Classic Experts November 2006

First go at the clubman route at the Classic Experts trial in November 2006, a 30 mile, 30 section trial around Rhayader

I”d looked at doing the Rhayader Classic Experts trial before, but decided that the twinshock bike I had wasn’t really up to the job. But, the SWM helped to compensate for my lack of skill so time to enter. With next-door neighbour Gavin and both the Honda TL125 and the SWM in the van we set off for the hour or so drive to Rhayader.

Gavin was planning to ride round on the Honda to support the rest of the South Wales twinshock contigent, but found himself with an entry, so it was off to the local cafe for a fortifying bacon butty and a cup of tea. Wheeling the Honda out of the van revealed its less than prepared status, including non-functional forks. However, the gear oil on the van floor was from the SWM, with the hole in the clutch cover leaking again, despite the mag welding to fix it.

Gavin Spencer at Tycwtta

The 12 Clubman twinshock riders were away first, followed by the Clubman pre-65s and then the Expert twinshock and pre-65 riders. The first section at Llywncwtta saw me do a classic 5 on a muddy step at the end, not a good start to the day and one that got captured by Jack Parker for TMX; glad to note that others also struggled on this first sub. The next group at Cefnllyn was in a stream with lots of slippery rocks, a couple of threes and some dabs in these. Gavin was wrestling the Honda round and was beginning to understand the Honda’s limitations …but managed to blast it though the mud in the top sub to impress the onlooking crowd.

Kevin Pettit at Tycwtta

A bit of road work then to the third group at Cross Keys, in some trees near the A470. The first double sub was fairly straightforward, but the next double was probably the trickest of the day, up a steep slope, a tight turn and down over some very mossy rocks…two 3’s on this.

The other lads from the “Tredegar Twinshocks” were also going well, in particular Alan Gould on his TL250 and Kevin Pettit on his newly acquired TLR250. Mark Evans and Mark Taylor were also in the group and they to were enjoying the challenging sections.

More road work down to Newbridge on Wye and then up to the group at Tycwtta, which were in a wooded gully. The first section had a nice awkward move round a tree, which Alan and Kevin cleaned. The second-double sub was straight up the stream, with a couple awkward turns; I managed to get through with only a dab, but Kevin cleaned it.

Malcolm Herbert at Tycwtta

An enjoyable off-road ride took us down to the next group at Horid were through some difficult rocks in a wood. The second sub was ridden well by Gavin and Alan, as it involved missing a large tree branch at neck height and going over a 3 foot boulder. I chose the wrong gear here and didn’t have the bottle to leap the boulder.

The two sections at Doliago were straight up a steep and rocky stream and a lack of forward motion meant I had a five in the second sub. The top two sections were slightly easier, but I dropped a couple of silly dabs here too.

Back down to the main road and after a trip to the petrol station, it was across the road to Ashfield, with two double subs in a stream. Managed to clean to bottom set, but had to take a 3 on the top section as I didn’t enough get enough drive out of the stream onto the steep slope out left.

The last group at Hillgate is only a mile or so from the finish and there was a large group of spectators to watch the Experts tackle the large rock step. The clubman went to the side of this, but it still a case of going for it up the narrow rocky stream bed. The last section had a tight uphill turn to finish, which meant a thrutching 3 through the last set of end cards. A great finish.

The first three groups were captured on video by Graham (includng the bloke trying to have a quick wee at section 2).

From the Clubman twinshock point of view, Alan on the TL250 took the honours, with Kevin in second. Myself and Gavin took 5th and 7th from 12 respectively. Not too bad, but an excellent trial which I’ll be back to do next year !

SWM TL350 Jumbo Restoration : Contents

List of articles on the SWM Jumbo restoration project, provided in manual-style layout and order

SWM Jumbo in action....


Starting work on the bike:
Getting another SWM
First Impressions

Engine Strip and Rebuild:
Engine Strip
Investigating the bottom end
Engine Reassembly
First Start for the Engine
Replacing the Piston

Carb and Exhaust

Bike Parts: Suspension:
Bars, Controls and Levers
Wheels and Brakes

Getting the bike running:
Starting the bike
Completed bike

On the Road
Getting the bike road registered

Bike Specifications
Specification sheets and diagrams

SWM TL350 Jumbo: Bars, Cables and Controls

All the cables were on the bike, some in better condition that others, but the bars and levers were in a basically knackered condition. The original bars were a little scruffy, so used a spare set of Renthal’s that I had.

