Anyone ride 4 stroke MX bikes?

Discussion in 'MX / ATV / UTV' started by Schmeal, Feb 17, 2009.

  1. Schmeal

    Schmeal

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    Just like the title, how often do you have to change the oil and adjust the valves? Is there other maintenance that has to be done and whats the frequency between rides? (the internet yields only differences in the riding experience, not real world issues) I have a 250 EXC and I'm thinking of upgrading to a KX 450 or a 450 SX/XC. All I do now is keep it clean and greased, change gear lube and mix gas. What am I looking to get myself into?
     
  2. mnewell

    mnewell

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    I've got an 07 WR250F. Here's my understanding on 4-stroke dirt bikes and valve maintenance...

    The earlier CRFs had major issues with valves. This would be from, I think, 2003ish until 2006. My buddy with an 04 CRF250X has replaced his head with a later version and ew think that solved his issues. One of the reasons why I decided to go with a WR rather than a CRF was because of the problems I had heard.

    True the 4-strokes will need more maintenance but the ease-ability when it comes to riding is why I like them. Although a 250EXC would be pretty sweet too...
     
  3. Hilux

    Hilux

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    Not to be a smart ass, but why don't you consult the owners manual or a FSM?

    I say that b/c I don't think all motors have the same head features. I don't know, but doubt all bikes have the shim under bucket design and I would think all manufacturers are different.

    Personally, if I can change the oil on it, (anything) I have a FSM for it.

    $crew paying anybody else to work on my stuff...

    I think what you want to know is how many hours until an oil change. (I believe it breaks down even when not in use) In that case I would get a hour meter. But don't hot wire those things...Davey Tree has a truck that will defy belief...the guy that put the meter in hot wired it and it runs 24/7. :lol:
     
    Last edited: Feb 17, 2009
  4. Schmeal

    Schmeal

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    Because I do not own a 4-stroke or really know anyone that rides one.

    mnewell, your probably right that newer bikes will have less valve issues. just want to know how much more maintenance A 450 4 stroke is vs. a 250 2 stroke. I've heard horror storys of racers having to adjust valve clearances and changing oil every ride not to mention the price of a blow up. The 250 EXC (2 stroke) is ok, but with the heavy fly wheel it really lacks punch. Good woods bike though. I hear the WR is an awesome trail bike. Theres also the new KLX out that looks like it may kick a$$.
     
  5. Hilux

    Hilux

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    I've herd pretty much the same, only 2 strokes are what they're talking about. 4's are pretty much problem free....but definitely not as fun. It's give and take. Scary fun? Frequent rebuild...Almost as fun, but not as? A dependable 4stroke.


    2stokes don't have valves....well, they have reed valves.

    Changing oil every time you ride, is 2strokes. Racers might do it to 4's but it's just to have max protection.
     
    Last edited: Feb 17, 2009
  6. sessions

    sessions

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    I ride a YZ250F, well did but recently sold it to pay off some bills, and I will stand by Yamaha 1000%!! I bought the bike new in 2003 and rode it every weekend super hard (5-10 hours a weekend)..until I sold it last summer. When I bought it I thought I'd be riding the track more but ended up in the woods trail riding. The 250f or 450f is more of a track bike, but with a few mods it can be trail ridden. So that is the first question you'll have to ask yourself, What type of riding will you be doing...track or trail?
    I worked at a Honda/Yamaha/Kawasaki dealership for awhile and between the shop guys, sales guys and customer feedback I'd stay away from Honda's 250f or 450f, they are jetted super lean out of the box, require tons of valve adjustments and are a B_tch to start!! Yamaha...hardly any issues followed by Kawi's. Honda does make a very nice trail bike though! The 250x or 450x are very nice and have electric start!! As for Yamaha either bike is awesome YZF or WRF! I'd personally get the WR450F, replace the throttle body stop with the YZF throttle body ($200 swap) as it only pulls half throttle out of the box, and then it is BA after that mod. Also the newer WR's have electric start with a back up kicker, the Honda's don't. The Kawasaki KLX just popped out the FI but as with any first generation FI I'd wait a few seasons to get the kinks worked out. The Kawi's are great bikes, however, I'm not a Kawi guy. KTM makes probably in my opinion the best woods bike on the market, but the price of the bike, parts prices and maintenance schedule pushed me to Yamaha.
    To answer the question of cost of maintenance between the 2 stoke and 4 stroke depends how long you are keeping the bike really...you can ride it hard and put it away wet..expect issues in the future, but if you maintain it you could potentially have a great running bike for a long time. After every ride/weekend in my case I'd clean and lube the chain, clean the air filter (key to engine longevity) and change the oil and oil filter. I never had any issues with my 250F and I beat that thing!! Though since the purchase and poor choice of bike for the type of riding I replaced the clutch once in a 5 year period of time but never had any valve issues!!
    At the beginning of each new riding season, in the Pacific Northwest that is about March to November, I'd take the bike to my dealer shop to have it tuned, fresh tires mounted and a valve check...really the only thing the tune up is are a new plug, oil change, oil filter change, clean air filter and valve check/adjustment, chain adjustment/cleaning which runs about $200 'ish'. After that I'd maintain it until next year ie oil changes, oil filters, air filters, chains and spark plugs. The cost associated is mainly in oil, oil filters and plugs ($30) as you can reuse the air filter and even the oil filter every other ride. Follow the FSM for exact periodic maintenance. It's nice to have a professional do a once over yearly in my opinion, as I'm not the best mechanic!!
    The 2 stroke usually requires replacing the piston and or entire top end yearly depending on the beating you give it. 2 stroke bikes are snappy quick and have a wicked power band and the 4 stroke is constant power all the way thru! I liked riding both 2 and 4 stroke bikes but I would ride a 4 stroke for life!!
    Just my .02
     
  7. SHERMAN FJ62

    SHERMAN FJ62 Charlestons' King of Cruisers

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    I will keep it simple. Depending on how hard you ride some people recommend you change the oil everthy 6th time after riding the bike for several hrs. Value adjustment when you hear them start chattering or 1 time a year if you only ride a couple of times of year.

