Modern Vespa

I have finally used the dielectric grease on the hidden fuse thanks to coaching from Lutherhuss (Shawn) and Jimc. For a "non-mechanic" like me it was not easy. I should add this is done on a 500 and may be different for a 250 or 400.

I would suggest you familiarize yourself with the layout before tackling the job. I have labeled photos below.

It is suggested (jimc) that you first disconnect the ground wire to your battery as a safety precaution. He explained it, "The advice to disconnect the negative is just because you have very high-current, unfused connections to the battery positive exposed on that relay - you really, really don't want those to make even the slightest contact to frame. You will lose your clock/temp settings and trip mileages, but not the overall odometer reading."

The compartment to open and get to the fuse is the one behind the battery held by a single screw (see photo with screwdriver in this location).

The hidden fuse is well hidden inside the relay. You must take it apart to get to it. When you first look at the relay (right side, only one with a red part) you will see in the back of it a spare. I suggest removing that spare before you start. You will be pulling the relay out of its holder and doing several things with it and you don't want to hurt the spare.

The relay is covered with a black rubber cover. The relay is held in place by two plastic fins which create its holder. The rubber has two slots which the fins slide through. You remove the relay from the holder by sliding the relay to the left, towards the center of the bike. (Jimc suggested sliding it forward. The 250 and 400 might slide forward. I am not sure, but the 500 relay slides out sideways. I think Jimc misremembered.)

There is a picture below of the back of the relay. In this position we can see that there are two red clips, one on each side, that must be opened to slide the red clip apart from the relay. Do not pry these open. Press them together at the back and the front will open - like two seesaws. Then slide the red clip out. This was VERY difficult for me to do but finally I got it. I had to use some long handled pliers. Be careful.

There is a picture of the relay open and the fuse exposed. Remove the fuse and use the dielectric grease on all the connections, including the group next to the fuse. At least that is what I did. Then put it all back together. Good luck. If you have a question, post it and I'll try to answer.


Relay separated - Hidden Fuse is green

Backside of the relay - squeeze back end of red clips to open

Parts of the relay

Area under seat to open (behind battery)


Last edited by jerryw on Tue, 30 Mar 2010 11:49:39 +0000; edited 7 times

Thanks.. I guess the sliding out will make sense when I actually have to do it..

I can never get the pictures to come out in the right order. Sorry about that. Check the "labeled" picture. It should show how the plastic fins slide through the rubber cover on the relay to hold it in place. You are just sliding the relay off those plastic fins.

If someone would give me a lesson on loading and rearranging the pictures I would appreciate it.

Great write up and pictures.

I find putting in pictures they appear in the order I attach them. However if I do a preview of the thread the pictures are in reverse order in the preview.

You did great Jerry. I can see exactly what you mean. Thanks for posting this.

Nice tutorial, Jerry. You're a 'mystery demystefier'... This will be valuable to all Mp3'ers.

BTW, You can edit your post to rearrange pictures if you want, not hard to do.

First, thanks Jerry for the very helpful post. +1.

Secondly, when 'attaching' pictures, they attach from the top, so that last one 'attached' will be the first one in the post. Clock this, and it becomes easy.

All good UK dealers now squirt huge amounts of dielectric (silicone) grease on every connector, relay and fuse holder they can get to at PDI or first service (which one depends on whether they reckon the customer will ever show again, usually). Solves loads of grief later for both them and customers down the line, especially in the rather moist UK climate, and where most scoots will be left outdoors in all weathers.

Well done, Jerry. I've procrastinated over tackling this 'major operation' for some time now.

But this weekend , I plan on getting right to it.

Thanks again........r

How do you edit to rearrange? Is there a way to drag and drop the pics? I loaded the picture of the hidden fuse separated first and it never left that position through 4 edits.

I should add that there are a bunch of connections in that relay and I can see that in some areas, especially near the coast, you could encounter some bad corrosion. It does feel better to know it's done.


My buddy, the magic grease

First off - cheers for the write up, I found my mystery fuse all corroded and missing a tooth, so it was a relatively straight forward to swap out.

Something that isn't mentioned in the write up is the other access panel on the side of the bike. 1 screw and some pushing gets it off, so once you have the relay off it's mount, you can drag the whole thing out of the side panel - much more room for your fingers!

Anyway, main reason for my posting - is there a reason this fuse goes, do I need to have anything checked over - or is this just expected behaviour from the mp3 500?

Depends on ones environment and willing to drive in all weather. If jimc would post the photo of his relay you would see that U.K. is not so kind for what,s under your skirt. How do those Scottish Highlanders do it?

Last edited by Maynard Schweigert on Mon, 27 Jun 2011 05:03:31 +0000; edited 2 times

Marvellous, I'm parking it up next to a river and planning to use it all year round - I guess I'll be getting a value pack of 30A fuses and a load of grease then...

