Fast Eddie
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- Oct 4, 2013
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Thought I'd start a new thread as this isn't really 'engine build prep' any more, but it is the follow on...
I've now managed to do some miles on the rebuilt Commando, can't be sure how many though, as the speedo has given up.
Here's a brief reminder of what's been done:
Power-train: JS stage 1 cam with lightweight lifters. Beehive valve springs. Lghtened, polished rockers. JS lightweight pistons and longer Carrillo rods. Dynamically balanced crank. Belt drive with Barnet clutch pack. Tri-Spark with Accel coil. 35mm FCR carbs. Various internal components ceramic and / or Teflon coated. Comstock auto cam chain tensioner and sump reed valve breather.
Chassis: Landsdowne fork internals. 6 pot caliper with Brembo m/c. Falcon shocks. New rims & spokes @ 18 rear / 19 front in correct widths for the new Roadriders tires. Norman White cotter pin mod to cradle. Comstock head steady. New AN isolastics. Corbin seat. Loads of stuff from Matt at CNW.
First impressions are:
1. It's SO smooth! Previously it vibrated below 3k but was pretty smooth above that. It vibrated worse when slowing down through 3k. Others seemed to suggest this below 3k vibe was normal. I now know it is not! The bike is now SO smooth everywhere, I am really surprised. As I've done so much at once, it is impossible to know what has impacted what, but the JS internals, dynamic balancing, Comstock head steady and AN iso's have combined brilliantly.
2. The handling is brilliant. It was good before, but it now really does feel like its on rails, well it would, but if it were on rails it wouldn't be able to change line as effortlessly as it does. It feels really light, neutral and accurate. The book said to tighten the vernier iso's and back off 1.5 holes and this will give 5 thou clearance. I decided to guess and as a starting point set them at 1 hole out, therefore approx 3.33 thou, and adjust them until it felt right. But it feels right like this, so I think I'll leave it be.
3. Performance. Obviously I'm not thrashing it yet (having invested so heavily on the internals, I am keen to prolong engine life), so outright performance cannot yet be ascertained. When I chose the cam I was looking to increase power above 3k, even at the expense of a power loss below that. This was because I wanted to keep out of the vibration spot and have strong power up to 7k. The initial, and low end torque is definitely less than before, as expected. The irony is that it now does not vibrate below 3k! So to be very honest, I am now questioning if I should have gone for a cam closer to stock (JS stage 0 for example) however this may change as I explore and enjoy the higher rev regions.
So, in summary, first impressions are great. If before it felt agricultural / Harley ish... it now feels tight and zippy, finely honed, almost modern in some ways. Hard to explain really, but good!
Unfortunately I am grounded at present due to a shoulder injury, but as soon as I am operational again, I'll be torquing down the head again and putting on some more miles. I hope to have it properly de-snagged and bedded in so I can explore the higher rev ranges and get it on the dyno before winter sets in.
I've now managed to do some miles on the rebuilt Commando, can't be sure how many though, as the speedo has given up.
Here's a brief reminder of what's been done:
Power-train: JS stage 1 cam with lightweight lifters. Beehive valve springs. Lghtened, polished rockers. JS lightweight pistons and longer Carrillo rods. Dynamically balanced crank. Belt drive with Barnet clutch pack. Tri-Spark with Accel coil. 35mm FCR carbs. Various internal components ceramic and / or Teflon coated. Comstock auto cam chain tensioner and sump reed valve breather.
Chassis: Landsdowne fork internals. 6 pot caliper with Brembo m/c. Falcon shocks. New rims & spokes @ 18 rear / 19 front in correct widths for the new Roadriders tires. Norman White cotter pin mod to cradle. Comstock head steady. New AN isolastics. Corbin seat. Loads of stuff from Matt at CNW.
First impressions are:
1. It's SO smooth! Previously it vibrated below 3k but was pretty smooth above that. It vibrated worse when slowing down through 3k. Others seemed to suggest this below 3k vibe was normal. I now know it is not! The bike is now SO smooth everywhere, I am really surprised. As I've done so much at once, it is impossible to know what has impacted what, but the JS internals, dynamic balancing, Comstock head steady and AN iso's have combined brilliantly.
2. The handling is brilliant. It was good before, but it now really does feel like its on rails, well it would, but if it were on rails it wouldn't be able to change line as effortlessly as it does. It feels really light, neutral and accurate. The book said to tighten the vernier iso's and back off 1.5 holes and this will give 5 thou clearance. I decided to guess and as a starting point set them at 1 hole out, therefore approx 3.33 thou, and adjust them until it felt right. But it feels right like this, so I think I'll leave it be.
3. Performance. Obviously I'm not thrashing it yet (having invested so heavily on the internals, I am keen to prolong engine life), so outright performance cannot yet be ascertained. When I chose the cam I was looking to increase power above 3k, even at the expense of a power loss below that. This was because I wanted to keep out of the vibration spot and have strong power up to 7k. The initial, and low end torque is definitely less than before, as expected. The irony is that it now does not vibrate below 3k! So to be very honest, I am now questioning if I should have gone for a cam closer to stock (JS stage 0 for example) however this may change as I explore and enjoy the higher rev regions.
So, in summary, first impressions are great. If before it felt agricultural / Harley ish... it now feels tight and zippy, finely honed, almost modern in some ways. Hard to explain really, but good!
Unfortunately I am grounded at present due to a shoulder injury, but as soon as I am operational again, I'll be torquing down the head again and putting on some more miles. I hope to have it properly de-snagged and bedded in so I can explore the higher rev ranges and get it on the dyno before winter sets in.
