15 RTX Front Arm Crack

[ksiesel]

I just returned from a trip to the UP and went to greasing the rear suspension. In doing so, I noticed grease pushing out this crack.

Is this a common failure? I did search and I’m not really seeing much.

Next question, would you replace the arm, or try to have it welded?

I did some part number digging and it looks like this part number is only used on the 14 and 15 RTX Viper models. In the Cat line, it seems to cover most 129” models from ‘12-15. Any idea what is different about the ‘16 Viper 129 arm and would it be a compatible upgrade?

Sorry for all the questions, just trying to get my head around a game plan to address this ASAP.

 

[DennyTuna]

This is very common, 16 is the same piece. Some have welded just not sure of the success. We have just replaced the arm, check with Travis at barn of parts.

 

[ksiesel]

This is very common, 16 is the same piece. Some have welded just not sure of the success. We have just replaced the arm, check with Travis at barn of parts.

Are you sure ‘16 is the same part for the RTX?

When I look up parts fiche, here’s what I’m seeing:
‘14-‘15 RTX- 8JP-G7331-00-00
‘16 RTX - 8JP-G7331-10-00
‘17-‘18 RTX and LTX - 8JP-G7331-20-00

The one for the ‘16 seems to be the cheapest. I guess I’m just looking for what is different between the ‘14-‘15 and the ‘16 front arm?

Also, the arm comes with new bushings. From some other threads I read, will I have to ream the bushings to get the axle to fit?

 

[DennyTuna]

100% positive, they made a slight change to the part. When they do that they go from the 00 to the 10 after the actual part number. I don't remember having to do ream the bushings but it's been a few years.

 

[RobX-1]

X2 on incrementing the second to last set of two numbers when making a revision to a part. Yamaha did the same back with the Apex arm in the mono when they were cracking and added additional gussets to the same arm and in doing so, incremented the original part number in the way DennyTuna explained it.

 

[ksiesel]

Hmm, the plot is thickening as I dig more.

'15 and '16 have different part numbers for the front arm as well as the lower shaft for the front arm. Further, it appears that the 15 setup has bushings and the 16 does not. See part 6 in the 2015 callout below. I suspect this is driving the part number change to the lower pivot shaft (item 7 in the '15 callout) too.

I also compared FT shock, FT spring, tunnel shaft, slide rails, and all those are the same. I also made the same comparison on the AC ZR7000 and came to the same conclusions.

I'm thinking due to the bushings, if I go with the '16 front arm, I'll also need the '16 lower shaft (part 6 of the '16 diagram) as my '15 lower shaft is meant to be used with bushings. Do you all agree?

Cost is about the same for the '15 arm (which includes bushings) vs the '16 arm and lower shaft. Which way would you guys go?

 

[SumpBuster]

I just returned from a trip to the UP and went to greasing the rear suspension. In doing so, I noticed grease pushing out this crack.

View attachment 177328View attachment 177329View attachment 177330


Is this a common failure? I did search and I’m not really seeing much.

Next question, would you replace the arm, or try to have it welded?

I did some part number digging and it looks like this part number is only used on the 14 and 15 RTX Viper models. In the Cat line, it seems to cover most 129” models from ‘12-15. Any idea what is different about the ‘16 Viper 129 arm and would it be a compatible upgrade?

Sorry for all the questions, just trying to get my head around a game plan to address this ASAP.

I have had so many arms crack on everything, I weld and then gusset all the corners, weld more metal over the stress areas, etc. A little 110 volt flux core welder works fine if you dont have a welder. Never had a welded one break again. OEM parts all break, even so called new better..blah blah..
Just found a crack in the front arm of our ski doo v800 4 stroke SWT skandic groomer. Not sure why that broke, the thing is built like a tank. Anyway, had great luck welding and making better. One rx1 front arm had 11 breaks and I welded them all as the guy wanted to ride the next day. Worked fine but we did buy a new one as it was pretty trashed riding miles with it collapsed.

 

[1nc 2000]

Most likely the crack is inboard from where the bushing stops.
The shaft with no bushing has more surface area to distribute the load to lessen the stress. The bad thing is when the arm wears out from no bushing it gets replaced....

 

[SumpBuster]

And it would seem my long departed father who was a professional welder his whole life, always said stuff cracks near the welds. That because the time taken to properly heat and stress relieve the parts costs money.