450 MXer Pitfalls?

[Coyote]

I'm looking at getting a 450 Motocrosser over the next 6 months once I've sold my CBR, prefurably a WR450. What I wanted to find out first is what are the problems with owning a 450 4 stroke? How often will I be looking at rebuliding it and at what cost? Could I learn to work on the engine myself and rebulid it or would it be too advanced for a inexperienced kid like me to work on?

[Badcat]

I'm looking at getting a 450 Motocrosser over the next 6 months once I've sold my CBR, prefurably a WR450. What I wanted to find out first is what are the problems with owning a 450 4 stroke? How often will I be looking at rebuliding it and at what cost? Could I learn to work on the engine myself and rebulid it or would it be too advanced for a inexperienced kid like me to work on?

that looks like a ron wood flat tracker - very similar to what i'm building...
are you thinking of building a WR 450 into a street tracker?
if so i can forward you some examples - PM me.

ken

[Motu]

From what I've heard the Yamaha is the most sorted of the modern 4 strokes,but they are still big on maintanence - lots of oil changes using expensive oil,and regular top end rebuilds....depending on use of course.The modern 2 stroke needs less maintenance than the modern 4 stroke these day,and cheaper too.

[cowpoos]

as motu said....or get a kawasaki KLX300r...light weight [105kgs i think?] 34hp...and shit they have a good chassis....
and they don't have the maintainance of the majority of mordern MXer's...I use mine daily...it gets a service every 3-4thou k...or 2mnths [i usually about the 3.5k-3.7thou every 2 mnths] I abuse the shiut of it...rev the stink out of it...crash it regualy...it simply won't die...and its a doddle to kick start...one kick every time......easy to wheelie...it has enough power to pull third gear wheelies...I keep up with good riders on kx250's crf250's etc and even the 400's if its twistie...I've got a brand new one coming in a week...the old girl is still fine...I just want a new one...!!!!

only thing wrong with them is the foot pegs fill up with shit easy...!!!

[cheese]

The new 4's also have to have the valve clearence checked every 15 hours. It's not like an old XR250 where they would go and go and go. They are as much, if not more, maintance than a 2 stroke.

From what I've heard about the different brands though...

Honda - have seperate oil tanks for the enigine and gear box, so all your clutch poo's don't get into your engine.

Yamaha - 5 valve head (wicked set up) slightly heavier.

I don't know abou the new Suzuki's and Kawasaki's...

My suggestion though is if you're racing, get a YZF, CRF, blah blah blah, if you're just going to play and it's more as a fun weekend hack, get more like the KLX or Similar. Not as high performance, but you won't be stripping it every 2 days and have your wife having a whine about the garage ss all full of bloody bike parts and can't get the car in there......

[Fryin Finn]

I have had a rather unpleasant experience owning a modern 4 stroke. My WR 450 sucked in sandy water at the Santoft enduro last year through the oil breather pipe - since relocated. This caused enough damage for the engine to be rebuilt. The cost of this work was $4700 and includes new barrel, piston, crankshaft, cams, oil pump, electric starter and bearings.
I loved riding the bike but couldn't bear to rebuild the motor if it ever suffered damage again. I have since traded for a GasGas 250 2 stroke which I rode for the first time at a MX this weekend and absolutely loved it. Nearly as much power as the WR but handled way way better. I may have to replace piston and rings more often but at least it's a job I can do myself.

[Brian d marge]

Maintanance...Honda usa are back logged with parts orders ....gasket sets etc ,,,They ARE a highly strung race engine ...so need the maintance

But ,,I find in the tight stuff the 4 stroke leave enough time per bang to get traction out of the corners ,,,and I cant catch them till 1/2 way down to the next corner ,,,,

One of the best Cr 250 hondas was the 93 to 96 cr range ..so much so that one supercross rider didnt change the bike ,,just the plastic in order to make it look like he had a new bike ..

