Need help cracked upper motor mount [Archive]

NacsMXer

06-14-2010, 07:48 AM

I would definitely have that welded up or replaced if it's really bad. You need that motor mount functional. Post a pic if you can, let's see how bad it is.

HY400EX

06-14-2010, 08:55 AM

Originally posted by HY400EX
My upper motor mount is cracked is it anything to worry about?

Barrymaxx

06-15-2010, 01:41 AM

It should be okay for a little while. Just make sure you tighten the mount bolt very well so it clamps the valve cover between the spacers firmly.

Keep an eye out on ebay and here to find a new rocker cover and replace it once your get one.

Out of all the mounts, its the least crucial one... But I don't recommend riding without it as it will stress the other mounts much more.

supraloud84

06-15-2010, 04:22 AM

Your best bet is to keep an eye out for a used one to buy. Both mine and my buddies cracked in the same place. I talked to another guy I know that builds jr. dragsters to see if it could be welded and he highly recommended against it. Its sand casted aluminum and will warp like crazy if you try to weld it. He showed me a perfect example of what he was sayg when he grabbed a sand casted briggs and stratton block that he welded a patch into and set it on the true surface of his mill. It might as well have been a rocking chair it pulled so bad

JOHNDOE83

06-15-2010, 08:47 AM

I dont know if youve ever pulled your motor out, but 90% of the time they crack because the motor mounts were put in the wrong way.

There are several of them front, back, top ,bottom...

if you tighten down one before all are bolted up, it stress's the frame and motor mount's causing them to crack...

HY400EX

06-15-2010, 09:21 AM

Originally posted by JOHNDOE83
I dont know if youve ever pulled your motor out, but 90% of the time they crack because the motor mounts were put in the wrong way.

There are several of them front, back, top ,bottom...

if you tighten down one before all are bolted up, it stress's the frame and motor mount's causing them to crack...

Motor has never been out. I was adjusting my valves and saw the mount was cracked.

jasonwayne222

06-15-2010, 09:43 AM

an alluminum welder will fix that and reinforce it with a strip across the top all welded up and it would be fine, probly wouldnt cost more that 40 bucks or so and u could bring the bike to the welder without pulling the rocker cover if u wanted

HY400EX

06-16-2010, 07:39 AM

Took it to an excellent welder with 33 years experience last night. Said he could weld it but we found 3 other small cracks down near the bottom. With that many cracks decided to just by another one.

400ex=awesome

06-16-2010, 08:25 AM

http://cgi.ebay.com/ebaymotors/99-07-HONDA-400EX-ATV-ENGINE-ROCKER-ARM-HEAD-CAM-COVER-_W0QQcmdZViewItemQQhashZitem2a07b96d4bQQitemZ18051 8219083QQptZMotorsQ5fATVQ5fPartsQ5fAccessories#ht_ 823wt_958

there you go :D

jcs003

06-17-2010, 01:35 AM

mts-2000 aluminum brazing rods.

NacsMXer

06-17-2010, 10:21 AM

Originally posted by jcs003
mts-2000 aluminum brazing rods.

Forgot about that, that stuff is awesome!

jcs003

06-17-2010, 11:49 AM

Originally posted by NacsMXer
Forgot about that, that stuff is awesome!

have you used it. im about to try it on my 250r case next week.

any tips or precautions?

NacsMXer

06-17-2010, 09:08 PM

Originally posted by jcs003
have you used it. im about to try it on my 250r case next week.

any tips or precautions?

Nope, just watched a bunch of the Youtube vids on it. I was pretty impressed. Sorry I was of no help, lol :ermm:

Good luck man, let us know how it goes...

jcs003

06-18-2010, 01:11 AM

Originally posted by NacsMXer
Nope, just watched a bunch of the Youtube vids on it. I was pretty impressed. Sorry I was of no help, lol :ermm:

Good luck man, let us know how it goes...

i watched those videos too. it should be easy. i hope.

NacsMXer

06-18-2010, 03:53 AM

Yeah it looks pretty simple. Hardest part appears to be the grinding/shaping to a finish product afterward. Just gotta make sure everything's nice and clean, and then clean it again before you start.

jcs003

06-18-2010, 04:15 AM

Originally posted by NacsMXer
Yeah it looks pretty simple. Hardest part appears to be the grinding/shaping to a finish product afterward. Just gotta make sure everything's nice and clean, and then clean it again before you start.

exactly. i know you need that small stainless wire brush too.

jcs003

06-18-2010, 05:44 AM

definitly looks like a DIy product.

http://www.youtube.com/watch?v=jijW310xvp4&feature=related

CJM

06-18-2010, 04:04 PM

Thats stuff is AWESOME!

sc400ex_rider

06-18-2010, 04:28 PM

I got some of that stuff but its called allumaloy. just heat the part up and let the rod flow in. they also sell it at harbor freight for a good price.

JOHNDOE83

06-18-2010, 06:02 PM

just watched that youtube vid!!!

I wonder if you could build a alluminum frame with that stuff???

I wanna get some just to test its strength...lol.

NacsMXer

06-18-2010, 08:13 PM

Here's another good vid that shows the many uses of this stuff! Definitely pertinent for guys in our sport.
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