Help needed Suzuki rm 125

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6/17/2018 11:38 AM

Hi guys I've recently bought an rm 125 2003 model. The bike is a really good bike. All fully rebuilt etc. The only issue is. The first time I rode it the gear shifter went very floppy after a couple of gear changes. I've stripped it down and the locating pin that sticks through the selector fork has snapped of from the casing. I'm not sure what this part is called I'm sorry. I'm just after some advise.....

Can this part of the bike be welded or is it going to have to be a new crankcase. I'm really annoyed as the bike is absolutely immaculate apart from this problem.

Any help/ advise would be greatly appreciated 

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6/17/2018 2:13 PM

Is it a possibility that this can be welded

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6/17/2018 6:27 PM

Get a case and then you will have no worries.

I would not have that welded. Its too critical of an area, the weld would need to penetrate a good ways to hold which could cause warping... and that could cause other shifting problems. Not worth the risk in my 2 cent opinion.

Now with all that said, new cases are $700+ if you can find them and used cases are hard to find on ebay. You might get lucky and find a parts bike on CL.

Or I hope you know a very good welder. Good luck. keep us posted.
-Bob

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6/17/2018 8:42 PM

Preheat the case until it will sizzle spit. Pot metal does not weld good. My bro welded this on a YZ450F and it saved a case exchange. I remember they cleaned it 5 times and preheated until no oil residue was left. Good luck.
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6/17/2018 11:40 PM

That metal looks like it's just waiting to come apart. I would replace the case half if at all possible. I personally wouldn't trust a weld.

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6/18/2018 1:18 PM
Edited Date/Time: 6/18/2018 1:18 PM

Considering the only pressure on that post is the shifter spring- I see no reason it should have failed. I'd put a new case on it just to make sure there isn't some other bigger unforeseen issue.

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6/18/2018 1:23 PM

New cases.

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6/18/2018 2:24 PM

What is "pot metal"? I am thinking it is called aluminum. Someone correct me where I am wrong.

OP, good luck on the search for a set of case halves or a massive effort to have it welded and repaired.

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6/18/2018 2:45 PM

KDXGarage wrote:

What is "pot metal"? I am thinking it is called aluminum. Someone correct me where I am wrong.

OP, good luck on the search ...more

I saw that too... It's die-cast aluminum.

The reason they don't weld easily is contamination (from oil, etc) and the type of alloy used in those castings (high silicon).

OP, you should just find a case, or a complete used engine. If that's not possible, welding & machining won't be inexpensive, but it will work if the job is done correctly.

Baking the casting for a few hours (when your wife isn't home) can help, then clean it a few times with a good non-toxic de-greaser (don't use chlorinated brake cleaners, etc. where you'll weld).

Get a guy who is skilled on the TIG welder and has experience with aluminum castings.
You'll have good luck with 4047 or 4043 alloy filler rod.

Rather than weld that piece back in, you need to build it up and then have a machinist mill it flat, drill, then tap the hole.

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6/18/2018 2:55 PM
Edited Date/Time: 6/18/2018 2:57 PM

It can be welded and its not a high stress piece unless you stomp on the shifter. I would watch Ebay for a case half and have it welded to use now or until you can find one. I have had great luck with both. Had RM case welded and also found several on ebay for cheap

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Ed Johnson

6/18/2018 3:49 PM

This guy is selling a lot of RM parts right now in the Bazaar. LINK

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6/19/2018 10:10 AM

Wow thank you for everyone's input. Much appreciated to you all. I'm going to risk getting someone to weld it. But may also see if you can geya r/h engine case. Thank you to you all

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