Engine

Engine

Camshafts, Crankpins,Oil pump & Cam drive gears

For all these items contact Gary Emerson direct on:

One of the hardest working components in a hicam engine is the camshaft. Twice the work of a conventional cam & not that well lubricated. The touring versions can usefully be upgraded with an X1 cam & a HC piston (then some valves & a bigger carb & a CDI ign!) & almost every engine with the X1 is by now showing some wear. There have been firms in the USA , in the past, which would repair & regrind or make a cam to race profile. They seem reluctant to do so now. Thanks to the efforts of one of our UK Parillistas the problem is now solved.

Completely new gear & chain drive cams. Made to X1 profile

Machined from EN36 steel & case hardened

Available with either 7 or 8mm lift for 175/250 usage

Gary is currently considering manufacturing the spindle for the cams if there is sufficient demand

Price for either version of the cam will be £138 UK plus P&P

News June 2007

Gary has made a batch of the following spares. Please note that this will be his last batch of Parilla spares for the foreseeable future - he wants to finish his Parilla restorations & get some riding done!

On many early bikes the lower chain drive sprocket is driven by a rivetted on fibre "slash cut" gear. The rivets loosen, the gear wears & either the teeth strip or the rivets shear. This allows valves to touch pistons & mayhem prevails within the engine. The answer is one of Garys steel replacements. No rivets to loosen as allen screws are used to hold the new gear to your old chain sprocket.

90% of Parillas have fibre oil pump drive gears. All the ones I've seen have worn or missing teeth. If you are using points ignition (LH side) then failure of this gear (or its drive rivets) stops the engine before the oil runs out. Lucky you! Stranded but with an intact engine. If you are using a points system triggered from the dynamo side or an MZ/Vape CDI unit the engine will continue to run until it seizes. The answer to both situations is to fit a steel drive gear. No rivets as allen screws are used & steel will run forever. Available in slash or straight cut. New hubs are also available should you wish to keep the OE unit intact for use as a paperweight or conversion into a handy pie crust crimper.

Finally Gary has made a batch of 32mm straight crankpins as used on the majority of 250 engines & some 175s. These can be supplied with the correct 1.5mm shims to reuse an OE rod or to fit with one of the new Arrow rods we have had made.

Contact him direct at the address shown at the start of this section for prices & availability.

250 inlet valves - 36mm head 7.5mm stem

All gone! No plans to make more for my own use but I will do so if enough people are prepared to lodge a 50% deposit & I can achieve a minimum batch number of 20 to get a reasonable price.

Previously unavailable but at last new valves are now here. Manufactured in the UK to the exact dimensions of the originals from modern 214N material. Stellite tipped & plasma treated....even a couple of grammes lighter than OE.

Sold singly: £18 UK plus p+p each

250 valve spring caps

Made to suit the above valves in steel

Sold singly: £9 UK plus p&p each

Racing Lightweight Valve Kits All gone!

All spare sets have now been distributed to Moto Parilla enthusiasts in the USA, UK & Europe. Depending on the outcome of testing in 2007 further sets may be available later on in the year.

As a result of discussions with two of the foremost race-engine component manufacturers in the UK we were advised that one of the first things we should look at, with a view to improving engine performance, was the valve train.

The Parilla 250 Valve gear is heavy & as such restricts the upper rev limits of the engine & also needs heavy springs to control it which in turn leads to increased wear on the cams & followers.

The result is that we have had complete sets of lightweight valve gear made for the 250 engine. They are made for our 250 racer project primarily but would benefit any hot 250 engine.

The sets consist of:

2 x 6mm stem valves, 36mm inlet, 33mm exhaust. 30% lighter than standard! Slim stems will also allow better gasflow into the engine.

2 x Colsibro valve guides. 6mm ID to suit the valves, Std OD to fit the 250 head.

2 x Titanium valve spring caps. 30% lighter than standard

4 x valve collets. 6mm keepers to suit valve & cap.

2 x lightweight cam followers. 20% lighter .

This all adds up to a very desirable weight loss & gasflow increase.

Cost of the complete kit £162.80 UK

250 conrods All gone - contact me if you are interested. I need to get 12 firm orders (i.e 50% deposits paid) or more before reordering.

For several years there has not been a rod available for the 250 Parilla engine. Ducati 250 rods are close but have a narrower big end (Duc racers use an Italian rod with Parilla dimensions as an upgrade!) & fractionally shorter.

Negotiations with Arrow Precision in the UK have resulted in a custom made rod to the exact dimensions of the OE.

Materials, treatments & surface finish are all to modern standards.

The batch size needed to get a reasonable price per unit has led to a small surplus to our needs here in the UK. We have a surprising number of 250 engines to rebuild here so the surplus is not as high as first thought when I made initial enquiries last year - be quick!

Arrow now have the drawings & CNC programme for these rods so more can now be made at any time.

Batch numbers of less than 12 units are unlikely to cost in (the minimum order is two at approx £500 +vat)

£187.00 UK per rod

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