650 tuning?

yes I do a few bits. there's a Dr_C here on the site who has done a lot to his. what are you doing for a chassis? is this supermono or what class?

Taffy

Hi

with the stock bore I would do

Stage 5 KTM RFS cam from thumperacing in the usa, this is one step up from the LX1 and 8/07 grinds

higher compression wossner piston to suit the later intake closing point, ask travis what he thinks is a good CR

FWIW wossner 8583D is a flat top that fits and comes with a 60gm pin should give you about 13.75:1

with the new head 04+ you should do 1mm Oversize Kibblewhite valves (ktm RFS part number) and KIbblewhite dual valve springs set at 65lbs seated search "all about valve springs with nice pics" can go even bigger intake valves with bigger seats, the exhausts can go to 32 on the stock seats. kibblewhite make seats.

if you can organise a big bore yourself then do it IMHO .. .see contimans Supermono 710cc build. 105mm bore, 82mm stroke, older head (37/32 valves) his cam is a cut7 810 .. which is nearly the same as a thumper stage 5

if you want top end only try hotcam 3015

carb can go to 43.5mm billet centre peices available from travis

if you port the newer head and go bigger valves it is not flat on top with a big bore. Mine gained 10% power everywhere from a 10% increase in cc, revs up just as quick and screams its head off as before.

lump of power did move down in the range going from 100 to 105mm but top end peak power was not reduced, after porting it moved back up again. but was never a tractor .. the 628 crank is too light for that

vortex ignition or ignitech from chezech would also be worthwhile ..

have fun ,, post some pictures please

canolman said:

Supermono, would a bigger bore produce more power but at lower revs than say a high comp piston of standard size? A tractor like engine isn't what I'm after.
Would a high comp cause any problems with starting or overheating?
Yes I've seen Dr_C's work, he's a genius sadly I'm not!

Click to expand...

"Genius" is far from it, but I can agree to "Persistent". But thanks for the kind words, Canolman!

In RR, manoeuvrability and smoothness beats power at most tracks. Generally, you need top end power at the tall straight, but a strong mid range to get out of EVERY corner. Even better is a really smooth and sensitive delivery at 0-15% throttle to be able to crack the throttle directly after letting go of the brakes.

But, of course, more power is always fun, costly and giving headaches! You have received good ideas from Bushie, so I have nothing to add there. My strongest recommendation is that after you have installed all hardware, spend a day at the dyno finding out optimum pre ignition, jetting, intake length, exhaust length (and restriction) and finally jetting again. All in that particular order! Use the dyno to get value for all the money you spent on expensive "go fast thingies"! Otherwise it's all like buying beer and firecrackers.. Bushie can explain.

oh forgot the intake and exhaust, thanks Dr_C

I have seen pictures of akrapovic Doma silmotor arrows full systems, some are 2 seperate pipes and 2 mufflers

Dr_C said:

"Genius" is far from it, but I can agree to "Persistent". But thanks for the kind words, Canolman!

In RR, manoeuvrability and smoothness beats power at most tracks. Generally, you need top end power at the tall straight,

but a strong mid range to get out of EVERY corner.

Even better is a really smooth and sensitive delivery at 0-15% throttle to be able to crack the throttle directly after letting go of the brakes.

Otherwise it's all like buying beer and firecrackers.. Bushie can explain.

Click to expand...

this is the best advice Ive read on power delivery for a long time and it applies to every form of racing except probably hillclcimbing and drags

increasing the minimum speed in each corner is the easiest place to make big gains but if you are not marky marques it is easier to go safe old man speed slow in the corner and have a good initial acceleration from the first bit of throttle, it is also easier to maintain the minimum speed, this is the main advantage my bike has over the smaller engined ones it jumps a bike length or so ahead when its time to go.... makes up for me being a slow old man it is also the reason i hate auto clutches since the initial take up is dulled

the firecrackers and beer are best when made at home in the shed from old shotgun cartridges and the hops of a kangaroo all on the same bench alongside a husaberg:ninja: