Seager Engineering

02/06/2026

This is another set of early 1978 ish Ducati 900 bevel heads.. these are almost certainly not off the same factory bike .. the intervening 50 years has seen this bike having various repairs..and replacements

I’ve seen some dodgy seat installations before and various methods of removing but these had previously the seats drilled on the edge to sort off cut them in half…WTF and left cuts and divers in the counter bore… out with the TIG welder .. the seats had been replaced several times before and were humongous… so we made new ones out of CA104 wrought aluminium bronze.
These were turned here out of solid along with our colsibro valve guides ..
we also did our exhaust thread repair using our bronze nuts .. totally unique to us…
Then the head faces were cleaned up.. and the chambers plus timeserts in the plug holes..

I can honestly say this write up doesn’t even begin to explain the amount of hours that have been spent over the last two years to produce these Ducati repairs…… from concept to 3D scanning the original nut to 3D print a model allowing for shrinkage and machining, inc lost wax casting the bronze nuts,from designing fixtures and making them to buying materials and machining parts to obtaining all relevant dimensions.. and the relevant tooling!!!
Then advertising it and making it happen and still make a profit…
I did this because these bikes are younger and will help future proof this business… hopefully before the politicians f**k it all up!!!

But the jist of all this is
“ you can only p**s with the c**k you’ve got” meaning we have to make the best of everything we can!

02/06/2026

Suzuki T250 barrels which have our stainless steel exhaust thread repair .
This is a very easy job as we have the inserts in stock… all the jobs we do which appear regularly are easy..because we have fixtures and spares already in stock..
Thank god there are easy jobs because if there wasn’t it like swimming against the tide with nowhere to “haul out” and catch the tide the next day..

Jim pockets the head completely removing the knackered exhaust stub and helically interpolate a new 1.00 pitch thread and fit the insert .. the insert and the pocket are accurately machined so the bottom of the insert and the shoulder of the insert bottom out at the same time.. loctited in and with a special installation tool pulled up FT and cured in the hot tank… finished off with a flex hone .. the barrels are ready to go back on..
Another job off the list but we are still restricting our incoming jobs till we’re ready 😃😃😃😃

02/06/2026

Ducati 900 bevel drive head…
This is one of our first fully engineered by ourselves exhaust thread repair inc our replica bronze exhaust nut.
This head although not the exact first one we have done it was the first with previous repair that had failed..
Like so many Nortons it had a parallel aluminium insert that had only the top welded and had due to heat turned to a toffee like material and stripped.. the aluminium insert expands and when it cools shrinks away from the head, this makes the insert overheat even more due to the fact it’s no longer in contact with the relatively cool head and absorbs more heat from the exhaust.. it eventually fails..
I had to weld this one up because the guy who did the last repair bored out the head so big our insert was like a prick in a top hat…NFG…
But after welding Jim helical interpolated a new thread to fit our insert and then coincidentally machined the new thread for our very own Cnc made nuts.. these are cast especially for us and are a perfect replica..
Seats cut and the tiniest skim of the head gasket face to ensure a gas tight seal …. There is NO head gasket.

Apologies for those who are still waiting.. we are ploughing through our backlog and I’m ashamed to say it’s still long.. but please accept that not all our work is quick and straightforward and we are chronically understaffed..
Don’t think I haven’t tried to alter this but it’s a more difficult problem to solve than most people think..
I am still not accepting projects till we are more upto date

