Which way to go-Big bore or shifter conversion

[thedeatons]

K guys and gals... It's that time to look seriously into what to do here. My daughter needs more power for the big dunes. She currently has an 07 DRR DRX2 with a No-Toil air filter right off the carb, clutch mods (spring/rollers)/kevlar belt with premix and perfect jetting for the altitude we ride at.

Her problem is that she is literally in tears that she can't ride up the bigger dunes. The poor 70 just buries the rear wheels on the bigger climbs. Granted, we were all shocked how well it did, but now she has gotten used to it, and needs more. We strictly ride dunes, my kids hate dirt...

I had originally talked about upgrading her to a Blaster hybrid, but now just want to mod the DRR. The DRR is already working great for her size-wise and suspension-wise. She doesn't jump at all, just likes to ride fast, do donuts, and be the leader.

My options now seem to be a 65cc or 80cc shifter conversion, or a big bore kit for the 70 that is in it now.

My question is about how much power is she running now, and what can I expect from a big bore? Which brand should I choose? I rebuild 4-strokes, so I assume building this 2 stroke engine is going to be a breeze... Advice? Thoughts? Cost comparitives? I have tried contacting Brad Loomis about a shifter conversion and am awaiting an answer. Not sure which way to go, but I don't want to break the bank...... HELP!

[thedeatons]

Okay, I just read an older post saying the stock 70 has 4.5hp and the stock 90 has 5.5hp.... A stock Kawasaki KX65 engine has ~13-16hp, and has a real tranny....

Does this make the decision obvious?

[mecheech]

Les at Extreme minis has a 65 shifter that he built and could probably help U out with deciding.

[jread14]

There are ways to get a ton more out of your 70 without spending a small fortune. You basically have a stock bike, and with a simple pipe and some porting your numbers can jump in a hurry. You can also take a look at the scooter version of the metrakit and the polini setup and throw a pipe on it and it will be a totally different bike as well. The graph below I believe is a stock bike with porting and pipe.

[QuadJunkies]

A stock 90 might only be what you quoted,but we are getting 15 HP on Brandons with a legal bore.

You could get a built 90 motor, or make a project shifter out of it. I know theres a few members on here that have done that and there would actually be less motor maintence with a shifter vs. the CVT.

That young lady didnt seem to mind dirt when she flat track raced it !!
:D

[thedeatons]

LOL.... Yeah, she did like flat tracking and has been asking about it again. She usually doesn't take to the hard rough dirt and rocks of trail riding....

Yeah, still torn though. KX65 motors are REALLY cheap, and I fear they may be cheaper than turning this 70 into a 90. Plus they make an 82cc Athena kit for them if we were to get bored with the 65 power, and that's not even counting porting!!

The CVTs really suck the power out of these engines.....

[QuadJunkies]

Originally posted by thedeatons
LOL.... Yeah, she did like flat tracking and has been asking about it again. She usually doesn't take to the hard rough dirt and rocks of trail riding....

Yeah, still torn though. KX65 motors are REALLY cheap, and I fear they may be cheaper than turning this 70 into a 90. Plus they make an 82cc Athena kit for them if we were to get bored with the 65 power, and that's not even counting porting!!

The CVTs really suck the power out of these engines.....

I dont think it wold cost less, to build a KX,just remember you will have some chassis work,welds and might have to flip the swingarm... you will want to do various upgrades including a dif radiator and might have to flip the swingarm, get CDI,stator, coil ect...
it all adds up.
:p

The shifters are a cool project though. Im sad in alot of ways that we sold Kelseys,but in some ways excited to see her grow with her new quad.

Sand riding in general sucks the power out of all quads. lol
I sure miss duning :(
We seen you this summer traveling to the dunes. We waved at ya but I think you didint know who it was. :p
If you need anything, give us a buzz.

[yfz450bb07]

I would just buy a 90 motor and put it in it and then when you want more upgrade to a 108-110. But if you haven't put a pipe, reeds and reed cage, bigger carb, and a port job your selling yourself short on thinking you need a different motor for more power. You have to build it to the max first then move to bigger bore.

