fa2st cyclinder for mini quad

Hello Big B,

I appreciate all info.

The engine is a 90 cc from the factory 52 mm bore x 42 mm stroke liquid cooled cast iron cylinder.

When you mention that the cases need to be machined for the crank, can you be more specific? What needs to be machined and why?

Anywhere near 18-20 HP would be a huge step up for us.

Does anyone know of a source here in the US for the Fabrizi products?

Thanks again all

Cast iron cylinder?? I thought the FHT kit was alu+nicasil.

If you use a 50cc engine, the stroke is 39.2. Fitting a 42 mm stroke crank, you will need more space in that 50cc engine to mount the 42 mm stroke.

So it should be made atleast 1.4 mm bigger. ((42-39.2= (2.8)/2)
Otherwise you crank will not fit.

That 90cc FHT kit should do atleast 20 HP. But the finishing quality issn't so super. A 2fast kit is cheaper and the quality is super.

Take a look at these pix (took them from other forum):

2fast8tr7.jpg


2fast4do3.jpg


Crank + cylinder is around 900 dollar like said and makes 78cc.

Still this kit puts out 24 hp or more easy!
 
Hey Big B,

Thanks again.

The current engine is in an ATV manufactured in Taiwan (Minarelli copy).
It is 89.2cc from the factory with a cast iron liquid cooled cylinder. The cylinder is marked FRC on one side and A-ONE on the other.
Bore is 52 mm
Stroke is 42 mm
Revs to 9,500 and produces 12 RWHP on a Land and Sea Dyno. This is after a little tuning to the very minimal ports. Transfers are a joke with the front right transfer having a cast in divet/indentation (why I have no idea) that severely limits flow.

The 2 fast for race cylinder and crank seems a lot more affordable than what I was quoted for the Fabrizi 47.6 x 47 set-up.

I have contacted a friend in Italy for some help. Our first race is in 4 weeks.

Thanks again all


Cast iron cylinder?? I thought the FHT kit was alu+nicasil.

If you use a 50cc engine, the stroke is 39.2. Fitting a 42 mm stroke crank, you will need more space in that 50cc engine to mount the 42 mm stroke.

So it should be made atleast 1.4 mm bigger. ((42-39.2= (2.8)/2)
Otherwise you crank will not fit.

That 90cc FHT kit should do atleast 20 HP. But the finishing quality issn't so super. A 2fast kit is cheaper and the quality is super.

Take a look at these pix (took them from other forum):

2fast8tr7.jpg


2fast4do3.jpg


Crank + cylinder is around 900 dollar like said and makes 78cc.

Still this kit puts out 24 hp or more easy!
 
Hey Big B,

Thanks again.

The current engine is in an ATV manufactured in Taiwan (Minarelli copy).
It is 89.2cc from the factory with a cast iron liquid cooled cylinder. The cylinder is marked FRC on one side and A-ONE on the other.
Bore is 52 mm
Stroke is 42 mm
Revs to 9,500 and produces 12 RWHP on a Land and Sea Dyno. This is after a little tuning to the very minimal ports. Transfers are a joke with the front right transfer having a cast in divet/indentation (why I have no idea) that severely limits flow.

The 2 fast for race cylinder and crank seems a lot more affordable than what I was quoted for the Fabrizi 47.6 x 47 set-up.

I have contacted a friend in Italy for some help. Our first race is in 4 weeks.

Thanks again all

In that case, you will just have to machine the crankhouse 1mm wider, because you allready can fit a 42mm stroke crank in it.

2fast cylinder puts out it's max power above 13,500 rpm
 
the Jog90cc engine for the quads you use have a 79,5mm inside diameter for the crankshaft & the 2Fast Minarelli crank only has 74,5mm diameter so no more need to machine the carters to make the crank fit.
 
the Jog90cc engine for the quads you use have a 79,5mm inside diameter for the crankshaft & the 2Fast Minarelli crank only has 74,5mm diameter so no more need to machine the carters to make the crank fit.


Tiba,

Thanks for the input. Are you sure about the measurements you quoted? I am a little concerned that the clearances might be too much.
79.5 mm - 74.5 mm = 5.0 mm
5.0 mm / 2 = 2.5 mm (.098" for us in the U.S.) clearance from crank web(journal) to crankcase.
Will this cause a problem with low end pressure (too much slippage)?

