Racers or race engine specialists, rear sprocket knowledge needed!!!

[livingoodnathan]

Guys it was just bait for Neil Sr to see if he was gonna post it elsewhere to try and smear my name; lo and behold he did. That 2-stroke was a POS I got for free; it topped out at about 35mph, maybe not even that I don’t remember; I sold it after riding it about 10 min for $250 and my 2 stroke adventures ended with that. Was during the time my 4-stroke was stolen and a friend tried to help me out. Jokes on you Neil.

However I think it is ridiculous to be talking high speeds with those. If you are getting 40-50mph out of one of those kits you are doing it right. Enjoy it and don’t break it trying to go faster.

Not a kit it's a pk 80 built by Fred at CR machine pic is when I first got it built before reeds and big carb.

 

[The_Aleman]

It doesn't have trouble reving over 7K rpm it feels like it's over reving. I feel like I should be going faster idk. I know for sure I'm restricted by this pipe.

Yeah, we know the pipe makes the powerband on these, ofc. You may get lucky adapting a 1-size-fits-all pipe to your engine, but part of the reason customizeable kits like the pipe SBP sells is that you can tune it for your drivetrain's setup and desired speed. You seem to be tuned more for low-midrange torque than max HP atm. That sounds good to me, but I'm I know you got a mean lil race-capable engine there. Fred knows his biz. So you have to tune your exhaust for better high-RPM driveability. Seems like some others in this thread already have experience with the pipe you're using, so you should def hear them out. You may find that you already have too-small of a sprocket once you're set up proper. I ran a 34T on mine mainly just to keep revs down at 20-30MPH cruise.

 

[livingoodnathan]

Yeah, we know the pipe makes the powerband on these, ofc. You may get lucky adapting a 1-size-fits-all pipe to your engine, but part of the reason customizeable kits like the pipe SBP sells is that you can tune it for your drivetrain's setup and desired speed. You seem to be tuned more for low-midrange torque than max HP atm. That sounds good to me, but I'm I know you got a mean lil race-capable engine there. Fred knows his biz. So you have to tune your exhaust for better high-RPM driveability. Seems like some others in this thread already have experience with the pipe you're using, so you should def hear them out. You may find that you already have too-small of a sprocket once you're set up proper. I ran a 34T on mine mainly just to keep revs down at 20-30MPH cruise.

I've been searching high and low for a good pipe and they aren't readily available unless you buy a new motocross pipe for $200+ and then you have to mood it to fit these motors and im no welder. Would love to find one soon so I can tune properly.

 

[JerboaJohn]

you could get a used MX pipe cheap if you ask ppl who have an ad selling a dirtbike bcs they have parts just like we do lying around. it might be scaly or dinged but probably still good.
then 50-75 take to a welder or put an ad yourself on Craigslist asking for small weld job needed. you'll have 100-150 in a full race pipe then.
but yeah it takes $ to go fast. you wake up that Fred engine and you'll be going really fast,, like really...

 

[livingoodnathan]

I've been looking around and im have found a few used mx pipes that aren't too $$$ and my buddy can weld. It's in the works it's just going to take a lil more time than I expected. Lookin to find an 11 tooth front drove sprocket now also. I'm going to take everyone's advise and hold of on the smaller rear sprocket and wait to see what a new pipe and five ribbing will get me. I've posted a tachometer along with five tuning jerry kit so we will see.

 

[Spare_Parts]

Think Bicycle Motor Works has the 11t front sprocket. Look on eBay for a used pipe. I just picked up a kx65 pipe for $70 shipped.

 

[livingoodnathan]

Think Bicycle Motor Works has the 11t front sprocket. Look on eBay for a used pipe. I just picked up a kx65 pipe for $70 shipped.

Cool thanks.

 

[inspectorcritic]

Not a kit it's a pk 80 built by Fred at CR machine pic is when I first got it built before reeds and big carb.

What do you call that seat bracket and where do you find them?

 

[livingoodnathan]

What do you call that seat bracket and where do you find them?

They are called lay back seat posts I got mine from kingsmotorbikes.com but they are widely available. Amazon, ebay exct.

 

[Schmitty]

We're going to need some video proof on that one mang.

I'll say