70cc quad racing

[70cc quad racer]

Well, the motor is running good from mid range and up. I think after I get the Keihin PWK 28 and inner rotor kit I will see how much better I can make it run.

A few more questions

What would be a baseline jetting to start at.
What spark plug should I have (currently have BR8HSA)
What octane gas should I use

Thanks,
Darrell

 

[Sandor]

men, are those elka shocks?

Your son most be good to be worth a set of elka shocks :winner:

 

[Big B NRG]

Well, the motor is running good from mid range and up. I think after I get the Keihin PWK 28 and inner rotor kit I will see how much better I can make it run.

A few more questions

What would be a baseline jetting to start at.
What spark plug should I have (currently have BR8HSA)
What octane gas should I use

Thanks,
Darrell

That 8 sparkplug is too hot! Get atleast a 9 heatrange.
Baseline jetting for PWK 28 is 145 MJ/50 PJ. Should be a good start.
Use atleast 98 Octane.

 

[FUracing8]

if you want a really long lasting durable 70cc racing crank, then there is no way you can go wrong with spending the money and getting a malossi team crank, trust me on this, I spent alot of money on metrakit and polini and hebo cranks to find that 1 good investment saved me alot more money than going cheap the first few times. Besides, the crank is the most important part of the motor when you think about it, why skimp if you want the build to be reliable?

 

[Big B NRG]

And what exactly makes that Team crank so good. I heard completly different storries...

Polini/Metrakit/Hebo all makes good cranks.

 

[70cc quad 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

Which 80lc are you referring to? My daughter races in the 90 class with the 90cc case. I am thinking about getting a 50cc case and doing a 80 or 86 kit. That would be nice to get a "perfect blend of torque and HP"

 

[50cczip racer]

its one of my own 80 or 86 conversions i do and your 90 cases are fine for the job u dont need a 50 case ,this conversion makes 4bhp more than a cobra ecx 70 quad and beats the big bore converted 90 class ecx cobra

 

[70cc quad racer]

I know that this is my old post but....The race season came to an end and we ran the 70cc a/c EVO with no problems. My question after I go through my last EVO piston I will be converting to L/C. I really want the Malossi Team 7t. I have a Polini 12 pin crank. Can I use this crank or do I need another one.

Thanks

 

[Big B NRG]

On mina you don't need a different crank.

But your engine needs to be milled. Because of the thick cylinderskirt.

 

[tiba_karotsu]

I know that this is my old post but....The race season came to an end and we ran the 70cc a/c EVO with no problems. My question after I go through my last EVO piston I will be converting to L/C. I really want the Malossi Team 7t. I have a Polini 12 pin crank. Can I use this crank or do I need another one.

Thanks

Polini crankshaft is fine, you can still use it, you are sacrificing too much perfromance going with AC, you should have gone with an LC engine setup in the first place & avoided buying another kit.

as anybody here have said the best 70cc LC kit in the market is the Malossi MHR Team 7T, hands down, no contest. build a C21 copy exhaust trhat will fit your quad & get ready to rip your competition to shreds.

what intake manifold are you using with the PWK28? i hope it isn't the shiny CT manifolds that are made in taiwan, it ddoesn't have anough cross sectional area to accomodate a 28mm carb, you're just effectively choking the carb that way.

 

[70cc quad racer]

Polini crankshaft is fine, you can still use it, you are sacrificing too much perfromance going with AC, you should have gone with an LC engine setup in the first place & avoided buying another kit.

as anybody here have said the best 70cc LC kit in the market is the Malossi MHR Team 7T, hands down, no contest. build a C21 copy exhaust trhat will fit your quad & get ready to rip your competition to shreds.

what intake manifold are you using with the PWK28? i hope it isn't the shiny CT manifolds that are made in taiwan, it ddoesn't have anough cross sectional area to accomodate a 28mm carb, you're just effectively choking the carb that way.

