How-To: Honda Z50R XR50R CRF50F Engine Rebuild 1968-2015
I’ve put together a full engine rebuild video that is 3.5 hours long for the 1989 Honda Z50R I recently acquired. The engine was fully disassembled in a large plastic tote, and I spent the past month piecing it back together. I was able to find a shifting problem, which made someone take it apart in the first place.
Year, Make, Model
The video features a 1989 Honda Z50R. However, I have flipped through all the manuals from 1968-2015, all these motors are all basically the same. Sure, there are a few differences, but this video covers the bulk of the information you will need to properly rebuild one of these motors. Also, the CT70 model is similar as well! If your motor looks anything like in the sample vid (OHC horizontal) then this video will be huge help, along with the service manual.
Symptoms
Here are several symptoms that indicate your engine may need to be rebuilt or disassembled for inspection:
- Low engine compression
- Engine is burning oil
- Any strange noises
- Transmission shifting issues
….or maybe you need a visual aid for adding the following modifications
- Big bore kit
- Cam swap
- Clutch spring and plate upgrade
- High volume oil pump
- Stroker crank
- Race head
Diagnosis
This post covers why this engine was taken apart.
What is covered in this video?
- Complete top and bottom end disassembly
- Splitting the cases
- Complete transmission disassembly and reassembly
- Clutch disassembly and reassembly (including plates and springs)
- Oil pump disassembly and reassembly
- Cylinder head disassembly and reassembly (with valve lapping tutorial)
- New valve stem seal installation
- Cam timing procedure
- Piston ring end gap inspection
- Some measurements (cylinder bore & piston O.D.)
What is not covered in this video?
- Engine removal & installation from frame. Video begins with engine on workbench
- Transmission blind needle bearing removal in engine cases
- Main bearing removal from crankshaft
- Some engine parts are missing during disassembly (parts are added during reassembly and covered in detail)
Special tools required
Lisle 21200 Small Valve Lapper (intake only)
BOA BO13010 Constrictor Aluminum Strap Wrench
Motion Pro 08-0015 Oil Filter and Clutch Hub Spanner 24mm ID
Motion Pro 08-0026 Flywheel Puller M27X1.0 L.H External Thread
Vessel Megadora 980 Impacta P2x150 #2 JIS Cross Point Impact Screwdriver
Vessel 125943 908 P3x150 Impacta Screwdriver
Other helpful videos
How-To: Honda 50/70cc Valve Adjustment (XR70R)
Honda 50 Flywheel Removal & Installation with Puller
How-To: Z50A Carb Clean & Rebuild / Pilot Adjustment
How-To: Carburetor Idle & Pilot Screw Adjustment Honda XR70
How-To: Motorcycle Carburetor Clean Honda XR70R
How-To: DIY Soda Blaster – Cleaning Motorcycle Carburetor
How-To: Install & Remove Crankcase Bearings With Your BBQ Grill
Comments
Has this video helped you out? Comment below!
The Motion Pro 08-0015 does not work for 1968-1975 Honda Z50 clutch nuts. It should fit just fine on later Honda 50cc and 70cc models. See this forum post for reference: https://planetminis.com/forums/z50-ct70-jdm-monkeybikes/37356-socket-clutch-removal.html
Thanks for the info.
Do you have a # for the correct motion pro? Aside from that tool good to go with this video for a ’73 z50 engine? This will be my first attempt at touching an engine.
I don’t have a PN for that tool handy. Look into the service manuals which should have a Honda PN for the tool. Google that number and you should be able to find the correct tool.
Video will apply for your year.
How do I buy the 1968 compatible Honda Z50 full rebuild video?
The link above is the video you want. There are some differences, however very similiar.
How do you purchase the Z50R video and what is the costs
Here is the direct link: https://gumroad.com/l/zBTB
Matt I’ve looked every where on this site and punched every botton and I can’t find how to by the 3.5 hr video?
Here is the direct link:
https://gum.co/zBTB
Hi, do you still have the 69 z50 manual available for download
Service manuals come with the video purchase.