Happy New Year Forum!

I purchased a pipe from Chris at Miniquad Racing for my son's xmas present. Its now installed on a Yerfdog 90, but did not have a chance to install the clutch springs. But both to my son's and I dissappointment, it is actually running much, much slower and seems to be bogging down when reaching high RPM's. I tried installing an electrical unit supplied with the pipe too but no difference. I've tried to adjust the only screw I can find on the carb which is only effecting the idle speed and seemed to find a setting which helped it a tiny bit but no where near from stock pipe. I took out the air filter and cleaned it, but still same results. Im going to Glamis next weekend for the first time and any quick fixes would really help. I will go back to the stock pipe before the ride.

Finally what concerns me is that Chris at MiniQuad Racing said I did not need to do anything to the carbs since my son only wanted to get a better sound. I have had no luch trying to reach him.

 

If the pipe increased power, I'd think it's pancaking the rear torque spring too soon..

errr..if this machine has a CVT tranny anyways. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Im not too sure if the new pipe increased HP, but I've put in a new spark plug, air filter, and fuel filter, but still same results. I took off new pipe and noticed quite a bit of black oil in the pipe. No time to worry too much since riding this weekend, but after putting on old pipe, wow my son's quad is screaming once agian. He likes the speed but really wants it to sound better. Other suggestions would be helpful. Thanks

 

OK, First off Chris should tell you how to set you rmachine up. I am not sure with Pipe he sells now so I will make some general rules for you.
1. Change your jetting. I guarantee the jetting needs to be way, way bigger.
2. Little the roller weights in the variator.
3. Change the torque driver spring to a heavier spring. 1500 to 200 rpm spring.
4. Change the clutch engage springs to 200 rpm or more.

You can't just put a pipe on and it run. Sorry, It requires alot more work than that.

 

Tommy is right. Reason it's bogging is the jetting. Once that's right, you'll go about 15-20 feet and it'll take off (assuming it's a decent pipe). That lag is your clutching.

Be sure you have the pipe sealed good. If it didn't come with a gasket, get some high-temp sealant.

 

as stated above you have to install a clutch and variter kit to get the benifits out of a high performance. what pipe is it, does it have an expansion chamber ?

Mark

 

TREXTommy51

Im very dissappointed with Chris at miniquad racing. I advised him what exactly I was trying to achieve and he informed me that I did not need jetting. Against everthing I read in this forum, I was hesitant to do business with him but needed a pipe for Xmas. Since then I've had no luck reaching them. I knew deep down I should have went with Billy at WRH.

Anyways Im was now wondering if simply going to a new larger carb will do the trick. I am not the at all a mechanic but I do know some basics. The pipe was custom built with an expansion chamber and did include a CDI and new clutch springs. It sounds that your kids race 90cc quad and I was going to setlle with another 90 like a viper or even a alpha sport cobra. (I have both for my other boys and the cobra is way faster than the viper) My son's Yerfdog is either going to be scrapped for junk if I cant get it going faster. Your help is greatly appreciated!

 

Mark,

The pipe I got was from miniquad racing and it does have an expansion chamber. Looks like that last few posts have had work done by Billy at WRH racing. Please read my latest post to Tommy51 and it should give you an idea. My son really would like a screaming 90 but for sand riding at glamis. By the way there are no youth racing companies here in Southern California where I can take my quads to get done for performance. Any input you have to just get quicker 90's will be very helpful.

Thanks

Joey

 

Hey I feel for you, I went through the same thing with Chris. He seems to be very busy. I was new to mini racing and I bought most of my stuff from him and I can't help but feel ripped off. The throttle cable I bought was about three feet to long the air filter is junk the lower mount on the plus 3" swingarm snapped off causing the shock to get wedged in the swingarm and destroyed the Afco shock which I had to pay to have it rebuilt.They said that they had never seen a shock in that bad of shape.My son had only rode on it for ten minutes before the mount broke. Oh ya it took Chris around four months to get the shocks to me in the first place. So to say I'm a little bit dissapointed is an understatement.

 

Even with a larger carb, you'll still have to rejet. Can't get around that. BUT it is easier to tune a 20mm Keihen. I can vouch for that much. Billy Holt's always had prompt service and bent over backwards to help me. And those parts and advice have made my mini haul some serious a$$. Can't say enough good things about the guy.