Friday, 25 July 2014

Yamaha YBR 125 Engine rebuild






Yamaha YBR 125 workshop manual

Buy now 





before starting make sure you have everything you need , bearings , the seals i buy direct from Yamaha and usually cost aorund £8 .

make sure all components are good and ready to fit , check cases for damage , check gears for
damage , check con-rod set up , check barrel and piston , hone the barrel ready for fitting
test the cylinder head make sure all is functioning and the valve seal correctly .



Fit gear box 


Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

make sure all gears function correct 

id then warm the engine to expand metal slightly prior to 
fitting the conrod which will have a bearing pressed on already 

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

crank in and gently tapping into correct seated position 

Yamaha YBR 125 Engine rebuild

align timing marks for balance shaft 

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

fitting cases i am told no need for gasket or glue but 
i glue , i do not want to have to strip and rebuild , if your skilled enough 
to see flaws in the mating surfaces and know better then go for it me
i am chicken shit .

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild
                                         place rag in cases as dropping something in engine now
                                           would be a nightmare .
Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild
                                        honing barrel before fitting  , it helps bed rings in
Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild
                                     feed timing chain through cylinder barrel
Yamaha YBR 125 Engine rebuild

this is tricky now trying to hold chain in position 
its probably the hardest part 

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

fitting timing chain gear TDC , valves on the rock 

Yamaha YBR 125 Engine rebuild

fit tensioner 

Yamaha YBR 125 Engine rebuild


Yamaha YBR 125 Engine rebuild


Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild
                                          timing marks on the flywheel
Yamaha YBR 125 Engine rebuild

timing marks on the cam timing chain gear 

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

Yamaha YBR 125 Engine rebuild

after you have fitted with marks in place , turn the engine over to 
ensure everything works fine .










see more Yamaha YBR 125 blog posts 

thanks for reading the Yamaha Owners blog , if you would like to support us you can by  buying your newYamaha YBR 125 off ebay uk here or buying  parts for your yamaha YBR 125 from ebay uk 


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