2012 AK sled build

[Jakelfin]

125amps was fine when I fixed one hole from friends nytro front cooler.

 

[Nikolai]

It was when welding the side plates which are 3/16. My welder will max out on 3/16 ok but when they are against the diecast it just robbed too much heat. The cooler itself is only like .080.

This is one that took a lot of heat. 3/32 filler rod and I wasn't getting good penetration. Once I pulled it from the diecast it welded up just fine.

I think what I'm going to do is finish welding the cooler 100%, then fill the lower holes with weld and redrill them where the cooler naturally wants to be. It won't be perfect but it'll keep me from scrapping the sled and building a tube chassis.

 

[Jakelfin]

That sounds good, just fit it in and redrill holes outside, no one knows but you, and internet... So, basically, no one. Doesn't hurt if some holes aren't so well fitted, of course time and stress will loosen rivets in bad holes, but you can drill holes little bigger and use some bigger rivets. I have made several aluminium parts and some of them tried to twist in different ways, usually I just twist em back. Press bench, rubber hammers, some friend maybe and use the force. Sometimes it helps, other times it is compromise, but still working. I'm really close to work on tube chassis too, but I want to know how my sled handles that 3x track, do I need more power or something different suspension or so.

 

[sxr70001]

Is there any way you could bolt it up in some kind of jig while welding so it wouldn't lose it's shape. Something that doesn't act as a heat sink of course.

 

[Nikolai]

In hindsight I should have built a jig to start with. I didn't think the diecast would make it that difficult to weld.

 

[Nikolai]

Temporarily changing subjects.

Nytro chaincase vs Apex chaincase. The non reverse setups are very similar in design with the brake caliper being mounted to the chaincase cover.

Apex setup.

Nytro cover

With both setups being close in design, the Nytro cover has an additional bearing for the driveshaft in the cover. I can't imagine this is for driveshaft support. My thinking would be cover support because the caliper is mounted to it, but the Apex has no additional support and they don't have any issues.


Of course I'm looking at this from a weight perspective thinking the Bearing could be removed and driveshaft cut shortly after the nut.

Stupid idea? Yamaha overengineering again?

 

[kinger]

Being familiar on this topic because I have the 06-09 apex chaincase. There is a lot of pressure on the driveshafts and many like myself upgraded to the micro HD shaft which goes from 1.061" Hex to a 1.25" hex shaft. Its also has a another strengthening process done to is like heat treating but not sure the right name off the top of my head. This shaft is almost bullet proof in the apex chaincase. Myself and others will pound this on rough trails/ditches with 250+ hp boost and it wont give up, nor will the case. Around 10K miles on the stock shaft they seem to break more frequently on stock sleds, boosted shortens this further. The HD shaft in a HEAVILY run/abused sled will still break but only MDKUNI is the one I know about it, and he drives his sled then most do their cars. If you remove him then its safe to say its bullet proof.

In 10+ they revised the chase and lengthen the shaft to include a bearing like the nytro. It also seems to fix any issues with the stock shaft.

Lastly I happen to have a 07 non reverse case sitting on my shelf in perfect shape if you needed anything/pictures from it.

Thank you!

 

[kinger]

I meant to also ask, you posted this before but I can't find the page where its mentioned but what does your front subframe weigh? The apex diecast front clip weighs 18lbs. This includes the suspension mounts, shock mounts, and houses the ECU/Regulator, etc. I was wanting to compare to a uber minimalist tube front end like yours. I am a super fan of the diecast unless you tell me it can be built for like 3lbs out of tube LOL

 

[Nikolai]

Thanks for the info, sounds like that extra bearing needs to be there.

I found the post with the subframe weight, it is 15.5 lbs.

It could certainly be made a lot lighter since I reused some factory tubing and could simplify it starting from scratch. I bet if I jig'd mine and used all new tubing I could get it under 12 lbs, maybe even lighter.