The main cables/levers/controls on the bike are:
– clutch: with the cable in two parts, with the patent lever system that SWM developed for the Jumbo to lighten the clutch.
– front brake cable: directly attached the the front brake drum.
– throttle: setup for an existing metal domino side-pull throttle.
– decompressor: originally didn’t know the bike had a decompressor as it was completely missing, though later found the cable.

The clutch cable is in two parts, with a lever arrangement mounted on top of the cylinder head, to lighten the clutch pull. It does seems that this is no better than and possibly not as good as the clutch on my TL320, though mine does seem to be very good. The search for Aprila clutch covers seems to indicate that these usually provide a lighter clutch for TL320’s (and possibly more robust cases). Both cables seemed rust free and servicable, so decided to reuse them

Clutch lever

I did buy a new set of Domino levers, which are very durable and usually bend,rather than brake. I’ve fitted them to the Honda TL125 and they’ve been good.

Front Brake
Again the cable in not too bad condition, but had a spare new cable from the TL320 that I used, again connected to one of the new Domino lever.The main problem was the mounting on the front brake arm. This was over-tightened before and attempting to undo it resulted in it shearing. I’ve initially repared it with Chemical Metal, but I’ll need to fashion a replacement.

The existing throttle needed the attention of the impact driver to remove the cable, so decided to use a new slow-action plastic Domino throttle. The cable was also damaged inside the assembly, so threaded a new insert and soldered on a new end. Nice smooth action, with the slider spring giving a nice snap.

The decompressor lever was missing from the old bars, so got a replacement from Martin Matthews. The cable was located taped to the bike, so again managed to re-use that, though the new lever meant I couldn’t fit the cable adjuster in the same way so this will need to be improved prior to using the bike in action.

I had a set of Rentals that I’d taken off the 2003 Beta before I sold it. The possibly original bars are very tatty so decided to replace them. The only problem here was that the handlebar clamps are quite low to the top steering head lock nut. So much so that they are fouling and stopping the bars sitting properly in the clamps. I made a modified top nut, with a lower profile to allow the bars to sit correctly.

SWM TL350 Jumbo Carburettor

The hidden secrets of the carburettor revealed. It was as bad as I thought it might be and again evidence of the bike being a long term non-runner.

Whilst working on the engine, I’d resisted the urge to have a look at the carb, knowing that the time the bike might have been standing and not run was going to have an impact. And, yeah taking of the float bowl showed the extent of the dreaded yellow gunge, solid in places. The carb is a -28 Del’Orto, which is slightly larger than the -26 carb from the TL320.

The Carb, before cleaning

Stripped down the carb, by removing the float bowls, main and pilot jets and then sprayed lots of aerosol carb cleaner. I used an airline and some paint-spray cleaners to work on the jets. I then went round and did it again.
Cleaning out petrol residue must down as the worst job for with any bike.

The main problem with was with the float valve needle, where the spring loaded rubber end cap was damaged. After assembling and fitting the carb, petrol just flowed through, so the float valve wasn’t seating properly. I had a spare one from a smaller 26 Del’Orto carb, so swapped that in and this then cured the problem. I didn’t adjust the float valve height and kept it as is, as once the bike is running I can then look at tuning the carb if needed.

The airbox, carb hose and inlet manifold were also checked. The airbox has seen some action and has felt the effects of the exhuast midbox. I used some silicon sealant in the largish cracks and filled in the holes. It looks like the original top of the airbox is missing, as the metal cover has has some rudemetary holes drilled in it and doesn’t look like the finished article on the TL320.

SWM TL350 Jumbo: Exhaust

Cleaning out the exhaust system on the Jumbo involved some serious surgery.

The exhaust system comes in three parts; the front pipe, mid-box and the rear can.

The front pipe was corroded by in a useable solid condition, with the mid box complete but full of carbon from 15-20 years of use. The end can had had open-heart surgery in the past, and was in a rough state. I’d sent the exhaust off to Redditch Shotblasting along with the frame and other bits and they shotblasted then spray the parts with PJ1 Black Satin Engine paint (ie heat resistant paint).

