Back cutting the trans

[rubberneck]

Ok, i remember finding a thread from way back in the day that talked about back cutting a trans for better shifting. If i remember correctly it even had some pics. I can not for the life of me find it again. Anybody have it bookmarked or remember what the hell im talking about. Im about 90% on what i need to do, just want to review before i chuck the gears up in the mill and start cutting every other dog and window off.

[AKheathen]

do you remember what the thread was called, and about how long ago? it would be an interesting read..

[AKheathen]

the search kinda sucks, but i was able to come up with these.......

http://bansheehq.com/forums/index.php?app=core&module=search&do=quick_search&search_sort_by=date&search_sort_order=desc&type=forum&type_id=1&search_term=dogs&search_filter_app[forums]=1&st=175

http://bansheehq.com/forums/index.php?showtopic=17268&view=&hl=dogs&fromsearch=1

[rubberneck]

I couldn't find anything in the search either. That second link may have been it, but i dont see any of the pics on that guys page. It looks like it doesnt exist anymore. It was from way back when though, so that could have been it. No matter, I cut it yesterday. I remember most of the details, plus i had an override sitting on the shelf to look at anyway. Here are some pics. They are from my cell so they suck. The finish came out nice and smooth. If anybody decides to try it, you will need carbide cutters as HSS just melted the end off. I ended up cutting 2nd 3rd and 4th gear

 

Here is 2nd gear. 2 lugs gone, working on the 3rd

 

Ready to reassemble

 

The bike im putting it in has RZ shift forks, Shift Pro roller, modded shift star and modded shifter shaft already. It shifts smooth as silk, but every once in a while when in a hurry (like shifitng mid hill climb) it wouldnt go in gear, so i think this should make it about as good as it gets without having an override. Plus i will still be able to backload and abuse the shit out of it.

[AKheathen]

lol, yah, the gears are pretty hard.......i noticed the roostfest site is down for rebuild, too....i think that may be where a large portion of the info was.........so, no back-cutting? when i cut, i'm going with 6 degree back-cut on the dogs, which is just enough to keep it fully engaged, but you can still push it out. i was told that some overrides use a pretty steep cut on the dogs, but then it's pretty much locked in. steep cuts do make sure it goes all the way in everytime o n an override, though. i don't know how they are cutting it full width, though in the windows......

[rubberneck]

Nope i didnt touch the remaining windows and i dont think you need to, but that is my opinion. Some overrides may be backcut at an angle, but my 1-5 duneable is not. They did exactly what i just did. They did put a very radical cut on the dogs but not on the drive side, it is on the coast side and cut such that it will make it come out of gear when shifting up. In an override bike, cutting that face may be ok, because it wont get that many shifts in its life time. I would be concerned with excessive wear if you didnt re-harden the material after you machined it on a duner or trail bike. I can tell you that the first .050" or so was much harder than the rest of the material. I do have some real world experience to back up my theory. My cousin had an old 250r that began popping out of 3rd gear and he took it to a shop that remachined the dogs and windows back square. It only lasted 2 trips and then was doing it again. I split it and found 3rd gear dogs very badly rounded and worn. I replaced the gears with new OEM parts and its been back together over 15 years. Maybe the shee stuff is different, but i doubt any of the guys that cut these for money are going to chime in and give us some tips, so im going with what i know. I have a feeling that as long as everything else is in good shape, there is no reason to change the angles but give it a try and let us know. Im not sure how you will go about actually doing it though. Even with a very small diameter cutter bit you will have a radiused inside corner in the window which is going to prevent full face contact with the dogs. I guess you could round the inside corners on the dogs. Any way have fun and let us know how it works.

[midlifecrisis]

I couldn't find anything in the search either. That second link may have been it, but i dont see any of the pics on that guys page. It looks like it doesnt exist anymore. It was from way back when though, so that could have been it. No matter, I cut it yesterday. I remember most of the details, plus i had an override sitting on the shelf to look at anyway. Here are some pics. They are from my cell so they suck. The finish came out nice and smooth. If anybody decides to try it, you will need carbide cutters as HSS just melted the end off. I ended up cutting 2nd 3rd and 4th gear

 

Here is 2nd gear. 2 lugs gone, working on the 3rd

 

Ready to reassemble

 

The bike im putting it in has RZ shift forks, Shift Pro roller, modded shift star and modded shifter shaft already. It shifts smooth as silk, but every once in a while when in a hurry (like shifitng mid hill climb) it wouldnt go in gear, so i think this should make it about as good as it gets without having an override. Plus i will still be able to backload and abuse the shit out of it.

 

What I want to know, is how did you get a milling machine into your "cell", thats a pretty liberal place, obviously not a turkish prison!

[rubberneck]

Sorry, i should have been more clear for the mentally challenged My cell PHONE. haha just fucking with ya

[AKheathen]

unfortunately, i don't have a mill, but i do work on $45k diffs and power deviders quite often........there are mainly 2 modles with minor revisions. when it comes to the engagement dogs, the 6 degree is enough to make a huge difference in reliability. the strait cut dogs are the only ones that have a tendencey to round and sheer if there is any wear on the fork shoes, or slide chanel.......the 6 degree only wears the chanel and shoes, otherwise not ever needing replacement...even with the operator "oops"es...

[rubberneck]

Ok cool, when you get it done post pics, id like to see how they did it.

[too_fazt]

i dont know if this is a dumb question or not...but is the only way to cut the dogs is using a mill, or could u grind it out with say a dremel? im looking to do something similar with the extra transmission i have. but havent found enough info on it yet.

[rubberneck]

well the material is pretty tuff so i would think it would be tough with a dremel. With enough patience, enough bits and a steady hand it might be possible, but you would probably be better off just paying a local machine shop to do it. It is really easy with a mill and a 1/4" carbide cutter. including set up it took me about an hour to do 2nd 3rd and 4th, i could probably do the next one in less time. A competent machine shop should have no problem with it.