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Need some advice on rebuilding the wr450f transmission after the 5th gear issue showed itself.

Just a little background so you guys know whats going on. Its a 2006 wr450f that has (I'm guessing) 6-10k miles. The majority of which have been street and supermoto miles. I was doing a track day at Musselman Honda Circuit in Tucson AZ and began to feel 5th gear slip especially under hard acceleration. Immediately after the track day I googled the issue and came upon the 5th ear issue of these bikes. Ive since barely used 5th gear and now have the time to tear it apart and see how bad it is. That gets us to where I am now. I split the cases and pulled out the gears only to find significantly less damage than I was expecting 20170811_232231.thumb.jpg.e7cccc472f4cc27d07fa0e481fe32638.jpg

The only very noticeable thing wrong with the whole transmission was the shifter fork (#2 I believe) 20170811_232417.thumb.jpg.ee6c2d66f201883d857deaca4d5432f5.jpg

I was expecting the dogs of the pinion to be trashed but they are only very very slightly rounded 20170811_232429.thumb.jpg.0a7f89e96595d4e0f194b7c8ec87e2de.jpg20170811_232448.thumb.jpg.f25f4223660f6ee320c0ba6fb90f3968.jpg20170811_232456.jpg.771fff262ba6f6610952aa1433e6fe24.jpg

 

To give you an idea of how shallow the marking is on this gear, I have trouble feeling it with my finger nail. Anyways what do you guys suggest I replace and what can I do to stop this from happening?

BTW thank you guys for doing all you do! I've gained so much knowledge about my bike from this site and I hope this post can help someone down the road. 

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You have different gears on yours than what failed on mine.   The reason you don't have much rounded off yet is most likely you stopped running it as soon as the problem presented itself.  I ran mine as gingerly as possible almost 2 hours ride time home,  but it definitely went into "slip" mode at least 50 times on the trip.

 

IMG_20170505_150454_zpsjv9knwam.jpg

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How do the adjoining gears mesh with each other when you preload the gears?  Do they push apart? Do they stay inline with each other?

 

With my transmission when you'd apply a load to the gears they'd try to push apart causing wear on the shift forks.  Since I rebuilt the whole transmission the problem went away.  Damage wise, the corners were much more rounded than yours, but my 5th gear wheel wasn't as polished as yours.

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Its definitely a gear slip. Sudden and doesn't get back into the gear until I ease off the throttle. Pine I actually took a better look at the gears this morning after completely disassembling them and there was a set that was slightly more worn. I can't remember exactly which one it was but I ended up ordering shift forks 1 and 2 (both had some play on their shaft), gears 1 3 and 5 along with pinions 3 and 5. At this point my bike is basically a stunt lot machine and it has stayed in 1st gear for 90% of the last ~500 miles so I will replace the slightly worn 1st gear. Total from boats.net (best prices I could find thanks to a tip from a wr rider) was a little less than $500 after it was all said and done and at this point its just waiting for parts. Will keep you guys updated if there's interest 

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Heres a close up of the rounded 3rd and 5th pinions 

20170817_045720_001.jpg.86747a1a796c0b5f6198cd0bdb71ac63.jpg20170817_045811.jpg.973f93db9873b6e21faa64fad2b4932f.jpg

I plan to attach an extension off of the frame to prevent the shifter from taking impacts on the ground. Ive bent back the oem lever probably 20+ times and have read a post by @Pinepig that says the impacts may lead to a bent shift fork. Parts should be here this weekend 

 

Edited by Cody Trego

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Had the same problem on my wr426. Took it apart and pretty much the whole trans was buggered (rounding on the dogs) - most likely because I was an idiot and kept riding it in the lower gears for a bit. My new parts should be here in about a week from rocky Mountain atvmc - keep us updated with your rebuild

 

Sent from my SM-G920I using ThumperTalk mobile app

 

 

 

 

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Best of luck @thredbo !

Got all my parts Saturday as they told me on checkout. Im making quite a few noob mistakes as this is my first bottom end ever. 

-Firstly I installed the circlips on the transmission without paying attention to orientation. Then I watched a few youtube videos on transmission install to get an idea how to put them in the cases, when the nice gentleman on the tube said circlips are oriented sharp side away from the washer. Redid transmission axle assemblies properly.

-Struggled immensely to get full transmission assembly into the cases but finally did it after about 30 minutes. A few minutes later after sealing the cases and beginning to bolt them together I see this: 20170821_224357.jpg.0669815569c45b33d7a886a4cf6b4e86.jpg

I somehow installed the shift drum completely backwards... (you may also notice to the left, my 7 month old JB weld job holding the cam chain guide thingy)

This is what it SHOULD look like:

20170822_032858.jpg.dd7a4a1bf8fa09b6cdecf4b3dfc69624.jpg

So I took the cases back apart.. scraped all the 10 minute old yamabond4 case sealer off the cases.. and proceeded to struggle with the transmission for many many hours. For some reason I could not get the assembly in as a whole now matter how long I tried or how many attempts I made. After some artificial mood changers and a few more youtube vids I tried again but this time did it kind of sequentially. 

