done this before by mounting the tap in my post drill but this would be tricky with the engine. So I came up with another idea. I make a template in aluminium attached to the cam cover by the cover bolts with a hole to guide the extension shaft attached to the tap.

I first cut threads when working in an engineering factory about 40 years ago. The threads were in actuator valves to control fluid flow in a pottery casting machine. The machine was exported to Iran, I wonder if it's still working? What I learned was to rotate the tap back and forward and clean the swarf out regularly.

Here I go cutting thread. If I get this wrong I've wrecked the engine - so no pressure then.

It's not a good ideas to allow chips of aluminium to enter the engine. To try to avoid this I coat the tap with grease and clean it frequently. Once the job is done I'll blow the cylinder clean with my compressor allowing any chips to exit via the valves.

The tap quickly starts to cut the thread. I work it backwards and forwards in increments and regularly remove the swarf and apply new grease.

The completed new thread - it looks good.

I apply thread lock on the outside of the insert. Hopefully this will hold it in place permanently.

The finished job with the insert in place

Thursday 8 December 2016

A Short Run to the Coast

After some freezing weather today was bright and very mild (13C/55F) so I went for a short (about 100 mile) run to the Ayrshire coast.

Ice cream cabin in Ayr shut up for the winter

Flat out along the beach

Now that is one huge horse. I think this pair are racehorses being exercised.

Ayr beach

This always makes me smile

The coast road south of Ayr

Donald Trump's golf course at Turnberry. It was a very pleasant day for a round.


A very calm sea south of Girvan

Wednesday 7 December 2016

CBF Clutch Fix - Part#2 - Putting it back together

I pride myself on being able to fix bikes on the cheap. Second-hand parts, making stuff, bodges etc but when it comes to engines there's no way around shelling out for new parts. The Honda parts are: clutch basket, crank gear, casing gasket & oil filter O-ring. The crank gear is symmetrical so could have been used the other way round but given the cost I got a new one. The oil filter O-ring is unrelated to the clutch but was replaced because it was a little damaged. I also bought a set of clutch springs and a new clutch cable.

The parts took some time to come. That's the downside to having a bike that's relatively rare. While waiting I had the vision of my parts on a slow boat from the Amazon (my CBF was, in fact, made in the jungle town of Manaus, Brazil) I have only myself to blame. I've known about the problem for a long time but waited until autumn before ordering the parts. 

Given the bike's mileage the cost of the parts was probably about three quarter of its value. But since the bike was otherwise ok I did the repair. The alternative was to scrap it, which seems a waste, and I'd have to have found another bike for the winter. I guess if this gives me another couple of years use it will have been worth it.
The bits

All the way from Brazil!

Now a slightly tricky part. The gear on the crankshaft needs to be held to tighten the bolt. I removed it by jamming a copper coin in the gears. This worked to get it off but I didn't want to repeat this when replacing it. Firstly I'd be sick if I chipped a tooth on the new parts and also with the clutch in place there is no space to use a socket and I wanted to torque the bolt to the specified value. The manual shows a special tool for this job and I set out to make my version of it. The tool was made from scrap - yes that plate on the right is an old brake pad!

The clamp holds the gear in place while I tighten the nut. The engine bars help here!

The rest is "reassemble in the reverse order of disassembly" as the manuals say and I'm done.

Well, as it turned out, I'm far from done. The bike was a bit reluctant to start to I removed the spark plug to check it was clean and the thread in the head stripped.

To be continued…………..


Tuesday 6 December 2016

CBF Clutch Fix - Part #1 - Taking it Apart

Earlier this year I took my Honda CBF250 off the road for its annual "spring clean". The little bike is my daily transport and runs through the winter so is affected by exposure to rain & salt etc. I didn't post about this since it was just the repeat of things I've done in previous years.

The bike, though, has a niggling problem. There is a whine from the engine. In the past I've put in earplugs and ignored it. But riding it again after a couple of months off I realised that this was bad enough to require attention. The whine was becoming a shriek. After a careful listen I was sure the noise is emanating from the clutch. It sounded like something metallic rubbing together. The bike has done 56,000 miles. That's a lot for a 250 but the bike is otherwise in good condition. I've didn't miss it over the summer - I've got my FJ1200 and new SV650 - but for winter I need the little bike on the road.

I'm comfortable enough taking engines apart. But, thinking about it, it's a while since I've had to do any engine work except for routine maintenance. In fact it would be in 1988 when I stripped another Honda 250 single, a CB250RS, to replace a broken gearbox selector fork. (Except for MZs, but they are something different) 

Like most bikes access to the clutch is simple. Drain the oil, remove the oil pipes, undo the screws and off it comes. 

There is a coarse oil filter inside

You need a special tool to hold the clutch body while removing the centre bolt. This is available but because this is (hopefully) a one-off job I made one.

Removing the clutch centre bolt

Examining the internals everything seemed ok except for the teeth on the clutch body. These had severe wear, to the point of having little flakes of steel scuffed off. This is a bit strange. There doesn't seem to be anything causing the damage. The bike has always been run on fully synthetic oil. The 250 is worked hard but there's only 22 bhp going through the gears. 

The crankshaft gear had slight scuffing
The clutch basket had some wear but it wasn't affecting its operation

The clutch plates were at the top end of the thickness range, ie there has been zero wear in 56,000 miles!

While it was off I took the opportunity to paint the engine casing.