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Morgan three wheeler

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what is in the box
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what is in the box
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of the
installing the bevel box mounts
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Fitting instructions for the
bevel box mounting kit
installing the Centa coupling upgrade
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Fitting instructions for the
Centa coupling kit
installing the Centa coupling upgrade
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drawings for the
Stage 3 Modifications

Since May 2016 I have been working to rectify faults in the transmission / drive train of the new Morgan three wheeler. The subject of my research has been a 2013 model, purchased by me in 2015. The machine had been fitted with the Centa flexible coupling and the NVH kit from the factory.

The faults were, from the start, an inability to pull away without increasing engine speed to 2,700 rpm. without lurching and banging from the transmission and an inability to pull away in any gear but 1st. Later, a loud bang and jerk developed when accelerating hard, especially when carrying a passenger. Throughout, the machine has vibrated excessively, most noticeably when accelerating through 3,000 rpm.

The result of my work is a vehicle which will pull away in any of the first three gears, without an excessive rise in engine speed and without any jerking or banging noises. The loud banging on acceleration has stopped completely. The vibration is much reduced and there is no need to avoid certain engine speeds to maintain a comfortable ride. The high torque developed by the engine which was the cause of much of the trouble is now available for use and the true character of the V twin engine is now evident when driving.

My upgrade for the Morgan three wheeler drive train comes in three stages


Stage 1 :-

The bevel box mounting kit

PRICE with fabricated steel mounts £ 414:52 including postage at your own risk. If you would like the parcel insured please add £ 25:00

PRICE with aluminium billet mounts £ 736:95 including postage at your own risk. If you would like the parcel insured please add £ 25:00

The kit consists of a complete set of bevel box mountings. There are three of them which satisfactorily secure the bevel box in all of the twelve planes / axes of movement. The bevel box mounts are clamped to the chassis to enable fitting without the need for welding and they avoid the need to grind away the residue of the old, original, rigid bevel box mounts. Neither welding nor grinding are desirable in close proximity to petrol pipes! The mountings for the bevel box are isolated from the chassis with polyurethane linings in all of the fixing clamps to reduce the transmission of bevel box noise to the chassis. If you are replacing the factory NVH kit then the components you remove will weigh 9.3 Kg and the new mounts weigh in at 3.8Kg a net saving of 5.5Kg.

If you still have the original welded in situ mountings then, in my opinion you do not need to upgrade. Any noise reduction achieved will be minimal.

The bevel box mountings must be fitted before stage 2 which can be fitted at a later date.

Stage 2 :-

The Centa coupling upgrade kit.

PRICE £ 356:00 including postage at your own risk. If you would like the parcel insured please add £ 25:00

The P.G.Bleazey drive train upgrade kit uses inserts, in the Centa coupling, of modified shape to reduce the free play. The shock absorption is achieved by combined distortion and rolling action of the inserts, not by rolling alone . The ones used in my kits are high temperature resistant and are true prisms and do not allow for misalignment, this function is not needed in the Morgan three wheeler application. The inserts incorporate a tab for ease of removal when installed with the stage 3 modifications.

The upgrade kit contains an extension for the shaft which supports the inner rotor of the Centa coupling, this extension runs in a plain bearing. The bearing is mounted in a carrier which fits within the Centa coupling outer rotor. The intermediate shaft is thus supported at both ends which creates a much more rigid, true running, unit. Please do not fit my design of inserts without the support bearing. In any case I recommend fitting a support bearing at the earliest opportunity.

Please be aware that the inserts in a Centa coupling are consumable - like tyres and brake pads- they have to be replaced at regular intervals. My non rolling inserts are designed with longevity in mind and I hope they will outlast any other alternative but in common with all the available alternatives, they are not immortal.

When the inserts come to the end of their life it is necessary to remove the engine in order to replace them - at least 12 hours work for a mechanic - UNLESS you go for stage three!

PRICE :- for stage 1 and 2 ordered together £ 726:40 including postage at your own risk. If you would like the parcel insured please add £ 25:00

PRICE :- for stage 1 (aluminium billet mounts) and 2 ordered together £ 1,050:40 including postage at your own risk. If you would like the parcel insured please add £ 25:00

Stage three :-

Quick change coupling insert modifications

Bell housing mod £ 120:00
inner rotor mod £ 90:00
Second insert retaining plate ( required if you do not fit my support bearing) £ 25:00 post included

While you have the engine out for replacement of the Centa coupling inserts, send the bell housing and the inner rotor of the Centa coupling to me and I will return them, modified in such a way as to make future replacement of the inserts a job lasting less than an hour and a task that could also be carried out at the roadside if you have the ability to raise the vehicle safely.

The modifications consist of an enlargement of the grease gun access hole in the bottom of the bell housing and the re-machining of the inner rotor so that the insert retaining plate can be removed from the rear end to give access to remove the inserts.

