Triumph Thunderbird top end rebuild

[ianyonok]

I'd done over 12,000 miles on the '59 Thunderbird but over a long period, due to limited opportunities before I retired. In fact the engine hadn't had a top end overhaul for about 15 years. The manual suggests decarbonising every 10,000 miles...... a bit different to a modern bike.....

The frame tubes look quite skinny with seat and tank off.

This is a Boyer Bransden twin coil with a Podtronics electronic rectifier/regulator mounted underneath. This set-up replaces the original Lucas coil, distributor, selenium rectifier and regulator.

Looking well used...

Does indeed need a clean-up

That's everything off and there is a broken barrel fin. The head and barrel are cast iron.

The timing side little end bush had been rotating in the conrod, so I red loctited that in this time.

Old gasket material cleaned off crankcase mouth

The valve gear was well coked up and it took some work with WD40 to get the exhaust valves out.

Welding cast iron is difficult and needs special rods and equipment due to different expansion rates if used non-matched material. But, I picked up this trick on the internet. Drill through the top broken fin and the fin below. Thread the bottom holes and countersink the top holes. Using countersunk socket head cap screws, bolt the broken fin piece down to the next fin with packing washers to the right height. It will never be noticed. I put some epoxy on the joint to avoid any possible vibration.

I need to replace the air filter hose, $48 on ebay. I patched it up for now using a bicycle inner tube patch repair kit. Will replace hose later.

I have nice stainless steel barrel studs. Coarse Whitworth thread lower into the aluminium crankcase and 26 tpi British Standard cycle thread upper. One of my whitworth spanners is a 60 years old "King Dick", inherited from my Dad....

Pistons and rings back on. The ring gaps are a little oversize, so I expect a small amount of smoking. I'll replace them next rebuild.

Barrel bottom gasket made from locally bought 1.4mm gasket paper (made in England, so suitable for the job....). The black paint I used on the barrel and head is ATM 1200 degree F in aerosol cans, bought from Nana Screws in Chiang Mai. Took over a week to go hard but appears to be good stuff. However, iron heads get so hot around the exhaust port I expect it will burn off after some time.

Barrel on.

Valve gear cleaned up, valves lapped in and head on.

Rocker boxes on.

Amal Monobloc carb and Toga "Burgess" exhaust system fitted. Amal carbs are now owned by Burlen Fuel systems and doing very well. They are re-manufacturing all the Amal models; Concentrics Mk1 & 2, Monoblocs, 276s, TTs and GPs. Plus full service kits and upgrade parts like chrome slides and "stay-up" floats.

The Triumph vertical twin must be one of the best looking motorbike engines ever made. Timeless beauty.

Ready to get off the stand......

..... and time for a test ride.

 

[Ian Bungy]

Wow Ian, Beautiful Work! Loved that Fin Repair! Looks like a Brand New Bike! Congratulations on a Job Well done! Great that Now You can Buy a lot of Brand New Parts for Old Bikes! The Power of Internet has been a Help also! When used a Positive Way!

 

[ianyonok]

Hi Ian, Thanks. I think there may have been some juicy engine photos missing, which should be visible now.

Yes, it's a clever trick with the fin repair and seems to have worked well. It is quite amazing that so much stuff is available, much of it new, for a plus 50 year old bike. Ebay is a wonderful thing. Lots of little companies are operating, re-manufacturing parts to keep classics on the road. I have also recently bought a reconditioned Lucas magneto and then a reconditioned Lucas dynamo for my 60 year old BSA M33, through Ebay, from guys who specialise in rebuilding these items. Both look like new, inside and out.

Thanks for the tip on the high temperature paint by the way, from Nana Screws, on the moat. It took ages to dry and I called up the shop questioning this. They said the paint was probably out of date and no good......... but they'd give me my money back. It would have taken ages to get off..... So, after some investigation online, I found some posts on thaivisa.com involving "Hoghead" talking about it. This high temp paint is weird stuff, made of silica ceramic. When washing brushes etc in thinners, it breaks down into tiny granules that don't dissolve. Hoghead had noted that it needs to be cooked on after application. I had to assemble the barrel and head with it still tacky (cooking engine parts in wife's oven would have been pushing my luck....!) then after running up the engine, it went really soft, like I'd just sprayed it on..... but now seems to have hardened.. I think it may turn out to be good stuff.

 

[Hoghead]

When back in Canada this summer I cooked my Healey brake drums in Mom's oven to cure the paint and she hardly complained at all
Turn it up as hot as it will go for 1/2 hour or so, turn the oven off and let it cool. Best to have the exhaust fan on as it will fume a bit but no more than the average understanding wife will tolerate if you do it when she is out shopping

Will do doing my Enfield head and barrel next week while Mrs Hoghead is out

Your bike looks great and I wish I had a way go getting my BSA B-31 across the Burma border

 

[KenYam]

Hey Ian

Top photo's and congratulations on rebuild, your knowledge on Triumphs is very professional. I rebuilt a 1968 650 Triumph Saint many years ago, a very enjoyable project that had a few hiccups finding parts. The internet makes life much easier hey? Hope your test run went well? I would not be surprised is she burnt a little bit oil as sometimes the piston ring seal has been disturbed - how did this go mate?
After waiting over 4 months I finally took possession of Gary's 1300 VStar last week, so I set for cruising around now all I need is the new highway into China to be completed and to give up working like yourself ha-ha.
P.S. I like the colour scheme of your bike combines old and new styling.

 

[ronwebb]

Just brilliant all these little tricks one picks up.
Thunderbird is look'n good Ian.

 

[ianyonok]

Hi Hoghead,

Presumably your experience is that the ATM 1200 is good stuff?

It does cook on with heat it seems. Mine has gone hard now after running the bike a little. Off for a good long run this weekend. In fact going to see a collection of classic bikes down south from here, which include a couple of Triumphs.

There is a 1949 B31 for sale in Mae Sai, at Chad's place, pretty well complete. I asked Chad about bringing more bikes over, but I think he got burnt and won't do it anymore. I know someone who is bringing a container of VW beetles (some convertibles) and an old Triumph supposed to be in good condition, in very soon. Don't know what the bike is, but I expect it will be for sale. This contact is a bit erratic though, so we'll see.

Hi Ken,

Yes, hiccups indeed in every build. The manual says 11-14 thou gaps on the two compresion rings. I have about 20 on both...... does seem to smoke a tiny bit on the timing side, but I couldn't be bothered to wait on an order of rings, so rebuilt with what I had. Next time though, I'll hone the bores and fit new rings.
The correct colour for my bike should be charcoal grey, but couldn't bring myself to spray that. The black and white is the correct colour scheme for the 1958 T110 Tiger, but I got a new seat made by the classic bike seat experts, RK Latham in Birmingham, but with a white top for the climate here.
I do have a wealth of info on classic Triumphs here, as it's been my interest for the last 20 years.

You'll love gary's bike, a big beast but super comfy I think.

 

[ianyonok]

brake034;282741 wrote: Hi Ian,

What paperwork is with the B31?

Simple answer..... none.
No problem living round here.
It's a lovely bike, tinware in good shape. Classic lines of tele forks and rigid frame.

The cafe racer is a '71 Triumph TR6R Tiger 650 that I've modified with clip-ons, rear sets, sweptback exhausts, mini Gold Star silencers and Morgo 750 conversion with high-compression pistons and big valves. Goes very well....... the tank is actually steel sprayed with a mix of clear lacquer and aluminium powder but it does look the part.

 

[DaRider]

Makes you wonder if someone will post a similar thread on any newly produced bike in about 50 years?

Many thanks for posting. I really enjoyed reading that.