    MX bikes require much more maintance and some are not that good for trail riding.

    Some of those MX bikes need constant adjustment and at the pro and jr legue level some of those guys change the fluid after every race weekend.
     
  8. sessions

    sessions

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    well put...I kinda got word vomit! LOL
     
  9. Mace

    Mace rock scientist.. Staff Member s-Moderator

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    You have no idea what you are talking about. New 4 strokes trump 2 strokes in just about every way.. Go look and see what most racers are using..


    No, it all depends on the bike. Some do require an oil change after each ride, others do not. Capacity of oil makes a huge difference.


    Depending on the models, the difference between a 2 stroke and a 4 stroke is you have to put oil in the gas of a 2 stroke.

    If you are really talking about MX riding, Sherman has it correct. Race, and change the fluids.. 2 stroke or 4 stroke..
     
  10. Hilux

    Hilux

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    You're jumping all over my s*** cause the new stuff?

    Why don't you jump all over the s*** of the people the OP heard that from?

    I don't study every bike as soon as it's made, and it SOUNDS like the OP doesn't either...

    Go find the people that we asked those questions to and bring them up to speed.
     
  11. jasonmt

    jasonmt

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    My nephew has a 08 KTM 250SX and I have a 03 Yamaha WR-450F and with either rider on either machine the honest truth is that the bike is not the limiting factor, either machine does have terrain that it is better in but quite a bit of that is setup.

    I have attached the maintenance intervals for my bike, I find that it is a lot less maintenance intensive than a comparable 2 stroke (IE a KTM-250SX) but it is in a different league than keeping a XR or similar machine running.

    I would get a 450 4 stroke over a comparable 250 2 stroke without a moments hesitation.

    For the ranting Hilux and the "new" note I am talking about a 2003 bike which is hardly new.
     

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  12. Mace

    Mace rock scientist.. Staff Member s-Moderator

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    By new I mean the last 10 years or so. What most people in the MX world would consider archaic..

    So yes, I am.

    The information you gave does not really apply to older bikes either. It was just plain bad info.
     
  13. sessions

    sessions

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    the biggest reason why all the pros are riding thumpers is due to the high emission levels the 2 strokes produce. The 2 strokes are slowly being phased out of production due to that. Honda stopped making 2 strokes in 08, Yamaha makes just a couple of 2 strokes still and so does Kawasaki. Not sure about the other brands but you can plan on all of them being out of production by roughly 2012.
     
  14. Schmeal

    Schmeal

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    Thanks for the responses guys. I originally stopped paying attention to this thread because Hilux was so far off. It's good to get straight information from first hand experience (who actually ride and maintain modern 4 stroke MX bikes) as opposed to speculation.

    jasonmt- that maintenance schedule really clears things up

    That said, I'll probably look for a 450 XC-W or something similar. 90% of my riding is done in the open desert and the only racing I plan on doing is hare scrambles. I'm not much of a track rider. Adjusting valves constantly is for the track monkeys; i like to wrench but not every single ride.
     
  15. Newps

    Newps

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    I have a 2005 CRF 450, I am the original owner. I took the bike brand new to Tokyo Mods (Tokyo Mods - They Build It, We Modify It!) to have a new bike prep. and his (Ron Woods) carb. mods. Now granted since I’ve owned this bike I have now had a chance to use a lot. I change the oil every other time when I go to the track and every time when I come back from a weekend of riding in the desert. I change the air filter every time I ride. I asked Ron what oils he recommends for a weekend warrior like myself. I am not a racer who beats on his bike every weekend. He said to run Mobil 1 10/30 in the engine and Castrol GTX regular 10/30 in the transmission. The key to maintaining these bikes is regular changing of oils and air filters. These bikes hold a tiny amount of oils. This is why changing them frequently is so important. I’ve never had any problems with my bike and it pulls just as hard today as the day I bought it. Clean and maintain your 4-stroke bike and it will last you a long time.
    Side%20Shot.jpg
    Side%20Shot.jpg
     
    Last edited: Feb 26, 2009
  16. Mace

    Mace rock scientist.. Staff Member s-Moderator

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    Exactly, if you want a 4 banger that you can ignore, make sure it has a larger oil capacity..
     
  17. jasonmt

    jasonmt

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    Checking/adjusting the valves on my machine is a 45-60 minute job that I generally will do after a few weekends of riding now that the bike is well past "broken in". Basically I checked the valves more frequently when new and when the valves started to consistently not need any tweaking I extended the check interval.

    ThumperFaq: Adjusting Valves

    Like others have said when the engine only holds 1 litre of oil frequent changes are a good idea but are also not real expensive.
     
  18. Straightjacket

    Straightjacket

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    I have the Honda version with training wheels,a trx450,it has been problem free since 04'.It's going to self destruct now! I have heard that there are two models now,a race version,and an enduro version.The race Tie valves,enduro,stainless valves.Tie valves lots-o-adj.stainless not so much.The trx was my first Honda,first quad,first 4-stroke.It rocks! the 250's are cool but the 450 is just wicked controlable power.If you can get electric get it kickstart is overrated,you've allready proved yourself!
     
  19. brwnj60

    brwnj60

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    My boss beats the living hell out of his 2004 wr450f and he is 325pounds- the only time the oil gets changed is when i can drag it away from him and do it (not enough !) and it is still going strong, although those titanium valves are starting to get noisy, it has been pretty maintenance free.
     
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