Questions about Minarelli AM6 engine rebuild

28 posts / 0 new
Last post
Questions about Minarelli AM6 engine rebuild

This is my first post here, so Hi everybody!

I've a little of extra work rebuilding a 50 cc Minarelli engine, some months ago did the same job in another engine, I had a problem then, but managed. I can't remember how fixed it, but this is the problem I've: when assembling the engine with all the washers correctly on, and all the bits, is normal that the shaft couldn't be moved? Have the engine be assembled in neutral and it will work correctly once finished?

I had this problem a time ago and I remember that I had to disassembly it and without touching anything it worked once running, and I'm not sure if I checked the shaft before mount it on the frame, so I'm not sure if I mounted it in neutral position...

Any ideas? any tips for mounting the gearbox? I think that all is correct, I found very easy the last time but today I'm baffled

Any help will be very apreciated

Nobody used with this engine?

ive got this problem as well. have you worked it out yet (have seen you posted in 05).ive put it all together in the right place, all the shims in the correct place but it wont go into gear.please help

I'm afraid the original poster's description was so pants, I'm not sure what the problem is. Are you talking about not being able to turn the crank? Or the gearbox output shaft? Or change gear? Or what?

I'd guess that Jordi was posting in a second language. I don't know the engine in question, but I always assemble engine units in neutral but check the rotation of the crank and gear shafts at every move - cases together, check they spin. Tighten bolts on cases, check again and so on.  


hiii i was just reding about your problem i  have a similar problem with my am6 engine  i have replaced the crank + bearings seals e.c.t  and have reassembled it and it runs but it slips into neatral very easily usualy after 4th =/  cant think how this has hapened =/  any ideas peepl ? thanksssssssssssssss

hi im getting a bit of an expert on these am6 thingys now,after smashing gearboxes one after the other after rebuilding.firstly make sure the little ball bearing is seated correctly under the selector drum or youll have a major lock up and a broken box,secondly when ready to put casings back together gear selector forks must be between second and third notch on selector drum then turn crank slowly to make sure all is free.hope this helpsmanual at

I am also having major problems getting this gearbox back together. Have the driven and driving shafts in place with the selector drum and and selector forks. I am unable to turn the gear shafts for more that around 1/2 a turn before they lock up. Any advice / photo's would be much appreciated. I already have the manual but that is not realy assisting me in this instance.

i have this em6 engine tooo peugeot xp6 Very good, very fast engine Parts are very expensive though

Good one !!! Lol...


your first post is so good.I had not post anything yet. coach outlet

Has anyone resolved the gearbox issue as I am also having the same problem!  I am also unable to turn the gear shafts for more that around 1/2 a turn before they lock up? I have rebuilt it according the numerous am6 manuals but engione still ceases when gearbox is put into 2nd gear and so on, 1st seems to be fine though! Any help would be great, hopefully someone has worked out a solution for this by now, this is driving me and my son bonkers!

Hi there, i have a new am6 engine and when i rev it once started it doesn't really do anything, please can anyone tell me what is wrong.

If you remember the ball bearing on the selector drum and ball bearing inside the cluth pin it should have no problems. Try to take apart the egiene not in gear. The selector shaft should be between second and third grove on the drum. And remember it can only put back together on the right hand side of the egiene as i stupidly forgot one day! Am6 always have the same problem jumping out of gear between 4-5 as the travel between those to gear is larger than the other so just give it a slight harder nudge than others.

Hello there, I have a TZR50 with the AM6 engine and the gearbox is useless. Clunks and clonks through every gear apart from 5 to 6th, but still gets stuck between these gears. Clunks are unbareable on down shifts. My dad seems to think its the push rods or selector arms are worn but we are worried  about taking the gearbox apart, what do i do?! many thanks

Here at . we are one of the leading motorcycle bodywork specialists providing a huge range of replacement and quality aftermarket motorbike fairings. Depending on the year and make of your machine, we can advise and offer excellent motorcycle fairing for all major manufacturers in addition to creating individual and bespoke motorbike bodywork for your pride and joy. Whether looking for Ducati motorcycle fairings or Yamaha motorbike bodywork panels, we are here to assist. Email:

does anyone know how much oil the gearbox actually takes on the Minarelli AM6 engine. i have a Peugeot xp6. (and yes i do know there is a level hole). but i just wanted to know the exact amount as i put 200 ml in from emptying the whole of it and wondered how close i am to it being full.

it says on the casing how much oil the engine takes, i dont know about putting it together but im actually having trouble splitting the cases

hiim having trouble with my am6 gearbox when in neutral it jumps into 1st gear also struggles to select neutral and when in gear it wont pull away also when i put it in gear it locks solid.any help would be appricated

Hi, i have had a problem with the gear slipping in and out mainly 3rd and neutral. i have just stripped the engine and looking at the gears, selector forks and barrel i carnt see any obvious wear or breakages. I dont know what to do as, if i just rebuild the engine i will have the same problem. I dont know what to do, other than buy a working second hand engine. Any help would be appriciated. Thanks. 

I used to race minarelli engines years ago, a common problem back then was instant gasket coming off the inside of casing and working it's way into the groves of the selector drum. This would become trapped between the end of the drum and the slide pin (on inside of selector fork) preventing full selection of the gear. With load change the gearbox would jump into nuteral. Root cause was to much instant gasket used during rebuilds. Remove the forks from the drum and check.

To anyone else having problems with an AM6 gearbox, I have found a workshop who rebuilds them (in the UK) called Firefox Racing up in Keighley, West Yorkshire. Phone: 01535 606200

Hi,I have a Rieju MRT with an AM-6 engine. I had a propblem that as I was riding, it would sometimes slip into neutral, an inconvenience but acceptable, but now it's gone bonkers. I'll be riding in 4th, 5th or 6th and go to change down but it seems to lose the 1st, 2nd and 3rd gears, I will have to put it into 4th and sort of hope 3rd is there, as when I press down on the shifter it feels like I'm in 1st, but I'm clearly not. This has me really confused as it's a pain when I come to junctions. Also, sometimes the clutch will smell, so could it be linked to that?? And help would be really appreciated, cheers!

Hi guys can anyone help?? heads really mashed.... just refitted the am6 engine with bearings and crank. Everything is back together as it should. When I Screw the crank casings back together its very very stiff to turn over and im struggling to get the casings back together when tightening. ive disconnected the gearbox from the crank and its the same. the only conclusion is that there is supposed to be shims on the crank? Thanks  

there are no shims on the crank, the correct thrust washers must be in the correct place on both gear shafts, the selector drum and the selector shaft,  I have this written down at home, unfortunately im at work, you need to assemble the gear box in the right hand case, and it must be assembled in neutral, once together before fitting the left hand case, if you push gently down on the selector drum you should be able to rotate the box and see that its in neutral, ive lost count how many of these engines ive rebuilt, presently having 7 of these bikes in the garage at present, i can send you the shim details tomorrow

Log in or register to post comments