Tow hitch for The Fire Bike, part 3 – 29 Jun 2016.

Here is the final part of my story about fitting a tow hitch to The Fire Bike. While the paint was drying/hardening on the pannier/towing bracket I turned my attention to the towing electrics.

I wasn’t sure if I was going to use the standard 7-pin UK towing socket and looked for more compact alternatives. However, I couldn’t find anything I liked better. I decided the best place to mount it was beside the number plate to a bracket sandwiched behind the plate. I drew a card template then cut the bracket out using my old “Monodex” cutters which I’ve kept from my car restoring days.

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It will screw behind the number plate using the lower mounting bolts.

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I trial fitted this to the bike but found it rattled and needed 2 additional small screws to reduce this. Here you can also see that the bracket has been bent forward so the socket will clear the left hand pannier when fitted.

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It was clear to me that, If I wasn’t careful there would be a “rats nest” of wires below the tail lamp and behind the number plate. This was because I still wanted to keep the connections for the lights I’ve fitted to my top box. Piggy-backing connectors together wasn’t going to be the answer. I decided to use a connector block which would allow four way connections. Only ones with screw down terminals were compact enough. The top connections would be for the wires from the bikes’ main loom and to its original lights. The lower connections would be for the top box and trailer wiring.

I cut the terminals from my top box wiring and replaced them with ring terminals and made a short ground connection.

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Then I added ring terminals to the end of a length of 7-core trailer cable. Only 6 of the wires are used. The blue one is for a fog light and is held out of the way with heat shrink.

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Rather than remove the terminals from the bikes’ wiring I made a pile of adapters and fitted them to the connector block. There is also a link joining terminals 2 and 3 together. This is because trailer wiring usually has left and right side tail lamps on separate circuits but, of course unlike a car, a bike only has one to feed them.

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The connector block was fitted with a bracket so it could be mounted to the lower tail lamp bracket bolt and the bike wiring connected up and tested.

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It’s still a bit “busy” back there and I might end up changing the bike wiring to ring terminals and junking my adapters after all.

I fitted the top box and trailer connections to the lower part of the connector block and then checked the number plate hardware would go back without trapping the wiring.

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The towing socket was wired up and fitted to the plate I made using its rubber seal. These sockets are easy to connect up and wiring diagrams are easily found on the net.

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Next the trailer wiring and top box connections were tested. Everything worked as it should.

The paint on the tow bracket was still not hard enough to handle so instead I gave the bike a wash to get rid off all the sand/dust that came down in the rain the other day.

This afternoon I remounted the chrome top rack and fitted the new pannier/towing bracket. I had to go and borrow a 1 1/8 in spanner to fit the tow ball to the bracket. It had to be held with a Stillson pipe wrench but I managed not to scar it. The panniers finally went back on and the job was pretty much done. I just added a rubber buffer to the back of one of the towing socket screws so it can’t dig into the pannier when I plug the trailer in.

I think it all looks OK.

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I need to hitch it up and go for some test rides now.

Oh, just one more thing. I made up a kerb weight plate for the bike and an unladen weight plate for the trailer. They’ve been stuck on with some double sided tape designed for fixing badges to car bodywork.

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Update 30 Jun 2016.

I have made a little change. Looking at the photos last night I was concerned that the socket for the trailer electrics obscured the “6” of the number plate too much (also see the comments below). I’m not concerned about the plug obscuring the number plate when the trailer’s plugged in as there’s a number plate on the back of that. It’s actually legal to remove the plate from the tow vehicle and fix it to the trailer. The UK regulations state;

“A registration plate must be fixed on the rear of—
(a) the vehicle, or
(b) where the vehicle is towing a trailer, the trailer, or
(c) where the vehicle is towing more than one trailer, the rearmost trailer.”

So there you go!

There isn’t clearance to fit the socket below the registration plate so the best I could do was to raise the socket in line with the top line so it will only cover the blank space next to the “E”. The regulations that apply to the old-style plates say there must be a 10mm margin beside the letters/numerals and there is 40mm here. I could have a plate made with the top row aligned to the right giving even more space but that, though legal, would look a bit odd.

Here are photos of the revised set-up with the bike solo and with the trailer plugged in. I should have done this in the first place.

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Tow hitch for The Fire Bike, part 2 – 26 Jun 2016.

Well, late the other evening, I had a phone call from Eifion at Tobruk Engineering to say that my new pannier frame/towing bracket was ready. I set off the next day on The Fire Bike to fit it at his works. It’s only 20 minutes each way but, before I got very far, the heavens opened and we had a welly-filler of a shower so I had to don all my waterproof gear.

