Replacing oil seal behind front sprocket

**arj127** · 17th March 2007, 17:36

I would like to replace the oil seal behind the front drive sprocket on my VFR400. Is this an easy task (like replacing the gearshift seal)??? Its a big seal, 52x34x13. Can anyone give some advise?

**desmo dave** · 17th March 2007, 18:42

Depending on the bike you may have to part the crankcase to fit the new seal. if this is the case, try abit of silicon sealer behind the drive sprocket then refit make sure everything in contact with the silicon is spotlessly clean.Worth ago if it's a major job

**arj127** · 17th March 2007, 19:20

ive got a feeling that the case would need to be split to change the seal. There is about a fifteen mm gap between the drive sprocket and the seal. Are you suggesting i try to push a little silicon around the seal and let cure to see what happens? I'm not even totally sure thats where the leak is. Ive changed the shift seal a while ago, but there is still a leak. I felt for sure it would be the drive sprocket seal, but when i removed the sprocket the seal was fairly clean, but the area around it was oily. I may have to totally clean the area, ride for a few k's and reinspect.

**desmo dave** · 17th March 2007, 19:29

will be best to check when its hot.If it is leaking there try the silicon nothing to lose. just make sure its clean.what bike is it?.

**arj127** · 17th March 2007, 19:31

a 1990 Honda VFR400. Should i use normal RTV silicon or the newer MS silicon? Thanx for your help

**98tls** · 17th March 2007, 19:35

May be well off track here..........does it have a seal for the clutch pushrod...if so and its located just forward of the sprocket its probably that.......a much easier fix...........

**arj127** · 17th March 2007, 19:37

have a seal for clutch pushrod, but thats dry and clean.
Heres a photo of drive area, after i have been cleaning it up

**98tls** · 17th March 2007, 19:49

Sorry mate but cant help anymore from the photo..........i would just clean it up with kerosine/paintbrush as best i could and go for a ride then inspect.......

**arj127** · 17th March 2007, 19:55

i think thats what ill be doing. Bike will be off the road for a couple of weeks now as its getting a repaint aswell.

**98tls** · 17th March 2007, 19:56

Good luck with it eh................let us know how you get on.........

**desmo dave** · 17th March 2007, 20:11

Originally Posted by arj127

a 1990 Honda VFR400. Should i use normal RTV silicon or the newer MS silicon? Thanx for your help

I cant remeber what type i used about 24years ago to stem the flow on a xr500 honda.worked though. Try to work out 1st if thats where its comming from for sure.

**Max Preload** · 18th March 2007, 21:54

to do that seal. It's simply a case of prising the old one out (being careful not to damage the alloy around the outside) and then lubricating both the inside and outside of the new one and fitting it by pushing it in squarely.

I usually just use a small flat screwdriver to do gear shift, clutch pushrod and final drive seals. The outer part of the seal is a hard cup, so push the screwdriver through the middle of the flat face and draw it tangentially. Be careful no to stab into the bearing that is behind the seal too.

Check that there is no scoring on the shaft and if there is simply fit a slightly wider or narrower seal or if it's a OEM only seal, get a 2mm spacer of the correct outside diameter made to go behind the seal which holds it out so the sealing is not being doen on the scored part of the shaft.

**Max Preload** · 18th March 2007, 21:56

the only reason the case join is there is for ease of manufacture (casting) and assembly (final drive shaft), not for actually clamping the seal - the fact it lines up with the seal centreline is incidental.

**rogson** · 19th March 2007, 07:50

If it won't budge using a screwdriver to hook it out, drill two small holes through the seal on opposite sides (just drill enough to go through the seal - no further). Screw two self tapping screws into the holes. Alternately grab the screws with pliers and pull. The seal will work/pop-out easy.