Home built XR 69 replica ( not mine)

[John Kat]

I found this interesting XR 69 build on the internet.
I believe the guy is from the Netherlands.
Everything is possible when you want it!
http://www.fmsp.net/t11306-suzuki-gs1000r-xr69-endurance-replica

 

[rapidray]

COOL thread! Thanks for adding it John!
Ray.

 

[dorkburger]

Ive never seen dimples and holes in the engine before.....interesting.

 

[JTGS850GL]

I would imagine it adds more surface area for cooling. I thought the dimples around the sparkplugs was most interesting.

 

[ozman]

Ive never seen dimples and holes in the engine before.....interesting.

most of the yoshi GS1000R engines were drilled like this, pops theory was that it aided airflow removing stagnant pockets of air from between the fins

 

[Fjbj40]

Ive never seen dimples and holes in the engine before.....interesting.

Extra surface area for cooling, there is a fair amount of non-cooled surface area around the plugs. My guess anyways.

Really cool thread though, I was toying with the idea of building a replica like this a few years ago. Maybe just a little beyond my abilities at the time, but I am getting there.

Here are some replica panels to help. http://www.airtech-streamlining.com/vintage/hammer.htm

 

[ozman]

our version of the XR69

 

[ozman]

Further proof of POPY's attention to detail
check out the gap between cyl 1 and 2 plus 3 and 4
between the cylinders and between the fins have been opened up with a porting tool

 

[ozman]

extra roller in bottom of head and mounting point for the top roller

 

[ozman]

cylinders drilled and sleeves cut away

 

[ozman]

smaller valve stems

 

[GSX1000E]

Reduced valve stem or just reduced shank at the head? Interesting that you posted pictures of extra cooling holes drilled into the head. I have never seen that before and have been opening up
the factory cooling holes on the past two builds for the same logical reasoning. Hmmm. Good to know!

 

[Guest]

I remember the GS1000 works valves were nominally 6.6mm , back in the early 80's i supplied 2 'works' yoshimura motors sourced thru dixon racing ,in Goldalming Uk, who were the official UK Distributor at the time.

 

[limeex2]

Beautiful work,tons of info.thanks for posting.

 

[GregT]

I was looking at an early pops built 1000R motor a few weeks ago, in the Steve Roberts built alloy monocoque which was the predecessor of the plastic fantastic glass monocoques...Anyway, the cases have hand cut grooving all over them. I'd assume, like the holes in the finning, to increase surface area. There's a formula for holes in fins or brake discs to establish what diameter actually increases surface area vs reducing it.
I've always been rather surprised at the retention of the 12mm dia Kawasaki valve shims too, you'd think if they went to the trouble of using lighter valves, smaller shims wouldn't have been a problem.

 

[Guest]

hi greg, the original genuine yoshimura gs1000 motors indeed used a smaller shim than the 13mm kawasaki one we typically use nowadays. i think it came out of the the little honda ss800 sports car motor.

 

[BadBillyB]

When I saw the pics on page one, I was sure I was looking at aluminum valve spring retainers. That made me cringe. They were notorious for keeper "pull through" back in the day. But slick old Popy used CB750 style keepers machined from titanium (more surface area) to prevent this. Nick is right, the valves were 6.6mm on the original Yoshi motors. Complete article here....Bill
http://ghutdc.com/pdf-doctc/john-ulrich-yoshimura-suzuki-gs-1000.html

 

[Moriwaki Kawasaki Monster]

can you repost that link pls... Or upload the file

 

[BadBillyB]

Linky no work now. Might have been this one.....Billy
http://www.readbag.com/slcelectronics-gs1000-build-yoshimura-specs