Thanks,
 
Tiba,

Thanks for the input. Are you sure about the measurements you quoted? I am a little concerned that the clearances might be too much.
79.5 mm - 74.5 mm = 5.0 mm
5.0 mm / 2 = 2.5 mm (.098" for us in the U.S.) clearance from crank web(journal) to crankcase.
Will this cause a problem with low end pressure (too much slippage)?

Thanks,

yup, i'm very sure, the Jog90 engine is very common here in my place & we have been tuning this type of engine long before you guys hehehe.

i dunno how much crankcase compression will be with that big a clearance but i think with the 2Fast cilinder kit's huge transfer tunnels it won't matter that much, besides a well designed pipe can suck all the air/fuel inside the crankcase & the carburator.

you can always try to use a smaller carburator to compensate for the extra volume or do another crankcase from a 50cc Jog engine.

my 2Fast engine uses a 50cc carter & i had it machined to give a 0,50mm clearance (75,5mm inside diameter) but MT says to do it to 76mm.
 
@FASTRTOO DUDE heads-up! the 2F4R 78cc is a 90cc KILLER! with the right parts and tuning, your chance against the competition iterms of leaving them behind is so HIGH!

Being FAS2T is not cheap but its well worthed!

Goodluck on your project dude!.
 
In some cases, a bigger crankhousevolume is positive on HP's :evil:

+100 Big B,
the days of high primary compression is long gone, if you have small transfer & tunnel area (cross section) a high primary compression might just work in the case of FRC & stock Jog90 cilinder kits but with the 2Fast's huge transfers & tunnels a bigger crankhouse diameter might actually do more good.

the key to getting high hp output on a 2Fast kit is a good custom pipe & lots of crankcase tuning, the crankcase must allow the kit to breathe at it's designed rpm to make real power.

our 2Fast kit's port timing is basically untouched, all i did was just smoothen the surfaces of the ports.
 
Actaully i have encountered this problem, and dont suggest you use the 90cc case. I have used many, and they are great for the bigger cranks that are ment for it. To use a smaler crank such as the 2f4r or in my case a FHT, you are going to lower the case compression too low. Despite the high rpm and high flow transfers.
Yes the 2f4r and FHT have huge transfers and can flow the volume, but even with a rights sized carb you wont have the true performance you would if you ran a 50cc case with the recommended .5mm clearnence. There is a reason why manufacturers ( BIG 4) build bikes with the tolernece this way.
I have built so many engines its hard to remember them all, and we have 90cc cases and 100cc ones for that matter. I have access to pretty much everything, and my suggestion is to find 50cc cases.
If you want true power, try to find a Yamaha Vino scooter since you are in the USA. Then you can get the better instake reed valve that will give better power on the low end. You can go with any of the top bore kits including the 2f4r and see huge power over the set up you have now. Also as Tiba mentioned the true key is getting the right pipe. IN your case since you cant run the scooter pipes, i suggest looking for a ATV that will have a similar layout to that as you see on the scooters here, but ment for a ATV.
We built an ATV ( SMC/Kasea) that keeps up with Yamaha 200s but was 99cc. Smoked every other quad in the class. I have yet to test it against a Cobra 70cc shifter quad???? we see soon....
Well this is just my suggestion, you can run the 2f4r, its good, but take note to the case clearence issue. The one i built had 2mm clearence and ran fast, good and great power, but ran even better when i used the 50cc cases.
 
If you have all the time in the world, you could even test with different volumes by making teflon rings in different sizes and press them in the casing.
 
Hello Tiba,

You the man. I split the cases and the crank wheel measures 3.072" or 78 mm and the crankcase I.D. is 3.130' or 79.5 mm. This yields a .030" or .75 mm clearance form crank wheel to crankcase.

If the 2 Fast crank is 74.5 mm O.D. this will give me a whopping .098" or 2.5 mm clearance. I called the ATV distributor to see if he had any 70 cc cases in stock, and he did. I asked him if he could measure either the I.D. of the 70 cc cases or the O.D. of the 70 cc crank wheel. Still waiting to hear back, not sure if he knows what to do.

Time is running out we got 3 weeks until the 1st race. I have the new V-Force reed cage and the PVL ignition. Just waiting to find out whats what on the cylinder and crank and case issue.

Do you by chance know what the 70 cc ATV cases measure?

