Jump to content
Sign in to follow this  

another issue with my rebuild!

Recommended Posts

I have the case split and cannot get the left case side off of my crankshaft. For some reason the cam chain gear on the crank won't let the main bearing slide over it, their is a little wear on the gear but not sure what to do now? How much wear on that gear is to much and should be replaced?

Share this post


Link to post
Share on other sites

Try to identify the tooth or teeth that is/are too tall and buzz the burr or whatever off it with a file.  If the gear is worn that badly, you're probably going to need at least that half of the crank. 

Share this post


Link to post
Share on other sites

that's what I was guessing to do but figured I better ask. To tell if the gear is bad will their be slop when you put the cam chain around it?

I've also been planning on taking the case halves to work and put them in a solvent tank with mineral spirits. That won't hurt anything will it? Still got bearings in just figured I'd assembly lube them up when it goes back together.

Share this post


Link to post
Share on other sites

Cleaning them in a solvent tank is fine, but be sure you thoroughly wash through the oil passages with clean solvent.  Also verify that the bearings are washed clean so the rotate freely and don't have a gritty feel when dry.  Best practice is to replace the whole set while you're there, but that adds up.  Careful inspection and your best guess is called for.  Be critical and selective.  New mains, new balancer shaft bearings, and the left side main shaft bearing (yes, the one in the blind hole) are on the top of the "don't reuse unless they're near perfect" list.

Share this post


Link to post
Share on other sites

alright thanks! My uncle tried to rebuild the motor for me last winter so I already replace a bunch of bearings and have less the 2 hrs since then. I tore it back down because he didn't fix the transmission issue I was having ( drops out of 5th ). The bearings feel smooth, but don't really wanna tear the motor down again for awhile.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

  • Similar Content

    • By BDTRENT
      Selling an FMF Power Core 4 exhaust system off my 450FX. Exhaust has 80 hours and is 100% functional. This will also fit the 14-15 YZ450F and 16-18 Wr450F. If needed I can also include new muffler packing although it does not need it. 
    • By Woody Oakson
      I have a 2008 YZ450F with a stock header pipe and Pro Circuit T-4 Slip-On Exhaust. I'm 99% sure the slip on is shot because its loud as hell and when I take it off and shake it it rattles. I would repack it but the screws are all stripped ect.
      Anyways I've gone over the carb multiple times and I've got it running pretty well. The only issue I have with the bike is that it sputters and pops around 1/2 throttle when I hold it there. When I give it full throttle from any RPM it runs great or when I give it about 3/4 throttle it spins up like a top to redline.
      Initially the popping and sputtering was way worse I made the situation better by moving the pilot jet up in a few sizes from a 45 (stock) to a 62. The issue has gotten way better since then but I'm not super sure what to do from here. Should I keep moving my pilot jet up in size because that's a pretty large jump right? I tried changing my needle clip position but that didn't help much if anything it just made starting it worse and little to no impact on the ride.
      Any input on this would be helpful. I don't want to buy other slip on. Also as for the rest of the carb I'm very sure everything else in it is what it needs to be at. I've replaced all the gaskets and O-rings cleaned all the jets, valve holes ect. fixed the accelerator pump timing. I just thinks its strange that my pilot jet size is going so far from the stock 45, but all symptoms point to the bike running lean.
    • By Haydenbaha
      Hi I was wondering if y’all have been using a 450 on your YZ250F?
    • By RockerYZWR
      Excel Takasago 17x3 front and 17x5 rear supermoto wheels with Metzler M3 tires in very lightly used condition. Less than 200 miles total on the setup. Warp 9 spokes. Rear has a Talon hub with 45T Sunstar steel sprocket and OEM rear disc, and front has a polished OEM Yamaha WR450F hub (for the stock speedometer), with a Motomaster 320mm disc. Included is a DID gold o-ring chain, 14T front sprocket, and front brake caliper adapter for a truly turn key setup. Everything is in excellent condition, not a single scratch on these wheels. Came off my '11 WR450F, but will fit many different Yamahas with 20mm front and 22mm rear axles. Asking $1400 plus shipping.
      **Will be driving up near Atlanta, then to northern Louisiana, OKC, and down through Dallas and Houston, TX soon -- can meet or deliver if in the area (Aug 31-Sep 9)**
    • By YZ426fNC
      Hi I’m new on the forum and I was wondering if a 2001 Yamaha YZ426f clutch is interchangeable with a 2002 Yamaha YZ426f clutch thanks , Coleman
×