Looking for some insight into stroking an RB20 kit with a BGM 60x110 crank. Any considerations to be made beforehand? I've never built a stroked a engine and interested in giving it a try. My next call will be to AF Rayspeed (since I bought the kit from them).
Thanks.
Anyone stroke a RB20 kit?
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- carlos fandango
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Well you wont be able to use that crank, unless your changing the piston ? the RB 20 uses a 116mm rod.ulyssescale wrote:Looking for some insight into stroking an RB20 kit with a BGM 60x110 crank. Any considerations to be made beforehand? I've never built a stroked a engine and interested in giving it a try. My next call will be to AF Rayspeed (since I bought the kit from them).
Thanks.
You could use a 60/115 crank, and you wouldnt need a packer, be sure to check the rings dont catch on the "fingers" of the boost ports at btc as they are pretty close normally .
Ive used a 58/115 crank and machined 1mm off the bottom of the barrel, after a three big end faliures with the 116mm rods

Russ
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- drunkmunkey6969
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You'll need a 116 rod, not a 110.
Im wanting to try a 62/116 stroke on an RB20 if any customers out there want one doing?
Main things to be aware of are deck height at TDC, over extended port timings, , piston skirt toughing casings at BDC, and if bottom ring drops below boost port legs at BDC.....you'll have to measure port timings and play with gaskets and packer plates until you get what you want. It can be tricky, but crack on and get stuck in!! ;o))
Im wanting to try a 62/116 stroke on an RB20 if any customers out there want one doing?
Main things to be aware of are deck height at TDC, over extended port timings, , piston skirt toughing casings at BDC, and if bottom ring drops below boost port legs at BDC.....you'll have to measure port timings and play with gaskets and packer plates until you get what you want. It can be tricky, but crack on and get stuck in!! ;o))
See our YouTube scooter channel for Tech-help: https://www.youtube.com/c/TheScooterFactory/videos
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I'll just use the BGM crank for my Jet and use the AF 58x116 crank that came with the RB20 kit.
Thanks.
Thanks.
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- Toddy
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Does the AF crank have a welded pin now?ulyssescale wrote:I'll just use the BGM crank for my Jet and use the AF 58x116 crank that came with the RB20 kit.
Thanks.
As my Dad used to say "Each to their own lad"
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Toddy wrote:Does the AF crank have a welded pin now?ulyssescale wrote:I'll just use the BGM crank for my Jet and use the AF 58x116 crank that came with the RB20 kit.
Thanks.
Doesn't look like it.
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- carlos fandango
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ulyssescale wrote:Toddy wrote:Does the AF crank have a welded pin now?ulyssescale wrote:I'll just use the BGM crank for my Jet and use the AF 58x116 crank that came with the RB20 kit.
Thanks.
Doesn't look like it.


When i was young my Mom said "if you haven't got anything nice to say, say nothing at all " ..................... and people wonder why I'm quiet around them !
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It's already been checked for true. I don't expect it to twist.carlos fandango wrote:ulyssescale wrote:Toddy wrote:
Does the AF crank have a welded pin now?
Doesn't look like it.another Chubby Checker ill wager
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- Muttley McLadd
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I'd get an adult to check the pin isn't a thou' too small then.ulyssescale wrote: It's already been checked for true. I don't expect it to twist.
CakeAndArseParty
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Can someone point me to a history/reports of this problem? This is the first I've heard of it.Muttley McLadd wrote:I'd get an adult to check the pin isn't a thou' too small then.ulyssescale wrote: It's already been checked for true. I don't expect it to twist.
A chicken ain't nothing but a bird.