Interesting topic on spannies

dave32 · Post by **dave32** » Sat Feb 02, 2013 2:08 am

http://www.pit-lane.biz/t3107-gp-125-25 ... lded-cones

dave32 · Post by **dave32** » Sun Feb 03, 2013 5:44 pm

But No Real conclusion by the looks of it

KR-1R · Post by **KR-1R** » Wed Feb 06, 2013 6:43 am

.
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the conclusion is you play snooker on square tables and not round ones

dave32 · Post by **dave32** » Wed Feb 06, 2013 12:41 pm

Yes that is true,as for the "Hydro Vs Cone construction",its still all talk and no proof.

TwoStroke Institute · Post by **TwoStroke Institute** » Wed Feb 06, 2013 1:37 pm

Have identical pipes one set hyroformed and another rolled cone pipes, only need the time to dyno them.
An interesting aside is I got a funny email for a sled tuner that knows my old mate well, said he got a good laugh from all that and most times he would prefer to "swim under the ice" in order not to talk to him. His pipes have a very "hit and miss" reputation.
As I said on the website, a long time since stamped and hydroformed pipes have been on GP bikes.

dave32 · Post by **dave32** » Thu Feb 07, 2013 2:02 pm

Yep your right,mid 80's was probably the last time they use hydrofomed pipes at GP level,think it was used on the V4's (YZR) alot as there was quite a torturous route thye had to take on the lower cylinders to get the required length.
I dont doubt that having a sudden change does have a benefit but i still dont understand,if its so important how can a Hydroformed pipe work well if at all?
Going back to road stuff,the KR's pipes are "pressed" so no sudden changes yet they work really well,along with Pete Gibsons that im running,also in the UK Derek Huxley used to make some Hydro pipes that worked well.
not doubting it works just would like to understand HOW and WHY they are superior.
Cheers again

scooble · Post by **scooble** » Thu Feb 07, 2013 6:25 pm

does anyone have any experience of Huxley pipes, I have a set that I haven't used (getting some flanges made at the moment) and would like to know if anyones tried them.

dave32 · Post by **dave32** » Thu Feb 07, 2013 6:52 pm

No ive never even seen a set of Huxley pipes for the KR1,judging by the other pipes he made i would have thought they would work well.
Im pretty sure though that he built the pipes for the specific bike they were being fitted to so they may have been made to work with a specific engine tune rather than a stock engine.
Only one way to find out though.

TwoStroke Institute · Fri Feb 08, 2013 12:28 am

My understanding is the header is best to be smooth as possible, the junctions of the diffuser/belly and belly baffle cones are very important for making a 'sharp' wave action response.
Later GP pipes took just a twisted path but were welded cone, look at every late GP pipe and they have clear,distinct, changes in cross section either side of the belly. Even standard TZ/RS pipes have that.
Hydroforming is eaiser to make.