To get the transmission assembly in I first put the 2 gear axle assemblies (with forks attached) just barely into their respective bearings on the left side engine case. Being this shallow in the bearings (or on the bearings) I could slide the shit forks to the side like double doors and allow the shift drum to come in. From here I lined up the shift fork detents? with their respective channels on the drum and shimmied the whole apparatus into place. A lot of patience was needed to complete this but once I started trying the "sequential" method it took maybe 10 minutes. 

 

Bottom end is almost done, got my handbrake setup ordered and got a picture of the subcage that a buddy is fabbing for me. Crazy excited to finish this build 

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28 minutes ago, Cody Trego said:

Best of luck @thredbo !

Got all my parts Saturday as they told me on checkout. Im making quite a few noob mistakes as this is my first bottom end ever. 

-Firstly I installed the circlips on the transmission without paying attention to orientation. Then I watched a few youtube videos on transmission install to get an idea how to put them in the cases, when the nice gentleman on the tube said circlips are oriented sharp side away from the washer. Redid transmission axle assemblies properly.

-Struggled immensely to get full transmission assembly into the cases but finally did it after about 30 minutes. A few minutes later after sealing the cases and beginning to bolt them together I see this: 20170821_224357.jpg.0669815569c45b33d7a886a4cf6b4e86.jpg

I somehow installed the shift drum completely backwards... (you may also notice to the left, my 7 month old JB weld job holding the cam chain guide thingy)

This is what it SHOULD look like:

20170822_032858.jpg.dd7a4a1bf8fa09b6cdecf4b3dfc69624.jpg

So I took the cases back apart.. scraped all the 10 minute old yamabond4 case sealer off the cases.. and proceeded to struggle with the transmission for many many hours. For some reason I could not get the assembly in as a whole now matter how long I tried or how many attempts I made. After some artificial mood changers and a few more youtube vids I tried again but this time did it kind of sequentially. 

To get the transmission assembly in I first put the 2 gear axle assemblies (with forks attached) just barely into their respective bearings on the left side engine case. Being this shallow in the bearings (or on the bearings) I could slide the shit forks to the side like double doors and allow the shift drum to come in. From here I lined up the shift fork detents? with their respective channels on the drum and shimmied the whole apparatus into place. A lot of patience was needed to complete this but once I started trying the "sequential" method it took maybe 10 minutes. 

 

Bottom end is almost done, got my handbrake setup ordered and got a picture of the subcage that a buddy is fabbing for me. Crazy excited to finish this build 

 

What is different in those 2 photos? I'm probably missing something but I can't work out what I'm supposed to be seeing

Also what hand brake setup are you going with? If you look at my post history you'll see one I rigged up for my yz, but I'm looking at maybe doing a diy hydraulics build for the wr. What setup did you order?

Got any pics of that subcage you're getting made?

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My bad shoulda put some arrows on the pics. Check the circle with 2 bolt holes around it. They look similar in the pics but they are completely opposite sides of the shift drum. 

I went with the 50 stunt dual bracket and pieced together the rest. No pics saved on the cage unfortunately :( gonna post a sweet vid on my channel once its done tho!

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My bad shoulda put some arrows on the pics. Check the circle with 2 bolt holes around it. They look similar in the pics but they are completely opposite sides of the shift drum. 
I went with the 50 stunt dual bracket and pieced together the rest. No pics saved on the cage unfortunately  gonna post a sweet vid on my channel once its done tho!


Yeah right that makes sense. What's your channel name?

Sent from my SM-G920I using ThumperTalk mobile app

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Channel is Squid WithGear if you guys wanna check it out. Ill put a lil video out once build is done.

I finished the engine a few days ago but just now got around to putting it in. got fluids all sorted and figured I should check if the oil is pumping. Looked around on the web and found nothing on this procedure, but I did find the 52,891 threads on how to prime a xr650 oil pump...

Gonna take the valve cover off and kick it with the spark plug disconnected until I see oil *hopefully*

Anyone have a better way??

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Kicked the bike for quite a while and couldnt see anything staring me in the face that was saying the cams were getting oil so I removed the little plug next to the oil passage leading to the head. (little 8mm bolt with an equally little copper washer) I kicked it a couple more times with the bolt removed and a small puddle of oil had developed on the side of my engine from the opening.

After seeing this I had to rid the urge of actually starting the bike and it fired up on the 2nd kick (after I remembered to reconnect the spark plug) I only let it run for maybe 2 seconds because Im still unsure of the oil delivery situation.

Forgot to mention, after I kicked it for a bit and before I removed the little bolt, I did check the dip stick and it read half way up. This says that the pump is forcing it into to frame? I dont know but Im scared to run it until I know 100% that shes getting the lube she needs.  

 

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Engine has been done for a few weeks and bike has been done for about a week. So far it feels great with no engine related issues... now if I could only get the &%$#@!$#IN' carb dialed in.

Anyways heres before and after pics

20170806_065316_001.jpg.fcdbdd247252c91ef4ce4b3ddd06ca6b.jpgIMG_20170902_143019_276.thumb.jpg.0a22d06cc004bb8690a0f894e44534a3.jpgIMG_20170903_230449_621.jpg.613feea8709b515823ff8dc4525585b4.jpg

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