Nikolai
TY 4 Stroke God
Picked up my ProRMK steering post bushings today. Everything pictured is 6 ounces. Not nearly as nice as the OFT pieces but the additional strength of the larger 1-1/8" post will be worth it. Even though I'm using larger tube, the overall weight of the post will be less since I won't have any braces.
Nikolai
TY 4 Stroke God
I've been wanting to do a chromoly subframe for a long time but I could never get myself to copy the oem design. I decided yesterday I would go an entirely different route. Not only will the subframe be chromoly (mostly), but I'll be permanently removing about 1/3 of the tube. A factory subframe without the swaybar is 18.54 lbs. The Diamond S saves 8 lbs, I'm hoping mine will come in under 10 lbs when done. Plan is to take my time and build this one so it's useable, then if it holds up to everyday riding I'll build an all chromoly one.
The main lower tube I'm working on now is 1-1/4" .058.
First task was to cut a few tubes out of the way so I could get an a-arm in and trace around the bushings.
With all four traced I could now see how far down I could sit my main tube.
Halfway done notching.
Took me 3 hours with a grinder, file, and schotchbrite pads to get the fit up tight.
Tacked in place.
Starting work on the next tubes in a few minutes.
The main lower tube I'm working on now is 1-1/4" .058.
First task was to cut a few tubes out of the way so I could get an a-arm in and trace around the bushings.
With all four traced I could now see how far down I could sit my main tube.
Halfway done notching.
Took me 3 hours with a grinder, file, and schotchbrite pads to get the fit up tight.
Tacked in place.
Starting work on the next tubes in a few minutes.
Nikolai
TY 4 Stroke God
Got the other two main lower tubes in. What a PIA to notch tube at multiple odd angles. I'm reminded why I'm not building an entire tube chassis (more props to Rick). Some of the joints aren't as tight as I'd like but I'll throw some little braces in later.
One more pic with the new .058 7/8" shock tower brace . Most of the tube I'm using is left over heavy wall from previous projects so some of the sizes might seem odd. Just trying to use all my scrap up.
I have to go out of town for work for about a week and a half then I'll be back on it. I should have my tunnel sheetmetal by then too.
One more pic with the new .058 7/8" shock tower brace . Most of the tube I'm using is left over heavy wall from previous projects so some of the sizes might seem odd. Just trying to use all my scrap up.
I have to go out of town for work for about a week and a half then I'll be back on it. I should have my tunnel sheetmetal by then too.
Sportsterdanne
TY 4 Stroke Guru
Awesome build !
I have so much ideas for a Nytro build just need some time and money
one idea is to modify the subframe and move the entire front suspension forward to have the spindle forward geometry with stock A-arms.
I have so much ideas for a Nytro build just need some time and money
one idea is to modify the subframe and move the entire front suspension forward to have the spindle forward geometry with stock A-arms.
Nikolai
TY 4 Stroke God
I had just enough time this morning to get the front cut out for my last two main tubes. These will be 1-1/4" .058 running from the lower main tube to the shock mounts. Once I get these in and everything welded, I'll go ahead and cut out the entire lower section of the subframe.
Nikolai
TY 4 Stroke God
Missed my flight today so I got a couple more hours on the sled. I haven''t played with my TIG in about a year so don't judge the welds to bad.
Subframed weighed 13.1 lbs in this photo.
After tacking in some braces and cutting the front tubes out.
More to come in a week.
Subframed weighed 13.1 lbs in this photo.
After tacking in some braces and cutting the front tubes out.
More to come in a week.
Nikolai
TY 4 Stroke God
Worked on the subframe all day. Aside from a steering post mount, some upper a-arm braces, and welding it's done. I'm going to leave it as is and see how it holds up. It weighs 12 lbs 14 ounces so with the steering post brace it should be right over 13 lbs. Another 5.5 lbs off the sled. I'm pretty confident an all chromoly subframe would come in under 9 lbs. As soon as I get some time this winter I'll jig the current one.
Sportsterdanne
TY 4 Stroke Guru
Nice work ! 
will it hold up? Im worried about the front lower a-arm mountingbrackets.. Even though you got a nice triangular shape it just looks so empty 
Off Trail Mike
Gone Riding!
Nikolai, that is awesome creativity....I hope the Yami engineers are watching!
I think it will be plenty strong as the triangular setup is much stronger than the stocker flat plate/tube. Not to interfere with the design, but on the strength issue, you might consider adding two small tubes in a "Vee" in back between your new horizontal piece and the "stock" perpendicular horizontal tube above it towards the back suspension mount. Basically the same "Vee" as you did in the front but in the back with much smaller tubes I know it adds weight, but its the only area I see that can be easily pushed up or sideways in an impact.
Are the shock mounts still in the stock position now? Been thinking of moving these forward, but it would take some plastic work as well.
Now, I gotta find me a subframe!
OTM
I think it will be plenty strong as the triangular setup is much stronger than the stocker flat plate/tube. Not to interfere with the design, but on the strength issue, you might consider adding two small tubes in a "Vee" in back between your new horizontal piece and the "stock" perpendicular horizontal tube above it towards the back suspension mount. Basically the same "Vee" as you did in the front but in the back with much smaller tubes I know it adds weight, but its the only area I see that can be easily pushed up or sideways in an impact.
Are the shock mounts still in the stock position now? Been thinking of moving these forward, but it would take some plastic work as well.
Now, I gotta find me a subframe!
OTM
Nikolai
TY 4 Stroke God
Thanks Mike. The a-arm and shock mounts are in the stock location. The rear will be braced as you suggested, I'm just waiting until I build my steering post as I'll incorporate the post bushing mount into it. I won't be using the nose cone either. I'm going to box the front and sides in with my extra .040 7075 and modify my hood to work with it. With the lower tubes gone I can also lengthen my shocks to 17" now and get some extra clearance and a little narrower ski stance.
I don't think strength is going to be an issue at all. I'm pretty confident it's stronger than stock now. My next one will most likely be .049 and and even cleaner tube layout. Chromoly is incredibly strong, especially when you get up to 1-1/4".
I don't think strength is going to be an issue at all. I'm pretty confident it's stronger than stock now. My next one will most likely be .049 and and even cleaner tube layout. Chromoly is incredibly strong, especially when you get up to 1-1/4".
Wow that is an amazingly well thought out process you went through and I agree should be way stronger since you are using a triangle and stock used a box.Awesome!
sorenson1610
TY 4 Stroke God
- Joined
- Dec 11, 2007
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- 2016
Looking good and very different then stock! Interested to see how it holds up this year. Keep the pictures coming on the build....
Sportsterdanne
TY 4 Stroke Guru
Is there any pictures of the crosscountry subframe ?
of the pictures i have seen there is no tubes below the lower a-arm mounting much like your subframe.
of the pictures i have seen there is no tubes below the lower a-arm mounting much like your subframe.