New to the club, and new to Guzzis. I acquired my 08 Stelvio about 6 months ago.
It has come round to service time and I have discovered the previous owner has stripped the gearbox sump plug and had got away with loosely nipping it up. That is until I’ve now removed the sump plug and the stripped thread came with it.
As a temporary “fix”, I have managed to get it nipped up semi reassuringly with 3 dowty washers..
This is of course, not ideal.
My question is, what are the simplest solutions to re tapping? I cannot get straight access for drilling with everything in situ, and even if I could I don’t particularly like the idea of drilling up into the sump and throwing metal into the gearbox.
Has anyone had this issue before? The previous owner didn’t tell me about the gearbox plug but he did tell me he’d stripped the engine oil sump thread before and that has been tapped up a size. Is stripping threads a common occurrence??
Thanks, as mentioned it was the previous owner. Hoping to find someone who may have come across the same issue who could provide some helpful advice to resolve.
Am I right in thinking the engine would need to come out and transmission separated to re tap off the bike?
Sorry my fault, not paying enough attention. I skipped the word ‘gearbox’.
I remember having an insert put into a final drive case (ditto, stripped drain plug hole), didn’t have to take it apart but he did warn about thoroughly flushing it out to remove all swarf. Nevetheless both seals failed some time later, which may have been the result of lingering aluminium ‘dust’ - or not. Obviously the FD had to come off the bike for them to work to it.
I think yes you may have to dismantle.
I don’t know what it is about drain plugs but some people want to welly them up stupidly tight, like they’re terrified it will unscrew and fall out while they’re riding. It happens with cars too.
I spent 9 years at an engineering firm doing field thread repair work. I’ve done plenty of helicoiling of stripped sump plugs on aluminium (mainly on cars), in situ. I used to fish out as much swarf as possible and it was job done. In 9 years of service no issues where heard of. Ideally though, remove the gearbox…
For a cylinder head, just start the engine without the spark plug in and the piston will soon clear out the bore- looks impressive watching it.
My colleague did a combined harvester, literally in the field. Had to lay over a huge puddle of oil to do the job. Lol.
My friends laverda 1200 mirage’s sump plug fell out whilst filling up with petrol in Pickering, North Yorkshire. He got a right ticking off from the petrol station owner!
Guess what- I bought a green tank Laverda 1200 mirage after him. It was either a Le Mans or Laverda. I thought the Laverda would be a more expensive and exciting bike, and then buy a le mans later, as a more ‘sensible’ option.
And now nearly 50 years down the line I need a nut insert in my upper jaw to replace a tooth!
That’ll be £3,000 please .
On one visit to the dentist the filling fell out before I got back home. It got blamed on the vibrations of the Le Mans 4 I that I rode to the appointment
Many years ago I stripped the gearbox plug on a Suzuki GT380. Took it to a mate’s friend’s back street garage We turned the bike upside down and a helicoil was fitted. Can’t remember if petrol poured out of the upside down tank but it must have…the things that happened back in the day
I also remember “fixing” a de-threaded car sump plug with araldite rapid glue. You leave the sump oil to fully drain for a couple of days, clean the plug hole with paint thinner or brake cleaner then smear in the araldite making sure that the threads have a good coverage then in goes the the sump plug. It always worked. Only disadvantage… NEVER EVER change your oil .
As someone recently said in here to suck the oil out instead of removing a drain plug.
The Laverdas didn’t even have an oil filter- just relying on oil changes every 1,500 miles with an expensive brand of oil…
My Guzzi has the internal oil filter so the sump comes off anyway.
A good idea @Fairytail! I have a laser vacuum pump which has saved the day in many similar scenarios. Only issue is the fragility of the plug now. It seems to be secure with the excessive amount of dowty washers, filled up today so will keep a close eye on it to see if it seeps before I take it out for a ride.
Hi Adam, I fear you haven’t received any information that is of real assistance so far. The gearbox drain plug is not easy to get to, for sure. You may gain access by removing the rear brake lever and loosening the rear master cylinder and moving it to one did without disconnecting the hydraulics. I’m not sure if removing the centre stand gives any more clearance. I think you ma have to remove the side frame or frames. I would consider this although you will have to support the bike from straps around a rafter or something similar. Taking the engine out of a Stelvio is a big job so I would avoid it if you can. I would have no qualms about repairing the stripped thread by Helicoil or Timesert. Hope this is useful. Cheers Phil
Thanks @Phil_Skinner, I think you are right on side frames as I wouldn’t be able to drill straight with them in situ. This still does leave the concern of drilling up into the gearbox though. It appears there is no way to remove the gearbox without first removing the engine either.
Hi Adam, that is true. You must take the engine out to get the gearbox separated from the engine. However if you do go that route you are still going to have to rectify the stripped thread on a complete gearbox, so the risk of swarf entering the box doesn’t change. You might as well persevere with the the engine in situ. What do you think?? Phil
If I went down the complete route of engine removal then I would also have to split the gearbox case to achieve. I appreciate this is a monumental task for a stripped thread.
Over the weekend I finished all the other service items, brake and clutch fluid changes etc. Gearbox sump plug has not weeped since. Planning to take on a short ride and see how it fares.
I think what you have mentioned about gaining access via centre stand and rear master removal may be the way to go, I just need to figure out if that will give me straight access to drill.
I’ve used helicoils on cars before with great success so that will probably be my route. Although standard helicoil have a tang to snap off once inserted.. I have seen they do a tangless alternative. Never used timeserts, do they have tangs?
.