For those who choose to have this mod done locally or if you want to do it yourself, I have made drawing and instructions available please click on the link at the top of the page. Having done the mods fix the plate to the rotor with four M8 socket head screws 16mm long NO LOCTITE. four more socket head screws 16mm long should be inserted and loctited in to the four holes in the aluminium outer rotor - these are used to turn the engine over while removing the securing plate and the inserts

To remove the bell housing you must heat the area of aluminium around the four fixing bolts to soften the loctite. The screws are imperial and you will need a long series 1/4 inch allen wrench driven by your socket set tommy bar. It is essential to re fit them with loctite and torque them down to 30ft lbs. or 40 newton metres. these are the bolts that hold the primary chaincase on to the crankcase in motorcycle installations. they are very small for the Morgan set up and need to be tightened correctly.

After the mod is carried out, with the vehicle safely raised to give access from below, you can get one hand in through the bell housing cut out. With the spark plugs removed, use a 1/4" drive ratchet hex key to loosen and remove the 4 M8 bolts. once inserted a sharp blow to the end of the ratchet with the side of your fist will loosen them, if the ratchet is short you will need an extension handle. Do not allow these screws to become contaminated with dirt or grit it is essential that they never sieze up in the thread or removing them will become difficult in the extreme! The four M8 socket head bolts in the outer aluminium rotor can be used, in a clockwise direction, to turn the engine over. Slide the retaining plate all the way back to the end plate. Use one of the bolts or a wood screw and push it in the the 7mm. hole in the insert and it can the be used to pull the insert out far enough to get hold of it with you fingers and extract it through the hole in the bell housing - you may need to get an assistant to wiggle the shaft back and forth while pulling, in order to get the first one loose. DO NOT WORK ON THIS UNLESS YOU HAVE THE IGNITION KEY IN YOUR POCKET - SAFETY FIRST!. To access the insert at the top you will have to turn the engine over - you should have the SPARK PLUGS REMOVED to make this easier. If all three wheels are off the ground, with top gear engaged, you can turn the rear wheel to turn the engine over. Alternatively remove the transmission tunnel cover and turn the propshaft with a long screwdriver inserted in the UJ.


Lugging the motor , an expression used by S&S and something to be avoided. The reason for this is not too clear without some research but I can give the following advice. Loading the engine up at low Revs. causes the pistons to be pushed to one side of the bore, this may be due to short piston skirt length. The result is over consumption of oil and all the problems which accompany this. In a recent 1500 mile road test I utilised the ability to accelerate hard at low revs. - very satisfying it is too - nothing quite as satisfying as hearing the rear tyre break away at every firing stroke! However - the cost was 2.5 litres of oil lost in 1,000 miles which will bring disaster if one continues driving in this fashion. The P.G.Bleazey drive train upgrade kit will allow you to do this but it is imperative that if you use low rpm, for example, in dense traffic, you only employ small throttle openings till the revs. rise above 2,500 rpm. Alternatively just change down a gear to get the revs up but DON'T just push the pedal to the floor at low engine speeds!

The internal splines of the Centa coupling outer rotor are made of soft steel. They run on a hardened, alloy steel, splined crankshaft. The fit is only on the driving faces of the splines making this a very vulnerable area. Lugging the motor may also result in the soft internal splines being hammered and distorted to the point that they will become loose on the crankshaft. To repair this is expensive. My machine has an alloy steel insert in the outer rotor, fitted on the drive faces and on both major and minor diameters, to avoid any recurrence of this failure.

On all of the machines I have examined I have noticed another likely cause of trouble. The bearing behind the clutch is not secured to the shaft other than by the interference fit. There is a circlip groove but it is about 3 mm away from the bearing inner race and has no clip fitted which could allow the shaft to move. The only retaining force would then be contact with the gearbox shaft within the spigot bearing.

I will not accept responsibility for such failures - they are caused by inadequate design and are not under my control.


The kit can be installed by any competent motor mechanic, professional or experienced amateur. A full installation manual is available in on another page, just click the links at the top of this page. I am happy for the installation manual to be printed off and for it to be passed to your garage mechanic if you are not doing the work yourself. Please feel free to study it before deciding to purchase a kit. I am also available, within the limits of my daily life, to give advice via e-mail or telephone to anyone with installation problems. To the best of my ability I promise to provide technical backup to customers.

With the exception of the stage three modifications ,the kit does not require any alteration of the vehicle components and can be removed and replaced by the original equipment, not that I can foresee anyone wanting to do this but it may bring peace of mind to the sceptical.

The P.G.Bleazey drive train upgrade kit can be described for insurance purposes as not being performance enhancing but merely comfort enhancing.

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Please contact me to check on availability before doing so.

I reserve the right to charge for alterations to the components in the kit if your machine is different from the standard model which has been the basis for my work

To register your interest in a kit, with no obligation, please click on the E-mail link below and e-mail your name, country of residence and the year of manufacture of your vehicle. Any comments or questions will be most welcome at the same time. I will compile a list of frequently asked questions as time allows.

My work has been published and I have no objection to individuals learning from my work in order to enhance their own knowledge or to make modifications to their own machines. Please, however, be warned that protection has been put in place to safeguard the intellectual property stemming from the research and development of the P.G.Bleazey drive train kit. It is a criminal offence to copy a registered design. Any person or organisation found to be copying or using my work for commercial gain will be pursued strenuously till they cease this activity and where appropriate, for compensation.

Phil and Claire Bleazey
At The Old Furness Street Stables

Tel:- 0044 (0)1524 849085

Last Updated March 2018

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