No holeshot

[redonkulousruntsracing]

Hey guys, I thought I could try again to pick some brains.
After yesterday, I can't take watching my boy not get a good holeshot any more. He practices all the time and is exceptional on the gate and with feathering the throttle. His technique is right on. But when the gate drops and he pins it, I watch his back tires just slowly start to roll then 10-15 feet out they really start turning. He is right there on the gas, and so is the motor, but the quad will just not repond. If he is rolling I mean just barely moving and he whacks it, it breaks right loose, but from a dead stop, he gets beat every time. He came off the track almost in tears cuz he got a bad start and couldn't make it up in 3 laps to catch the top 2 kids (he was gaining on them but over driving the track) also on 50's that just left him sitting at the line. He is tired of him arch-nemisis smoking him off the line.

This is his 09 Apex 50: 19mm Kehin carb, 108 main jet, 48 pilot.
3g rollers, Malossi red torque
spring
2000rpm KOSO shoe springs
stock 780 belt
Stock front slipper sprocket
torqued to 110ft.lbs (marks havent moved)
32 tooth rear
The quad runs just about perfect, on track it seems to be shifting in and out where it needs to, the motor is topping out where it needs to. It doesn't seem to bog down anywhere. Everything seems good except for his off the line performance. Every time I clean the clutches everything looks good in there, the varitor is running up to 3/16th of an inch to the top. I still have the 1mm shim in between the halves. I'm out of ideas. I have been trying to keep it ATVA legal, but after going thru tech at a National event, and having just my number plate being checked, I'm not caring much about that now. I know a 50 can rocket off the line cuz I have seen it happen. I want my son to be able to whack the throttle and dig holes do China or flip his quad over, dammit!!!:devil:

[EthansDad]

>>I have been trying to keep it ATVA legal, but after going thru tech at a National event, and having just my number plate being checked, I'm not caring much about that now.

--I'll remember that if I see you show up at a national :D

Your clutching seems good for your setup. have you measured your stall rpm, or the point at which it starts moving? should be around 6000 rpms with those clutch shoe springs, might want to make sure that is what you are getting. might also want to increase your final gearing from a 32T to a 34T to see if it helps the motor get into the sweet spot sooner. with that much belt travel, I doubt you will lose much on the top speed.

-EA

[neveready]

Is this the same jetting you were running in the cooler weather? You may need to make an adjustment to the needle? How old is that torsion spring? When we set-up with that spring it gets changed EVERY race! It could be letting the belt drop before the bike starts rolling at the gate, but would appear to be shifting properly on the track. 2000rpm shoe springs are usually too high for that torsion spring as well, I am willing to bet it doesn't take off with the belt up top of the rear pulley.

Just a few things to check out, keep us posted.

Originally posted by sickairseth
Hey guys, I thought I could try again to pick some brains.
After yesterday, I can't take watching my boy not get a good holeshot any more. He practices all the time and is exceptional on the gate and with feathering the throttle. His technique is right on. But when the gate drops and he pins it, I watch his back tires just slowly start to roll then 10-15 feet out they really start turning. He is right there on the gas, and so is the motor, but the quad will just not repond. If he is rolling I mean just barely moving and he whacks it, it breaks right loose, but from a dead stop, he gets beat every time. He came off the track almost in tears cuz he got a bad start and couldn't make it up in 3 laps to catch the top 2 kids (he was gaining on them but over driving the track) also on 50's that just left him sitting at the line. He is tired of him arch-nemisis smoking him off the line.

This is his 09 Apex 50: 19mm Kehin carb, 108 main jet, 48 pilot.
3g rollers, Malossi red torque
spring
2000rpm KOSO shoe springs
stock 780 belt
Stock front slipper sprocket
torqued to 110ft.lbs (marks havent moved)
32 tooth rear
The quad runs just about perfect, on track it seems to be shifting in and out where it needs to, the motor is topping out where it needs to. It doesn't seem to bog down anywhere. Everything seems good except for his off the line performance. Every time I clean the clutches everything looks good in there, the varitor is running up to 3/16th of an inch to the top. I still have the 1mm shim in between the halves. I'm out of ideas. I have been trying to keep it ATVA legal, but after going thru tech at a National event, and having just my number plate being checked, I'm not caring much about that now. I know a 50 can rocket off the line cuz I have seen it happen. I want my son to be able to whack the throttle and dig holes do China or flip his quad over, dammit!!!:devil:

OK your problem is get rid of that junk spring the Malossi only last for about 20 minutes so if you ran it longer than that get rid of it. Also get a 787 16 30 belt as the 780 wont let you reach the top. I had the same problem then went with the ZTR 1500 and still never had a problem. IMO the red malossi should be used for the trash can only!! Please change the rear torsion spring and let us know because that is your problem call James at ZTR and get a real spring and leave the junk for the junk.

[redonkulousruntsracing]

TG, I guess ya dont like the Malossi spings huh?? I have thought of going to a ZTR, but was advised that the 50 might not have the power for it, but maybe? The 787 belt is longer right? Does That help on low end?

The spring is about 5 races old. The only reason I didn't think it was the problem is that when it comes to uphill climbs, it seems to backshift fine and the rpm are right there, he actually bounces on the seat to try and get traction. But even when it was brand new I had the same problem.

