MOPED ARMY

Are you after just cases? I have a p4/6 with a broken con rod. Piston was seized in the barrel. The gearbox is all there though.

Just an FYI, check the poster's location. He's in the UK.

Yeah I'm in the US so I didn't really want to try and ship anything from over seas. It's not for a specific bike, I'm embarking on a project to build a 50cc Grand Prix esque moto gp style racer (Think Kreidler Va Veen or Derbi Angel Nieto full fairing style). After a lot of research and consideration I decided the Minarelli P4/6 engine would be the best platform for it. Unfortunately, they are far and few between in the US.

Surprisingly enough though, a few of these engines were actually imported in the 70s ish on behalf of the Indian motorcycle company for some of their dirt bikes. The coolest part is that they came in a few different flavors on displacements: 50cc, 70cc, 75cc, and 80cc, as well as with two different transmission: 4 and 6 speed.

Luckily I was actually able to snag a 75cc P6 (they call this, I believe, the P675 engine off of the Indian MX76 or 74) yesterday on eBay for under $200 with a dellorto carb. I was told that it came off either an ME or MX 75 bike, and the cases have 75cc and P6 imprinted on them. There is a lot of information on these bikes here, but looking at catalog scans I can't find any that use 75cc P6 engines, only 70cc. So I am not sure of if it is a 4 or 6 speed but we will find out. I'll attach a picture of the same type of engine so you can see what I mean.

I have a feeling the gearing is going to be a lot different than some of the P6s that are overseas for grand prix style asphalt racing, favoring the low end torque needed for dirt racing, but it's pretty wicked that it's already 75cc. And I'll likely go with a smaller than normal rear sprocket to attempt to compensate this difference. But, I won't even need to kit it! An extremely similar engine, possibly even the same model, sold here on moped army a couple years ago. You can find it if you search 'FS: Minarelli P6".

Sorry that was long and you didn't ask for all that information lol but I figured it might be useful for someone else in the future. I'll likely be creating a separate thread to discuss these engines and also to document my build.

I just searched up "Minarelli P6" and there happened to be a listing ending within 24 hours. I think I got lucky, because before I placed my max bid I did some research by viewing completed listings and saw one other listed at $400+ buy it now or best offer, and the seller accepted a best offer.

The Kreidler Van Veen was a huge inspo for taking on this project but I'm just infatuated with all of the insanely high revving 2 stroke racers from back in the day. Don't get me wrong I love my variated vespas but something about a 50-75cc two stroke with a 6 speed manual gearbox is so amazing. This project is going to be a complete pain in the ass though I can already tell. I highly doubt I'm going to find a frame for this engine. And not to mention the fairings/bodywork and tank cost an arm and a leg. . . I likely won't be able to get those for years. There is a replica unpainted fiberglass seat cowl/pan and tank for sale on ebay rn for a derbi angel but shit it's so expensive!

I'm probably going to begin by focusing primarily on the engine and getting it running to start. I'll build a stand so that I can mount the engine w/ carb and exhaust onto something in my garage, fashion a temporary fuel tank and get a throttle hooked up. This way I can be sure the engine and it's ability to run is all sorted through, before beginning to actually source/build a roller.

Man that is a killer deal! I sifted through all the completed listings, and never came across yours . . . Wish I could have jumped on that! I'm happy with the price I paid so it's all good.

What are you doing with your P4 if you don't mind me asking? Have you had the chance to run it yet?

I thought they did a shorter stroke conrod and a longer stroke conrod or is it a shorter and longer crank? Does anybody know what the p4/6 means on the engines? Obviously a p6 is a 6 gear but what's with the extra 6 on a p4 engine? I asked an Italian guy selling some gears on eBay and was none the wiser.

I've worked on and ridden the late model P4 (M4), both Compact System head and Radial fin.

Great, simple motors and they are mad fun.

As far as the Indian variation of the Minarelli engines goes, which seem to be the most common to find here in the US, this is a good link that shows the various different types of engines. Using this page to determine the model of the associated bike, you can then go to this link to further nail down some of the technical specs for the engine.

Other than this and some very small conversations on MA and Facebook, there really isn't much out there in the way of information on the internet for these engines in English. I am working on compiling a database of all the useful and translatable information that I can find and will share it once it's a little more substantial. There are also service manuals for the Indian bikes that do go through some engine internals and stuff, that you might find helpful.

Regarding P6/P4: as I understand it, the evolution of the P4 into the P6 was not just related to the addition of 2 more gears . . . I read this on an Italian forum that asked which engine people preferred. Here is the link. I am not fully aware of what changes were made, though. But I think that the "P6/4" was an engine that included all of the benefits from the evolution to the P6, but uses the four speed gearbox. I think some racers like the 4 speed gear box better for whatever reason.

Bairdco I think I have one of those tucked away in the garage somewhere. I also have a fantic 4 engine I was going to put into a peripoli giulietta that has a 3 speed on it at the minute. All this talk of minarelli engines made me buy another from Italy last week, just waiting on it to arrive. Does anyone have any tips on how to split the cases? They do seem to be very well stuck together!

That's not my bike, mines in a bit worse condition! But that's what the giulietta looks like.

Hey all, the thread is up:

https://www.mopedarmy.com/forums/read.php?1,4366233

I didn't mean the rods. The lobes of the crankshafts can be different sizes, where it won't fit in the wrong type of case. Also different strokes from 39mm all the way to 44mm and up