Fork Seals and Bushings

[Jakobi]

Yesterday I installed some new Race Tech fork bushings for a 2008 CRF450R. I also ordered a Motion Pro seal driver for the same model. These were to go into the 48mm Sachs forks.

Upon installation I realised the seal driver is for 46/47mm legs, and that the outer bushings slide up into the fork without the need to be driven. Basically finger tight only. All went together with SKF seals and wipers (the wipers are a super tight fit) and the fork action feels nice.

Just doing some post installation research and its hit me that the outer bushings are probably for a 47mm fork as well, and the inners too. In 2009 they changed to a 48mm and the part numbers for the bushings changed too.

Would you run these still, or would you pull the forks back down and change the bushings out? What risks are there? I noticed the outer bushing was a snug fit on the lower fork, and only finger tight in the upper forks which would make sense if its for a fork a mm smaller. It could possibly result in faster wearing of the dlc i guess. The previous bushings had heaps of play between the upper and lower legs, which has now been reduced significantly.

Thoughts??

[GasTimppa]

Hi Jakobi!

Did you measure the bushings? When I did that same thing I bought H**da original parts from H**da shop. I had my old bushings with me and we measured them. I'm now not quite sure were they -08 or -09 models.

8 CASQUILLO FRICCION 52/48 L15 / BUSCHING DU 52/48 L15 BE200252509
9 CASQUILLO FRICCION 49/47 L20 / BUSCHING DU 49/47 L20 BE200302509

(Those are from GG parts fiche) H**da parts were exactly same. I don't have that Honda number anymore...


Being -09 might make sense because they used 48 KYB s that year.

[Jakobi]

I didn't measure them.. but from what you have said I've definately installed the smaller bushings.

Part numbers
Outer: FMBO 47152 (49/47 L15) or 47x15x2 (IDxHeightxThickness)
Inner: FMBI 47201 (47/46 L20) or 47x20x1 (ODxHeightxThickness)

For anyone looking to get the right parts they are:

Inner Fork Bushings (pair) FMBI 48201 P
Outer Fork Bushings (pair) FMBO 48152 P

Now my question remains. Where to from here? I don't really want to pull them back apart again if I don't have to. Mainly because the dust wipers are so tight it'll I'll probably end up damaging them on the way out. Which will mean more $$ on wipers, bushings, and more time down and out.

I had checked each fork leg through its stroke when they were off without the carts installed and they slide nice and smoothly. They still have a little play between the upper and lower fork legs as well. Once installed on the bike with the front wheel on they still slide very well and aren't binding at all.

[Jakobi]

Doing some more thinking.

The correct spec from a few different aftermarket supplies are 48x15x2 and 47x20x1

I have installed 47x15x2 and 47x20x1. Going over it in my head, and the logic might not be quite right. The smaller size should simply be a snugger fit on the lower fork leg, which will result in a slightly larger end gap. The issue could arise if the 47x15x2 was too tight as this slides on the fork and it could wear the coating off the fork leg however this doesn't appear to be happening as the lower fork slides freely without binding or scraping. The bushing was hard to slide on the fork leg if it wasn't lubricated, but with some oil it freely slid.

Does this logic make sense or am I making excuses?

[Jakobi]

Followed up my thoughts with a visual inspection. Lucky I did. Both inner and outer bushings seem to be taking the load on one edge predomidantly and showing wear after just an hours use. They've been pulled out and will be replaced by the 48mm ones listed above, along with fresh oil (contaminated from the wear).

I also noticed that one of the bushings on the TTX cart (one leg only) is showing wear while the other one isn't. This was noticed before putting the Race Tech bushings in so its not a result of that. Will get onto an Ohlins dealer to get that part.

[GMP]

Get that crap out of your fork and order the right parts! 47 does not equal 48.

[Synergy-Seals]

Originally Posted by GMP

Get that crap out of your fork and order the right parts! 47 does not equal 48.

We have them.....worlds better than skf....and you can remove the seals then reinstall them over and over again.....if needed!

[Jakobi]

Originally Posted by GMP

Get that crap out of your fork and order the right parts! 47 does not equal 48.

Thanks Glenn, You told me what my brain was telling me the whole time! Just took you longer than normal being preoccupied with your new toy

Synergy, are you saying that the SKF seals I bought will probably leak now that I've pulled them? I have already ordered the correct bushings for the job. Was hoping I'd be able to reuse the oil seals and wipers.

[GMP]

Been spinning wrenches at night not on the web screwing around and socializing with you guys. Seriously though, that might eat through your inner anodizing quickly if most of the load was over a small area, and it would be because the circumferance is different, and when forced around the larger tube would no longer be round.

You can't move a seal over the bushing land without a bullet tool, bag, or tape protecting it. If you clean and tape the land(only way for removal), grease the tape, it should be OK to remove.

[blitz11]

Originally Posted by Synergy-Seals

We have them.....worlds better than skf....and you can remove the seals then reinstall them over and over again.....if needed!

Sorry for the hijack.

Will Synergy-Seals make bushing for 43 mm WP forks? I just installed Synergy seals and dust wipers, and for my next service, I need bushings. I'd like to get them from Synergy as I really liked the fork seals and wipers, and would like to support someone who supports this site.

Thanks.