Author Topic: KX250/500 front motor mount question.  (Read 4986 times)

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Offline The Flyin Hawaiian

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KX250/500 front motor mount question.
« on: December 18, 2010, 02:57:48 PM »
Ive been noticing that a few guys have cut the 250 cradle out and installed a 500 cradle. I have been worrying about the front motor mounts cracking when using 250 style weld in brackets. Instead of replacing the whole cradle would it be a problem, strengthwise, to cut out the area where the front motor mounts are and weld in the frame pieces with the 500 style bolt in mounts? I would use some sort of steel slug to insert into the tubes. Im probably worrying too much, I have a competant welder to do the job.
A couple of 03 and 04 KXs, a few YZs, 3 PE 400s, a DR and a TS.

Offline sintax

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Re: KX250/500 front motor mount question.
« Reply #1 on: December 18, 2010, 04:12:22 PM »
yea, no reason at all to cut the cradle out.

honestly you only need to reposition 1 set of engine mounts (front) and make or buy a headstay mount.

That portion of the job took about 30min, 45 tops. (2000 engine into 2002 frame)

structurally i could see there being a problem with those cradle swap if the welder does not handle it right.

Offline jonny500

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Re: KX250/500 front motor mount question.
« Reply #2 on: December 18, 2010, 05:31:18 PM »
i agree with sintax, i think the cradle swap should only be done if there is no other way. i made new mounts for my  99-02 250/500. i had them tig welded on, they look very strong but are un tested. i looked at trying to replicate the standard 500 mounts on the 250 frame. the tubing on the 250 is smaller but will work. but the main reason i didnt do was, it would be hard to drill the frame accuratly. i just dont have the equiment to mount and drill a frame so the alternative was a pistol drill and i didnt fancy that. also on the 99-02 frame the space between the cradle tubes is less than the width of the front engine mount on the k5 engine so the alu mount plates would not be straight. i am going to see how the welded mount holds. if it does not i will be going for alu plates and bolts. my frame is away being powder coated, when comes back i will post a pick of the front mount on my thread
regards
john

Offline The Flyin Hawaiian

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Re: KX250/500 front motor mount question.
« Reply #3 on: December 19, 2010, 01:53:05 AM »
Thanks guys! I think Ill just stick with welding in the mounts and see what happens.
A couple of 03 and 04 KXs, a few YZs, 3 PE 400s, a DR and a TS.

Offline jonny500

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Re: KX250/500 front motor mount question.
« Reply #4 on: December 19, 2010, 02:00:00 AM »
you can aways modify it further down the road

Offline ZETTNORCAL

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Re: KX250/500 front motor mount question.
« Reply #5 on: December 19, 2010, 03:55:35 AM »
I would think that the removable 500 style mounts , make it alot easier to get the engine in and out.

Offline jonny500

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Re: KX250/500 front motor mount question.
« Reply #6 on: December 19, 2010, 04:06:53 AM »
i agree zett, i would have liked to have done it that way but it seemed like a lot of work for me. if mine crack i will definatly be having a go

Offline junk man

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Re: KX250/500 front motor mount question.
« Reply #7 on: January 17, 2011, 06:00:29 PM »
I was thinking about welding inserts for the front engine mounts but the frame is to narrow
and i didn't want to to modify the cases. I think if you use two piece mounting tabs would work better than one thick tab. on mine so far its good

well good luck JM