I find the 4 strokes a little more forgiving when riding ..A bitch to start after dropping them ...and gain more traction

2 stroke lighter ,,,less expensive ... ( I moddded mine for low down grunt ,,,and its MUCH better )

I wouldnt be buying a 4 stroke in a hurry ,,if I can find some 93 to 96 barrels ( Hensteeth) ...I wont change at all ... apart from the newer suspension The 92 Rm ( from memory ) had the valving right ...and the newer CR s have high speed and low speed damping ....So if a set does pop up I will buy it ....

BTW The biggest expense this year has been ,,,Atf oil for the gearbox ( a one race wonder but does make clutch feel lighter ,,,also use it in forks and rear shock,,,,) and chain and sprocket ..Honda genuine ,,which was quite cheap ....oh and a stiffer rear spring

Mx ,,,95 percent the rider ....5 percent the bike ..........

There you go a completely un biased opinion ....

Stephen

[chris]

I'm looking at getting a 450 Motocrosser
Do you want a dedicated MX'er, 'cos a WR450 isn't? If you want something to do MX and trail, GasGas EC range.

[Oscar]

If yer just after a medium sized trail bike, get a DRZ400 (or KLX).
CRF's and WR's are not n00b friendly...

[Coyote]

I'm looking at a 450 Motocrosser type bike as I want to do Supermoto/motard racing (Hopefully enter the S2 class at Taupo and do a few races at Manfeild), but I also want it as a dirt bike cause we can easily access the Masterton MX track so I can get bike time over there, and I want it to be able to register on the road for when I get my full licence. I was thinking of getting the WR as it is road legal plus it has the 5 speed gear box unlike the YZF making it better suited for motard. As far as I know, the main difference between the WR and YZF is the electrics, muffler and cam timing.

I knew 2 strokes would be easier to maintain, but I wanted to know how much worse it is looking after a 4 stroke and whether I could handle and afford it or not. Also wanted to know if it was possible for me to do engine rebuilds given a bit of time or would I have to take it to the mechanic every 4 hours. I was told that a 4 stroke would make a better motard because of their power delivery but I haven't ruled out the idea of a 2 stroke. The main reason why they aren't high on my list is that the only road legal 2 strokes I've seen are the RMX and CRM which aren't any good. Not sure if KTM make a road legal 2 stroke though

As for the pic in my sig, it has nothing to do with this. It's a pic of a road legal Flat Trackker bike CCM have in development, and I just think it looks awesome.

[TonyB]

Modern 4 stroke MX bikes are very highly strung and require a hell of a lot of maintence. For instance the CRF450R. I believe Honda recommends piston replacement every 40 hours. Some racers are wearing them out in 10-20. Even trail riding apparently you would be pushing it to get 60-80 hours. The pistons in these things look like they have come from an F1 car

[Eurodave]

Heres some updated pix of my CB450 street tracker project
Currently Im working on the the paintjob & upholstery. The exhaust pipes in the pix are the patterns that I tacked up & Ive taken them to Autobend to copy & then theyll get black hi temp powder coated.
The mufflers will be replaced with a pair of black shorty reverse cone megaphones.
Next the motors coming out & the frame will get powder coated dark blue
Its great to make some progress after a long time on the back burner!!

[NordieBoy]

As for the pic in my sig, it has nothing to do with this. It's a pic of a road legal Flat Trackker bike CCM have in development, and I just think it looks awesome.
And these...

[Brian d marge]

add to that ...crankshafts..on 2 smokes ....I have just done mine in I was running 40 to 1 as per ,,,but I think I ballsed up the top end jetting not sure will see later...anyway its was pissing down today and the clay went to mud and over the rough the engine was hitting Max Rpm as the wheel spun ....I thought it was bogging a bit ,,,so on one straight I wound it out in second .....and presto ...I have a new crank to rebuild ,,,,

If I do it myself ( as per usual ) its going to come in at 10 000 yen all up

Today was an expensive day !!!!

( and I didnt even get any air time !!:crybaby::argh:)

So there you are another thing to watch out for on a 2 stroke !!!!


