bottom end rebuid

[85YZRacer]

hey vintage racers,

can i rebuild my bottom myself with the proper tools or do i need to take it to a shop. I'm planning to replace the crankseals and bearing and the crankshaft. trying to save money if i can do it myself.

 

[jason33]

get a clymer manual-30.00- if you don't- :bang:
take pics as you tear it apart-- or video-
order the parts first-if you can
it is a puzzle-
clean the motor before taking it apart
keep the transmission together--(the gears on the shafts)
and take a pic of the shift forks -so you will put them in right-
even some books don't show certain year bikes!!!!
use good sealer-i hope they made a center case gasket for your bike- otherwise youll have to use (yamabond -crap)sealer
follow the book---
you can make a crank case seperater from a steering wheel puller some times- they want waaaaaa too much for one of motion pro's
its tough the first time - but fun- :nod:
use locktight on the bolts ,and screws ect...- it keeps them from vibrating loose
you can get most stuff from dennis kirk- :nod:
great winter project---

?? im bord send it to me ill do it - :) lol

 

[CRazy250]

if you plan on putting a new rod on you should have a shop do that, unless you are buying a whole new rod and crank assembly you can do it yourself.

 

[85YZRacer]

na, i checked the rod, it seems pretty good. I guess im just gonna replace the water pump seal, crankcase seals and bearings. And i dont think that my crankcase has a gasket. i didn't see one on the engine blueprint. so how good is that yamabond

 

[zoommx]

That yamabond is good stuff. Has a wonderful smell too. Honda bond is good too. Thats just the way yamahas go together (at leaast the ones I've worked on).
Harbor freight has less expensive pullers that will work too.:
click HERE for harbor freight puller

 

[jason33]

yea - me my self - i make a gasket from a roll of material,it takes some time but its a better seal-with sealer as well
i have used the yama bond and it leaked- since then i wont use it
the cases really need to be lapped-or matched up,ect... for a flat surfece-and the shifting/ internals ,have a certain amount of tollerances if lapped too much it will be too tight- but that was my experience- it was made for easier use- mabe its better stuff now-?

 

[whenfoxforks-ruled]

Crank

Most crank guys beat on the journals with hammers when its out of alignment, I believe ForwardMotion does it mobetter! Its important that the flywheels be concentric with each other, while youn have it out check it, and beating to within specs is not the right way to do this! Also pay attention to the 4 bearings the trans shafts run on, replacing them is not that big of a deal money wise and as long as the shafts are true and within specs it makes a dif on how tight it feels and for how long. Short of all new oem parts I've wondered why they don't remain tight? The thickness of a center gasket added where it don't belong smells like trouble, Use the sealer on both sides let it setup then slap it together, seal the exhaust connecttions with high temp silicone and start it in 24 hors.

 

[wirefryer#85]

If it was mine I'd have a good shop put in a rod kit and true the crank just for one less thing to worry about.

And give the sealer all time you can stand to set up before you put the tranny oil in.

 

[Pete Payne]

Yeah , like wirefryer#85 said , if ya go that deep , rebuild the crank also .