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timing for 421 cub


tomtunas

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I have a 421 +4 stroker cub, it seems the bottom end is not there i'm running 35mms strikers with 150 mains, if I get the adj timing plate and go +4 think it will help? I have a '00, it sat for 4 yrs and just got back into riding bout 6 months ago and just put 8,000 in this bike, just trying to build it to its full potential.

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I have a 421 +4 stroker cub, it seems the bottom end is not there i'm running 35mms strikers with 150 mains, if I get the adj timing plate and go +4 think it will help? I have a '00, it sat for 4 yrs and just got back into riding bout 6 months ago and just put 8,000 in this bike, just trying to build it to its full potential.

Tell us how you intend to ride this,just drag or?That way I may be able to steer you in the right direction.Oh and also what exhaust are you running?

Edited by bansheeseat$$
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I ride half and half sometime long straights and pits. no trails. I'm running shearer in frames, and the cylinders are ported, it just seems fat on the bottom but I dont want to lean my new motor out too much. when powerband hits it hits hard. its a great top end motor, but i'll take the good with the bad anyday. I already ordered the timing plate so I guess i'll put it on.

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the plate will help alittle on the bottom, but you did build a drag motor not a trail bike just to let you know. what domes do you have in it?? whats your compression?? what type of fuel are you running?? who ported it and is it a clean up port or a drag port??

Running pump gas with 20cc domes, and a clean up port, nothin big. I love the motor, she screams I am very satisfied. Only prob was I had to go +6 on the swinger, but that was a good problem! It was ported by a local shop they did a pretty nice job.

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Yeah, Shearer pipes, twin 35PWKs and a cub motor? Bottom end doesn't exist.

 

You could bump up the compression, advance the timing to 7 or 8 ( I run a ton of timing on mine) and switch to a 1 into two carb, 35PWK or 38PWK...that will pick up the bottom a little.

 

But then again, as said...a cub has drag port timings from the factory. You really only need a clean up port OR clean up and raise the exhaust a little tiny bit. Mine is cleaned up only. I'd like to see a picture of your porting...the out of the box porting on these cubs are a piece of art work!

 

I'd almost bet they only cleaned it up....removing casting flaws and shavings.

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Put the timing plate on and I am impressed. I went with+4.5 advance, and there is noticeable throttle responce. I am satisfied now. The stock cubs had terrible over cast so I had to get the clean up, but the bike is running great now thanks for all the input! How are you guys with this setup doing against piped banshees, and 450r's on drag racing? And what kind of hp think I'm pushing?

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That sounds real good! I'm running turf tamer rears, alot of guys dont like em but I think they hook up pretty good. With that much power I think any tire you put on is gonna spin.

 

 

Running that bike with turf tamers in the trails is like taking a top fuel funny car to the grocery store...

 

It's meant for dunes and drag, which...means ashphalt slicks or paddles....

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Running that bike with turf tamers in the trails is like taking a top fuel funny car to the grocery store...

 

:yelrotflmao: Good analagy..............

 

The timing helps get some of the bottom end back, plus you will notice more if you swap those 20's out for 19's or better yet 18's. But then you are changing the compression, which wont allow pump gas anymore, but hey whats the fun in that..................... :headbang:

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