$3500 top end overhaul

[Marc.com]

I guess it is part of the 2 str / 4 str debate but this is pretty sobering article from Rick on the cost of overhauling a modern 4 stroke.

http://twostrokemotocross.com/2010/02/shocking-four-stroke-costs/

[Tossa]

what a rip off

[mx250]

I have heard of a few people who have been 'burnt' with a mechanical mishap with a modern 4T. A dropped valve can write a bike off - it's cheaper to sell the wreck as a rolling chassis than it is to even buy the replacement parts . It doesn't pay to skimp on maintenance .

Ya gotta love the 2T - new piston and rebore, and new bottom end, a $1000 later it is factory fresh .

[Marc.com]

I remember you could do a 202 engine for about $1200 back in the day and it has 6 pistons.

But think of the recycling opportunites for blown up CRFs

[TT]

Not exactly new information, but still interesting reading.
A mate of mine bought a YZF450 that blew a crank before he wore out the first set of chain and sprockets and the Yamaha dealer didn't seem surprised. 

[Nathan S]

The cylinder thing is Hunky showing his age - aside from the CR500, I can't think of a performance 2-stroke that has had a boreable cylinder since the early 1990s. Even XR600s ran them for a couple of years before Honda chintzed-out and went back to a cast liner.

I dunno how they work in the modern 4-strokes, but a half-way properly maintained plated bore in a 2-stroke lasts about as well as an iron liner - without the cost of reboring it along the way.


None of which is to claim that a modern 4-stroke is cheap to fix...

[All Things 414]

As much as we all hate the modern four strokes (4T. There you go) I'm seriously thinking of parking one of the new-age YZ 450F's next to my 465. What a great set of book-ends for everything else that came in-between.....

[JohnnyO]

The modern 4 strokes are great bikes. I've had several since i got one of the first '98 YZF400's and never looked back.
$3500 is very exagerated for a top end rebuild. It would have to break a rod, destroy the cylinder and smash all the valves and piston to be anywhere near that. While that is possible it's usually due to poor or no maintenance. Regular oil changes and valve clearnce checks are required.
I've never had anything break in 12 years of owning modern 4 strokes.

[MX?]

Shit! I had the top end of the Z900 re-built incl: rings, valves and seals some letting of the piston crowns heli-coiled over a dozen threads, gaskets etc. etc. for $2,800.00
Sounds expensive for a single pot??

[BAHNZY]

Husaberg 1998 FC600
Piston: Genuine $475 - Woosner $395
Con Rod: Genuine Only $350
Valves: $120 (Each)
Valve Guides: $45 each
Gasket Kit: $220
Roller Rocker & Pins $125 (eachx2)
Bearings: $300 (engine & gearbox)
Cam chain: $130
Consumables: $60 (Oil/Filter/Spark Plug etc)
Machine work: 4 Hrs @ $80 per hour

$2500 and that does not include;
- Labour
- Gearbox or clutch work
- Removing & refitting the engine
- And all the other things that typically need doing like repacking the muffler.

If you have a early Yamaha 5 valve, most of the above, but be warned, if the cam  chain and gears are flogged, add a complete crankshaft as the crank gear is machined into the left crank web and is not able to be separated, oh..... and there is another valve to add to the list.

[Mick22]

The thing that worries me with the modern 4 strokes is even if you do the right maintenance and look after the bike some of the manufactures manage to put out an absolute lemon that still blow up, for example the current KTM's and the CRF250's a few years back. You'd think they would be able to get it right by now!
Recently I've seen way to many of my mates brand new bikes (less than 1000k) heading back to the dealer for engine tear downs / rebuilds

KTM525 rebuilds come in at about $2000  and thats with nothing broken, if I dropped a valve and had to buy a head and cylinder, I hate to think what it would cost, luckily I think its very rare for it to happen.

I reckon your spot on Nathan, anyone bagging plated bores is a bit out of touch. I had several blow ups on plated bores and most times the plating has survived even if the piston is melted all over it, a couple I've had to replate - no biggie cheaper than all the rebores I would have had to pay for along the way

[JohnnyO]

Why all the doom and gloom about modern 4 strokes? If they were such shit boxes they wouldn't be selling any..
Sure they cost a lot more to rebuild than an XL350 but they also perform a little better and performance ain't cheap.
Most of them are very reliable and there are a lot of them out there.

[frostype400]

Just as a point of veiw thing ktm300's you have to be on a waiting list for a new one of those.

[mx250]

The modern 4 strokes are great bikes. I've had several since i got one of the first '98 YZF400's and never looked back.
$3500 is very exagerated for a top end rebuild. It would have to break a rod, destroy the cylinder and smash all the valves and piston to be anywhere near that. While that is possible it's usually due to poor or no maintenance. Regular oil changes and valve clearnce checks are required.
I've never had anything break in 12 years of owning modern 4 strokes.

The young guy I know had a second hand WR426 and was actually riding back from the dealer (stealer) after asking his opinion about a small valve clatter/noise - "that's normal. Don't worry about it" . The exact sequence might be speculation but a valve head was broken off and pounded the head and bent and damaged every other valve and seat and generally pock marked the head. The quote was for new parts but included all the head, piston and maybe a new barrel (I can't remember) - $4500 for parts only.

Yeah, you probably could do it cheaper but it still wasn't gunna be cheap .

[mx250]

Why all the doom and gloom about modern 4 strokes? If they were such shit boxes they wouldn't be selling any..
Sure they cost a lot more to rebuild than an XL350 but they also perform a little better and performance ain't cheap.
Most of them are very reliable and there are a lot of them out there.

The point is that they are great while they are going great but...........