Where to start?

[Rayzer]

We have an 08 70cc liquid cooled stock motor and clutch. I am wanting to get some more performance out of it for next year but I am not made of money. After port, polishing, and clutch what are my options (best for the money) PVL, Pipe, crank?

[kenjolly]

try a stock 90 pipe it will be better than the 70 pipe and if thats not enough then try some of the others. You can lighten the fly wheels, Gary has some done already. i would do a crank before the pvl but those 2 will be the most money.

[Andyman17dad]

Suspension/shocks!!!

[Rayzer]

Already have the Long travel A arms and +2 rear swingarm with Elka's. That is what made him progress as fast as he has this year but he is maxing out on the motor now.

[bulldogfallon]

PVL is over rated at times....

A nice pipe that actually works would be a good choice after minor motor mods and the clutch upgrade.

We are testing a pipe on our 70 (same set up as your potential changes) with good results.

Pipe selection is critical....don't buy a name...buy a pipe that works from someone with first hand knowledge of the pipe working on a set up like yours.

We have a few more tests with this pipe to see what else it will work on...MK etc...

[Logan #34's Dad]

Do yourself a favor and save on the headaches. Break down and buy the Metrakit cylinder and Metrakit pro-pipe. You can get away with the cylinder only with a 90cc pipe until you can afford the overpriced pipe. (but it works).
My ported MK cylinder (along with everyone else) got smoked to turn one at ATVA Nationals in Virginia buy a stock MK with ported cases and the pro-pipe in both motos. And we won moto one!
You will have to have the cases "gasket matched" or do it your self with a dremel. Relativley easy to do. Set your squish and bolt it on. I also believe that the high dollar cranks are over-rated. Your stocker will be fine. And an unlimited ignition will be fine to. IMHO

[Nichols Atvs]

Im with you Rocky. We have been running a stock metrakit all year long with the pro pipe and our 70 flys . Minor set back with crank seals but hes first in points at our local track in two classes running against 9 and 10 year olds on 90s and 105s. Last couple of races hes been 1/2 a lap ahead of the others and hes 7 years old .
GO MK

[bulldogfallon]

MK is hard to come by right now, but we are working on it. Our experince with the MK stuff has all been very very positive though.

The Polini kits have also been very popular with good results.


With the lack of MK kits/pipes you may have to look at other options if you are under a time restriction.


Even an OEM cylinder ported and matched with the right pipe will make good motocross power....


RPMs don't always mean the fastest MX bike...you have to be able to use them to see the benefit

Build the bike for your rider.....not the opposite.

[kenjolly]

I have a MK motor and it is very fast , but very expensive.Gary is building Hayden a 70cc motor that should be very close to the mk and not as much money using parts gary can get anytime. we should be testing this motor in a week or so, i will let you know what Hayden thinks. It will be a different power more low and mid which is were he rides more than the top end.

[Logan #34's Dad]

Hey Ken, If it is not to late - do some 100 - 125ft runs and time them THEN when you get the new motor do the same and compare the results. Apples to Apples.

[ukguy]

just my experience in leading 3 out of 4 national champs at the moment, all the metrakit stuff including the bikes they have sent us have been pooh, we had their race winning bike last year to try and it was not to good, have they made significant progress ?? we have worked with the metrakit technicians and indeed even had to set their bikes up for them, there are better and cheaper options than the metrakit, dont go wasting big money on pvl full circle this and that, a very good cylinder that we sell in the uk, in standard form destroys the apex etc etc, buy a cylinder with a good boost port configuration, but with port timings low enough to give you the torque required, yes you can match the cylinder to the barral to increase the flow slightly, also look for a good manifold to increase the speed of the gases, a lot can also be gained from a good transmission set up see your PM, just my thoughts but no doubt not everyones:D

[kenjolly]

i will be doing that and even better, i have both quads and will be able to run them side by side. and if Gary wants to try his new toy out will will have some great data. but it all comes down to your rider and what they like and are comfortable with.
as far as the MK it has allways been strong and very reliable,bolt on power but a little pricey but worth it.

now if you want to send me a cylinder i would be glad to compare it to both of ours, UKguy.

[Rayzer]

Thanks for the input. There is still alot to consider. I don't plan on tearing it down until after the last race at our local track in October. But I would like to get it back together and dialed in for a couple of district 13 races before the end of the year. I am leaning toward the head work, new stock crank, bearings, seals, carb, trans brash bushing, and a pipe. I will take any suggestions you have, especially on pipes.

[kenjolly]

call Gary he has a much better tranny fix than the bushing. I think the thread got away from what you wanted,pick out what will help anf throw the rest away.
good luck keep us posted.

[Rayzer]

What is he doing for the trans fix, double roller bearings? I will take everything into consideration. I am not looking to set him out front. I would much rather have him take a slower quad and make it fast by learning how to get everything out of it. I just want to get enough under him to keep him excited and competitive for now. After all if he is having fun thats what it is all about.

[kenjolly]

Yes, save some money on gears and do the tranny first, you have to finish the race.
trust me been there broke that replaced broke again replaced etc etc etc.

[JIM GRACE]

the mk pipe and cylinder rip's. it is very loud, you can hear it
across the track. and the muffler get's routed in the center like an
ltr-450r.

brandon's dad #55

[ukguy]

dirtrider pm box full

[hotquads1]

Originally posted by Rayzer
Thanks for the input. There is still alot to consider. I don't plan on tearing it down until after the last race at our local track in October. But I would like to get it back together and dialed in for a couple of district 13 races before the end of the year. I am leaning toward the head work, new stock crank, bearings, seals, carb, trans brash bushing, and a pipe. I will take any suggestions you have, especially on pipes.
.
.If you intend to change crank either way, then condsider upgrading to a quality replacement for long life and future mods, at this point the cost difference is minimal. a pipe and cyl kit combo is most performance for the dollar, and the MK is a very good choice very broad power range and lots of torque. also the Polini evo 1 is good for quad mx the evo 2 has to turn a few more rpm's not quiet as quad friendly, and well ported stock cyl can perform well but it will cost as much as a name brand aluminum race cyl kit , reguardless of your choice for power 'CLUTCHING IS KING" the cvt must be dialed in to get good results. good luck.
marc

[Rayzer]

Thanks to everyone for your input it is greatly appreciated. As far as clutches go I had planned on the Hit clutch by Dr pully. Will I need to order a second bell with that or is that clutch easy on the bell if set up correctly?

[Rayzer]

What is the expected time frame on getting the MK head kit and pipes in?

[hotquads1]

Dr pulley clutch comes complete with new bell. a couple of days for cyl kit and pipe.
marc