70cc quad racing

[70cc quad racer]

Hello,

My 7 year old son currently has a 50cc quad with a Minerelli air cooled engine. Next season he will be moved up to 70 class. What 70cc kit would work best. I like the single ring piston / cylinders. I don't do motor work but I can remove and replace anything on this quad. I would like something that can compete with the Metrakit 70cc. If needed I have a friend that can clean up the cylinder. Any information is appreciated.

Thanks

 

[Big B NRG]

Does it still have to be Air Cooled?

A nice Polini Evo70cc will keep up with the Metrakit 70cc Cylinders.
Changing to such a cylinder, you have to replace some stuff to make it work (crank/bearings/carb/transmission/exhaust)

 

[DRXRACING]

Hey Big B, What's the hottest tuned air cooled 70cc cylinder for the same quad? Anything that can keep up with the metrakit?

 

[70cc quad racer]

Does it still have to be Air Cooled?

A nice Polini Evo70cc will keep up with the Metrakit 70cc Cylinders.
Changing to such a cylinder, you have to replace some stuff to make it work (crank/bearings/carb/transmission/exhaust)

Big B,

No it doesn't. I would change it over if there was something better than air cooled set up. As far as changing the items you said, I knew that was gonna happen. I want a better set up than the metrakit. I was just hoping there was a cylinder kit out there that didn't need porting work. Or work to make a crank fit. It's not out of the question, I was just hoping to not have to take it to someone to do work. If I have to do it I will.

I have read some of your other advice / set ups and I appreciate what you have to say.

 

[Björn`]

I don't know if you really want to get into this, but this project might be interesting for both you and your son. :+

The Custom MHR speed Quad

Cheers!

 

[70cc quad racer]

I don't know if you really want to get into this, but this project might be interesting for both you and your son. :+

The Custom MHR speed Quad

Cheers!

Bjorn,

From the looks of the pictures we are doing a similar mod. Were are taking it apart for a total tear down. We will be gusseting the frame, then powder coating it. He already has the best suspension available (long travel w/ triple rate Elka shocks).

Thanks

 

[Mr.Aerox]

he also means engine wise. If I were you, I would change it to LC and get a mhr team 2 7t kit. one of the best kits in the market, and for sure better than a metrakit, and it doesn't need porting because out of the box already pulls more than 20 hp. Your main concern would be a good exhaust, therefore you would need to adapt one or get a custom made one to fit your quad.

 

[Big B NRG]

Hey Big B, What's the hottest tuned air cooled 70cc cylinder for the same quad? Anything that can keep up with the metrakit?

I think a Polini Evo 70cc AC will be allready faster untuned then a MK.
Tuned I have seen Evo AC cylinders do 20 hp!

But I don't know if that will work for the reliability

 

[Big B NRG]

Big B,

No it doesn't. I would change it over if there was something better than air cooled set up. As far as changing the items you said, I knew that was gonna happen. I want a better set up than the metrakit. I was just hoping there was a cylinder kit out there that didn't need porting work. Or work to make a crank fit. It's not out of the question, I was just hoping to not have to take it to someone to do work. If I have to do it I will.

I have read some of your other advice / set ups and I appreciate what you have to say.

Well, if you can change it to a LC engine (waterpump + radiator), you have alot more choice.

I don't know if it's aloud to use bigbore kits?

Here's a list of cylinders that are defently faster as the MK (untuned);

- Malossi MHR Team II (7 Transfers) (70cc)
- 2Fast4Race Kit (80cc)
- Team Cristofolini Racing kit (88cc)
- Malossi MHR Team II Big Bore kit (80cc and 86cc)
- Polini Evo I/II kit (70cc)

All of the above cylinders are (alot) faster as the MK cylinders.
All the 70cc cylinders + the Big Bore kit from Malossi (50mm bore instead of 47,6) are the most "easy"

With all cylinders you will need to match the blocktransfers with the cylinder transfers to get the kit working properly.
But, that's quite easy and there are some guides on this forum that will show you how to match those transfers.

If it was my money, I would go for the Team II (70cc or 80cc), just the best power/money/quality ratio.

 

[70cc quad racer]

Big B,

Is the crank a simple remove and replace. Or is there clearance issues.
Matching is no problem for the case/cylinder.
So the HP on the Malossi 7T is around 20HP out of the box. This sounds like a great set up. I already have some of the clutch upgrades, Malossi Delta clutch, wing bell, Malossi springs. Keihin 24 carb.

Not sure which way to go with ignition. The PVL's are so expensive.

Thanks again.

 

[Big B NRG]

Big B,

Is the crank a simple remove and replace. Or is there clearance issues.
Matching is no problem for the case/cylinder.
So the HP on the Malossi 7T is around 20HP out of the box. This sounds like a great set up. I already have some of the clutch upgrades, Malossi Delta clutch, wing bell, Malossi springs. Keihin 24 carb.

Not sure which way to go with ignition. The PVL's are so expensive.

Thanks again.

Replacing the crank is just out and in, no clearance issues.
Out of the box the Team II will even do over 21 HP if you set it up right. If you get lucky, you will even push it over 21,5 HP!

You can use a Malossi Ignition, those are plug and play.