In an attempt to clean out the rear box, I’d swilled around some paraffin in the box, then moved it out of the workshop into a the field. I took the blowtorch, attached it to a long stick, lit it and applied to the end can. The resulting explosion only moved the end can a couple of feet, didn’t split it, but for sure loosened the crud inside the exhaust.

However, still thought that end can some needed some attention, so decided to cut out the back plate and weld on a new one. Remove the packing at the same time, as it was completely knackered. Then, with some trepidation, decided to take the air saw to the till-now virginal mid box. Allowed me to clean it out and again removed the packing.

Work on the exhausts

Both welded neatly by Pete and then sprayed again with PJ1 Satin Black, three coats and with the space heater in the workshop cranked up to get up the required 21 C for spraying.

SWM TL350 Jumbo: Getting the engine started

After spending most the proceeding 3-4 days in the shed cleaning the carb out, and then using the airline round at a friends garage to clean it again, thought it was time to see if the engine started.

Connected the tank from the TL320 (the tap on the Jumbo was still full as slime), but the carb flooded. When cleaning it earlier, Pete and I had noticed that the float valve was damaged and the rubber cap might not seat properly; it didn’t. Swapped the float needle from a spare 26 Del’Orto carb that I’d got for the TL320 a few weeks ago and put it back in place (will need to replace that if possible)

Applied the choke, pulled in the decompression lever and she started first kick., a bit noisy as I was in the process of spraying the exhaust boxes at the time.

Clip of the second attempt….

Getting the engine runnng is good, but not sure what the timing etc are like, so still plenty to do before I have a complete running bike. But after lots of set backs (and splitting of crankcases) its good to make some real progress.

Engine in Frame

SWM TL350 Jumbo : Forks

When I got the bike, there was something wrong with the forks, in that they made a rather wierd hissing noise when depressed and seemed very notchy.
Looking at the fork components on the bench:
– the are 35mm diameter forks, not 38mm like some of the Jumbo’s
– there seemed to a lot less componentns than there should be
– the forks are in fact different.
SWM forks (dismantled)
Looking at the right hand fork (RH side in the picture), the bottom bush is not metal, but nylon and the bottom of the fork tube has been hammered over to hold it in place. A quick call to Martin Matthews confirmed that this is a little non-standard. The Nylon bush is an 16mm diameter hole for the bottom rod to pass though, which is a little tight. A dry-run assembly of the fork shows whilst the fork seems to have worked in the past, it now can’t be loaded.

The RH fork has some heavy corrossion around the area of the clamps, so replacing the tube with the bottom bush is a possibility.

The hissing noise is caused by the fork tops having their venting system not in place. Inside each top, there is a ball-bearing/spring arrangement to allow over air to escape if their is too much pressue. This is not in place.

Fitted to the new seals to the the fork bottoms, which were rubber backed unlike the original metal caged seals. These are 35mm inner diameter, 47mm outer and 10mm depth, double lipped.

SWM TL350 Jumbo: First rebuild

After getting the engine into the frame, the stator plate went in and then set the contacts. I’d put in new contacts and condensor, just to make sure they worked, though it did take two condensors. Getting the condensor out of the stator place takes some persuasion with a hammer and a bolt and a little bit of heat on the plate.

Anyway, connected in the electrics to the ignition coil, connected a plug and hey presto, a spark (something the bike hadn’t done since I’d had it). Checked the gearbox, still worked, but after a few more kicks, the kickstart siezed and would turn over. Arghhhh. You could still the engine over on the flywheel, though it seemed to tight.

Over the next three or fours sessions in the workshop looked to debug what was going on. I stripped the engine back out of the frame and removed the clutch and flywheel. The kickstart worked, so therefore no need to break the cases again (thank you). Looked closely at the clutch assembly, but putting it back in place seemed to have no adverse effect.

To cut a long story short, when I took the bike apart I had to use an impact driver of three mangled screws that hold on the plate behind the stator plate. I’d replaced these with some I’d got from Metal Work Supplies but the counter-sunk heads were slightly taller and in were rubbing against the flywheel. A simple thing that took me (and friends) 6-7 hours to suss out exacltly what was going on.

Engine back into the frame, check the gearbox again and onto look some of the other parts on the bike