Thanks to Bob for his help with this. I get just a very slight leak at the primary chaincase, which I think might be from the grommet area. Can I just ask for clarification of something (email to/from Bob seems to be playing up, probably at this end). To fit a new grommet where the wires pass through the casing, I'm guessing it's pretty awkward unless the grommet is split (cut) lengthways so that it can be slipped over the wires (inside the primary chaincase, as access outside the case is difficult) without disconnecting them? If the grommet is not split lengthways, then obviously you'd need to disconnect the wires at one end or the other to get the grommet on. If you would normally cut it like that, and slip it over with the wires staying in situ, does the split affect it's oil tightness much? (obviously I would put a good dob of silicone sealant on.)
Phil.
Dont cut it. Slide it over the wires. Its not difficult. Grommet should be pretty supple. Soak in hot water to make even softer if you want to.
Disconnect wires from the Bullet connectors.
Hi Phil
These are the grommets I used. I just cut one side to fit over the wires and pushed it in the hole with a good helping of silicone to hold it in and let it go off.
Thanks Bob, so you cut your grommet in order to get it on, and it worked.
Bess advises don't cut it, but rather disconnect at the bullet connectors and slide the grommet over the wires. I can see that not splitting the grommet would in theory probably be preferable in terms of oil-tightness. The problem is it's very hard to reach/see/feel the back of the hole. As I recall (I'm not in the shed at the moment), you certainly can't reach/see it without taking off the rear chain guard, which itself is pretty awkward. Once the chain guard is off, I'm not sure whether the hole is reachable/visible even then. But it is in a difficult place - it's hard to get at. Maybe if I disconnect, then pull the wires through into the primary chaincase, fit the (unsplit) grommet, push it into the hole (with its silicone ration), and then push the wires through until they appear somewhere. Of course it might mean taking the bullet connectors off the wires first.
So I'm thinking maybe, next time I have the primary chaincase cover off, I'll try Bob's method of splitting a new grommet, and giving it a generous dollop of silicone, and if that doesn't work then I'll see if I can somehow fit an uncut one. Thanks a lot for your help. By the way - anybody else had this problem? Phil.
Yes I was rather miffed after carrying out the rebuild and forgetting to put a grommet in place, so for ease that's what I did and it seems to be ok without any leaks. I did try to feed the wires through the hole without cutting it but I couldn't drive the ends in the right direction to come out through the top hole.
The picture of the grommets you are using shows that they wont form a tight seal around the wires. They are for protecting cable from getting chaffed when routing through a metal panel such as a mudguard.
I have no problem in cutting these to fit them - also makes it easier to locate in the panel/engine etc. If you want to seal them, then you will have to use a bit of silicone or alternative sealer ( I used to use some of the black goo for coating the edges of car wings before screwing them together - it doesn't completely set but does the job ). The problem with silicone is you buy a tube, use the tiniest amount and the rest goes to waste over a period of time!
It's difficult to fault Bob's choice if it's doing the job, but I take your point Adrian. Which type would give a tight seal (even when split)? Maybe the one Draganfly sell especially for the job? Phil.
I don't think any of them seal that well. The ones that have to be punctured are probably better but if you want a complete watertight and oil tight seal, then you probably will need some sealer. To be fair, I've never had much of a problem with grommets you puncture and feed the wires through and left them without sealant.
The ones that have to be punctured?
I guess in this case you'd have the same issue, ie awkward to access the back of the hole.
I am not sure of the correct term but they look like a normal grommet but have a skin of rubber over the surface . Examples are found eg in the wires going into a security light connection box to try and prevent ingress of water. They may be called Blind grommets?
"Blind grommets" I believe.
These I think.