 

[70cc quad racer]

Where would I look to buy one of the Malossi 7t kits. English website preferred. LOL.

 

[Big B NRG]

Where would I look to buy one of the Malossi 7t kits. English website preferred. LOL.

Does it matter from which country you buy?

You got different options;

www.scooter-attack.com (Germany, website in english)
www.euroscooters.nl (Dutch, option for english)
www.sip-scootershop.com (German, option for english)

Euroscooters and Scooter-attack are the cheapest. I allways order from euroscooters.nl

They have allmost everything in stock, are fast and reliable

 

[knuckle]

Be careful with this.
A 20 hp cilinder can do the trick, BUT this can also backfire.

A kid want it for play, fathers want them to race

Mostly the fathers want to go faster, way faster then the kids would like.

So instead of going faster, your kid could end up with fear of what is beneath him.
And don't want to ride it anymore.

trust me, saw it happen many times.

ps, the engines used on a quad are not minarelli engines but copies of it. They called Herschi engines.
but most parts will fit.

 

[70cc quad racer]

Big B,

If I decide to stay A/C, which is a better cylinder, The Polini Evo or Malossi MHR. Either one would be the 12 pin with racing crank. . Are the prices listed in US dollars on each website. Sorry for my ignorance.
Is this Malossi a complete cylinder kit or just cylinder.http://www.euroscooters.nl/shop/product_info.php?cPath=1581_1583_1794&products_id=216
And also the Polini Is this just a cylinder? http://www.euroscooters.nl/shop/product_info.php?manufacturers_id=133&products_id=6579

Thanks for the websites.

I know which way to go if I go L/C. Just don't know if the cost with making it L/C is worth it.

Thanks

 

[Big B NRG]

Big B,

If I decide to stay A/C, which is a better cylinder, The Polini Evo or Malossi MHR. Either one would be the 12 pin with racing crank. . Are the prices listed in US dollars on each website. Sorry for my ignorance.
Is this Malossi a complete cylinder kit or just cylinder.http://www.euroscooters.nl/shop/product_info.php?cPath=1581_1583_1794&products_id=216
And also the Polini Is this just a cylinder? http://www.euroscooters.nl/shop/product_info.php?manufacturers_id=133&products_id=6579

Thanks for the websites.

I know which way to go if I go L/C. Just don't know if the cost with making it L/C is worth it.

Thanks

That price is for the complete kit. So cylinder, piston, all clips, gaskets etc
The Evo is the fastest out of the box. The problem is that high RPM AC cylinders overheat quicker, because they have less cooling (air instead of water)

If you want to convert the AC to LC, you only need a waterpumpcover (or electric waterpump), hoses and a radiator. I think you could be done for around +/- 100 euro if you buy used stuff.

If you want to be fast and reliable the costs that come with making it LC is worth it I think. AC can also be reliable, you need to have bigger tollerances (higher squish, little richer in mainjet etc) so that is costing you some power.

Cheapest option is keeping with AC, changing crank/bearings/transmission/exhaust/carb etc and set the engine up with higher margins.

Like knuckle says; playing is more important then winning

 

[50cczip racer]

quad racing class
? are u racing in england and if so which class/club are u hoping to race in
the choice is a lot more difficult for a quad than it is a scooter as there is a lot more torque requirement over different terrain,ive built quad motors at 50/70cc lc 80cc lc 86cc lc and tuned the 100cc air cooled and liquid cooled and the best have been the stroker 80 and 100 tuned motors the 70 gave a little more power but lots of revs and struggled with traction somewhat whereas the lower revving 100 made great torque and revved lower and dug in well to give an almost identical show of performance around the track, the latest 80lc was a perfect blend and was a cheap conversion to do

 

[70cc quad racer]

Be careful with this.
A 20 hp cilinder can do the trick, BUT this can also backfire.

A kid want it for play, fathers want them to race

Mostly the fathers want to go faster, way faster then the kids would like.

So instead of going faster, your kid could end up with fear of what is beneath him.
And don't want to ride it anymore.

trust me, saw it happen many times.

ps, the engines used on a quad are not minarelli engines but copies of it. They called Herschi engines.
but most parts will fit.

Knuckle,

I hear what you're saying. This is all about safety and fun for him and me. Every child is different, take for instance, my 11 year old daughter races and doesn't like to jump. She likes to go fast though. She doesn't need motor work on her 90, she is content with what she has and so am I.

Now, my boy can out ride his sister, and I don't want him to get beat because the other quads are faster. I don't care if he gets beat by a better driver. I want and he wants to compete, not just ride around.

Thanks for the update on the engine name.

 

[Mr.Aerox]

whats the maximum cc allowed in the next class? if you are allowed to go up to 80cc, and you want something really fast for your son then you should go for the TCR 80cc kit.
check these clips of a quad with the tcr kit
[ame="http://youtube.com/watch?v=_dcxiMi8NEQ"]YouTube - Cristofolini TCR Quad 3[/ame]
[ame="http://youtube.com/watch?v=jVH2mn2xI30"]YouTube - Cristofolini TCR quad 2[/ame]

 

[70cc quad racer]

The next class is 90cc. My daughter is in that class now but she isn't ready for 25+ hp. That's alot of power.