[BradLoomis]

Originally posted by mecheech
Les at Extreme minis has a 65 shifter that he built and could probably help U out with deciding.

I built this quad for Cody and the CR85 that I just built for Ozzy.
The 65 is an easier fit and Cody has really punished this bike on the track and off with no failures. Ozzy hasen't had a chance to ride his yet, and I am concerned about the horsepower difference between the two. I am hoping that it holds together like all of my mini frames do, but this will be a real test.

I agree with yfz450bb07 that a 108 - 110 CVT will bolt right in and with a good pipe will easily be twice the motor you have right now with the same weight, no modifications to the chassis, that you have right now.

[thedeatons]

So what are we looking at for costs.... There is a KX65 engine on Ebay right now with an 82cc Athena kit for $650, buy it now, which is cheap enough. I understand there are other things to buy, but using that initial figure I cannot see the engine/electronics/carb costs being over $900, plus she would have a shifter....

I don't want to get trapped with a strung out, overbored DRR engine that eats belts all day...

Costs for a big, fat DRR engine would include an aftermarket pipe, crank, piston/cylinder, carb......

[QuadJunkies]

Originally posted by thedeatons
So what are we looking at for costs.... There is a KX65 engine on Ebay right now with an 82cc Athena kit for $650, buy it now, which is cheap enough. I understand there are other things to buy, but using that initial figure I cannot see the engine/electronics/carb costs being over $900, plus she would have a shifter....

I don't want to get trapped with a strung out, overbored DRR engine that eats belts all day...

Costs for a big, fat DRR engine would include an aftermarket pipe, crank, piston/cylinder, carb......
Sounds like you have your mind made up already. :)

How old is she now?

[BradLoomis]

James, your PM is answered

[thedeatons]

She is nearing 7 years old....

Thanks for the PM Brad. I wish I had a completed product laying around to stare at for hours and decide.

Oh, and I wish one of the big four would get off of their liberal minded butts and start throwing down some awesome kid's quads like the great kid bikes they build.... sigh

[yfz450bb07]

I've got a built 70 that my older boy rode and we have never once ate a belt. We had built 90's and a 108 that never went thru the belts, and yes we rode in the dunes. The biggest thing that you have to remember is to run the crosstube like the predators have that keeps air running into the side case to keep it cool. You should only shread a belt from heat and that should solve the problem.

Just remember to ask your daughter if she is ready to shift yet? Cause sometimes we think that they are and really they are not and they get frustrated with it and choose not to ride as much. And trust me I'm speaking with experience on that!!

[QuadJunkies]

Agreed on the belts!! ^^^

WE experienced that last year and part of the beginning of the racing season,but once we figured out how to keep things cool the belts have held up really nicely.

[TTracer#22]

I have an air cooled 48mm Stroke 54mm Bore Motor in my sons play bike and he goes to the top of comp hill at Dumont dunes with very little problem rides the dunes all day long and have never had any belt problems. Keep the clutch cool and aligned properly you will have no problems.

JMO

[thedeatons]

Can you guys enlighten me as to the costs of some of these built DRR engines? I usually do all this stuff myself, and have no idea where to go for builders & aftermarket parts.

The last thing I would want to do is buy a bunch of brand names and try and get them to work together in harmony.

Does anyone have a system you can with all parts that are tuned for each other?

[bulldogfallon]

I think your best bet is to go with a 90cc engine....If your 70 is modded it will still require a smaller cc to be pushed harder and require higher performing parts to get the results you are looking for.

We put out a simple 90cc package...

A stock 90 cylinder that is ported by Grissom and and a hit clutch added...

This set up uses the stock pipe and carb and really dollar for dollar is very hard to beat....

It also uses stock internal components and makes usable power...you don't have to rev to the moon to make the power needed.

This set up has done very well in local series all around the country.

It is a simple bolt on proven pkg that you can depend on.

[thedeatons]

Can you give me power comparisons between my 70 (stock pipe, jetted, with open air filter mounted to the carb), and your 90 kit?

Price?

Are you saying I can use MY pipe and carb? I have the OKO carb, can't remember what size though....