Thanks for the post, I've looked at the relay before but couldn't figure how to slide the relay off and left it for another day. Well after seeing the pics and description, today was that day. Only took about 10 min to do. Gotta say that 30amp fuse was in there tight. Now just one thing less to worry about.

Cheers,
Tross

You made it look simple there Jerry!

It's funny how things get simple after you try and fail 3 or 4 times.

Hi there,

I have just checked my hidden fuse and it was terribly corroded. The fuse had literally melted in the housing. Does anyone know the part numbers so I can replace both the holder for the fuse (black casing and green casing and the circular metal thingy?. (i'll replace that also as a safety measure)

Thanks for your help

Sorry cant seem to post images will try later

your local dealer can get you one.

TinTin: first, welcome to the forum as a poster. Second, it would be very helpful if your profile said what kind of bike you own, because the various MP3s have different parts drawings. Some parts are the same, some are not.

Profile updated & hopefully picture shown. Also might purchase a new red connector as it's a little damaged.

If I order one from the dealer what is it actually called.


Amazing knowledge on the forum btw. Been lurking for a few weeks know and gradually doing a few 'fixes'

Gotta luv model specific forums..

yup that starter relay is toast.
part number 640692
on page 101 of the parts manual which you can find in the wiki and download it straight to your hard drive for quick access

TinTin

Curious question:
1-How many total miles or km on your bike?
2-Do you store your bike outside?
3-Also how old is it?

There's a used one for sale on eBay if your interested. Just see how much the shipping is to the UK.



http://www.ebay.com/itm/PIAGGIO-VESPA-BV500-BV-500-MP5-X9-07-08-09-STARTER-RELAY-SOLENOID-FUSES-/271098117425?pt=Motorcycles_Parts_Accessories&hash=item3f1eb4fd31&vxp=mtr#shId



Hope it helps,
Tross

$14.70 USD

Last edited by peartree on Fri, 06 Sep 2013 09:52:06 +0000; edited 1 time

Hi it's a 2007 model, completed 13k miles. New to me but previous owner stored in a lean to under a cover.

I'm going to be be using it for approx. 17,500m pa so intend to run it for as long as I can to recoup my outlay rather than commute on the train.

Getting all the small fixes done before I start using it in the New year.

Sent email to AJ Sutton to get the bits ordered

Here's a little trick to get to the starter relay fuse: Two clips hold the red "Top" fron the relay block. Getting your hand in there to hold the clips open and separate the red from black parts with your other hand requires a vascular surgeon's hands. Take two round toothpicks and insert them under the red clips, just fore of the little black clip button. Now you can separate the parts with both hands. You may need to gently start the separation with a thin blade...gently.

I take the side cover off and pull the relay out through there and have both hands on it if needed.

Silly question I know but can someone tell me what side the negative and positive battery connections attach to on the new style relay switch. It shows M and B not - +

Thanks in advance

Best to use your multimeter to work it out. The big connector for the battery +ve is also connected via the fuse to where the feeds from the regulator come in. The other big connector that goes to the starter motor isn't connected to anything else. That just leaves the coil connections which aren't position dependent.

One would suspect that 'M' stands for 'Motor' and 'B' stands for 'Battery', but never take these things for granted. Neither of them goes to the battery -ve.

Perhaps I'm being lazy fr1n63, but could you post a picture of the side access hole you are talking about? Cheers

Fr1n63 posted both of his/her posts on the same day almost two years ago. I doubt if he/she has been lurking the board waiting to see if someone responds to their posts.

yup, that person has exactly 2 posts on modernvespa and both on the same day.

Thanks for everyone help bike is now charging

where is this on the 400?
i've greased all the other connectors so far but have not done this yet.

I just changed + and - in my battery (I'm old and stupid), and 20A and 30A fuses both has been explode. I for a longtime searched with circuit diagram, whereis locate 30A fuse, until I remembered about this forum
You are best!

Hi,

I've been using this board for years solving various problems I've faced with the mp3. I took the liberty of creating a video showing the same info as the images above in relation to how to find the hidden fuse. If it helps anyone then I'm happy.

https://youtu.be/l7A1-MnDljM

FYI for anyone who owns a 250. I have a 2007 250, and the starter relay is bolted to the right side upper frame, just underneath the lower right front corner of the seat, hidden behind the "rear fairing". Very hard to get to, but that doesn't matter because the fuse in question is not mounted on the relay housing because the relay is much smaller than on other models.
The fuse that is (electrically) between the regulator and the battery is (geometrically) right next to the battery, part of a fuse panel that is plainly visible at the very beginning of your video, just to the left of the battery. It's the last one of 5 fuses in the panel, a green 30A one.
It's immediately accessible. Don't do what i did