Stephen

[Coyote]

Modern 4 stroke MX bikes are very highly strung and require a hell of a lot of maintence. For instance the CRF450R. I believe Honda recommends piston replacement every 40 hours. Some racers are wearing them out in 10-20. Even trail riding apparently you would be pushing it to get 60-80 hours. The pistons in these things look like they have come from an F1 car
Apparently a friend of mine has to do a top end rebuild on his YZF250 every 4 hours :pinch: Luckily his dad owns Whitehouse motorcycles in Upper Hutt.
I know there's going to be mantainence involved. My brother has a KX125 and almost every weekend is spent working on it.

And if I do get a WR, this is a must: http://www.motoworldracing.com/One-Industries-2005-YZF-250-426-450-Hurricane-Graphics-Kit.html

[Badcat]

Heres some updated pix of my CB450 street tracker project
Currently Im working on the the paintjob & upholstery. The exhaust pipes in the pix are the patterns that I tacked up & Ive taken them to Autobend to copy & then theyll get black hi temp powder coated.
The mufflers will be replaced with a pair of black shorty reverse cone megaphones.
Next the motors coming out & the frame will get powder coated dark blue
Its great to make some progress after a long time on the back burner!!

man- that's gonna be sweet when it's finished...
i'm already planning my next street tracker - maybe a TRX850..........
anyway - keep the pics coming dave.
i love the seat you made for me by the way - will have it painted as soon as the sr500 arrives from japan - possibly come down to CHCH to pick it up in the next couple of weeks!

ken

[cowpoos]

get a klx300r $7995 brand new...including procircut exhaust and moose bars...
then ring these boys for this kit http://www.thequadshop.co.nz/index.php/cPath/94



and by the way:"" KLX 300 is only 3~4 kg heavier than a KDX 200 and only 1~2hp down. Compared to a KLX/DRZ 400 they are nearly 15kg lighter and down 8~9hp, however if you were to look at this in a power to weight perspective (hp/kg) it would look something like this: KLX 300 0.314 hp/kg, KDX 200 0.336 hp/kg KLX/DRZ 400 0.351 hp/kg."" [quoted from a website]

also check this out... http://www.thequadshop.co.nz/information.php/info_id/24?sid=f47621d54def8d4e746bbd5cc95c3781 and its a nz firm!!!

And I bet you'll get a better bike for the $$$$$ more reliable....and buy some switchgear and a battrey and get the larger magneto out of a klx250 and reg it!!!!

[laRIKin]

I would like to add that the MX motors do not like to be held at full throttle
for a long time.
They are made to be held at full noise for a short time only.
As when you are on a MX track, it is shorter fast burst's.
Supermoto/motard racing kills the motors faster, so I'm told.
Unless the track is short and tight.

Years ago you could not hot up the SR500 as much as you could on the XT/TT500's.
White Brothers use to say this in their book, for the reasons I have mention above.

I have a KTM640 LC4 and would like to do Supermotard racing on it.
But mates that have had LC4's for years, have said that even the LC4 motors life expectancies are shortened when they are Supermotard raced.
And things happen to the motors that normally do not happen when trail ridden.
I may still race it, but only on the short track, to be easier on the motor.

I have spent up to just under $1500-1800nz on a complete 2 stroke rebuild.
They where real major rebuilds.
But most 4 stroke rebuilds seem to be more like $4500+nz.
The cheapest I know of was $3500nz.

Racing is not cheap and has got a lot dearer now days when you are talking MX/trail bikes.
And that's why I went back to an older type motor.
I have saved so much money on oil and filters with the LC4 motor alone.

What would I race in a Supermotard?
Properly what I have, lots of power in a mildly tuned motor.
Than a smaller motor that's a grenade.
That is unless I really really wanted to win and had backing or lots of money.

Rik

[NordieBoy]

The LC4 is the engine in most of KTM's road motard offerings.
Seems to be reliable enough if looked after (like any engine).

