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I have heaps of stiffer shock springs for them in stock, $135 for OB members. 5.7kg
Engine is clean, where are my gears?!
I’ll do more than look, a few gaskets and the shift drum sector bearing is what you will have replaced. No sense in breaking gearboxes when it’s preventable.
Toby comes from an MX background and likes an aggressive bike in both power delivery and suspension. Knight is a trials rider who adapted to Enduro, he’s getting on in years now but is no slug. Like Stoner he tells it how it is and it comes across as whinging about the machine. Personally I think it’s ok for a rider to speak freely about how they are struggling with setup. Better that than the stiff upper lip attitude.
Hope Yamaha have the gears in stock. Wishful thinking perhaps. May as well throw a timing chain at it while we are there. Ill have a goof look at the rear of the bearings tomorrow after its all washed up.
I’ll strip the head too, give the seats a cut. Might port the head if I’m bored!Makes me laugh, he kept wanting them to smooth the delivery out as it was too abrupt on surfaces that offer little grip. Typical factory bike, stock is not good enough so lets give it MORE power and see how fast they go.
He still loves the 300, looks really good on it considering the size of Knighter but he needs a 450 plus machine to be competitive in WEC to lug his heavy arse.Good bike that 96, took them until 2003 to make a better one
Nice to see the 400 has not been forgotten, was a very capable little big bike.
That 532 cam profile is an HRC grind, I sent John at Waggots an original HRC 400 cam to take a master off years ago, did the same with the HRC 650 cam.Ok, a couple of pistons have turned up 104.7mm. Got 2 just in case of an accident.
Stock 600 is 97mm bore and 80mm stroke, 591cc 650L is 100mm bore and 82mm stroke, 644cc.
So, if i use the 104.7mm piston with the long stroke crank i get 706cc. Good for some.
I’m going to use the 75mm stroke crank and 104.7 bore so we get 646cc.
Why? When there is no replacement for displacement!
I want to get the bore x stroke ratio up.
A CRF 450 is 96mm bore and 62mm stroke, stroke to bore ratio is .65
the XR stock is .82 and the 104.7×75 is .72.
More rpm means more wear but what price do you put on fun?Want an 86-89 for the pre 90 class.
They won by over an hour. That’s enough time to have a shower, get a feed, wash the bike and be well packed up and start drinking. KTM camp would have been shaking their heads watching.
Air get in past the seals when dirt starts to accumulate in the seal. it’s the first sign you about to get a leaking seal. the amount of air that escapes from the bleeders increases, then the seal starts to weep or can “blow” if there is an air build up in the fork and the pressure pushes the oil out.
Forks are more prone to leaking because the seal is not self energised, there is a steel spring in the seal to keep the lip in contact with the shaft. A shock seal is self energised, the 150psi plus in the shock pushes the seal lip into the shaft. if I service a shock and left it overnight with no gas it will leave a puddle on the bench the next day, the seal needs the be energised to work, as do the o rings in the shock.
Secondly, the fork is in a much harsher environment. there is mud and dirt being sprayed onto the fork tubes constantly, flying rocks, crash damage. The dust wiper can only remove so much dirt, some of it makes it’s way into the seal.
In contrast, the shock shaft is well protected from debris and crash damage. if you remove the flap that protects the shock shaft from the rear wheel roost the shaft is peppered very quickly and the shock leaks shortly after.All good, you are keeping John and Pete at Waggotts in a job, I’d rather you used them than bought Taiwanese made cams from the USA.
The hard faced rockers are the go, they can live without oil and never wear out. John will be getting some rockers from my 600 when i’m up to that part.
run them in hard and they go hard….Lot of theories here. My 5c.
I can only answer from what Ive seen and done.
I don’t like bleeders that screw in place of bleed screws. They can leak, both vacuum and pressure and they are susceptible to being snapped off from tie downs and flying rocks. the screw is less glamorous but it’s 100% reliable and free with the bike.
Regardless of the type the pressure needs to be equalised with the front wheel off the ground. The air in the fork is a secondary spring to your main spring (comes under Boyles law for those with the inclination to research it) If you equalise with the fork compressed you lessen the force of the air spring so the fork will become softer. there is a chance the seals could actually be sucked ‘in” but I’ve never seen it. Wives tail.
In the past we have used air pressure to stiffen the overall fork action. It’s not a great solution as the fork becomes very stiff initially. The fork will happily run with 40 psi in it, your wrists won’t like it much though….
The manufacturers deleted the use of Schrader valve fittings when they woke up and realised no one was using them to add pressure.
In 2013 the air fork is back in the KX and CRF450. NO SPRINGS just air. 32-36 psi. they get around the inital harshness by using very long/stiff top out springs to oppose the main springs. 2 guys ran the KX450 at the 4 day this year, both DNF’d because the forks would not hold air for a whole special test, even with a pump in the bumbag. Different type of seal to our current seal as the high pressure makes seal drag a big problem.
I do some hydraulics work myself (skid steer loader, was making new pins and bushes for the 4 in one yesterday) and one of my friends is a tool maker who specialises in making/repairing hydraulic rams (XR650 nut too, putting a 916 Ducati swingarm in it) sliding friction is no problem for hydraulics, gland seals are meant to be bloody tight. how would that feel in your forks?
As for the brake side leaking first, yes there is some twisting motion involved, brake dust does not help either.
Bottom line, with the low friction fork seals we all use the working life is short, manufacturers suggest 10 hours, most of us can get 40 if we do everything right. Slapping a new set of seals only, no wipers, not polising the fork tubes and not having a really good look and feel of the bushes is not a fork service, that’s another leaking seal waiting to happen. -
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