I dont know what rpm it's kicking in at, but I do know it's pretty high. Higher that a couple of other 50's I know of. I have been thinking about rigging some sort of tach up so I can see things like this.

The jetting seems to be good, the temp has been roughly 60-75 for each race.

Honestly thinking about putting a 35 tooth rear sprocket on it, The tracks around here have alot of turns and hills, not too places where he get to really wind it out.

Maybe the longer belt and a bigger rear sprocket will work. There is still 3/16 - 1/4" left of the marks on the variator. Dumb question, do I just put the belt on or do I have to change shims around??

Heres your quote : I have thought of going to a ZTR, but was advised that the 50 might not have the power for it,

Ok James at ZTR also sell 1000 torque spring so if the 1500 is to big try this one. I promise you will like it. Its the only way to go in the rear torque spring. Its the best spring period IMO. Your shims are probally in the middle of the variator if you are good on the front and its a 780 16.5 28 you need to go to a smaller shim or take it out to compensate for you intial take off.The belt should be at the top of rear clutch and all the way against the sleeve in the variator. Also you may need to do a little work to the rear clutch maybe?? Serious call James and get a 1000 or 1500 no bigger than 1500 tho. Let me know.

[nordic quad]

Mr Cheeseman is right on the money here.The ZTR 1000 spring is the closest to your red Mallosi spring,but still a little stiffer,another option for your 50 may be the blue Hebo spring but i still think the ZTR springs are better!.Before changing any sprockets i wold follow Cheesemans advice and take out the shim in the front vario.You may also try the Malossi 6112742 belt.As Cheeseman says you want the belt to be at the top of the rear pulley.Here is the set up on our slightly modded 70.

Yamasida front variator with Dr Pulley 3g sliders and no shim.

Stock clutch with Koso 1500 rpm springs

ZTR 2000 torque spring

Malossi 6112742 kevlar belt.

[redonkulousruntsracing]

Man, I wish I still had some of my dad's machinists tools. He had a valve spring tester for diesel engines that read in lbs of force. I would love to actually see what the values are of the torsion springs that we all buy. That way I would know what I actually was getting and what I DO have in my box of junk in the garage. Is it really that hard to list a specification on products, or maybe they dont translate to our language?

A white Koso is softer than a yellow Malossi which is softer than a ZTR 1000 but that is stronger than a red Malossi which is weaker than the Howyadoin' Special and about the same as the GotchYoMoneyNowSucka1500....:blah: :blah: :blah:

[nordic quad]

Well give Gary at G-force a call i think they sell all above mentiond springs exept the GotchyoMoneyNowSucka1500,he shold be able to steer you in the right direcktion on the right springs for a 50cc.:D

[ZTR_MAN]

Originally posted by sickairseth
A white Koso is softer than a yellow Malossi which is softer than a ZTR 1000 but that is stronger than a red Malossi which is weaker than the Howyadoin' Special and about the same as the GotchYoMoneyNowSucka1500....:blah: :blah: :blah:

Now that's funny!!! :D

[nordic quad]

Yeah thats funny alright:D .How is Tanner doing James,last time you posted it seamed like he was doing a lot better.I can also report back that after adjusting our ctvs with the ZTR springs Sondre has taken every hole shot and every moto so far this race season:D So thank you for your suport.

[ZTR_MAN]

Originally posted by nordic quad
Yeah thats funny alright:D .How is Tanner doing James,last time you posted it seamed like he was doing a lot better.I can also report back that after adjusting our ctvs with the ZTR springs Sondre has taken every hole shot and every moto so far this race season:D So thank you for your suport.

Glad to hear it. I will post about Tanner in the original thread, thanks for asking.

Here is the strength of the ZTR springs:

1000-27.5 lb/in
1500-33.5 lb/in
2000-40.1 lb/in

So if the 1000 spring is compressed 3 in the force is 3 in * 27.5 lb/in = 82.5 lb.

Hope that helps.

[redonkulousruntsracing]

Well I finally got it, after months of messing around. Neveready had it pegged. I bought an old cover and slightly modified it (see pic)so I can see what is happening in there, and sure enough, the belt was moving down ito the rear pulley almost an inch before the shoes would engage. I put Koso 1500 shoe springs in and Voila, she rips now. It comes in perfectly now. Last race was at Royal Mountain and they have a concrete starting gate, it spun the tires leaving the line!! I lowered the air pressure down to 2psi and he took off like a rocket!! We are both very happy now, it really digs, now all I need to do is add some weights on the rear grab bar, kinda like a tractor pull setup so he will really hook, lol. China here we come!!

[redonkulousruntsracing]

There was some confusion I think between the torque spring and the shoe springs on my end or whatever. 3 - $2.50 springs was what was making his quad take off like a lead turd. Learn and Live, now I know, after I threw that cover on, it was like DUUUHHHH, there's my problem dumb-a#s. Oh well, it's all good, now, I just wish I would have done that a dozen or so races ago.:blah:

[raptorobbie]

that's a great idea to see exactly whats happening!!! you could probably sell those covers! lol

[vindell]

GotchyoMoneyNowSucka1500 . LOL . clutch still a issue, keep up the great advise. Learning alot !! Vindell