Thrust washers high as bearing or rod big end?

Formula

Member
Sep 21, 2000
59
0
I with the help of you guys at DRN have finally gotten into the case halves of my 1990 RMX. I am in the process of getting new main bearings seals etc.
Now that I can really take a good look at my con. rod big end I see a few things I'm not sure about.

Should my thrust washer’s outer diameter be equal with the needle bearing or should they be as large as the o.d. of my rod big end. I notice that the rod can be moved side to side about 3.5mm since it travels over the thrust bearing. The side clearance on the big end bearing is getting high and will be done with this rebuild but how high up should a thrust washer go? If I look close I can see where the rod big end has rubbed on the crank itself from being able to migrate over. Is the function of the thrust washer to eliminate this?
When looking at new generic Hot Rod kit pictures it looks like the thrust washer is higher/taller than the bearing thus preventing the rod from contacting the crank. Is my application different?

On a side note last year I broke the pistons intake skirt (no or little premix, loose tolerances?) and the skirt whipped around the case for a few seconds, which left little indentations in my rod. I rebuilt the top end and ran for another month or 2. Now that it's all apart again I most likely will replace the connecting rod but the cheap skate part of me has to ask should/could I still run it with these little dents (looks like it was shot peened with giant slugs in a random fashion), I will post pics of it if need be.

Thanks for all your help again - getting into the lower end was a fear but with all the help from DRN I can say "Fear is obviously not a Factor for me" - a line given to the winner or Fear or should I really call it Skill Factor TV show.
 

Formula

Member
Sep 21, 2000
59
0
I phoned Wiseco Canada and they took a CR138 Hot Rod kit out of the box for me to look at the thrust washers. They were only as large as the needle bearing. When I looked at the factory microfiche again I saw 2 out of 5 drawings showing the little washer and the rest showed the taller one. I just don't want to put it back together and hear that I should of used the taller washer - which in my limited knowledge seems like a better choice since then the rod can’t migrate over too far with that in place.


Any thoughts from Expert Eric?
 

eunos

Member
Jan 17, 2002
61
0
I know CRs and KXs have thrust washers the same o/d as the connecting rod, unsure about the RMX. The side play is certainly excessive, on the 2 mentioned about 10-20 thou would be normal. Don`t the rod and big end come as part of the kit? So you will end up replacing the rod anyway.
 

Formula

Member
Sep 21, 2000
59
0
For Suzukis you can buy the Wiseco Hot Rod kit. A CR138 kit fits many applications - but when checking the factory microfiche you can see that they put a larger thrust washer on later models. I want to know if I should use larger late model factory thrust washers with the HotRod kit instead of the small ones the kit comes with.
 
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