I was impressed with the workmanship. Eifion has produced a copy of the original pannier bracket but in steel bar instead of tubing. He has added the lower strengthening points as we agreed but not the upper diagonal braces as he felt it was strong enough already. Having seen the finished article I am inclined to agree. At the back, of course is the 6mm thick plate to take the tow ball.

We offered the bracket up to the bike and it bolted straight on. Quite a bit of time had been spent getting it right. It’s not just the welding. All the bends, brackets and mounting points had to be accurate. Eifion built a jig first using the original rack and got everything spot on.

It wasn’t so wet on the way home but somehow the bike and I ended up filthy. It looks like we were covered in wet sand. Within half an hour of getting the bike in the garage, the new frame had begun to rust – Welsh rain and sea air!

Of course I had to offer the trailer up to the bike to see how everything would sit. By now the sun was shining in through the windows.

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Once again I got my wife to measure the height of the tow hitch while I balanced on the bike. After adding on the height of the tow ball, I calculated that the distance from ground to the mid point of the ball was 388mm. This is 23mm higher than I had worked out originally (365mm). This actually makes things better as we get closer to the 35mm difference I had been aiming for. Trailer coupling height of 420mm less bike tow ball height is 32mm. That’s good enough for me.

I fitted the panniers to the new rack after making rubber pads to go between the pannier boxes and brackets as all but one was missing. The panniers fitted straight on.

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Now everything had to come apart again so that I could paint the new bracket. Being made of steel bar it’s heavier than the original rack but, surprisingly, not that much.

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The following day I had to drive past the works to do the supermarket shopping and called in to pick up my original rack. Here are the two together for comparison. You can see the extra bracing between the lower loops of the framework.

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Since then I have spent an hour rubbing the metalwork down with emery cloth before giving my new bracket two coats of red Hammerite Smooth paint.

Painting that thing wasn’t very easy. I put a threaded rod through the two front mountings to give me something to hold on to and then clamped it in the vice by the tow ball plate. That meant I could paint everything apart from the plate and turn it round to get to the other side.

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While the paint was still new and a bit soft I scraped off the paint that had got onto the tow ball mounting plate. This was so I wouldn’t get a line when I painted that part. That last bit then got its two coats of paint as well.

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I’ll need to leave the paint to harden before trying to fit the rack to the bike and even longer before I try and rub the runs down – oops. In the meantime I’ll have to make the electrical connections and will be back with part 3 soon. The colour of the Hammerite isn’t far off the bikes original but it’s a bit too orange.

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Adding vacuum take off points to the V7Sport – 22 Jun 2016.

Since putting The Racing Rhino back on the road it has performed beautifully. It’s strong, pulling right through the rev range, ticking over properly and is just a joy to ride. However, almost immediately the right hand exhaust pipe turned yellow then blue. I’m not sure, but I think it’s continuing to slowly get worse.

Chrome turning blue is caused by it getting hot and there are various reasons why this might be. A weak fuel mixture is a common cause but, in this case, if anything the bike might be running slightly rich as it now has air filters where originally there were none. Carburettor jetting is still standard. Both spark plugs are the in same condition – a sort of brick red with the odd sooty spec on them. Ignition timing has been checked twice and the valves readjusted after re-torquing the cylinder head nuts. I have also successfully removed all the leaks from the exhaust system using silicone sealant.

Interestingly, my previous experience has been that both exhaust headers will go blue pretty quickly on these bikes. So the problem side could be the left, possibly colder one. Another suggestion has been that the quality of the chrome is different on each pipe and that is why they behave differently. The cylinders of the Guzzi engine are offset with the right hand one further forward. This means there is a shorter distance for the very hot exhaust gasses to travel to the bend in the exhaust header on that side, and so more blueness.

Just before writing this post I saw that Hans, another Guzzi WordPress blogger, is having the same issue with his newly restored 850GT here – I paste the link into Google translate to see what’s going on.

Anyway I decided that one last thing I could investigate further was the carburettor balance. Perhaps there is more load on one side than the other. I wanted to use my vacuum gauges but there were no vacuum take off points. I’ve done this on The Fire Bike which has had them added at some point by a previous owner. Later Guzzis have a drilled “boss” on the intakes for the purpose.

Here is the drilling added to the left hand intake manifold of The Fire Bike

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and this is the same point sans drilling on The Racing Rhino.

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I had considered making this modification when the bike was being rebuilt but “chickened out”. This time I plucked up the courage and reasoned that, if I made a total mess of it, I would buy a set of later inlets with the fittings already in place.

