Ariel scrambles spec engine and thoughts.

I've been collecting parts for a high power 500 engine since April and have just completed the fitting. While I'm cannibalising the old Long Stroke 557 engine, I'll have a look at how it's fared over the past year with all the dusty and muddy off road riding it's had, and a general wear and tear examination after 9000 miles in 12 months. The tuned 500 has HS cams and followers and a JP 9-1 piston, the crank has been balanced by Conway Motors and the initial ride up and down the road shows it to be very smooth, but we'll see how it goes off road once it's had a chance to settle in a little. When I started it up for the first time, I used the Short Reach plug out of the iron engine, when I fitted the correct Long Reach plug, the piston kissed it enough to bend the side electrode, so there isn't a lot of space inside there at all. Needless to say I'll find a more suitable plug. Conway Motors rebored my cylinder, and fitted new big and small end bearings, and rebalanced the crank to suit the new piston.
conway-motors.co.uk

[@steamwally]

Hi Dean, nice work you're doing! Out of interest, how did your engine builder go about balancing the engine, has it been balanced for smoothness at normal "cruising" revs? It's generally very hard to effectively balance a single. It has been interesting following your exploits with the bike and it's development.

[@thra5herxb12s]

Thanks Phil. Yes he gave it a balance factor of 66% which is what they balance their Vincent singles to, and is 1% more than Ariel balanced the road going engines to at the factory. Cruising speeds back in the 50s were around 60mph, and the top speed for the road bikes was around 87mph, but this is a competition engine with almost 10bhp more, so will hold higher revs in lower gears. Obviously a single will always vibrate at some point in the rev range, and a different factor just moves that point. It's very smooth so far at in town speeds, and around the lanes at about 40mph, although I wont be giving any more throttle for a few more miles yet. Hopefully it will be very smooth on the A roads at 60mph plus. With the long stroke engine, I never felt the need to balance it beyond whatever factor it was already, and on the furthest day trip, to the National Motorcycle Museum in Coventry, it felt really smooth at between 60 -70mph, and gave an amazing 90mpg.

[@steamwally]

@@thra5herxb12s Thanks, appreciate the comprehensive answer! You've obviously got an engineer of the old school there- safe hands.

[@classicrider5274]

Thanks for the update on the Ariel, I picked up a few tips from it. I used the Draganfly alloy gaskets on my iron head NH and they fitted ok but have had problems with some sets, as you mentioned. The new motor should have good performance so I look forward to watching some videos when you are on the road. Do you still have the WW2 van?

[@thra5herxb12s]

Thanks. Yes I used one of the alloy gaskets on my VH iron head and it fitted ok but not perfectly. I've never had a van though.

[@classicrider5274]

@@thra5herxb12sAustin Tilley 1943?