IMO, a full tube chassis could be built lighter(if smart with the tube design) than reusing the diecast sides by a couple lbs. I do have plans to build a tube chassis after mine is done and I'm 100% confident it will be under 400 lbs, especially I do my belt drive. Lots of ideas in my head, just not enough time.

 

[Nikolai]

Been working on the cooler when time allows.

Piece for the starter.

Piece to clear crankcase cover

My aluminum welding isn't the greatest so I ended up grinding the welds around the starter piece flush and welded over it again. The sides of the plates were a little bit of a pain. I shoved scraps of 1/8 and 3/16 in the gaps then welded over them.

This is where I'm at right now. Putting it back in the sled to fit the tubes.

I also bolted some pieces of heavy steel angle to it and was able to straighten it most of the way back.

 

[Nikolai]

I finished the cooler tonight and I'll never do that again, ever. Way too much work. I needed the welding practice though so it wasn't a waste.

100% complete frankencooler

Kinda heavy

 

[Nikolai]

Ironically, while digging through my scrap bin tonight I found extra CMX cooler extrusion, enough to do a 3rd pass and not need a front cooler

Fairly light

Just enough to do the 3rd pass.

Keeping the front cooler is probably the lightest option since Id still need to build a front plate to replace it. But deleting the front cooler and adding to the rear cooler moves another 3-4 lbs (counting coolant) from the center of the sled to the rear which I think is better.

 

[kinger]

Wow nice work! Your correct to much work, I wouldn't have even started it LOL. The weight balance thing has me perplexed at least on my apex. I used to think its front heavy and I need to move more weight to the rear, however when you 4 scale weigh it, I'm rear heavy with 65% on the rear and 35% on the front skis with me on the sled. It would be fun to know what the distribution of your sled is. If you look at a new pro they are front heavy (as a percentage of total weight) sitting there without a rider and when a rider sits on it it goes to like 55/45 R/F. So a pro has more weight as a percentage of its total on its skis then my apex. Yet feels light while mine feels heavy. Looking at total weight I have about 20lbs more on my skis then a lightweight pro does (140 pro to 160 apex). So this would tell me I need to ADD weight to the front to get a ratio similar to a Pro. Its obvious that is not the case so I am missing something but not sure what. I'm already 20lbs heavier per ski so maybe the ratio isn't as important as the actual weight. The ratio being closer to 50/50 moves the center of transfer to the rider so the rider can move the sled around easier. So the pro being so light can tolerate a near 50/50 ratio and keep the actual weight on the skis less then my apex. I guess it proves what mountain guys have said from the start, lighter is better and taller bars the better to add transfer and make it easier to ride.

With yours being so light you may want to be careful where you start relocating that weight to. I would say you have a real good chance of having less than 140lbs per ski and in which case you would probably WANT more weight up front. At least it seems to make sense at some point you will reach a tipping point that offsets that motor with all your other weight reduction.

 

[Nikolai]

I've never put much thought in to it. I always figured the more weight out back the better but maybe that's not the case. I do know I've removed a significant amount of weight from the engine back so I don't know that my sled would have that problem.

I put the subframe on tonight to check clearance to the lower outlet by the crankcase cover and it just clears. That's a tight spot.

 

[Nikolai]

For a long time now I've wanted to figure out a way to modify my chassis so the engine could come out without pulling the subframe. I think I could build a stronger overall structure while also reducing weight.

I was looking at it again tonight and came up with something I think might work. I do have an extra set of diecast sides I can cut up first.

The two 3/4 tubes taped together would be one bent piece and tie into the 3 yellow dots(castings which I would drill & rivet/bolt through), tie into the hoop where it bolts to the back top of the diecast, and be notched & welded into the subframe at the bottom. I'd then have to modify the 3/4 tube from shock to hoop(long piece of blue tape on it) for engine clearance and triangulate it into the bent tube somehow.

The tube would run on top of the diecast with a tab on each side. Excuse my drawing skills.

I should probably mention the chaincase side would be left alone, only the clutch side would be modified.