Honda TL125: Assessment

The Honda TL125 hadn’t been used at a trial for a few months, so it was good to see Lee (eventually) finished the Wye Valley classic trial at Bowley Court at the end of October 2006.
The bike did break down twice:
– a connector on the electrics came apart, outside of a section and whilst I dashed back to the van for a plug spanner, Lee found the loose connection. Replacement and improvement of the basic wiring desirable.
– the split-link on the chain failed: luckily Mark (with the KT250) had the right split link with him. Need to get a replacement chain or sort out the tensioner and some spare split links.

Also, on the list of things to look at:
– front forks: the TL125 forks are woefully weak and despite putting spacers into the tubes, they bottom out on a regular basis on most sections with steps or steep downhill
– re-wiring of the electrics
– rear sprocket; have a replacement but also need to change a couple of the mounting bolts
– chain tensioner needs an overhaul

The bike has already had some significant mods and the engine overhauled following it generating lots of smoke at a trial in January 2006. The main mods are:
– changed to the carb to one half of a set of CB360 carbs; far better throttle response. Use a clip on filter rather than the original airbox
– Miller 150 cc kit was on the bike when I acquired it [[The conversion kit that results in a wafer thin liner, that you can flex with your fingers.]]
– Domino throtte and levers on a new Renthal bar
– new rear shocks from NJB. There a couple of plates welded to the swinging-arm to that normal (13.4″) shocks can be used rather than the original (longer) shocks

Anyway, given time on other projects, will work on the TL125 in order to improve it further, but always limited by what was a pretty ordinary bike in its day. They were cheap then and you can tell.

SWM TL350 Jumbo: Reassembly again

A thorough check and testing of the gear cluster proir to another crankcase reassembly; seems to work this time.

As mention in the previous article there seemed to be a couple of machined washers missing from the gear cluster, so with replacement and movement of the washers to the right place, I put the cluster back into the right-hand crankcase. You need two pairs of hands [[comment from someone at the Wye Valley trial yesterday was that you need three people to reassembly a SWM gearbox; two people to work on the engine and one to be on the phone to the SWM dealer]].
Gear cliuster in neutral with the selector gears not engaged to the main drive sprockets

After moving a couple of washers around and some experimenting, tests on the gears with the crankcases apart seemed to be ok. This time, the primary drive socket on the shaft was put on with the cases apart and it seemed there was space for the tab washer to engage correctly and the shaft seemed to still work correctly. Decided to therefore go for assembly of the cases (for a second time), with the crankshaft still in the left hand case.
Gearbox cluster in place whilst being tested
Pushed the cases together, making sure that the kickshaft spline was engaged and then with a 7-10mm gap between the cases pulled them together using the bolts around the crankshaft, making sure they came together evenly. I used some (black) Loctite flange sealant around the case joints, not using too much. Put the kickstart sprockets on the outside of the LH case [[Make sure these sprockets, the idler in particular) are on the right way round.]] and then put the clutch assembly back on. Put the piston and barrel back in place, making sure the piston rings were placed correctly by their pegs. The pegs are pointing to the front on the piston, but not sure it matters which way round they go. Put the head on and tightened the bolts using a circular order, having replace a coupled of the knackered elongated head nuts earlier. There is no head gasket and it was clear that the bike had been run (badly I guess) with a gap between barrel and head because of the stripped head nuts.

I then put the engine in the frame, prior to putting the stator plate and flywheel on the RH case. It’s much easier to get the front engine bolt in place without these in place and I put this bolt in first, fairly loosely. Then put the top bracket in place, followed by the swinging arm / engine mounting bolt at the rear.
Engine in frame

SWM TL350 Jumbo : investigating the bottom end

Initially the plan was to change the crankcase seals on the Jumbo motor, but re-assembly of the gear clusters and selectors involved the exploration of some deeper mysteries.

To reassemble the crank cases, you need to move the gear cluster and selector to the LH crankcase, so that you can engage the gear change to the selector drum prior to reassembly. Though seemingly straightforward, it turns out that this is not infact the case….

After reassembling the crankcases, I checked the all the gears could be selected, that there was a neutral and the engine turned over in each gear. Prior to putting the engine back in the frame, I attached the primary drive sprocket to only notice a little later that the gear selection was now more difficult, there was no neutral and that the engine locked in bottom and top gear. Crap.

Therefore stripped the engine again and looked more closely at the gear cluster.
Jumbo Gearbox diagram
After speaking my mate to Graham, who’d help with the previous assembly of the crankcase, it occurred to me that the problems only occurred after I’d install the primary drive socket. Washer (25) may not have been in place. Tightening the nut had possibly moved the shaft (11in the diagram) and caused the locking to happen. Its possible that a washer was missing, or that one of the sprockets was on the shaft the wrong way round.

Also, washer (7) was missing, meaning that sprocket (9) was free to move along the shaft and didn’t always disengage from the selector sprocket (6). Further testing of the cluster is needs, with it mounted into the LH crankcase, though only with the cases put together can you really test the cluster.

