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Stock stroke cub jetting and timing


md7571

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The new setup is, Cheetah cub with mild port work 68 x 54 mm, i think it is a 392cc. I have an RK tech head with 19 cc domes. I am running v-force 2 reeds and 35 mm keihins with separate K&Ns. I have a k&T adjustable timing plate and lightened flywheel. I am running CPI small bore inframe pipes. I know somebody on here has this setup, all I can seem to find is info on a 4mil. Just need some info on a good place to start for Jetting and timing. I mostly run at 5000 ft elevation. I have also considered running about a 50/50 mx to get about a 100 octane if needed, Let me know what u guys think or any other questions.

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What is your compression? With 19cc domes and 5000 ft, I'd GUESS you'd be safe on pump or 50/50 mix...but you need to measure the compression first.

 

BigRedX has a similar package as yours (think he has a stroker motor) and he's at 7500 feet.

 

Might wait for him to chime in and help...

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What is your compression? With 19cc domes and 5000 ft, I'd GUESS you'd be safe on pump or 50/50 mix...but you need to measure the compression first.

 

BigRedX has a similar package as yours (think he has a stroker motor) and he's at 7500 feet.

 

Might wait for him to chime in and help...

 

 

Just looking for a place to start, I dont know enough about the motor yet to know where to begin, just lookin for info so I am not doing an immediate rebuild due to burn down.

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Well if your worried why dont you just start out with something a lil rich? that way your not going to run it lean and burn up a piston? that is what I would do

 

 

same here man , i rather foul a plug or be runnin rich then a , DAMN I WISH I WOULDA COULDA !!!!!! well u get the point

 

50-55 pilot , 158 or 160 main thats where id start at sea leval... not sure on elevation miami seems to not have any elevation

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yeah ...id use cgl needles and probably 150 mains and 45 pilots with needle in middle for starters

 

 

thanks, I will give it a shot, The reason I asked is I have never done anything with Keihin Carbs before and dont quite understand the jetting and jet sizing

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thanks, I will give it a shot, The reason I asked is I have never done anything with Keihin Carbs before and dont quite understand the jetting and jet sizing

 

You and me both.... I just got my 35PWKs about 2 weeks ago, but I can jet the shit out of stock carbs...

It's the numbering scheme that throws me off, I like Mikuni's numbering scheme better...by 10s on the main, 2.5 on the pilot... :)

The tonz of different needles screws me up too...but, after all this research, most agreed CEL needles are my ticket.

 

However, I've scoured this site and PS, looking for those with similar setups, similar temps, elevation, locale...etc., and asked advice from several members whom experience and opinions I trust.

And...whaddaya know...they were all within 1 jet size of each other's recommendation for me.

 

Like you said, you want to be close...I think you've got some pretty good starters...

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  • 2 weeks later...
  • 2 weeks later...

I have your exact setup. I'm at about 300 ft elevation. Not sure which needles, but I running the clip in the middle, 45 pilots (I think), and 170 mains. It's rich as hell (oil buildup on ends of silencers) and needs some fine tuning, but I've yet to foul a plug and it screams. You'd obviously have to go leaner with your elevation. I'm gonna see for sure which pilots I've got and probably go down to 165 mains until it cools off outside.

 

Edit: I'm running a Noss head w/20 cc domes and 112 octane gas.

Edited by J-Madd
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FYI: I checked my pilots and they were 48's. BTW I bumped them up to 52's. From what everyone is saying 48's are a little lean for 300 ft and even 90+ degrees. I also dropped my mains to 165.

 

 

Hope this helps. I'd be interested to see what your jetting is when ya get it dialed in. I know mine still needs some fine tuning.

Edited by J-Madd
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