A4DE 250 4 Stroke Wheel Of Misfortune

[laRIKin]

I read this on an other site.

I am astounded that nearly every 250 CRF, Husky and RMZ/KXF (and a few WR's) either DNF'ed due to valves closing up or saw the rider trying to check clearances and re-shim in a work period.......
I even saw one of the NZ riders replace the whole head on his yellow bike half way through the day.

And this from a rider.

"If you went out in the woods today,
you'd be in for a big surprise,
cos everywhere the land is littered with broken down 250's"......
One poor bugger had been stuck out on the trail for most of the day and was willing to torch his "P.O.S." just to stay warm!

As you can see there is alot of very upset owner's.
And this was also said.

I'm unsure of just how long it will take the manufacturers to get back some confidence in the market after this debacle.

And of course this is the reasoning they have come up with.

Single cylinder 4 stroke, revving to over 13,000rpm, very small oil capacities - all this doesn't add up to long term reliability For me there are analogies to high performance race cars - engines designed to last only 1 or 2 races.....
Manufacturers are trying to squeeze more power out of a machine weighing lighter and hence more fragile.....
Fairly impressive, but are the manufacturers trying to build bikes for MX's wins only and not to be able to ride 800klms???

So I guess thats the heads up on what you may expect from these high
revving little monsters.
Do you expected more out of a dirt bike, I do.
Know wonder 2 strokes are making a come back.

[merv]

Jeez I hope this isn't a sign of things to come with my WR.

[laRIKin]

Jeez I hope this isn't a sign of things to come with my WR.

They did say that only a few WR250 had problems.
In a 4 day race, you must expect a few bikes of each make to have problems.
Not like, most, and they made it sound like all of some brands went belly up.
I for one will be reading the results with alot of interest.
If I find them (the results) I will post them.

An up date to make you happier merv

All of the bikes that had valve problems at the 4 day were mxers. The RMZ/KXF and YZF all suffered, the most noticeable seemed to be the CRF due to the sheer numbers that started riding them and never finished. I think only one crf finished the event. It seemed that the wr's were ok but the yzs were dropping like flies as well. But in saying that, KTM's, Huskys, TMs, VORS and Husabergs or all sizes were all having various problems as well.

And the plot maybe thickening and their is hope for the owners of some bikes.
But bear in mind, most people do not ride their bike as hard as you do on a 4 day enduro. It is a true test of man and machine, and that will show up any
weakness in man or machine.

I think this is really strange the guys over here have done far more than 800k's on all these bikes and had no issues. They go to the 4day and have valve problems?? XR 250's worked really hard with poor fuel also did this type of thing. I think the fuel quality maybe the issue. It seams strange for so many to fail all at once but not before the event don't you think ! I'd be getting the fuel tested.

[merv]

I read this on an other site.

Can you post the link to the site you found this stuff on?

[denill]

Giday Merv

That thread and another on the a4de is @ http://www.silver-bullet.co.nz/news.php3?id=2854

Cheers
Bill

[laRIKin]

Can you post the link to the site you found this stuff on?

denill has already dun it for me mate.

Some interesting reading, wouldn't you say.

[merv]

Thanks Bill, just been reading it. There is a bit of finger pointing at the fuel and a bit at the new type of valves with coatings on them. WRs still suffered, if I believe the posts on that site, 4 out of 35 machines 11%. Not good. Hondas were over 50% failure rate and KTM450s (which I thought of buying) were 24% failure rate.

p.s. you dirt riding at all these days or just cruising on the ST? Me I've just kept doing a bit of dirt and road since the HBMCC days with you and I guess you saw my Pukemanu pics.

[laRIKin]

Merv from what I under stand.

It's the titanium coated valves and the titanium coated valves seats that
are the problem.
They do not have seats as such, the heads are just coated with titanium
where the seats would be.
Once the thincoating is worn through, they are toast.
Since some of the bikes do not have enough room for a valve seats, it means
a new head. because you can not mod the heads for some.

The KTM's have proper valves (stainless steel I think) and proper valve seats.
So you should not have a problem, and if you do. You can do a valves a grind.
And you can not do this with the titanium valves and seats.
You can if it goes all pear shaped, you can replace just the seats.
Thats why I have got a KTM, and boy are I now glade I have one now.
So buy the 450 and feel save, just change the oil and check those valves.
And you will be OK.
If you are realy worried about the motor, and still like the idear of a KTM.
I think that you may like the LC4 motor, they are heavier but bullet proof and
are a low maintenance motor.

[Motu]

I'm sure you've just cheered Merv up no end.

[merv]

Nah Motu, no worries as the failure rate quoted for the KTM was more than twice as bad as for the WR and that wouldn't make any difference to the gear ratios I was bitching about anyway.

If I believe the posts on that other site it said the KTM EXC has the stainless valves while the MX or SX have titanium and the numbers quoted didn't separate the types. I would have bought the EXC as it is the road legal job.

Moral of the story it appears is don't take my bike to Australia. No comment was made as to whether this is anything to do with the alcohol content in the fuel already commented on elsewhere on this site.

[denill]

p.s. you dirt riding at all these days ?

Nah Merv. At long last the body told me "enough is enough!" damn it...........

Posting on SB has kept me in touch though.

Still remember you as the cheeky little bugger that came into the Honda shop on most Friday nights.

Keep the wheels rolling
Cheers
Bill