Thumper Club Forum

Club House => Chatter => Topic started by: JOOLZ on December 23, 2010, 01:49:44 PM

Title: interesting engine and unusual head
Post by: JOOLZ on December 23, 2010, 01:49:44 PM

Hi I ran across this while browsing another site, and put the pics in galleries projects latest.  Wonder how the 6 valve head works ?!!!

(http://www.thumperclub.com/drupal/system/files/imagecache/node-gallery-display/photographs2010/188153600c643aa5dbaan4.jpg)

(http://www.thumperclub.com/drupal/system/files/imagecache/node-gallery-display/photographs2010/bmr2pmm5.jpg)

Title: Re: interesting engine and unusual head
Post by: guest868 on December 23, 2010, 07:12:31 PM

Is it a Fuchs built motor? Radial valve head.

Title: Re: interesting engine and unusual head
Post by: johnr on December 24, 2010, 05:43:12 PM

it might be a yamaha development motor. when they were designing the fzr engines, they experimented with heads carrying 4,5,6 and even 7 valves, eventually settling on the 5 valve head that they used for the next decade or so. this pic might be one of the single cylinder motors built to test various concepts.

Title: Re: interesting engine and unusual head
Post by: el vencejo on December 25, 2010, 09:22:20 AM

Aamzing head, not much metal between the valve seats, a real "heavy breather" .

Title: Re: interesting engine and unusual head
Post by: Steve H on December 26, 2010, 09:04:50 AM

I'm confused by the chamber around what appears to be the exhaust port on the left of the head and the fact that in the side on picture the inlet and exhaust would appear to be connected.
I had assumed the chamber around the exhaust was for coolant, but why cool an exhaust ?. I'm now wondering whether its a transfer port and its using crankcase compression to charge the engine. Not sure why you would run the inlet charge past a hot exhaust though, so if I'm correct the port on the left isn't the exhaust, also if the chamber is a transfer port then its not very smooth.

Title: Re: interesting engine and unusual head
Post by: johnr on December 26, 2010, 11:18:29 AM

are both these pictures of the same head? the top one has an obviously central spark plug, the bottom one shows a side mounted spark plug which isnt visible on the top pic showing the valve layouts. i looked at these for quite a while trying to work out the orientation of the top pic compared to the lower one, and all i think now is that they arent from the same engine.

Title: Re: interesting engine and unusual head
Post by: JOOLZ on December 27, 2010, 06:20:25 PM

Quote from: johnr on December 26, 2010, 11:18:29 AM

are both these pictures of the same head? the top one has an obviously central spark plug, the bottom one shows a side mounted spark plug which isnt visible on the top pic showing the valve layouts. i looked at these for quite a while trying to work out the orientation of the top pic compared to the lower one, and all i think now is that they arent from the same engine.

no they are not from the same engine