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<  Scooter Performance Garage  ~  Not All 70cc Cylinder Kits are Created Equal

Hyazuma
Posted: Wed Oct 08, 2008 1:30 pm Reply with quote
Joined: 06 Oct 2008 Posts: 172 Location: Denver, Colorado
Hello. This is my request for the experienced scooterists on here to do a demystification of common 70cc kits and what to expect from them. One concern that caused me to write this post is that there is a bit of misinformation out there about which 70cc kits are better than others and what we can expect from certain kits (the trash talking sales guys). In my experience, I have found that the AirSal-T6 is not powerful enough to push an overrange; in fact its so underpowered that my fiancee's zuma that only has a 70cc Athena piston kit and pretty much stock throughout the tranny can spank my scooter (it is not ported!). My scooter has just about every modifiction done to it right now, so looking at her tranny and seeing a basically stock setup is saddening to me (no this is not a tuning issue).

I wish someone would do a comparison and contrast among popular 70cc kits available so that people don't go buying a ton of crap that they don't need to go faster. These kits are pretty expensive and not everyone can go around experimenting with different kits until they get it right. This is why I am posting this thread.

This analysis would include:

1. The difference between a sport 70cc kit and a regular 70cc kit
2. The difference between specific brand name 70cc kits
3. The price trade offs between specific brand name 70cc kits
4. The reliability trade offs between aluminum and cast iron 70cc kits
5. The facts about which carburetor you should use with 70cc kits (stock zuma carb is phenomenal with the Athena 70cc kit!)
6. Do you really need to change the carb?
7. Do you really need to premix with 70cc kits?
8. How much did feel each kit is worth for the performance they provide?
9. Anything important that I missed here


Thank you for your highly valuable input on this scooter related issue?

Comment on the numbered list so that we can keep it organized as possible. Thank you.

Oh, and if you don't have a comparison to do; leave a review of the cylinder your using now.

(Sorry if this is a repost; you all have some good insight on this stuff)

Maybe this might turn into a "buyer guide" for cylinder kits?

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rickystudds
Posted: Thu Oct 09, 2008 2:15 am Reply with quote
Joined: 07 Aug 2007 Posts: 364 Location: Greensboro NC
Sounds like its pretty impossible to compare all the popular 70cc kits because everyone here has a different type of engine for example
I have a minarelli am6, some peeps have morini and so on.
But never the less I will post what I think...

1. The difference between a sport 70cc kit and a regular 70cc kit
reg is for street ; pro - is for race
reg revs range (8500-13000) pro revs range (10,000-15,000)
because Port timing is different
reg lasts longer pro wears quicker
Pro has detachable(replaceable) two piece head with better cooling
reg-can be cast iron to last even longer

2. The difference between specific brand name 70cc kits
Metrakit is popular in my case and most useful
SP-great for street use PRO- only race use
Polini provides a 80cc version which looks nice
No experience with Air-sal
Athena I heard is good




3. The price trade offs between specific brand name 70cc kits
prices everywhere are so different its impossible to tell
buy expensive so its more reliable
I heard good things about Hebo Manston kit
I think it 80cc

4. The reliability trade offs between aluminum and cast iron 70cc kits
Cast iron lasts longer .proven. if you want a kit for a while go for cast iron.
even better hand made cast iron.


5. The facts about which carburetor you should use with 70cc kits (stock zuma carb is phenomenal with the Athena 70cc kit!)
you mean like which size?
or which brand?
Dell'Orto is popular
there's also OKO



6. Do you really need to change the carb?
Yes you must change the carb - why would you increase the ability to burn more fuel in order to produce more power and NOT give your motor more fuel that it needs. Same with the pipe.


7. Do you really need to premix with 70cc kits?
Its recommended but not essential.

8. How much did feel each kit is worth for the performance they provide?
I like my Metrakit but its expensive i think like 450 retail from cycleimports.com
9. Anything important that I missed here
Jet size is kinda important but thats more carb tuning which you are gonna need any way.
If you need even more power for racing put in a digital ignition for a few more degrees on the spark.
and you need a good foamy air filter for better air flow for your 10000 revs.
and if you wanna get up to the level of the Admins on this forum ( which i am not) you can do some engine porting and cylinder mods to expand ports.

Wait...... I forgot to mention that you will need a new crank to handle all this new power at the top end to bring it to the wheel and it better be nice and full.