More stuff to come please keep looking… 😃😃😃

30/05/2026

27/05/2026

Norton 750 atlas
… it’s an upright 750 commando really but used a 6306 ball race on the timing side..
Like the early “ combat” commandos that the main bearings failed..
They failed because the crank flex “jammed” the rollers on the drive side and made them skid instead of rolling.
Now all crankshafts flex… not just in Norton commandos, but three piece Triumph cranks and one piece Triumphs too…. That’s why eventually they crack and break… but for the same reasons you need C3 fit bearings in Triumphs… C3 is the loosest radial clearance to allow for a bit of movement but still roll…. All Japanese cranks that run on bearings like Yamaha TZR 250 even though they have 4 main bearings and are all C3 fit still flex and often have fretted the cases so the bearings are loose…. The 4 stroke Japanese singles can do the same… only sturdy well supported shell bearing cranks turn all the piston pressure into torque… and not bend the crank.Engines now have larger mains but narrower and bigger ends but narrower and 5 mains for 4 cylinders… producing a short engine which can easily fit transverse in a car… modern bikes are the same..
Infact the Triumph TSS 750 increased its big end diameter and narrowed the rods again to stiffen and strengthen the crank.
However this Norton was changed like most of Nortons big twins to a twin roller superblend FAG bearing supplied by Andover Norton.. these have a increased radial clearance with slightly barreled rollers and should be set up with 0.010”-0.024” endfloat to allow for the crankshaft to “grow” width ways as the revs and horsepower increase.
This one had fretted the casings and we fitted tolerance rings to maintain the bearings in a well supported continuous grip.. they require a press to fit the outer sand slide in on a 1/2 ton arbour press with medium pressure feeling reassuringly firm yet not over tight. You can vary the fit by decreasing or increasing the diameter of the housing and there is a convenient table that lists sizes to torque figures that can be achieved with recommended fits for applications.. truth is these tolerance rings will provide constant grip on the bearing and allow the crank to flex and still remain fully supported unlike the original housings.
We also stripped and fully cleaned the crank, ground the ends ,fitted new crank bolts, supplied new steel rods… honed the bores, supplied new rings, New big end shells, set up the end float to 0.018”and Dynamic balanced the crank..supplied a new chilled cast iron camshaft and refaced the followers..
Yesterday was bloody hot and exhausting so I went to sizewell and then onto Aldeburgh for my supper and cooled down and relaxed overlooking the sea on the dirty wall next to the Martello tower.. a redundant bit of defence architecture from the early 19th century built to defend against a Napoleonic invasion😳😳😳 ironic really 😳😳😳
In the tranquility I wrote this ….
Only to come in today and Jacob my saluki has been sick and we have developed a loud and worrying squeak on the Cnc spindle..
Coupled with the current situation looks like the heat is getting to everyone and everything!

23/05/2026

Another Triumph Triple head that needed a few things correcting.
It had a dent in the rocker box and in the gasket face.. plus a damaged head stud hole all of which I welded and peened to toughen up the alloy and then machined.. the biggest problem was the centre spark plug hole had been helicoiled on the p**s and was not sealing at all.
So we mimicked the angle and position off the previous Trident head, by using a threaded adaptor and the digital spirit level… opened up the hole and threaded it 11/16” x 26tpi and recessed the top … made a headed alloy threaded bush and screwed it in FT with 648 loctite and spotted it down and fettle the inside to suit the chamber.
We made new colsibro guides with facility for our modern stem seals on both inlet and exhaust.. this was how it was … whether you fit them on the exhaust is up to personal choice.. personally I wouldn’t.
It had 6 new seats in top quality high expansion material suitable for modern petrol.
I matched the manifolds to the ports and we marked them Right,Middle and Left so they could go back the same.. we supplied new G&S short top valves, inlet studs and insulators.
And we also fitted our billet exhaust stubs.
I did go in today but boy is it hot and really didn’t sit well with me to be getting covered in oil and swarf..
So I did a bit of admin and came back home …it too hot for the dogs anyway at work.. they are better off here..

This head was given to me last year at Beaulie… that’s Sept last year😳😳😳….we are getting stuff done but this type of job is fairly time consuming and when you get as much of it as we do it can pile up so this week,we sent more out than came in, I’m limiting what we take on to the regular customers emergency jobs and not projects..
I have turned down 20 jobs in the last two weeks … some so ridiculous it hard to believe… I think YouTube misleads lots of people ..giving them untruths just to get clicks.
So the only way at the moment to get less in the shop is to filter out and be brutally honest and possibly we will have to do that on an ongoing basis..
There just isn’t enough of us..

One thing won’t change is our commitment to quality and for everyone’s information the invoice for all the labour and parts inc VAT was
£1900 … our hourly rate is half a main dealer garage but more than a tyre and exhaust centre.. and we have more machines and individual tools than both of those together😳😳😳

22/05/2026

1961 Matchless G12 heads
These heads needed new valves and guides… Jim made colsibro guides because the cast iron ones supplied we too loose. Seats cut and faced . But I had to repair the exhaust pipe hole where it had been drilled to retain the pipes and also repair a broken fin and tidy everything up.. the fin repair is almost invisible… so much I can’t really see it..😳😳😳
Jim also spotted down the head bolt recesses so the full force of the head bolt clamps the head
But they are done and ready to be sent back…
For those who are waiting we are doing our best and I must again reinforce we are not taking on any work at the moment till we get out of this pressured situation because it’s pushing both of us to a point that we don’t want to be in.