[Coyote]

Looking at the info in this thread, I've been turned away from the idea of a motard. Maybe it would be a possibility for me in the future when I have a bit more money. Untill then whilst my Dad is helping me pay for all this, it'll probebly be best if I down-grade to a RG150 and continue racing streetstock and keep the rest of the CBR money aside for any repair bills

[TonyB]

get a klx300r $7995 brand new...including procircut exhaust and moose bars...
Quote from a very experienced mechanic/rider at a local bike shop:

Kawasaki's are great bikes, don't get me wrong. But they don't last. They're made out of cheese. Everything is done on the cheap, they use cheap alloys and while it goes great initially, they require a lot more maintainence than a Honda or Yamaha

[cowpoos]

Quote from a very experienced mechanic/rider at a local bike shop:


must be a honda mechanic...they like to talk there products up..I had a bet with a honda mechanic once...I won...lol...[I mean the suzuki won]...my old KLR250 had 76,000km on the clock used no oil....started first pop...one kick
my current KLX300R is coming up 3yrs old...it is still great...nothings gone wrong with it...well there have been the things I broke...canning off...
I do 120-150 km a day on it...you do the math...and I thrash its arse off...

Still starts first time every time....uses no oil....I swear by kawasaki....every kawasaki I've own has be brillent machine...no hassles...majorly cheap to run...reliable...well built...

I have heard alot of people diss kawasakis reliabilty,build quality,longevity,etc
I've own alot of bikes...ridin alot of bikes...far more than I should have for my age...and I know....I'm never buy another yamaha...hondas have there place [like toyota...reliably boring and ugly] coz they still work when they shouldn't...suzuki make a bloody good product all though they build to a budget...they are hard to beat value for money...and thats why they are the top brand in this country aswell as havin a good product...

I still believe kawasaki have a superiour product...they bolt good shit on to kawasaki's...and they are a focused product...

[laRIKin]

The LC4 is the engine in most of KTM's road motard offerings.
Seems to be reliable enough if looked after (like any engine).

They are still very reliable when motard raced and are a strong motor.
Sorry if I gave the wrong message there.
But any motor that lives at the high end of their rev range, pays a price in longevity.
And from what I have read more and more guys in Europe are now starting to using the RFS motors.

Rik

[dellow]

Just do it man.Every bit of time/money spent on maintaing a big four stroke is well worth it.(in my opinion)

[Cary]

From what I've heard the Yamaha is the most sorted of the modern 4 strokes,but they are still big on maintanence - lots of oil changes using expensive oil,and regular top end rebuilds....depending on use of course.The modern 2 stroke needs less maintenance than the modern 4 stroke these day,and cheaper too.

I disagree, my YZ will only get a new piston/rings engine check at 100 hours. Talking to guys today at Power twilight ride said they have a CRF450X with 300 hours in shop and have only had to replace piston/rings, rest was sweet.

The WR's, CRFX's etc are the modern brick shithouses of the MX world. :2thumbsup

Coure, if you do self distruct a modern 4 stroke its gonna cost a bloody fortune to fix :sick:

[Brian d marge]

How does a mechanic at a local bike shop know what material has been used ????
I use a Vickers hardness test then narrow the material down to about a handfull

Currently doing exactly that to calculate the estimate life span of a conrod .....so HOW does wonder mechanic do it ??

at a stab ,,they all ( the manufacterers ) subcontract out to specialist smaller companies
Yamaha has stumbled upon a good casting company ( I like there casting work ,,,v nice )
but at the end of the day all the propriatry bit ...springs widgits ,,,torsion bars and giggly pins are all sourced from china at negotiated prices ...wether its honda /haharly /onda /or shinray
Try buying 3 million yen worth of springs at 1/4 yen each ....and find they all have a differing spring rate than the specified drawing ,,,,then tell me you had a bad day at work ...( wasnt me !!!:spudwave:but a good friend :argh:)

..
Personally I would keep me eyes on the emergin nations ,,india /china /tawian ,,,as they are investing heavily in tooling AND have that flexiable approach to manufacturing ,,,that IS delivering a quality product at prices WELL below the big 4
Trade me Shineray??? is it ..MX bike for 2k NEW apart from conventional forks it looked ok to me 2 K approx NEW

Drifted off topic again ,,,never mind ,,,that means I am 1/2 way to not being sober ,,,and thats a good thing I suppose
Nite all

Stephen

[Coyote]

Just do it man.Every bit of time/money spent on maintaing a big four stroke is well worth it.(in my opinion)
Time isn't a problem, money is.