SWM TL350 Jumbo: Splitting the Crankcases

This article describes the process of splitting the crankcases for the SWM TL350 Jumbo as part of the rebuild/restoration process. I’ve (currently) done it a couple of times; first to change the crankcase seals and subsequently to sort out locking gear problems

Initially I decided to split the crankcases in-order to change the crankcase seals. I followed the following process:
– remove the engine from the frame; there are three mount points, bottom-front, bottom-rear (through the swinging arm) and the top plate. I removed them in this order and you will need to take the spark plug and decompressor out of the head in order to remove the top plate
– remove the clutch cover and flywheel covers from the bike
– remove the flywheel, you’ll need the Rotax flywheel puller or a suitable home-made tool. Looking at state of the nut and the ignition coils om my Jumbo, someone didn’t use only a basic (ie a hammer and chisel). Make sure the woodruff key is retained (you may want to replace it).
– remove the stator plate,(see figure 1). Then remove the rear plate with the three screws (I needed an impact driver to remove the butchered screws). You can then take out the wires and then the stator plate.
ignition plate
– remove the head bolts, noting the location of the types of bolt. Remove the cylinder head. There are two hex bolts holding the barrel in place; it should be then be possible to lift the barrel off the piston.
– I removed the piston before splitting the cases, by removing one of the circlips from the piston and pushed out the gudgeon pin by hand.
– I decided not to remove the clutch assembly before splitting the cases; this was mainly due to not having a suitable tool, more on this later, but unless you are changing the crankshaft seals you shouldn’t need to remove crankshaft nut (A in the diagram). This nut seems to be some form of an interference fit; its bloody tight.
LH crankcase
– remove the crankcase bolts; there are a set round the edge of the right-hand case and 5 by the crank shaft. The is one bolt on the left hand case.
– the using the pry-points on crankcase I started to level the crankcases apart and then using a soft headed hammer, then hit the RH end of the crankshaft. The crankcases should come apart fairly easily.
– the gear cluster remains with the RH crankcase (as the clutch is still in place, see figure above, mark B), with the gear selector remain in the LH case. This means that to put the cases back together, the gear cluster, selector drum and selectors will need to placed in the LH case, so that the gear change can be engaged prior to re-assembly.
– to remove the cluster, I then undid the clutch plate nuts and then the main clutch nut. starting by folding back the tab washer (the one on the Jumbo seems to be rather thick). I jammed by faithful 2p coin into the gear cluster and heated the nut to undo it. There is a special tool to hold the clutch basket AFAIK, but did see a trashed clutch basket (courtesy of Martin Matthews) which has made me wary of too much aggression in this area.
– you should then be able to remove the gear cluster, ensuring that you keep all the sprockets, washers, rollers etc in the right order.

My strip (and subsequent strip) of the engine was to change the crankshaft seals and then to resolve problems with the gear cluster and its tendency to lock. More of this later in a seperate article.

SWM TL350 Jumbo: First Impressions

The flush of excitement as getting a new bike (whatever state its in) is usually ended by the close inspection of your purchase in the comfort of your own shed.

It was later in the week that started to have a closer look at the bike. The engine didn’t have a kickstart, but I’d already obtained one from Martin Matthews so a couple of kicks proved that the engine wasn’t seized. However it confirmed that there was no spark. Swapped on a spare ignition coil I had from my TL320 and still no spark, though the multimeter showed a pulse. Pulled off the flywheel cover to discover the chisel marks in the flywheel nut and the need for the patent Rotax flywheel puller to get to the ignition coils and points.

The Rotax tool isn’t cheap (I found it on a model aircraft tools site which has since dissappeared) at around £45. Quick discussion with my next-door-neighbour, Gavin, produced a home made puller and off with the flywheel. One of the coils, the lighting coil was damaged (probably by someone trying to get the flywheel off without the right puller). No obvious problem, so planned to replace points and condensor.
flywheel puller
Cranking the engine over with the plug in seemed a little too easy and after discussions with Gavin suspicion fell on the crankcase seals and the likely need to strip the engine to replace them. Therefore a major rebuild/restoration project had started and I commenced with the strip down.

Other problems that were noted
– the head was loose on the engine probably due to two of the head bolts being stripped
– decompressor cable was present, but the level and mouting bracket were not there (I didn’t realise it had a decompressor in the first place)
– the rear exhaust box had had some form of surgery in the past and the mid-box was clogged full of crap
– the footrests were completly shot and worn-out
– the forks make a wierd hissing noise when depressed; there is a valve in the top of the fork legs which seem to be stuck open

So, unsurprisingly a major project had started.

SWM TL350 Jumbo: Getting another SWM

I decided it was time to get another SWM, as my TL320 had turned out to be such as a good bike. Always thought that Jumbo’s looked nice (in Bernie Schreiber’s book), so time to get one.

I’d mentioned to Martin Matthews (of that I was thinking of getting another SWM as my TL320 was going well and I needed another project for the shed.

He put me in touch with Terry in Scotland and after a few emailed photo’s and a couple of conversations on the phone, I did the 11 hour round trip to go and pick the bike up. Its always the way that the bike in the flesh never looks quite as good as the photos. [[This may explain why some bikes on ebay (say Honda TLR200’s) go for silly money.]]
Scottish Jumbo
There didn’t seem to be too much missing from bike, though the rear and front mudguards were knackered and the decompression level/cable was missing. There was no spark from the ignition so its unlikely that would have been run recently.
Anyway, after travelling 340 miles, it was always on the cards that I’d buy the bike, so it went into the back of the van and I headed back down the M74….. goes SPIP

I’ve decided to give SPIP a go as a CMS for, so will be working on putting in some content over the next few days to see it goes

SPIP is a PHP/MySql wiki-type tool; it seems easy to use and I’m keen to test its functionality over the next few days. Will let you know how it goes, but hopefully will provide a good way of writing up information my bike restoratation projects and also information on East South Wales and Herefordshire trials locations.

Trials Bike Restoration Projects

Start in setting up articles on trials bike restoration projects,, basically as I have to write up information on the SWM Jumbo rebuild I am currently working on

Start in setting up articles on trials bike restoration projects,, basically as I have to write up information on the SWM Jumbo rebuild I am currently working on

I am hoping to have a guide to help others in similar projects, hopefully the information will be useful.