This job cost £1200 inc vat and delivery

19/05/2026

Triumph T15O head which came in for overhaul sometime ago..
both of us are working simultaneously on different jobs and trying to double up operations to minimise set up and keep dirty jobs together and clean jobs separate. Today is a weld and fettling day… so I do all the fin and chamber work and any other fettling work as well as ordering bits and dealing with HMRC😳😳😳😳
Jim is busy fitting guides and seats etc.
Would you believe it, HMRC are coming to see me and check that I’m doing the inward processing correct, that’s a laugh I said we are yet to process one transaction… to which he replied “well you will struggle a bit because your using small parcel couriers and not importers”….( he means shipping containers)
it’s difficult because people send stuff and put ridiculously high insurance value and we get clobbered.
I said to him.. had he not realised that all temporary imports were either repairs or samples as the word temporary suggests and HMRC should be making it easier for us small business to repair and EXPORT our labour…. the government is making it easy for Turkish barbers and v**e shops…. 😳😳😳😳
After all we will be spending it in this country…. To which he uttered a slight giggle disguised as a cough..
So for those who think this is a time consuming waste of my time… I’m typing this whilst eating in my time! and all be it slightly political if we get penalised for doing the right thing …. I’m just not going to do it… and others in a similar business say exactly the same…Andy at G&S said he has the same problem with sample valves… hopefully this fella from the customs can help us make working for people outside the uk easier… and before people say blame Brexit … no because most of our work doesn’t come from Europe… it’s USA,Canada and Australia .
Any hoo …
This triple head had all the Rockerbox threads timeserted 1/4 inc, new colsibro guides ( we make these individually to fit) G&S valves and assembled with new springs
This whole job cost £820 inc vat and delivery and collection… that’s a door to door cost

18/05/2026

A Triumph 5TA head that was a bit sorry for its self … not too bad but as always what looks like nothing gets bigger… so an area in the exhaust rocker area had what looked like inclusions … ie it had been welded and not very well machined.. initially I thought just cut it out and TIG weld it but cutting it back found more area that was cold lapped… that’s a welding term for filler rod that is layed on but not fused together.. I started to weld it and run out of Argon.. the weld goes all crusty and oxidised… I then had to clear out my van and get a full size bottle of Argon… that was Thursday.
So Friday came and with that came more drama in the form of a local joiner with a machine breakdown … so we fixed that …..had to because it’s hard to watch a grown man cry😳😳
Then We had to investigated an issue with a A65 we built a year ago,this had repeatedly been kicked over because of ignition and carburettor problems for most of the intermediate time and the engine build l**e had subsequently dried out… the main bearing bush requires the pump to generate pressure to lubricate the full width… ie it’s the pressure that “spills” along the full width ,so that had to come apart and we polished the crank and honed the bush and reassembled the engine with engine build l**e.. the bushes have 0.0015-0.00175” clearance but need oil pressure to float..Any hoo that was done,
in between all this we loaded a Ford 6610 short block which we had resleeved and overhauled with all new components but in all the excitement I forgot to load the cylinder head into the truck …😳😳😳😳
Then a guy came in about his Trident head that’s been here since I met him at Beaulieu last year… At 4.45 pm I was exhausted and said “ bu**er it” and went home.
So I came in Saturday early and welded the Triumph 500 head with a big lump as it all was a bag of sh*te and a couple of other heads and dealt with other stuff to make this week better.. finished at 6pm and was up at 5am Sunday to deliver the said tractor head and complete lots of other things and I got home at 10 pm Sunday night and then got up early Monday morning to meet with a utility company to price up a new underground water main as our 200 year old row of cottage’s 60 year old shared main has failed catastrophically… Now that is a big problem..made worse because of dealing with others with different ideas and agendas.
Jim came in Sunday and machined the top Rockerbox lug and drilled all the holes and fitted guides and cut the seats . Basically making it all as new.Fitted all the new stuff ,all the usual top quality parts to it as it was all “shagged” and finished the head off completely.
So we are battling on today against all odds..and hopefully winning🤣😂😂🤞🤞🤞

12/05/2026

Ring testing triumph crankshafts