Greg Brillus Racer

[Monkeypants]

Right now it is still in the rpm/heat limited break in phase, so I am riding it like I paid for it.
Sounds like Greg got his racer thru this phase rather quickly!
maybe road bikes get babied too much.
Glen

 

[roy the mechanic]

many years ago, a famous manufacturer built two identical race motors. One was run-in carefully, the other was thrashed mercilessly on the race course. they were both dynoed afterwards, the result was both motors made (as near as dammit) the same b h p ! They reckon a good race motor is halfway wore out from day one. Remember, you are only running-in the rings, the rest is " running-out " from day one ! Roy.

 

[greg brillus]

Thanks for the comments guys, Yes Roy is correct.....I guess the last thing anyone wants is their engine to Nip up, and a road engine needs to survive on the road for a long time, so a more careful break in time is wise, although all new engines I build, I don't recommend babying them either. I think a lot comes down to the climate we live in as well, so because I live in a hot climate, I always give the pistons a touch more clearance than stated in the piston manufacturer's specs. I don't think that for my first outing on the racer, that I thrashed it.....but I didn't muck around, and also the track was a short one, and it was a cold weekend. Having been a mechanic all my life ( from about the age of 6....) I think you can tell how to "Push" something you have built yourself. That's what makes the whole experience so much more enjoyable.....It's just not everyday you build something this quick and with beauty to match....the attention it gets from others is quite something else, and that is a nice side affect......Greg.

 

[vibrac]

low ex pistons 3 thou max by the book but I always put 5 in for racer

 

[roy the mechanic]

Went 4 on the new vin, 5 on the aermacci racer. So, that means 3 hot-rod vins first runs in around 10 days, how many others out there? Roy.

 

[greg brillus]

The Horner brothers have just ran their ex Bob Williams Rapide/ racer for the first time too. They are taking it to Goodwood for the event you have over there. I will be interested to see how it goes. It looks more like a standard Lightning than mine, but with the original alloy engine, not painted. Ours was already painted, and even once I stripped it back, the primmer was too difficult to remove, so I just repainted it in Black Dupont 2 pac eurothane.....or however you spell it..? Makes it very tough, to resist oil and fuel.....Trust me I've had a couple of descent leaks from those Amals, tiny particles of muck in the fuel...so now I am running fuel filters until it's all gone..I also ran with 5 thou on the pistons, and the pushbutton decompressors work very well, just helps the crank on the first couple of rotations......Greg.

 

[Monkeypants]

Greg, would those pushbutton decompressors be effective with a kickstart?
I'm thinking they are ideal to get the engine rolling for e start or starter rollers, but the short jab of a kickstart is a different operation.
I wonder if a decompressor like the one on my Maico 490 might be a good solution. It reduces effective cr from 12 to one down to about 9 to one for starting purposes. At 9 to one the engine starts just fine and can be kicked over with relative ease, whereas at 12 to one it is a beast to rollover.

Glen

 

[greg brillus]

Glen, I think you are quite correct, the buttons on the decomps pop back out once the engine fires, so like you say it lowers it to a more subtle level. I know you are running twin plugs, but it might be worth a try. The twin plug system is probably less effective on a road bike verses a racer, except you will need to raise the Ignition timing again. I found running one of those heads on a single, that the plug worked better on the left side more than the right....most noticeable to get a good idle...with the plug on the right side, the engine would die at idle..cheers, Greg.

 

[vibrac]

I have just got the cooking Comet running well on the Mikuni I had fitted a HD decompressor but since I am running a lowish compression anyway I dont need it for starting and just use it if I want to turn engine by hand. Anyway after a good run I got home and she stood there thump, thump, thump like a concrete mixer with the throttle off. I made a note that I should fit a cutout button to the mag and leant over and pressed the button in, the thump thump changed to pish pish pish but she kept running,and the button did not pop back must have been about 4:1 compression!

 

[greg brillus]

Geez Tim did you reach up and toot the whistle... Yes I found the decompressors also very handy for turning the engine over, without removing the plugs. This makes valve checks and ignition timing very easy. I gave the racer back to my good friend Noel, who did my exhaust system, and got him to make up another muffler and a straight exhaust extension pipe. The new muffler is much smaller and gives much better ground clearance than the first one which was too bulky, but would be great for engine runs at home. I have enough extensions to suit any track restrictions now, and I spent some time also sorting a couple of minor leaks, mostly from the return lines, and replaced the rear carb fuel bowl with a zero angle one to get the float level correct, as when it was on the rollers, the level was out too much causing the carb to drip quite a bit. So it should be ready for another run now....Cheers....Greg.