2 Strokes Down Under

Think of how it will look in red then.

By the way, I just checked my bikes dyno curve against other bikes to see where we were up to.

Oddly, the bike in its currently state with overly rich jetting makes the very same hp/tq curve as a KTM LC4 640

fred99999au wrote:Yes, it made a sweet sweet noise, then farted through the carby and that was that, no more smoke.

Onward and upwards Jeram. Gives you a bit of time to clean the oil off the undercoat (?) and then me a bit of time to make it red.

What about the fuel You should do the riding next time, not good letting it free rev after the run.

What's the difference between that and a long downhill straight?

I agree that the fuel should be mixed more accurately (must clean that off my boots) next time. And be more bountiful.

fred99999au wrote:What's the difference between that and a long downhill straight?

the throttle should be open

Worked out this afternoon what killed the top end, the powervalve never opened past 85% which took the exhaust duration down into the 180's.

Its all been reprogrammed to correct this now.

Looking forward to making some monster hp next time at the dyno

This week I've rebuilt the bikes front brake calipers while I wait to be able to apply the final coat of paint.

I had an issue of sticky brakes, If I spin the wheel I'd only get 1 full turn from the wheel before it stopped.

So I pumped the pistons out one by one almost to the point where the fell out, you know they are almost ready to fall out when you can rotate them easily.

I then hit them with some brake cleaner, wiped-down the pistons and inter-caliper.
I rubbed the pistons down with some 1500 wet/dried as best I could, washed the pistons down with more brake cleaner and dried them.

I then tried a trick I saw on the forums - I applied some dry film teflon to the pistons.
They then slid back in like a hot knife through butter.

I then de-rusted the brake pad pins and springs and re-assembled the calliper.

Final test was to make sure the pistons would quickly react to the brake level and then release slightly after the brakes are released. Everything gets the tick of approval.

Re-installed the callipers, rebled the brake lines and make a few adjustments to the spacer bushes to make sure everything was perfectly alligned (rubbing phophor bronze bushes against a bastard-file for 10 minutes removes a few thousands of an inch and gets the matting-surface perfectly flat/smooth like a mirror)

I then reinstalled the callipers and tested them.

The pads are still dragging against the disc, but is slightly improved from before.
Now Im thinking that it could be a combination of brand new pads and wider than usual discs (EBC cast iron).




anyone have any thoughts on this?

Discs have no way of retracting like drums. Drum pads have springs to retract them.

What you're seeing now is quite normal I would think. As long as your pistons still have some inward travel to account for some expansion (test manually prying them back in with a screwdriver etc), I wouldn't worry about it.

I think you are right.

This is why I think ceramic wheel bearings are a waste, because bearing losses are nothing compared to dragging brake pads!

My main obsession with this dragging issue was because everything is a miss match of parts from different bikes and custom bushes/adapter plates... all it'd take would be one part out of alignment and you could kiss my ass goodbye comming into honda corner!

But I think Ive obsessed over it long enough. the brakes are good to go!

Now, while Im waiting to get my rear end back, I'll give the forks a fluid change and see if it improves feel. I have no idea on the condition of these forks so itl pay to check them out.
They feel a little odd to me.
If I put a zip tie on the fork leg with fork in at rest postion under the bikes weight, I pull up on the handlebars to extend the forks, I let go and let the forks settle.
The forks dont fully return to their original position, it rests 5mm above the zip tie.

To me, that sounds like too much compression dampening maybe (I can adjust this out easily), but want to change the fluid first so that I have a good baseline.

The pistons will adjust for a *slight* misalignment to one side. The main thing is that pistons on both sides can pull away from the disc enough including allowing for some heat expansion. But yeah, usually the pads will ever so slightly touch the discs because there is nothing to push them any further.

just needs to be ridden and the brakes worked over very hard. Ceramics are worth every cent

what you reckon about the forks? sound strange?

ride it on the track and get John Orchard to fang it

I'd rather get the forks sorted before any fanging takes place. Ive never seen a fork do this before

Ill pop some new fluid in them and if they still play up I might have to get my mate dave to look at them.

My suspicions were unfortunately confirmed this morning.

Took both fork legs off the bike.

Left leg felt OK. right let felt horrible. It would squeak when compressed and would actually get stuck towards the bottom of the stroke and would require a tap with a mallet to free it up.

Soooo long story short, Im getting a quote from promecha to inspect and fix the forks.