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DRZ400sm problems?

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I just got my '05 DRZ400sm last week and love it.

I do have two worries about it since this is my first "brand new bike"

Last night I was going about 75mph and the front end had a terrible head wobble...should I be worried about it, or is there a remedy?

Also, I just put my second tank of gas in it, calculated my MPG, which it was 43MPG. I have searched on here of people running 55-65 MPG with stock gearing out of the box, so should I be worried about this also?

Thanks for any imput...I probably am just overreacting, but I just want to make sure everything is good to go before I take it out of the city and to the twisties of the mountains.

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your mpg will go up some as your bike breaks in more(usually). I'm not sure about the head shake, I rode today all the way to work(30min) between 120km/h(75mph) and 140km/h(86mph) with absolutely no headshake(that I noticed atleast).

Ninja edit- I have no idea on my MPG, never calculated it.

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Since the 400S and 400SM weigh 291ish Pounds they are very susceptible to turbulent air from anything bigger than a Subaru. Were you hitting bad air form some other vehicle? It happens to me alot. I just throttle past them. :applause:

Your Speedometer is probably 10% off. All of them are, so you need to take that into consideration.

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I just picked one up last month. I have the same problem with the head shake but it starts at about 80 - 85. I just press forward on both bars and it stops. I don't think the bike is really made to run that fast very often. I would imagine that you could get a steering dampener for it but I am not sure (My other bike is a CBR600) I don't know a lot about SM's yet. And I am getting 44MPG's. Have fun on it! My CBR has not come out of the garage in a month. This thing is just too much fun.

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There was nobody around, smooth road, going down hill, no wind.

Could it be a suspension problem? :applause: I increased the preload, and I am at 124mm race sage...need to increase it more to the 103mm range, but could this effect the front end?

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I am not sure about the suspension question but I believe mine comes from the wind resistance on that huge front fender.

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last tank I got a caluclated (from the odo) 55 mpg the one before it was 72 mpg but that was taking it silly easy not normal riding

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55mpg riding nice 40's having fun. Slight wobble is normal, lean foeward and loosen up your grip on the bars to stop the wobble.

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((I increased the preload, and I am at 124mm race sage...need to increase it more to the 103mm range, but could this effect the front end?))

Yes it can,

But need to grease your steering bearings anyway, do that and then snug them good. It will help, or eliminate.

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are the bar-end weights made to help this?

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Bar-end weights will damp some vibration in the bars.

The headshake is probably just the nature of the beast. It's a tall, long travel suspension, horribly un-aerodynamic, relatively lightweight streetbike. Any little gust of wind has a pretty significant effect on it. I was able to induce a little wobble on my way into work this morning going about 70. It wasn't a problem at all, and it stopped as soon as I stopped trying to induce it. Just relax your grip on the bars - the death grip is the worst thing to do when you experience some headshake or a tank-slapper.

As for mileage - I just filled up for the first time - got around 42mpg that first tank. Some highway miles, commuting, and lots of wheelies in the parking lot. I expect it will go up once broken in.

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I've been getting 60+ mpg since the bike was new. Funny thing is, that's what I get no matter how hard I drive it. According to the factory odometer, at 117 miles I'd better be reaching for the reserve switch.

I've also had the headshake. The first time I hit 80 on the bike, it did it. I've never experienced that before so it scared the crap out of me. The thought of me skipping accross the asphalt at 80 quickly entered my mind. Like the others have said, just loosen your grip on the bars. If all else fails, slow down!!

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From my exp with street legal dirt bikes and SM is that they are twitchy... thats why they turn so awesome. I do not notice the head shake at all anymore... My 1st road going dirt bike scared the piss out of me on the freeway.

Now the only time I notice the headshake is when I am behind a semi.

the suspention settings will affect the way the bike handles, turns, shakes... because you change the rake of the fork in relation to the road. A low back end will result in increased rake which in turn will make the bike more stable at speed. However it also slows steering response. Like wise lowering the forks in the clamp will decrease rake and make it twitchier. (the way I like it) :applause:

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I had headshake on my S above 70mph until I balanced the tires.

Never had it since on several sets of tires from slicks to aggressive knobs.

If its under warranty they should re-balance for free, shouldn't they?

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Yeah, this bike has a steep rake for the highway. I say.. get the wheels spin balanced, then set the rear for the proper sag, around 100mm (I think is what I have). Raise the forks in the clamps if you don't have them flush now. Also, I've noticed those handlebar mounted mirrors are affected greatly by wind turbulence and create steering oscillations or "wobble". :eek: A steering damper would probably work wonders with high speed stability. :applause:

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Yeah, this bike has a steep rake for the highway. I say.. get the wheels spin balanced, then set the rear for the proper sag, around 100mm (I think is what I have). Raise the forks in the clamps if you don't have them flush now. Also, I've noticed those handlebar mounted mirrors are affected greatly by wind turbulence and create steering oscillations or "wobble". :eek: A steering damper would probably work wonders with high speed stability. :applause:

Just to make sure...I should drop the forks in the triples so that the top of the forks are flush with the top of the clamp? I am about 260lbs...do you think I can squeeze out 100mm race sag out of the stock shock? (I don't want to buy a new spring right yet) Thanks for yours and everyones help!

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If the bike is set up for it, an S model will blow through potholes all the way to 100mph , and rail 80mph + highspeed sweepers like a cutting tool with excellent stability.

End Quote

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I have not had any head-shake at all on mine and it needs a fill at little over 100 miles. (not counting reserve)

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