Trumph 1940 Speed Twin

[Hoghead]

Excellent job! Plugs....always worth a double check.

[Dexter]

Excellent job! Plugs....always worth a double check.

So working through setting the carb up its running a Amal TT9 and some of the issue wasn't helped by being to rich on the mixture screw , i also talked to "The Green Spark Plug Co" who highlighted that that carb set up could be leaving a deposit on the plugs which would cause the lack of spark, this was sort of proven when following a 40 mile ride the following day no pops or bangs - fitted new plugs fired up first time, so still some more tuning work to do will be taking the main jet down a size to see if this make any improvement but this will be done at the track.

[datadavid]

Sweet bike, im gonna get an overbore done to mine too soon. Ring gaps about as wide as yours but it doesnt smoke..just getting sloppy, bottom end needs done too..
Anyway, about the stock rr56 hiduminium alloy rods. The thing is they are very durable but the alloy weakens with age and heat cycling. May last forever in a stock, cool running motor. But I'm changing my conrods next time i tear down the engine, and my rods are probably 27 years younger than the ones in your engine. I dont remember how many hours they lasted before being replaced in the merlin engines but i think they were a bit more stressed there lol

[Dexter]

You could be right on the rods - I had no play and I knew if I took the bottom end apart it would end up doing the works and all that Castrol R would need to be cleaned up off the cases.....so I have resisted so far. I am on the look out for another set of crankcases so i can do a full build but that's going to be this winter if it happens - right now its all about riding, good luck with your build be interested what you find when it comes apart

[KnuckleShove]

I spend A LOT of time in London for work and on weekends travel around a bit. The thing I love about the UK is many still have this love of classics. I read through this thread and it was great thanks for keeping this up. What an amazing bike and adventure.

[Dexter]

I spend A LOT of time in London for work and on weekends travel around a bit. The thing I love about the UK is many still have this love of classics. I read through this thread and it was great thanks for keeping this up. What an amazing bike and adventure.

Thanks plenty more to come yet.....next plan is to build up a new front wheel with an 8inch drum brake for some more stopping power along with some other tweaks

[datadavid]

You could be right on the rods - I had no play and I knew if I took the bottom end apart it would end up doing the works and all that Castrol R would need to be cleaned up off the cases.....so I have resisted so far. I am on the look out for another set of crankcases so i can do a full build but that's going to be this winter if it happens - right now its all about riding, good luck with your build be interested what you find when it comes apart

Oh, i know exactly what I'm gonna find lol..
Mismatched conrods since it was what i could find 15 years ago and one small end was toast. Had a new bronze bushing made for the timing side, fixed a few pulled base studs, guess its due for the rest now. Anyhow, last time i checked the main bushing was getting well worn and vibes have increased. May as well have my engine guy have a good look at it when i bring him the boxes. He appreciates getting everything disassembled and degreased lol.

[Dexter]

Loud exhaust to be expected as since its straight through......but no good for the planned track day with an imposed noise limit of 105db, bought some slip in baffles which has helped some, looks to now be right on the limit so maybe some fibreglass insulation wrapped round the baffle from the loft with be the ticket.

[Hoghead]

Loud exhaust to be expected as since its straight through......but no good for the planned track day with an imposed noise limit of 105db, bought some slip in baffles which has helped some, looks to now be right on the limit so maybe some fibreglass insulation wrapped round the baffle from the loft with be the ticket.
[ATTACH=CONFIG]108328[/ATTACH]

Had varying results with that kind of baffle. Noise limits have been an issue at British circuits for a long time. Brooklands Cans were the answer years ago.

Must have worked:

The Tiger 100's sporting pretensions were later further proven through Freddie Clarke's 1939 lap record at Brooklands of 118.02 miles per hour (189.93 km/h) on a bored-out 503 cc Tiger 100.'

[Hoghead]

Loud exhaust to be expected as since its straight through......but no good for the planned track day with an imposed noise limit of 105db, bought some slip in baffles which has helped some, looks to now be right on the limit so maybe some fibreglass insulation wrapped round the baffle from the loft with be the ticket.
[ATTACH=CONFIG]108328[/ATTACH]

BTW- don't use loft insulation fibreglass , the right stuff for silencers is easily (and Cheaply) obtained.

[Dexter]

Track days what an epic idea, so come the day set off early and arrive around 8 at Castle Combe, dry weather so all good. We were in a group organised through the Brooklands Museum so a cross section of old bikes, Combe is a fast flowing circuit with some chicanes added to slow up the bikes, there were cones out to show turn in apex and braking locations but to be fair my plan was to stay on the bike and feel my way in + the engine was run in but untested in track condition ( bit like the rider
No real issues during the day Noise test passed no problem, the plugs look very white after the first run and although the main jetting felt ok on the road it was clearly too lean, we carried out a couple of main jet changes ending up with 320 but there is more playing to be had when the rider gets up a few more brave pills. The bug has certainly bitten and with this in mind I am now have some new crankcases and all the bits to do a bottom end build so I know its history - some of the old engine will be used like the crank but I want to see what cams its currently running before I make that choice. Anyway here's some pics from the paddock

[Dexter]

Fitted up with a classic style belly pan

[Dexter]

Things have taken a few twists and turns recently with the ST developing a misfire and dumping me at the side of the road.....good job its light for the push home So simple these bikes not much to go wrong found the timing wheel had slipped on the mag taper and on closer inspection ( it was an alloy replacement fitted when i bought the bike) to have a hairline crack not the main issue but added to the fun...

Friend sent me a STD timing wheel with the fibre wheel but steel centre and after some fun a games on the lathe I had made up a steel centre alloy geared timing wheel so stage 1 complete.

Then the real fun started - check spark Nope, take the mag ( Lucas K2Fc ) out try it on the bench Perfect spark even jumps a 5mm gap, return to the bike & check for spark Nope, rinse and repeat till your convinced you have lost it, put it in the post back to the guy who rebuilt it a while ago but no real miles see what he could find. While this was going on had another job checking the clutch pulled the centre out and found the internal splines had more wear than I was happy about - this type come apart and have the rubber cush drive but buying parts looked to be more expensive than buying the whole thing so......why not buy 2 so I have one for the other build.


So clutch got a rebuild and in the process a new tab washer and securing shouldered nut so that should be that, also had a tip off of another mag for sale which had a recite for a extensive rebuild good price so pulled the pin ( always sell one later - sun is out you know the score)

New mag arrives looks good guy has spent the asking price for the rebuild so looks a good deal - had to make up new leads as the old ones when with the old mag just in case, all fitted up and timed just need to do the kick start thing, in other news the old mag had a broken wire to the condenser which was potted in the windings so causing an intermittent spark.....so at least I am not going mad this needs a complete rewind so 5 weeks out but he's doing it under warranty so lets see, this one has the manual advance where the new one is fixed so maybe a change back when its home again.

So the suns out and all it needs is a good kick I hope - wish me luck......

[Dexter]

New clutch works just like it should

[farmall]

BTW- don't use loft insulation fibreglass , the right stuff for silencers is easily (and Cheaply) obtained.

Various stainless steel wools are also available.