I disconnected the battery and removed the fuel tank so that I couldn’t damage it with my ham-fistedness. I took off the air filters and then set about removing the left-hand carburettor.

I undid the clamp that holds it on the manifold and managed to wiggle it free without removing the throttle cable or fuel line. The three allen bolts holding the inlet manifold to the cylinder head were undone and the manifold taken to the bench.

These are my vacuum take off adapters which have an M6x1.0 thread

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I spent a lot of time measuring where the hole was drilled in the V7 loopframe manifold and copied that carefully although I’m not sure how critical this actually is. I was finally happy(ish) and marked the spot with a marker pen. You might be able to see in the photos that I had made several attempts at this!

I don’t have any expensive tooling but managed to get the manifold clamped in a machine vice, supported at what looked like the correct angle and positioned in my hand-cranked pillar drill. It’s old (90 years old?) but can be relied upon to drill a hole accurately. I drilled a small pilot hole first.

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Cutting the M6 thread requires a 5mm hole so, after checking that the pilot hole was at the correct angle, the larger diameter was drilled.

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The thread was then cut.

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I carefully removed any swarf from the manifold as well as any sharp edges. I measured the thickness of the manifold casting through the hole as 5.7mm. The blanking screws fitted to the V7 loopframe manifolds are 10mm long. Fitted to my newly tapped hole it’s too long but, again, I’m not sure how much this matters.

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I made a shorter blanking plug (about 7mm), added a fibre sealing washer then refitted the manifold and carburetor.

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I repeated the job on the other manifold. Here the carb is off and hanging by the throttle cable.

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Once this manifold had also been drilled, tapped and plugged everything was reassembled – air filters, fuel tank and battery ground cable.

I checked that the bike started and ran properly. I don’t think the plugs in the take off points leak at all. With the engine running, I sprayed them with “easy start” to see if the engine “picked up” and it didn’t.

I think the modification has been a success and hope to soon have a go at balancing the carburettors using my vacuum gauges. I did this on The Fire Bike a while ago with good results.

Tow hitch for The Fire Bike, part 1 – 21 Jun 2016.

As I’ve already mentioned, I recently bought a trailer to tow behind my bikes. My first idea had been to build myself a single-wheeled trailer but the chance to buy this one at a good price from a friend was too good to miss. It would have cost me more to put something together myself.

I want to tow it with The Fire Bike so I needed to come up with a design for a hitch. A number of people had suggested just welding a bracket to take a tow ball onto the pannier frame. Now this sounds fair enough and, although the rear loop looks to be at the right height, the frame is only designed to take the weight of the two small metal panniers.

The first thing I did was to offer up the trailer to the back of the bike and spend some time looking at what I’ve got.

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I needed to do some calculations but, the only guidance I could find regarding tow ball height relates to cars. The tow ball height (to the centre of the ball) on a car should be between 350 and 420mm with the vehicle laden. While trailer coupling height ( to the centre of where the ball would be) should be between 385 and 455mm with the trailer level and laden. From this it looks like I should aim for the trailer coupling to be around 35mm higher than the tow ball. However, these figures allow the extremes  of a trailer coupling 105mm above the tow ball or 35mm below it.

Bearing this in mind, I got my wife to come out and measure the height of the underside of the loop on the back of the pannier frame, while I balanced on the bike as best I could, to give a “laden” condition. The measurement was 315mm. The tow ball I intend to use will add 55mm giving a height to the centre of the tow ball of 370mm. With me off the bike this goes up by 40mm. Now, if I were to carry a pillion passenger the laden weight and compression of the suspension would increase. I thought about this and decided I am unlikely to carry a passenger and, if I did, I would increase the pre-load on the rear shocks to compensate.

I then got the trailer level and propped it in place. The height of the centre of the trailer’s coupling (where the tow ball would be) is about 420mm. I got this figure with the trailer unladen so it will reduce a little when the suspension is compressed.

All this means that, if I had a bracket welded to the back of the pannier frame to take the tow ball, the trailer coupling would be 50mm (or less when loaded) above the tow ball. This should be alright.

I removed the panniers from the frame.

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Then the frame itself.

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You can see that, if I just hang a bracket for the tow ball on the back of the pannier frame, there is no straight through pull to the rear footrest mounting. The panniers themselves, being made of steel, would stiffen the frame but I think modifications are needed. My idea was to add a piece between the inner and outer lower loops and perhaps a diagonal on each side to triangulate the frame like this.

