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Contents 1 Garelli Vertical Motor - 75cc Mec Eur Kit Installation 2 Fix your clutch issues first: 3 The kit will absolutely not fit in the case. 4 This kit doesn't seem to be cleaned up from the factory in any way. 5 Some kits don't fit. 6 Cylinder head work.

Garelli Vertical Motor - 75cc Mec Eur Kit Installation

Here are just a few notes about installing the 75cc Mec Eur or even the 75cc Polini kit. I'm no expert, but after screwing things up a time or two, I can at the very least give some golden advice to the many people out there thinking about or about to install one of these kits. The overall gist: This is not a bolt-on immediately kit. Even if it did immediately bolt-on, you will be looking at some serious problems without some work.

Introduction: Assuming you have all of the numerous problems worked out on your VIP, Avanti, Gulp, etc, you may very well be ready to install one of these kits. The very first thing you should notice when you get one is that it is somewhat poorly made. The casting has a few flaws, the ports are very sharp and not chamfered, and sometimes (in my case, 1 out of 2) the stud holes are not aligned properly. To be clear, this kit can be made to be very powerful and will most definitely have adverse effects on your clutch system. If you fix your clutch to the point that it is tight and with proper oil and oil level, you can minimize damage over time to a manageable level. I often tell people about their clutch systems and how important it is to maintain them as to not have them broken within a month or two.

Fix your clutch issues first:

1. Replace 10, 20, 30 year old oil. Just do it.
2. Just use 30W Non-Detergent - there is nothing wrong with it and there is no need to try anything else.
3. Keep the oil level at an appropriate level, tune with your ear and don't overdo it.
4. Too much oil and you will get much more "slip" on your first gear and won't be able to accelerate well on flats.
   1. This will not help on large hills
   2. Slipping will cause the 1st speed clutch to heat up rapidly. Rubber tends to break down quickly when hot. You can and will smear the inner clutch bell with rubber. This rubber will later fall off and clog your clutch oiler holes causing a lack of lubrication between the clutch and the shaft - then the whole clutch seizes to the shaft, sometime ruining both.
   3. If you slip the clutch enough on a large, steep hill, the 1st speed rubber will wear out extremely rapidly. Too much oil is probably the worst thing you can do to the first speed rubber.
   4. If you are trying to blast your way up a hill with a really good low-end pipe, you might get to 2nd speed. This causes oil to make it's way back between the first speed rubber and inner bell. If the RPM drop is so rapid that the bike starts to bog, the 2nd speed will eventually disengage, causing the bike to drop back to 1st speed. This may happen repeatedly. When it drops to 1st speed there is quite a bit of slippage and heat buildup. If you care about your clutches, just keep it stuck in first speed up the hill, don't slip it, and keep the oil at an appropriate level.
   5. Listen for higher than normal revs when going certain speeds uphill.
5. Too little oil - clutch engages much sooner. Very problematic if there is play between your outer clutch bell and the engagement plate.
   1. You will hear clanking when shifting if there is play in the clutch.
   2. The clanking is actually expanding the space between these parts.
   3. The rubber "guys" will break in two, clog the clutch oilers, etc.
   4. Eventually the clutch engagement plate will break, your outer bell will be damaged.
   5. I have personally sheered off an outer clutch bell on a large hill.
   6. These parts can be very hard to find.
   7. Shifting to 2nd too soon will cause the bike to bog, it will repeatedly drop back to 1st speed, may never get to 2nd without a long flat. This also happens with too tall gearing.
   8. You can get the gap in these parts welded in, and then just file then back to their original condition.
6. Be sure your clutch is "tight". Don't allow noises to go untreated. I installed 3/16" aluminum pop-rivets for my engagement plate to keep it tight and so far I haven't worked on my clutch for a year. I also do not beat up the clutch by having a super good low-end pipe.

The kit will absolutely not fit in the case.

The case will need to be ground or cut to make room for this enormous kit. Pictured is the area that needs work. I won't go into much detail, this type of work is pretty serious and there are different methods, some easier than others. All I can say is that you don't have to take a lot of material off, the kit just needs to fit inside the case and you cannot under any circumstances leave shavings, dust, sand, or other impurities in the case. If you aren't confident that you can do this, don't bother, you will ruin the kit or the crank. If its your first time, just ask around about how you should do this. I got some really good advice and it worked awesome, but I'm not confident that everyone can keep the metal shavings out of the case, so you might want to just split the case and work at it like that. DO MEASURE BEFORE YOU SPLIT THE CASE. Get some tools and be sure to do it right, that's all I can say.

This kit doesn't seem to be cleaned up from the factory in any way.

The ports and skirt all need chamfered. You can get tiny files anywhere. Pictured are files which are safe and effective, but in reality I'm going to use a dremel because I have huge balls. Seriously though, if you don't know what "chamfered" means, don't go crazy and just start filing away. Go read up on the process. Do not overdo it, its only just enough so that the rings don't catch port windows and the piston doesn't get scraped up.

Some kits don't fit.

On one of the kits I have, the cylinder does not fit very well over the studs. It is tough to get onto the studs and will not slide down them without a lot of force. The holes will need measured or eye-balled and filed down so that they kit goes into the case smoothly without almost any force at all.

Cylinder head work.

You may or may not know that there is indeed a gasket inlaid into the head. Sometimes it's impossible to see the gap between the head and the gasket, but it is most certainly there. You can pull this out with a pick and then install the gasket that comes with the kit. Unfortunately, the gap left over is not ideal and the geometry isn't great. The gasket can also move around within the gap and it may not make a good seal. If you feel up to it, you can figure out a way to mill down your head and cut yourself a squish band for a little more power. When I did mine, I left the outer ring left over from the original gasket so that I may insert a copper wire to ensure there isn't a leak. For now, I have just been putting gasket sealer in the ring.

When I was young and stupid, I didn't know that there was a gasket there. Instead, I just installed the head without this seemingly useless gasket and ran the hell out of the kit. After a while the bike started to knock and ran sorta bad, but what the hell, it was rally season and I was having fun. In Louisville, it suddenly made some scary noises, some clanking around in the cylinder, so I stopped, got it on a truck and got it home. With all the pressure between the head and the cylinder, the inner leftover part of the original gasket started bending inward toward the piston. It would heat up and the bike would then pre-ignite at high RPMs causing the knock. Eventually it bent inward so much that the piston would bang against it. Eventually parts of the original gasket broke off into the cylinder. Luckily it didn't do a lot of damage and I got the bike home, only to chip off the rest of the original gasket and ran it some more. (Pictured first) Later, I wanted to get some more compression so I decided to sand down the head and cut a squish band. It works great. (Pictured last).

--Sliceofbread 16:29, 3 October 2010 (EDT)