Tiba,

Yes, I know I should have done it the first time, but after the suspension upgrades I could not fork out $1,300 for the LC conversion and 7t cylinder. Im not sure which intake it is, it's the one that came stock.

As far as the PWK 28 is concerned. I could not get it jetted right so I switched to a Keihin PE24 which has worked great so far. (I still have the 28 though)

Which company is the easiest to deal with in trying to avoid the VAT overseas. When I bought the Malossi inner rotor they charged me for it. Is there anybody on this site that wants to sell the Malossi 7t.

Thanks

 

[Big B NRG]

Look at the Marktplaats section on this forum. It has enough for sale. Otherwise I can help you out.

 

[tiba_karotsu]

Tiba,

Yes, I know I should have done it the first time, but after the suspension upgrades I could not fork out $1,300 for the LC conversion and 7t cylinder. Im not sure which intake it is, it's the one that came stock.

As far as the PWK 28 is concerned. I could not get it jetted right so I switched to a Keihin PE24 which has worked great so far. (I still have the 28 though)

Which company is the easiest to deal with in trying to avoid the VAT overseas. When I bought the Malossi inner rotor they charged me for it. Is there anybody on this site that wants to sell the Malossi 7t.

Thanks

have you tried alvertano.com (malossi dealer in florida) & roselle imports? (malossi importer & distributor in the usa)

as for the intake i think the stock manifolds are too small, if you can port the manifold to the same cross section as the carb it would definitely improve power.

as for carb tuning what problem is it exactly are you experiencing with the PWK28? i have them both on my 70cc 6T Speed & 2Fast 80cc engines, i know PWK28 tuning.

 

[70cc quad racer]

as for carb tuning what problem is it exactly are you experiencing with the PWK28? i have them both on my 70cc 6T Speed & 2Fast 80cc engines, i know PWK28 tuning.

Tiba,

There was a bog on the bottom end that I couldnt get rid of. If he stabbed the throttle it would hesitate or die. The 24 does not have that problem. Maybe it's just me but I could not get it to work.

 

[tiba_karotsu]

Tiba,

There was a bog on the bottom end that I couldnt get rid of. If he stabbed the throttle it would hesitate or die. The 24 does not have that problem. Maybe it's just me but I could not get it to work.

i se, it's sudden lean condition due to the very quick opening of the slide, what needle are you using? what's the diameter? on my dragscooters the JJH needle worked the best, my rider would pin the throttle full at take off with no hesitation or bog whatsoever.

what pilot jet size are you running btw?

 

[DRXRACING]

If you have set the air screw accordingly and has the correct pilot. (42 or 45), and the needle is a JJH then you either needed to richen the needle one clip. Or lighten 3 rollers 1/2 gram each. Possibly both.
What Tiba said.

 

[CRP]

We have been using 24 flatslide mikuni carbs converted with Dial-A-Jets for all our in-house build 90 and 100 cc race auto quads. We have always had beter results than the tuners using 28's. We have found that the variable drive and clutch sustem still puts the engine under extreme load under offroad conditions, especially jumping. This is very different to a race scooter. We have solved many of the heat siezes and holed pistons with the Dial-A-Jet set up. Anyone who has developed auto race quads will know how important getting away with high compression is and also how often you get a crank case full of alluminium and a hole in the piston. Load is definately a problem with these machines. We use the same set-up on the enduro auto quads that have to run for 1hour non-stop and have very few problems.

 

[70cc quad racer]

I have seen that these jog type motors come in short cases and long cases. My question is what case does my quad engine have short or long. Sorry for the dumb question but I could not find the answer.

 

[tiba_karotsu]

I have seen that these jog type motors come in short cases and long cases. My question is what case does my quad engine have short or long. Sorry for the dumb question but I could not find the answer.

most likely it's a short case, care to post a pic of it?

 

[70cc quad racer]

It's on the red one a few posts up in this thread. I will post another pic if necessary.