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It was actually about two weeks ago that I took the pannier frame down to a local engineer. He agreed with my ideas and had previously seen the panniers fitted on the bike. I asked him to copy the frame so that I could store the original. He said, in that case, he would make the lower rails from solid bar rather than tubing. I’m not especially concerned about the increase in weight and I’d rather have it over-engineered than too flimsy. I’m not sure how long Eifion will take making the new frame/tow hitch. I’m waiting for his call.

Meanwhile, The Fire Bike doesn’t look too silly without the panniers.

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I’ve bought a trailer – 11 Jun 2016.

As indicated in my last post, I have bought a trailer to tow behind my bikes. I know many motorcyclists can’t understand why anyone would want to but, I like my comforts when I go camping! I have a large tent, take an air bed, like to have a comfortable chair and loading this onto the bike with sleeping bag and a few clothes leaves no room for cooking equipment or anything else.

Moving my luggage from the bike to the trailer will get rid of the top-heavy load secured with various straps and will provide some security. Also I won’t have to squash as few clothes as I can get away with into as small a space as possible and, as the trailer is water tight, I don’t have to use a lot of individual waterproof bags.

I’m not a fast rider so the speed restrictions imposed by towing don’t bother me.

I bought the trailer from a friend in the local “Old Cranks”motorcycle club who’s given up camping. He used to tow it behind a Panther single so my Guzzis should be able to manage it.

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Sorry Brian, but I’m going to have to remove the panther stickers!

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It’s a motorcycle specific trailer designed to meet UK regulations which state (as at Jan 2016);

  • You can use motorbikes with an engine size of 125cc or more to tow small trailers.
  • Your motorbike has to be clearly and permanently marked with its kerbside weight.
  • The trailer must be no more than 1 metre wide and must be clearly and permanently marked with its unladen weight
  • When the trailer is loaded it must weigh no more than 150 kilograms or 2/3 of the kerbside weight of the motorbike – whichever is lighter.
  • When hitched, the distance between the end of the trailer and the rear axle of the motorbike must be no more than 2.5 metres.

The trailer doesn’t have anything to show its unladen weight. I’ve spoken to two other people with similar trailers and theirs don’t either. The Fire Bike’s not marked with its kerbside weight (243Kg/536lbs) either but I can make up the plates easily.

The bike has swivel hitch so there is no restriction when the bike leans over.

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The trailer was made by Consett Trailers who are no longer in business. However there are still plenty of their trailers in use here.

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It’s made of plastic mouldings mounted on a steel chassis with rubber-in-torsion suspension.

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It has a lockable lid which should keep the water out.

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The trailer can be stored on end to save space.

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I weighed the trailer at each wheel and under the front prop on the bathroom scales then added the figures together to establish an unladen weight of 50Kg. This gives me a luggage allowance of 100kg behind The Fire Bike, which has a quoted kerb weight of 243Kg, but I have no intention of carrying that much stuff. It’ll be more bulk than weight.

I’m guessing that the trailer was made in 2002 as the date codes on the three tyres are the 13th and 14th weeks of that year and I suspect that they are the originals. The spare doesn’t look like it has ever been used.

I offered the trailer up to The Fire Bike to see how it would look and took some measurements to work out the tow hitch height but more of that another time. I found that it’s actually only 40mm wider than the fairing but I don’t think I will be doing much filtering!

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I’ve given the trailer the “once over”, re-greased and adjusted the wheel bearings, pumped grease into the swivel hitch and tested the electrics. There wasn’t much else to do. I’ve just got to get a registration plate made and should make up something to show the unladen weight.

Cylinder head re-torqued – 8 Jun 2016.

The Racing Rhino has now been back in use for 3 months and completed 537 miles so it was time to re-torque the head bolts.

The first thing to do was to take out the spark plugs and select top gear so that I could turn the engine over using the back wheel. I decided to do the left hand side first and removed the rocker cover.

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The rocker arms are different colours but that is how they’ve always been. It must be something to do with manufacturing as the exhaust rocker on the other side is brown as well – the same part.

I then turned the engine in the correct direction using the back wheel until the piston was at TDC on the compression stroke so that both rockers are loose. I then slackened off the adjusters. The rockers were removed by undoing the locking screws and sliding out the shafts. Parts were kept together so they couldn’t get interchanged. There’s a washer, spring, rocker arm, shaft and locking screw with spring washer for each valve.

Next I removed the 26mm blanking plug and its crush washer from the top of the cylinder head.

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This covers the top cylinder head mounting nut which needs a 10mm Allen key. This is what I use.

