Malossi MHR Racing Cylinder Question

Hello, a friend of mine gave me a Malossi MHR Racing cylinder for free for my Beta Ark LC. I was wondering if instead the standard single ring 47.6mm bore piston i could install a double ring 47mm bore piston to be more reliable because i want it for every day use, and not to change the standard crank.
Thanks

 

I wouldn't recommend using the standard crank with an MHR. Not tough enough by half.

 

What about the MHR Rep

 

It's really not a good idea to try using a 70 cc cylinder with a stock crank. Honest. And if the pro rep is anything like the Team 2 then you can't just slap it on there anyway. It won't fit without altering the crank case. Which is a great opportunity to deal with the admission, transfers, and fit a propper crank !

 

He also gave me the Team 2 exhaust. Im thinking about getting the MHR Rep, fitting the TEAM 2 exhaust and keeping the std crank. What do you think? I dont have a lot of money to spend

 

no point if you're gonna keep the standard crank, if it goes then it's going to do a lot more damage than just buying a decent crank in the first place

 

But if i add a crank will it cause problems? I don't have the money to keep sending my scooter to the mechanic

 

Agree with Subwoofer 100 percent - Seriously - keep the kit & the exhaust & do it when you do have some money. And you're going to need some transmission bits, a bigger carb, and other bits. Hi end parts require hi end preparation & set up. What you need is some knowledge & tools. You can't run hi end engines all days without it. It won't work - (even with a 'forgiving' cylinder like an MHR) - They just won't run properly (or at all).

 

why would adding a crank cause problems? Fitting a stronger crank and heavy duty bearings are essential with a high power setup, otherwise your bearings are going to go, or your crank will. Have them fitted properly and there should be no problems at all.

 

So if i add a crank and the MHR Racing will they be suitable for everyday use?

 

Strong crank and bearings and it should be okay

 

But it will need uprated springs everywhere - a better variator (Malossi), a 21mm carb at the least, and a bunch of rollers & jets to make it work. I'm not saying 'don't do it' - but I am saying 'don't do it if you have to rely on a garage to do it for you'.

What is your complete set up today ? Have you ever fitted bearings to a crank & installed it or changed a cylinder ? Be honest.

 

My mechanic has told me that by adding the MHR Racing i would need to change the piston every 2 months or so and the water pump regulary. Also he told me other problems may occur

 

My current setup is malossi variator with polini rollers 4.2g and malossi belt. Also Stage 6 pro rep pipe. I have never changed bearings or anything and never changed cylinder.

 

He is trying to dissuade you from doing it. Because he doesn't want you in his garage every five seconds. He is right. That is not to say that his analysis is right. You can run a high end kit (well set up) for about 6000 km before you need to change anything. But that don't mean it will work better than a mid race without fiddling with carbs & transmission almost on a daily basis.

I most respectfully urge you to abandon the idea of racing 70 cc engines until you can do it all yourself or you win the lottery. On the other hand - you can learn - and it's not rocket science. But get the knowledge before you start spending money.
Very best regards -

TV

 

So are you saying that a MHR Rep and crank would be close enough to daily use without many problems and the need to change anything?

 

An MHR Racing and an MHR Rep are very different things..

 

What do you mean?

 

I think he means that the MHR Team II is more violent than the Replica. But I say both will tie your standard crank in knots.

 

if you're going for something for everyday use, why not the Stage 6 streetrace 70cc?