So are the 4 strokes just like the 2 strokes as their piston and ring is the only thing they need replacing regulary? If that's wrong, what does need replacing? At what cost and how often?

[Coyote]

How long do 4 strokes and 2 strokes normally last before needing to replace the piston and rings?

[Cary]

How long do 4 strokes and 2 strokes normally last before needing to replace the piston and rings?

All depends on your use of the bike really. A pro rider is going to change it often to keep it at peak performance, say after every race meet or two. I think most manufactuers recommend 15 hours.

Mine gets a hard time but not a complete thrashing and is still going strong at 75 hours, I'm going to change piston/rings at 100hrs whether it needs it or not!!

I change oil every 6 hours and oil filter every 18, clean air filter after every days riding maybe every 2nd depending on conditions.

[Coyote]

All depends on your use of the bike really. A pro rider is going to change it often to keep it at peak performance, say after every race meet or two. I think most manufactuers recommend 15 hours.

Mine gets a hard time but not a complete thrashing and is still going strong at 75 hours, I'm going to change piston/rings at 100hrs whether it needs it or not!!

I change oil every 6 hours and oil filter every 18, clean air filter after every days riding maybe every 2nd depending on conditions.
Pretty much sounds like the same routine with my brothers 125. Does it cost much more than a 2 stroke for the piston and ring and to get it sorted by a shop? Liked to be able to do it myself but thats unlikely

[Cary]

Pretty much sounds like the same routine with my brothers 125. Does it cost much more than a 2 stroke for the piston and ring and to get it sorted by a shop? Liked to be able to do it myself but thats unlikely

Yes as there is the cam chain etc involved but for shop it's not a major as have tools/experence, so a simple job.

I haven't had one done by a shop but would only figure on 2-3 hours labour.

[Windy]

This is my first post, so I'll make it count. <leans back and cracks knuckles>

Yes 4-strokes need more maintenance, they have more moving bits to wear. But if you change the oil every 500 miles, or after each race engine life is better than a 2-stroke (2-strokes have given me a very sensitive clutch hand :)).

Yes Supermoto is hard on MX bikes, particularily the gearbox, as they invariably won't have a cush drive. Thrashing an MX bike around a supermoto track is no different to engine life than thrashing it around an MX track.

Re. piston life. If anybody is quoting times like "10 hours", then they are talking 'race' hours, and if the average race is only 15 minutes long that's 40 races at top level racing standards (or a whole season). At 'club' level you should get years.

Re. valve clearances. Get a Yamaha, or any other bucket and shim engine. That way you can check them as often as you want but you will rareley have to do anything. Buy a Husaberg, for example, and you do need to check them very, very often.

So change the oil (any good 10/40 will do), and there is no reason why a 4-stroke will be any less reliable than 2-stroke. The only thing to add is that when it goes bang the four-stroke will be more expensive to fix.

I have just completed my first season at supermoto on a seven year old bike and have only had to do oil/filter changes, and air filter cleaning. I will be having a peek at the valves, but I doubt if anything else will need attention other than swingarm bearings and fork seals (but that would be the same regardles of the bike).

But if you want to do the SM thing I would go WR because of the 5 gears, just get the YZ timing mod done and you are away.

Long post I know, but I hope it helps you to decide :niceone:

[Coyote]

This is my first post, so I'll make it count. <leans back and cracks knuckles>

Yes 4-strokes need more maintenance, they have more moving bits to wear. But if you change the oil every 500 miles, or after each race engine life is better than a 2-stroke (2-strokes have given me a very sensitive clutch hand :)).

Yes Supermoto is hard on MX bikes, particularily the gearbox, as they invariably won't have a cush drive. Thrashing an MX bike around a supermoto track is no different to engine life than thrashing it around an MX track.

Re. piston life. If anybody is quoting times like "10 hours", then they are talking 'race' hours, and if the average race is only 15 minutes long that's 40 races at top level racing standards (or a whole season). At 'club' level you should get years.