Thanks

yup, i'm very sure, the Jog90 engine is very common here in my place & we have been tuning this type of engine long before you guys hehehe.

i dunno how much crankcase compression will be with that big a clearance but i think with the 2Fast cilinder kit's huge transfer tunnels it won't matter that much, besides a well designed pipe can suck all the air/fuel inside the crankcase & the carburator.

you can always try to use a smaller carburator to compensate for the extra volume or do another crankcase from a 50cc Jog engine.

my 2Fast engine uses a 50cc carter & i had it machined to give a 0,50mm clearance (75,5mm inside diameter) but MT says to do it to 76mm.
 
I think stroke is like 50cc engine? 39.2. So it will be around 40mm I guess.

Edit, I'm really an emo..

Stroke is 39.2, so the case can never be 40 :X
 
Last edited:
yes! i am the mang! :D

50cc crankcase measure 73,3 to 73,5mm, most crankshafts have a diameter of 71,5 to 71,8mm.

70cc's use the same crankshaft as the 50cc's.
 
George,

I had sent a e-mail to the address you gave me, but I never heard back. Did you get the message?

We only have 3 weeks before the 1st race. I spoke to the distributor for the ATV's in AZ and the said the part numbers for the cases for the 70, 90 and 100 ATV's are the same. Plus yesterday the lady said they had them in stock and today I was told they were not.

They can supply a crank with either 39.2, 42 or 45 mm stroke that will fit my current cases and yield a .75mm or .030" crank wheel to crankcase clearance.

What did you tell me on the phone about using a EVO cylinder and a ?? stroke crank and spacer plate?



Thanks,

Thanks

Actaully i have encountered this problem, and dont suggest you use the 90cc case. I have used many, and they are great for the bigger cranks that are ment for it. To use a smaler crank such as the 2f4r or in my case a FHT, you are going to lower the case compression too low. Despite the high rpm and high flow transfers.
Yes the 2f4r and FHT have huge transfers and can flow the volume, but even with a rights sized carb you wont have the true performance you would if you ran a 50cc case with the recommended .5mm clearnence. There is a reason why manufacturers ( BIG 4) build bikes with the tolernece this way.
I have built so many engines its hard to remember them all, and we have 90cc cases and 100cc ones for that matter. I have access to pretty much everything, and my suggestion is to find 50cc cases.
If you want true power, try to find a Yamaha Vino scooter since you are in the USA. Then you can get the better instake reed valve that will give better power on the low end. You can go with any of the top bore kits including the 2f4r and see huge power over the set up you have now. Also as Tiba mentioned the true key is getting the right pipe. IN your case since you cant run the scooter pipes, i suggest looking for a ATV that will have a similar layout to that as you see on the scooters here, but ment for a ATV.
We built an ATV ( SMC/Kasea) that keeps up with Yamaha 200s but was 99cc. Smoked every other quad in the class. I have yet to test it against a Cobra 70cc shifter quad???? we see soon....
Well this is just my suggestion, you can run the 2f4r, its good, but take note to the case clearence issue. The one i built had 2mm clearence and ran fast, good and great power, but ran even better when i used the 50cc cases.
 
Hello Tiba,

Spoke with the ATV distributor today and he said that the 70, 90 and 100 all have the same case part numbers. This leads me to believe that the crank wheel diameter is the same on all as well. He told me I could choose a 39.2, 42 or a 45 mm stroke crankshaft. I couldn't source a set of cases from him anyway as they dont have them in stock.

Clock is ticking,

Thanks,


yes! i am the mang! :D

50cc crankcase measure 73,3 to 73,5mm, most crankshafts have a diameter of 71,5 to 71,8mm.

70cc's use the same crankshaft as the 50cc's.
 
then that isn't a real 50cc crankcase or he is talking bullshit, there is no production crankshaft for a 70cc with a 78mm crank diameter unless the Taiwanese or Chinese made it especially to fit the Jog70 crankcase.

those measurements i gave you came from a 50cc crankcase, to make a 70cc engine you just put a 47 or 47,6mm big bore kit, throughout my experience i have never seen a 39,2 stroke crankshaft with a 78mm diameter on a minarelli scooter engine.
 
Tiba,

Im not sure.
He is not very technical, business type interested in moving units.
I did check the parts list on the 70, 90 and 100 cc crankcases and sure enough the part numbers were the same. This might be an error.
The ATV Co. is fairly new in the US (about 1 year), the quads are made in Taiwan of course.

I can't even order a set of the 70 cc cases to measure for myself because they said they do not have a set in stock.

