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Reviving an atk 406 mx 2 stroke from abandoned

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No, it does not have 65hp. Not even close. No, the CRF is not 65 lbs heavier. Calm down!

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On 2/2/2019 at 10:05 PM, Patrockyj said:

Also my personal opinion is I would much rather have that 200 dollars spent on reliability and comfort upgrades, than a decal set, I am just looking to see if my opinion is unique? 

Not at all. I kind of like a rat rod look for my vintage bike. My YZ465 is mechanically perfect with good wheels and Race Tech suspension. It looks like hell but goes like hell.

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22 minutes ago, SMarquez said:

Not at all. I kind of like a rat rod look for my vintage bike. My YZ465 is mechanically perfect with good wheels and Race Tech suspension. It looks like hell but goes like hell.

Plus I figured on this bike, most of the younger generation will never know what ATK means anyway, lol. You can always spot the performance guys (and gals, I know several) vs the restoration geniuses. Some bikes are 50 yrs old and look and run exactly like the did new. It is an art form I have not acquired but I absolutely respect. Then you got a bike with a black pipe when the factory was chrome no decals, but when that exaust tone starts to sing you pray that thing is as insane as she sounds. I am a member of the latter group. Just my 2 cents.

Edited by Patrockyj
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On 2/9/2019 at 9:53 AM, Piney Woods said:

No, it does not have 65hp. Not even close. No, the CRF is not 65 lbs heavier. Calm down!

I got a good laugh out of that myself. Probably in the neighborhood of 35hp. I got to ride one once. The motor had good bottom end torque but not much on top. A Yamaha IT465 has more top end and they are only 38hp or so.

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1 hour ago, GreenMT_Rider said:

I got a good laugh out of that myself. Probably in the neighborhood of 35hp. I got to ride one once. The motor had good bottom end torque but not much on top. A Yamaha IT465 has more top end and they are only 38hp or so.

I apologize I was off on the weight it's about 30lbs lighter, than a 19 crf450r. There is no way this is a 35ish hp bike, I also own several others, including a crf450r, and I was shocked that this 91 atk will flat out, out power a 2015 honda. 450r On any flat or uphill. Now the atk cant compete with anything but power, so how does a 29 yrs old 35 hp bike out run several modern professionaly maintained modern mx bikes? I am not meaning this as a challenge I am trying to figure out why? I am tempted to run a dyno to figure answer this. I am not trying to sell or promote this bike, parts are a nightmare. But similar cc rotax 2 stroke snowmobile engines make 65 to 105hp. Why are power specs not published anywhere on this bike? I might be totally off base on this, my specialty is Performance Auto, not the imports, but high hp v8 classics. 

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Something is obviously wrong with that '15 CRF450. No comparison in torque or HP. The ATK is a nice, older bike of a different era with a very interesting history. That's about it.

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11 minutes ago, Kevin Kelley said:

I have a 01 yz250 and there seems to be some water in the crank oil any thoughts What it might be  

You need to start a new thread in the appropriate forum.

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Stock HP for the 406 Rotax engine was 43 as advertised in Canam MX-6B

ATK used different exhausts and carbs, probably putting out more HP.

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1 hour ago, GB1073 said:

Stock HP for the 406 Rotax engine was 43 as advertised in Canam MX-6B

ATK used different exhausts and carbs, probably putting out more HP.

Ty and I read in a motorcross mag, Atk was getting 10 to 12 more hp out of that engine. So I will be the 1st to say I was wrong on 65hp, but 53 to 55, is possible. Not probable but 2 strokes in this cc class from the same maker exceed this.So could explain it  by no means does it measure up to Modern standards, it would be like putting a 401 hornet against most new cars, the old Hornet would kick iass in a straight line, but with no power steering or brakes and the suspension, that much power was scary as hell. And that Hornet is goofy as hell, but she really did Kick-Ass in a straight line

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10 hours ago, Piney Woods said:

Something is obviously wrong with that '15 CRF450. No comparison in torque or HP. The ATK is a nice, older bike of a different era with a very interesting history. That's about it.

There is nothing wrong with the CRF, she runs Beautifully, and in any bumps corners or anything other than a straight line, the atk loses badly, but in a drag race, she beats the crf, now granted I am certain the CRF has a higher top speed, there was snow, and we did not have a clearing big enough to test that. But again I ride for fun I was not making competition statement or challenging anybody that owns a CRF, that is just a bike I have as a comparison. My specialty is Automotive engines, so I'm not bashing any of you guys, rather I really appreciate your input

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1 hour ago, GB1073 said:

Stock HP for the 406 Rotax engine was 43 as advertised in Canam MX-6B

ATK used different exhausts and carbs, probably putting out more HP.

I appreciate that info, and after researching Can-Am equivalent, the factory bike had three shims in the head gasket (between head and cylinderl this engine has 1 which would mean someone has attempted to increase compression. Thankfully I have an Murphy's gas station here centennial, CO, that sells 93 octane non-ethanol gas, which I run in all small engines. Plus at this altitude the high compression engines do not require the same octane levels (burn retard) as lower altitudes.

Edited by Patrockyj

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ATKUSA still sells parts and has manuals and brochures on their site with lots of information available.

American Dirt Bike also sells parts and has a lot of information on their site as well.

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8 minutes ago, GB1073 said:

ATKUSA still sells parts and has manuals and brochures on their site with lots of information available.

American Dirt Bike also sells parts and has a lot of information on their site as well.

 Thank you  ATK has been very helpful they are also super fast replying on email. Rotax is the pain point.

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14 hours ago, Patrockyj said:

 Thank you  ATK has been very helpful they are also super fast replying on email. Rotax is the pain point.

Try vintagecanamparts.com, Remi carries and remanufactures parts for Canam's and Rotax engines.

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14 hours ago, Patrockyj said:

 Thank you  ATK has been very helpful they are also super fast replying on email. Rotax is the pain point.

That's the nice thing about TT.  If anyone, even a total newbie, comes here to ask questions, as long as they don't act like an ass, other TT'ers are glad to help.  They will suggest a different sub-forum if it will be more helpful OR the mod's will move it anyway.  I've seen the other side of that coin too.  A first-timer comes to TT, asks a question and wants the answer NOW.  If after a few hours, he hasn't gotten anything, he posts "This web site sucks - I'm never coming back here".  And the question is so obsurd like "Can I put '99 yamaha YG3 forks on my '65 Honda SL202".  And of course, he asks this rediculous question in the middle of the day when a lot of guys are at work anyway.  

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