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Who makes the best domes?


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Here's a head I did a few years back for my dirtbike to cure a detonation problem.

yra5epeq.jpg

Ok, what about the previous dome was causing the deto, what did you do to that head, why did you do what you did, and what is the ride report?

 

Just curious. Really wanting to learn the combustion situation.

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20140814_165849.jpg

This is the type of stuff I'm talking about. Definitely from the same guy with similar profiles except one is wider squish band. Were the compression ratios similar on both of those domes possum? And what were the differences in performance?

 

 

 

 

I've got a ton of stuff I can post, just wondering if anyone will step up and really break down what is what. Kinda getting sick of having to go else where when I wanna really dive in to a specific topic.

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the 23s on the left for a 10cub run well. with moderate squish they rev well, and power is there, with lil heat build up with no signs of deto. the 20s on the right I have yet to try, they are for a 4 cub. I like the squish band and profile. So im assuming ill be hapoy with them.

apporox 8.5mm squish band on right one.

apporox 10.5mm squish band on the left one

Edited by possum
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Ok, what about the previous dome was causing the deto, what did you do to that head, why did you do what you did, and what is the ride report?

 

Just curious. Really wanting to learn the combustion situation.

That head is off a '92 WR500. It's the same head design as the YZ490 except with a little less compression. The YZ490 and WR500 had a flawed head design from the factory that caused some pretty severe detonation. From my experience on the WR, it would buck pretty hard... it wasn't a ping it was a PANG!!! The factory cure was to drop the compression on the WRs, but the problem was the squish area was too wide.  

The popular solution is to cut another angle @ 30° 8mm wide where the squish transitions into the dome. In addition to that, I cut the cylinder base to "0" deck, turned the head down to a 0.030" squish band, and modified the carb slide to make it a 3.5mm cutout. 

Compression is at 210psi and it runs no ping on premium... which surprised me because I had set it up with Eric Gorr at Forward Motion to cut the dome area.

The first ride after getting the carb set was awesome! Took it to the track and had no problems with power... actually took a little bit to get used to because of having to watch how much I blipped the throttle before going airborne.

I regeared for last year with the biggest front sprocket I could find to tame it a little... only thing it changed is that it made 2nd usable instead of pointless, and its got more topend. When we go to Michagan, I ride the bike more than the Banshee, it's just crazy fast, and it has a more comfortable ride.    

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Driveline was a good addition to BansheeHQ. BHP can get info while he's there cleaning the toilets.

Yes, superior idea!

 

Just curious, how does the whole sponsor thing go? Do you just hear about guys doing well and ask them about sponsorship or do they mostly come to you?

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Yes, superior idea!

 

Just curious, how does the whole sponsor thing go? Do you just hear about guys doing well and ask them about sponsorship or do they mostly come to you?

 

For the most part they e-mail me. Sometimes in the winter when I have more time I will send some e-mails out to companies that I think would fit well here.

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