Thats is my 5 cents
Rickystudds[/img]

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Big B NRG
Posted: Thu Oct 09, 2008 2:48 am Reply with quote
Joined: 21 Sep 2007 Posts: 1661 Location: The Netherlands
You should take a look here;

http://www.scooterinvasion.net/forum/viewtopic.php?t=253&highlight=setup+profiles

Maybe a mod can make this a sticky? It contains alot of usefull information, but if nobody replies, it keeps going down to page 100.

And how are you that sure that it's not a setting up issue with your scooter?

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scootertrog
Posted: Thu Oct 09, 2008 7:59 pm Reply with quote
Joined: 12 Jul 2007 Posts: 1501 Location: SW Missouri
I want to say that is thread would be almost useless for several reasons:

A - Ultimately, the engine's performance will be dictated by the sum of all parts. The best (whatever that is) cylinder kit will run like crap if not matched up properly with all the other components.

B - Same for the tuner doing the install - I'd rather have someone like OverRev or Big-B set up an el cheapo cylinder kit than some numbnuts do a 2Fast for Race install.

C - Some brands act so different, for example, Airsal T6 gets hammered a lot, and that is mostly due to poor installs. I have found the l/c Airsal to be freaking bulletproof, but the a/c T6 not as trouble-free - here again a/c kits are more sensitive to jetting mistakes.

D - Everyone has their personal favorites, for whatever reason. That is fine and it's good that folks can (and should) try different stuff. Very Happy

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StepVino
Posted: Sun Oct 12, 2008 3:10 pm Reply with quote
Joined: 05 Feb 2008 Posts: 1916 Location: Houston, TX
Part 9
Hyazuma, if you have the inclination, it's surprising how
much can be had out of the stock engine by just adding
a pipe and some porting, a new variator, maybe a different
length belt, different tires etc. This all needs to be done
anyway, after spending hundreds on a cylinder kit,
but if you do it first, maybe you find out you don't even
need the cylinder kit.

http://www.youtube.com/watch?v=R24p70vlvrs
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JCmotorsports
Posted: Sun Oct 12, 2008 9:01 pm Reply with quote
Joined: 25 Jun 2008 Posts: 109 Location: Connersville,in
Thats why you pay a pro to build a engine.You cannot just put a 70cc kit on and expect to go 75 mph,just like any engine there must be supporting mods.
So the best answer to this post would be on said engine(minarelli h)how fast can i go with $100,with $300,With $1000

most good tuners on this site will be in the same ballpark if they know squat about these motors.

My example of a decent 70 mph build(most bang for buck)

Any brand cylinder kit,dont really matter as long as its 70cc so cheapos will do
(usually the mrp does great because the power is at a lower rpm,matching the rest of the parts better ime)

technigas rs70 or equal(lots of debate here,remember were going only 70mph ~10hp

Mrp intake manifold with dual stage reeds(allows use of oko carb mainly)

21 or 24mm oko carb Really depends on what brand cylinder here,mid cylinders get 24,cheapos 21

Thats all you need as far as power goes,you will need clutch springs,lighter roller weights and torque springs at the very least.

Better would be a complete variator kit with kevlar belt.

Really its alot of trial and error,ive built alot of scooter engines so i know what works and what dont.I spent alot of money in the wrong directions also,thats part of the learning curve.
Bottom line,if you dont want to mess with what works and what dont,consult a pro and have them put a kit together for you.It will save you lots in the long run and have a better more reliable engine!

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wireburn
Posted: Wed Oct 15, 2008 4:19 pm Reply with quote
Joined: 07 Jan 2008 Posts: 626 Location: Muskegon, MI USA
I can almost guarantee you won't be going 70mph with those mods.

-Mike

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JCmotorsports
Posted: Thu Oct 16, 2008 12:03 am Reply with quote
Joined: 25 Jun 2008 Posts: 109 Location: Connersville,in
wireburn wrote:
I can almost guarantee you won't be going 70mph with those mods.

-Mike


Try 73 mph gps certified bud.That was with a 19 archee carb,it wend ALOT FASTER WITH THE MRP MANIFOLD AND 24MM CARB

I love when guys think they know how fast my scooter can go,Have you built a triton?Didnt think so

We are talking about a min h,not some kymco or morini crap engine.

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scootertrog
Posted: Thu Oct 16, 2008 12:38 pm Reply with quote
Joined: 12 Jul 2007 Posts: 1501 Location: SW Missouri
JCmotorsports wrote:
not some kymco or morini crap engine.