As we only have 3 weeks to decide motor layout and get the pipe built, this is what Im thinking, please let me know your thoughts all.

Must use my cases. The excessive crankcase clearance issue using the 2 Fast kit has me thinking that it would be a wad of money (850 Euro x 1.34 = $1139.00 plus another 75 or so for shipping) to spend only to find out that the extra clearance killed my primary compression and performance. George has mentioned (in an earlier reply) that is was a noticeable difference changing from 2 mm to .5 mm clearance and I will have 2.5 mm clearance.

What if I use my cases with the available 45 mm stroke crank (cost on the crank is only like a $150.00) and I will have the correct wheel to case clearance.
Then use a readily available high performance 47.6 mm cylinder such as the Malossi Speed 7T or the Polini EVO that was designed for the 39.2 mm stroke. I have a machine shop that is helping us out and he can make a 5.8 mm thick spacer (the difference between the 2 strokes) to use under the cylinder. Will this work out? All help welcome on this.

I recently purchase a V-Force reed cage and PVL ignition. Im going to order a 28 mm Kehin PWK carburetor on Monday. Any input on the manifold? The carb currently faces rearward and the tubing style manifold is quite long and is only 24 mm I.D. We would like to maintain the rear facing carb to keep it out of the mud path.

Thanks



then that isn't a real 50cc crankcase or he is talking bullshit, there is no production crankshaft for a 70cc with a 78mm crank diameter unless the Taiwanese or Chinese made it especially to fit the Jog70 crankcase.

those measurements i gave you came from a 50cc crankcase, to make a 70cc engine you just put a 47 or 47,6mm big bore kit, throughout my experience i have never seen a 39,2 stroke crankshaft with a 78mm diameter on a minarelli scooter engine.
 
damm i just typed a long reply and i was logged off :(
Well anyways here some of the info you asked for
the 45mm crank i have is out of taiwan and has a outer dia. = 77.8mm Also the taper on the stator side is of the larger jog style. So please check what your new PVL ignition is? If its for a 50cc (39.3mm) crank it wont work. Also you have to take into account that the larger "stoker" cranks out of taiwan are usually ment for the "JOG 90" style trans, meaning the spline is larger with less teeth. So if you are using a stater motor, the Pulley and ramp all have to match your new crank.
You can swith the crank to that of the 50cc style as ( most of italian cranks are) and still use all the same flywheel, ramp and etc.... on that crank. From what i gather you have all the "jog 90" style trans and stator so not sure what direction to recommend you take now? Sorry but it is a confusing set up that you are going for? Let me know if you still want the crank, i got a few left.
 
George,

Thanks for the feed back.

The stock crank has a wheel diameter of 78 mm.

It is the larger size crank O.D.. I have the correct PVL for the larger end crank. The difference I was told by the PVL tech guy is .043".

The trans side of the crank measures .620" O.D. and has 15 splines.

Is there any HP cranks (Full Circle) available that meet the requirements above?


No electric starter, kick only. There is a large diameter gear with a large roller bearing that was behind the front variator (did I spell that right). It appears that this would be for an electric starter. The ATV came with no starter but there is a block off plate where the starter would be located. Should this large gear unit be removed or is it good to have this extra spinning mass to store some flywheel energy for drives out of the corners?

Quick question on your intake manifold. Can you provide me with some dimensions like the I.D. (I want to try a 28 mm PWK), also the overall height (I need to be careful as the fuel tank sits right above the carb. and there is not a lot of clearance.

Thanks,



QUOTE=CIH racing;2283300]damm i just typed a long reply and i was logged off :(
Well anyways here some of the info you asked for
the 45mm crank i have is out of taiwan and has a outer dia. = 77.8mm Also the taper on the stator side is of the larger jog style. So please check what your new PVL ignition is? If its for a 50cc (39.3mm) crank it wont work. Also you have to take into account that the larger "stoker" cranks out of taiwan are usually ment for the "JOG 90" style trans, meaning the spline is larger with less teeth. So if you are using a stater motor, the Pulley and ramp all have to match your new crank.
You can swith the crank to that of the 50cc style as ( most of italian cranks are) and still use all the same flywheel, ramp and etc.... on that crank. From what i gather you have all the "jog 90" style trans and stator so not sure what direction to recommend you take now? Sorry but it is a confusing set up that you are going for? Let me know if you still want the crank, i got a few left.[/QUOTE]
 
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