Re. valve clearances. Get a Yamaha, or any other bucket and shim engine. That way you can check them as often as you want but you will rareley have to do anything. Buy a Husaberg, for example, and you do need to check them very, very often.

So change the oil (any good 10/40 will do), and there is no reason why a 4-stroke will be any less reliable than 2-stroke. The only thing to add is that when it goes bang the four-stroke will be more expensive to fix.

I have just completed my first season at supermoto on a seven year old bike and have only had to do oil/filter changes, and air filter cleaning. I will be having a peek at the valves, but I doubt if anything else will need attention other than swingarm bearings and fork seals (but that would be the same regardles of the bike).

But if you want to do the SM thing I would go WR because of the 5 gears, just get the YZ timing mod done and you are away.

Long post I know, but I hope it helps you to decide :niceone:
Give that man some rep. Thanks for all that info. That's what I wanted to hear :niceone:

I'm selling the CBR for sure, I know that now, but I'm more likely to get an RG at this stage. Got some info on motorcycle/scooter couriering from Texmo and was thinking of doing that over my school break to earn some money that could go toward a nice motard in the future. Also it'll give me some bike time on the RG if I choose to race it, which is likely. Also thinking of saving some money for a cheap van/ute to take myself up to Manfeild without relying on my Dad and the trailer, just something cheap on trademe

Also selling the CBR and buying a cheap RG will give my dad the money to get the trials bike he's wanted for a while

[Garvani]

Well thank god for your post Windy.. you guys had nearly completly put me off the idea of getting a bike..

Heres the deal, im new to all this, i want to get a reasonably new bike say a 2001, and was pretty much sold on a yz250f (possibly a wr250f??)until i started reading about all this damn maintence you need to perform on them, i don't plan on racing (well not for a quite a while anyways) just for firebreaking & some track practice. Can someone break down the maintence costs for me? as in taking it to a shop to get done etc.. (im pretty sure i can handle an oil change myself tho :-) How often is a rebuild really needed? far out i hope not to often at $4,000 a go.... And how much is a set of pistons & rings gonna set back a guy...
Im not that financial so thank god i didnt just go out headfirst and buy a bike like i was going to do then find out a couple weeks later what i was in for. So yeah if someone could write me up a cost summary (along with the recommended hourily usage they should be performed at) cos at a guess i would think i would be doing at least 8+ hrs a weekend fanging around the local firebreaks etc...
Anyways hope i don't sound like a complete tool.

[Eurodave]

Heres a pic of the latest progress on my Honda 450 street tracker
Ive nearly finished the paintjob & my home built exhaust pipes are going in to be hi temp powder coated black very soon
Also Ive been doing a lot of polishing of all the alloy bits, dirty ,time consuming work but theyve come up a treat!
Ive made a pair of what seem to be called 'beauty plates' out of alloy,to hide the gobby fillets & Hondas pidgeon shit welding around the swingarm mount.
The chassis punches have been exercised too, check out the holy chainguard
Next up is a total strip & frame sandblast/repaint in 2K

[Badcat]

that looks sweet dave!!!!
the seat you made me is away being painted as we speak - will post pics in my XT500 street tracker thread when i have them.

excellent work!

ken

[Eurodave]

that looks sweet dave!!!!
the seat you made me is away being painted as we speak - will post pics in my XT500 street tracker thread when i have them.

excellent work!

ken

Cheers bro! Cant wait to see what youve been up to!!

[clint640]

They are still very reliable when motard raced and are a strong motor.
Sorry if I gave the wrong message there.
But any motor that lives at the high end of their rev range, pays a price in longevity.
And from what I have read more and more guys in Europe are now starting to using the RFS motors.

Rik

I wouldn't get stressed about thrashing an LC4, They are probably the most suitable dirtbike engine for sustained high speed. The current LC4 motors are the product of the 10+ years of development that has kept KTM winning Dakar on them every year, they are made to be held WFO all day.

That street tracker is sweet Dave!

Cheers
Clint