Ouch! Careful! Crying or Very sad

scootertrog
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Areomyst
Posted: Thu Oct 16, 2008 3:49 pm Reply with quote
Site Admin Joined: 10 Jul 2007 Posts: 5040 Location: Haw River, NC United States of America!
JCmotorsports wrote:


Try 73 mph gps certified bud.That was with a 19 archee carb,it wend ALOT FASTER WITH THE MRP MANIFOLD AND 24MM CARB

I love when guys think they know how fast my scooter can go,Have you built a triton?Didnt think so

We are talking about a min h,not some kymco or morini crap engine.


I have seen some impressive speeds out of the Char-Mo 70cc cylinder that MRP offers, but I would still rather have a better quality kit. I have done several builds on engines that are the same as the Triton engines. The Vento Zip is pretty nice for tuning also. Out of the box, the Char-Mo cylinder could use some heavy cleaning work on the ports, but I like the exhaust w/ the auxiliary ports on either side, I think that gives the cylinder more bite than similarly priced ones.

I'm not a fan of the Morini engines, but the Kymco engines are far from crap. They're some of the best engines I've ever worked on. If I didn't stand behind that statement then I wouldn't own 2 of 'em. I'm hoping to see greater than 70mph out of my Super 9, and I think it's going to be relatively easy to achieve.

~Josh
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wireburn
Posted: Thu Oct 16, 2008 8:36 pm Reply with quote
Joined: 07 Jan 2008 Posts: 626 Location: Muskegon, MI USA
Without including a gear-up mod how can you possibly get to 70? And yeah, MY bike is a Triton down to the last detail. It is the same bike with a different name when PSF bought the rights to sell them off Vento in 2006.

I have seen an MHR mina build that could come close to 70, but he was heavily modded and was turning well over 14,000 rpm. I'd like to see you sustain those RPM's on an iron Charmo kit and stock crank. The stock Triton gears are good for a little over 60. For 70 you'd have to be turning over 15k rpm. The stock crank is as good as toast at those speeds.

Anyway, yeah, I guess I call BS, unless there's more you'd like to add to your mod list after the fact for your "decent 70 mph build".

-Mike

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JCmotorsports
Posted: Thu Oct 16, 2008 9:31 pm Reply with quote
Joined: 25 Jun 2008 Posts: 109 Location: Connersville,in
Call bs, call the cops,i could care less what or who you call.IM not some kid claiming i have done all this or that,just because you have a vento triton knockoff and cant get your scooter to perform well isnt my problem.
The vento i had had very tall gears and i wouldnt put that pos anything past 10k nor did it need it.If you tried to get those china cases running 14k that was your problem,lol

Just to add my speedfight runs 75mph with a stock crank and a mhr replica cylinder with no porting done,just basic clean-up.Verfied with gps and my KOSO guages,what bike do you have again?Its not a triton,triton have alum wheels,not stamped steel.
Production changes all the time,you might have gotton different rear gears than mine,mine was tall anddidnt have enought power to pull it all the way

If you cant get 70 mph out of a full mhr set-up you need to start working on 4 strokes Rolling Eyes

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JCmotorsports
Posted: Thu Oct 16, 2008 9:34 pm Reply with quote
Joined: 25 Jun 2008 Posts: 109 Location: Connersville,in
I want to add kymcos are a good engine,just hardly any aftermarket for them and the power to cost ratio is too high for me.
My favorite is min h for ease of parts but for power it would be a piaggio all the way.

Sorry to be so stearn with you wireburn,your calling me out and i dont like being called a liar,expecally when it was my bike,I DID THE WORK ON!

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scootertrog
Posted: Thu Oct 16, 2008 9:52 pm Reply with quote
Joined: 12 Jul 2007 Posts: 1501 Location: SW Missouri
I'm not sure this subject thread is going anywhere - and I think I alluded to that in my first post that this might be the result. Sad

scootertrog
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wireburn
Posted: Fri Oct 17, 2008 5:43 am Reply with quote
Joined: 07 Jan 2008 Posts: 626 Location: Muskegon, MI USA
I don't know where you got that I have stamped steel wheels. It's a Triton through and through. I have worked on several and it's the same bike.

There's nothing wrong with the performance of my bike. You're just full of all kinds of strange guesses, aren't you?

I agree, this isn't going anywhere, and neither is your 70mph build.

-Mike

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