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This will make you all cringe but i’m not a fan of running in a modern engine. By the time it’s warmed up the first time it’s run in.
Impossible to change the oil too much, most engine disasters are from oil issues, be it long change periods of contamination, usually fuel. short skits pistons, single rings, big radiators and EFI really get the oil full of fuel. that’s the killer.
Treat them mean, keep them keen.just found two 432 grind XR400 cams, like an HRC but a bit more bottom end. Was looking in my old cam box for XR600 cams…
$100 if you want one.
In all the auto decomps i pulled out at Ballards i never plugged the oil gallery. Why? well it never caused a problem. What burns up cams in RFVC engines is lack of oil pressure from having no oil in the engine or the cam bearings are backwards…
Be careful when you refit the cam bearings, the RHS bearing must have a seal on it to make the oil pass into the cam. if you use the open bearing all the oil falls out and you have no cam oil pressure. Same happens if you loose the dowl in the end of the cam, oil falls out.Running too rich. the carbon deposits get between the valve and the seat, makes the valve overheat. common XR600 problem.
The Safari bikes in 2004 had 59.5hp at the wheel on a Dyno Dynamics. I have heard of 75hp in Europe but i think it’s the dyno operator making his customers feel good.
Having said that we did have the factory KTM 700’s out here in 2004 and Jamie/Paul said that they could lost nothing to them on the hardpack, it was only in the deep sand the KTM made some ground. they were reputed to have 75hp. Hard to compare dyno numbers, eddy current/inertia different days, different tyres..
We pulled a genuine 183 km/h in full safari trim, not very aero dynamic, Max and i made the windscreens with a jigsaw, heatgun and some wood. Jason Hill made 190km/h at finke on his with a stage 2 hotcam but it wouldn’t last the run down to finke without snapping the rocker arms off….
Suffice to say a stock derestricted 650R was usually 42-43hp. add a pipe and the HRC air box lid mod and you get to 46-47. From there with porting, more comp, HRC cam, vortex ignition and not much else you get 59 ish.
We had to use Staintune pipes, they were writing cheques for The Penguin and money comes before performance so we threw away 3-4hp from not using a reverse cone megaphone. I asked staintune to make it, they could but it looked too goofy to race on one pipe and sell another. We did have a small win though, I kept whining the header pipe sizes were too small, in fact the whole system was too small. Staintune eventually made a big bore one and we found some more power. it became the production item after that.
The HRC cam is very similar to the stage 1 hotcam. i had the HRC cam copied in 2000 as HRC kits were $2500 and when your “Honda Racing” parts budget for the year was 5K it made things too tight. in 2004 it was no different, the engine Jamie won on in 2004 used a copy HRC cam, think it had the little timing chain in it too.
You can make bigger hp numbers out of the 650R but it takes RPM. We were making peak hp at 8200 from memory and shifting at about that (unless you initials are GB, then you bounce off the limiter at 9200 and i raise it to 9600, waiting for the crankcase to vent to atmosphere)
Big cams like the stage 2 will make more power but you loose torque under 5000 and if you rev it to use the power the rockers become unreliable. Never broke a cam chain though.
As for the carburettor, Burner used a stock carb in 2000 to win thumpers. In 2001 he swapped mechanics and they fitted an FCR41. from what i could see on the side of the track the bike was having a hard time driving out of corners, the power became quite snappy and 60hp is a lot for a 110 knobby, i think it’s the limit.Tthe stock carb works fine as long as you ride it like a thumper, clutch out all the time, smooth throttle, no brake sliding into corners, clutch in and snapping the throttle open, goon style.
Interestingly enough, Glen Bell tried an FCR on his thumper nats winning XR600 in 1995, he also found it too snappy, Pip went back to the stock carb and that’s what they won on in 1996.Hi Nathan,
The 450X is firm stock for sure, on paper the settings in it look more motocrossy (is that a word?) than offroad. While this is good if you are pushing it, after a short time most of us get tired, sit down and get beaten up.
As for the 90kg, you are just a bit heavy for the stock rear spring, you need to bump that up a rate, what sort of rider/static sag heights are you getting?
My suggestion will be a slightly more off road fork and shock setting plus a rear spring.
i don’t need the whole bike as long as you can set the sag up yourself.That broken mainshaft used to happen whenever we removed an auto decompressor from the cam. it runs the kickstarter idler gear. was never designed to take that much force. we never snapped one off on a racebike, was always the trailriders who broke them.
The subframe repair is standard issue for the brace above the airbox, the 600 does the same. Little late now but the best fix is to remove the flimsy tube and use 20mm RHS square tube. Just use a MIG welder and be neat.
There is a good cam to put in them too, we worked with Tighe engineering in the day and i think the 432 profile was the cam to use, bit smaller than the HRC grind, it was too desert racing orientated for enduro use. send dean up an old burnt cam and he’ll weld it up and reprofile it. John from Waggot will do the same, similar price to buying a Hotcam out of the USA but a better cam.Hi Action,
OK the 01-02 WR 250 ran a light fork /shock spring combination, 0.41 and 4.8kg/mm in the rear.
The current WR250 is 0.44 and 5.3kg and it’s OK for 80-85kg riders.
If you would like to know what i suggest for springs go to http://www.teknikmotorsport.com/modelsearch
and put your bike type and weight in.
the 01-02 WR250 was the closest to the YZF they made AND if you buy a YZ exhaust cam you get the auto decompresser and more power, makes the bike so easy to start you won’t miss the electric leg.Hi Action,
Can i ask what the bike is? Kinda hard to give advice without that information.
Shock springs are $180 to OB members and pretty easy to fit yourselves.
The 90km/h comment was top speed, yes.
The 350 did an 80km loop without the reserve light coming on so it’s pretty frugal. Can’t see Daniel sparing it either.
I think it was Ben Grabham who said it’s kinda a trials bike with a seat that can do trails/single track.
The 99kg is not light on paper but it looks very svelte in the flesh.
Adventure bike? If gong to red hill is an adventure then yes. Pretty quite too, good for sneaking around those urban fringe type places that you shouldn’t really be BUT if no-one can hear you then are you really there/I agree with everything in your post STM, unfortunately for me i HAVE to make PSF work for the 2013 on MX bikes.
I thing the SFF has dual sport applications BUT it’s always going to rely on big axles to keep it all rigid.
I ride MTB too and have fox air forks now (Giant Trance) and i really don’t like the feel, would rather my Marzocchi Z1 bombers with perpetually leaking seals.
As the cartridge in the PSF is 32mm now i can’t retrofit coil springs :blink:
Lot of scope for the secondary chamber to be external to manipulate the pressure.I’ve got a KX250 01 engine that needs a KX250F 2012 frame…..
Just had a look, 23hp. Hey that’s what an XR250 makes!
hey TB do you have any of the old spokes? Do they run a long and short spoke?
I had a 90 YZ250WR in 91 or 92, still remember the engine. Angry was the only word to describe it.
When i was a kid in shorts i used to walk up to procycles in Hornsby a few times a week, bug the hell out of Frank Pons, Dave Middleton and Vincent Teseriero. Frank was prepping belly’s YZ’s at the time and the dayglo orange paint was a nightmare, had to be repainted after every race to keep Malbro happy.
I do remember getting a reed block spacer made to try and give it some bottom end and fitting a heavy flywheel to tame it and help the lightswitch not flick as hard.
Forks and shock were awful too, no idea about suspension then, if you saw a bump you just had top do a wheelie… -
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