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Discussion Starter #1
Decided to get into mini moto with my 8 year old since he's been begging to ride. I got a grom and I am getting smoked by crf100's on the straights my first trackday out. Had the bike completely stock. Now I've got rear sets so the pegs will stop dragging, trying to find new tires, got some gafler brake pads and lowered 1 tooth in the front to 14.

Does an intake and exhaust and ecu make that much of a difference? My biggest problem was corner speed mid corner and out of the corners and at the end of long straights. I couldn't go fast enough in the corners cuz the stock tires would slip and if i did manage to get some grip in a corner the pegs would scrape nearly wrecking me all day.

I'm hoping with the tires and gear change and rear sets I'll eliminate those issues but wondering if I need to do the an intake exhaust ecu upgrade to keep up with the crf100's? I'm used to racing big bikes and having too little power has not been the issue so this is a little new to me.
 

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The bolt-on's make a difference, but they probably won't be enough if you're getting "smoked". You probably need more aggressive gearing than just -1 in the front. I would play with rear sprocket size. The stock cylinder head is what really chokes the motor up. There's guys who are seeing really good gains from porting work.
 

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intake and exhaust and ecu make that much of a difference?
it does a lot of difference but not enough for pushing you out of a corner as you would it be...


+ if youre 190 cm x 100 kgs does not help
 

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talk with other Grommers (the fast guys) of what sprocket combo's being used, and tire pressure.

As for tires, see your other thread ;)
common sprockets to use would be 14/36 14/38 and if you have more rpm then you can do 13/39 for most go kart tracks without long straights. This gearing would put you down right around 60 mph top speed. Tire pressure changes depending on the tires you are running.
 

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Discussion Starter #9
The bolt-on's make a difference, but they probably won't be enough if you're getting "smoked". You probably need more aggressive gearing than just -1 in the front. I would play with rear sprocket size. The stock cylinder head is what really chokes the motor up. There's guys who are seeing really good gains from porting work.
Starting with the beginning of the corner I would lose speed as soon as I started to turn in due to lack of confidence in the tires. It was 55 degrees and I was on stock tires. Mid corner I couldn't accelerate because I would start dragging pegs in some corners and the rear tire would lift off the ground. By the time I was coming out of the corner I just had no drive and the 100's would always pass me coming out of corners. I bought a 13 tooth and 14 tooth front sprocket, some better tires, brake pads, and rear sets. I am hoping that helps me going into the corner and mid corner. I'm going to try the 14 tooth sprocket first.
 

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Discussion Starter #11
have you upgraded your suspension? if not I would start there then get go fast mods
Thats on my list but I am going to start with the cheap stuff first. I don't feel like it's nose diving but I would like to be able to lower the compression in the rear.
 
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