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19 May 2020

Lockdown Project

Part one

Dave Newman

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How many bikes should a poor boy have? Can you have too many? I think we all know the correct answers but we will ignore them and get just one more. Just the one more.

Most of mine are either oldish or old and range in need, from a bit of TLC to complete rebuilds. There is just never enough time.

Well I may have resolved that particular issue by resigning from my job. Potentially an irresponsible move but hey, you only live the once and if something doesn’t make you happy……. So once all the decorating and other long awaiting household tasks are out of the way, I will start on those bikes. Maybe even sell a few of them.

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In the meantime this here bike kinda fell into my lap. It was through my job that I came by the bike. My work has for many, many years been with motor projects, mainly using off-road motorbikes. Over the years there have been a couple of stand out bikes for working with young people. Number one has to be a Yamaha DT 125, once the most stolen model in the UK. These bikes were never the quickest or lightest but very rideable, strong and reliable. Another favourite was the Honda CRF 230 an air-cooled four stroke single. Disc on the front, drum on the back. A simple reliable machine. It was one of these that I have now got.

As a teaching aid it is certainly a fine tool. The power is gentle but adequate for the job, the suspension is Honda soft. However my desire is to improve on these areas to make the CRF a more viable long distance (relative term) trail bike.

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The bike was all there and ran OK but tired and unregistered as it had been used to teach young people how to ride on a dirt track for many years. It was very clean but that belied the amount of use ie had on a muddy/dusty track at the hands of young herberts followed by intense jet washing. That high pressured water gets into all the nooks and crannies which takes its own toll over the years.

My other off-road bike is an 06 KTM LC4, in comparison with the CRF it is a huge beast with its 625 motor, 21 litre fuel tank, racks for panniers. It weighs about 40 kg more than the Honda and is 75 mm taller at the seat. The KTM is a great, reliable and relatively comfortable bike and I have done big miles on it. However on the more slippery, technical, nadgery tracks and trail it can be a bit of a handful.

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I will now introduce Mark into the situation. He has been a friend for more years than we care to think about. Mark is very good at understanding clever stuff and fixing stuff. For example he can explain, in detail, how suspension works and why. For many of us the boingy bits on the front and rear go up and down helping to keep the bike going where you want it to over the bouncy bits and helping to make it all more comfy. We may know a bit more about rebound and compression, maybe not. Mark is one of those that knows the whole why and wherefore and as such an “essential person”. Mark has himself a CRF 230, which was also a well used bike when he got it and in need of some restoration. Therefore he is the perfect person to go to, having already researched and developed the necessary mods.

What we didn’t want to do was turn the little trail bikes into something they are not. If one wants a high performing, powerful bike there are many easily available. No, we just want to improve on areas where Mr Honda chose not to, probably for budgetary reasons, and release the bikes potential.

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The plan was to get the bike sorted for a two day trail ride in Wales towards the end of March and then the to head to Spain in June to take part in Austin Vince’ Pyrenees Up followed by some extra days trailing in the Spanish Mountains.

As with the Best Laid Plans of Mice and Trail Bikes we have become victims of THE VIRUS. In the grand scheme of things, fairly insignificant victims. Both events were of course postponed, so the work on the bike became less urgent and slowed down but not stopped. After all most of us have time on our hands and spares can still be bought. Where possible the spares have been sourced via a reliable and reputable company, can’t remember their name right now but I’m sure it will come to me later.

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The one thing that does have to wait is the required letter from Mr Honda. A letter from the manufacturer confirming the Year of Manufacture is required before a bike can be registered. Supplying such a letter is one of the services that has been put on hold whilst everyone is working from home or furloughed.

So, what work is being carried out?

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Firstly suspension.

I am more than qualified to explain in great detail what has been done to the rear suspension. It has been replaced. A superior unit from Alf Hagon has been bolted on, simple.

The forks are a different matter and a tad more involved. Within forks there are damper rods that have holes in them that allow the oil to go in and out at certain rates. The holes on the 230 rods are too large so they are welded and re-drilled which gives improved damping. The springs also require attention. The top 6 inches of the springs are more tightly, the idea being to provide a “progressive” action. However this doesn’t work too well so Rome radical action is necessary. About half of the tight coils are cut off. The top of the spring is heated red hot and ground flat then a spacer made to fill the gap reducing the pre-load to 1-2 mm.

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Chasis.

Basically all the bearings are replaced following the aforementioned hard use and jet washing.

Carburation.

The “snorkel” on the air box seriously restricts the amount of air that the poor little bike can take in. Consequently it is consigned to the bin.

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Honda jet the carburettor far too lean. (Too much air, not enough petrol). Therefore jets with bigger holes will allow more petrol in the mix. The needle has been raised a notch too. None of this is an exact science and some experimentation can be required so we will need to have a couple of rides before the best result is achieved.

One other mod is to remove the “return” throttle cable. The spring in the carb is more than strong enough to ensure the throttle does not stick.

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Engine.

Once the oil filter had been cleaned, not much dirt in there, the bike was run up and it smoked a little. I say a little but enough to justify taking the top off to check the wear. It is worn. Not terribly but a new piston is in order, half mm oversize will be fitted soon and a new cam chain as it would be churlish not to.

Whilst checking the cylinder head, Mark noticed the inlet manifold did not line up correctly so a little judicious grinding has smoothed the pathway for the fuel.

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Valves have been reground and new stem seals are awaited.

Electrics.

Leaving the best till last.  

If suspension can be confusing it is nothing compared to the secret world of electrics. AC/DC, current going one way then the other, volts, amps, watts all silent and invisible. T’aint natural I tells ya! And yet essential.

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In standard trim the CRF only requires electricary to turn the starter and charge the little battery. The ignition is self generating, so is independent of the battery. However, now we will need sufficient current to run lights, brake light, hooter, speedo and maybe an output for a GPS. This means we want to do something called “floating the earth”. I have no idea but it sounds cool. We will utilise a bridge rectifier. It has four diodes, a diode is a one way valve for electric current. To be honest after this much information, along with talk of AC current and two inputs to the regulator/rectifier, I become bemused and confused. More information will be forthcoming with news of progress.

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That is about it for now. Hopefully things will improve for the whole world and not just us. We can keep our fingers crossed and look forward to getting out and about, perhaps on the bikes we have been working on whilst we wait.

Thanks to the good folk at WEMOTO for keeping us supplied.

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I will let you know how the work on the 230 progresses and maybe how it rides.

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