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All six of the nuts on the cylinder mounting studs are now accessible and should be slackened a half a turn or so in a diagonal sequence. I do the top sleeve nut first with the Allen key then change to a 17mm socket and loosen the nut by the spark plug. Then out of the remaining four I do lower left, upper right, lower right and upper left.

It’s now time to get out the torque wrench and tighten them all up again. The factory manual quotes a torque of 29 to 32 ft/lb and it’s easy to set my click-stop wrench to 32 so this is what I use. I do the tightening in the reverse order to the loosening, finishing with the top sleeve nut.

The blanking plug is replaced with the crush washer. It needs to seal or oil will leak onto the top of the cylinder barrel and work its way around the cylinder till it appears below the plug.

Next, the rocker gear is replaced. I hold a group – washer, spring and rocker arm – together and fit it in the support. Then I use a screwdriver to line them up as best I can before inserting the rocker shaft. The shaft has a screwdriver slot in the lower end so you can turn it till the hole is in position and the locking screw can be fitted. It is important that only the correct original length screw is used to hold the shafts in place. If the screw is too long it will block the oil feed to the rocker. Not good. Also, the torque figure for that screw is fairly low at 4.2 to 5.7 ft/lb so I just tighten them with a short spanner.

With the rocker gear replaced, and the piston still at TDC, I adjusted the valve clearances. The factory manual gives a figure of 0.22mm. I set them all at 0.2mm which is close enough given that there is a very small amount of wear in the pads on the ends of the rocker arms.

The rocker box went on next after adding a bit more grease to the gasket so that it will come apart easily next time. I generally tighten all the small Allen bolts in a diagonal pattern using a short key so as not to over tighten them and strip the threads in the head.

The same job was then done on the other side.

First engine oil change.

I decided that I would change the engine oil now that the first stage of “running in” is complete.

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I rubbed the oil between my fingers and it seemed pretty clean which was a good sign. On the spur of the moment I decided I would remove the sump and check for any nasty bits of metal. The V7Sport doesn’t have an oil filter cartridge, just a filter screen.

I removed the screws but the sump wouldn’t come off. It was well and truly stuck. I replaced the drain plug and gave it a bash with a mallet but it didn’t move. I know better than to thump the sump itself as there’s a good chance the fins will break off. Wedging screwdrivers in the joint face is a no-no as well. I have a very thin-bladed scraper which I carefully knocked into the gasket itself to split the gasket material. Having got it off, it was clear that I hadn’t greased the gasket before fitting it during the engine rebuild and, after fighting to get the sump off, it was good to see there were no nasties in there. So, I just wiped it out.

I then had to spend a long time carefully scraping off the remains of the gasket without damaging the gasket faces. That was easy enough on the sump but, I had the bike on the ground and had to scrape the bottom of the engine block while laying on the floor.

Eventually all was cleaned to my satisfaction and I refitted the sump with a new gasket. I didn’t have the correct sort so cut the redundant parts off a gasket intended for the later models with a cartridge oil filter.

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This time I made sure the gasket got a coating of grease so it shouldn’t be stuck next time. On these bikes you don’t need to keep taking off the sump to change an oil filter but, I still like to take it off and give it and the filter screen a clean from time to time.

Then it was sump plug back in with a new crush washer and 3.5 litres of engine oil added.

That’s it for today. However, I’ll be back soon as I’ve bought a trailer to tow behind the bikes! Hmm.

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2nd Marches Italia bike meet – 5 Jun 2016.

Today I climbed aboard the Racing Rhino and headed over to The Powys Arms in Lydbury North, Shropshire, for the 2nd Marches Italia bike meet. I went last year on The Fire Bike and, like then, the weather was perfect.

The 85 mile run there was enjoyable with surprisingly little traffic about. My route takes me up the coast of Wales to Aberystwyth then inland to Llangurig and Newtown. Then on to Bishop’s Castle and Lydbury North.The weather forecast was for rain on the Welsh coast for my return but I managed to make it home just as the first drops fell. At times today it did feel like my main purpose in life was to kill as many flies as possible. You should see the state of my riding kit!

The meet takes place in the pub car park. You can see that the turn-out was pretty good.

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The Rhino was parked among friends.

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There were plenty of Guzzis. I took photos of some of the older ones.

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This is a Quota-engined T3 hybrid.

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Then there were the Ducatis.

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There were a couple of Laverdas. I particularly liked this one.

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Big and little Morinis.

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There was a lot of more modern stuff which was nice to see as well. I enjoyed my chats with old Guzzi friends, made a couple of new ones and was able to put a faces to those I’ve only met via the web.