Final KR Based Race Bike Project

maccas · Post by **maccas** » Sat Dec 08, 2012 11:45 pm

I was thinking the same thing Janbros, I would expect a kr1 frame to be heavier than the 1S frame to be honest due to the ridged main frame spars. I heard somewhere that the kr1 frame is stronger?

Dan

john-b · Post by **john-b** » Sun Dec 09, 2012 12:24 am

i know the KR1 steering head angle is tighter so it should turn faster.

You need some flex hence carbon wheels dont work on 125's so a racer told me who runs in the british championship and if you can afford to run a seal engine you would probably know. Having said that they reckon on a 2t if you get the bracing/ strengthening wrong on the frame the resonants will be wrong and your engine wont rev?

Im no expert by the way but 1 kg is supposed to be worth 1 hp so bread and water, be careful where you weld what and a very tuned kr1

Luders · Post by **Luders** » Sat Dec 15, 2012 6:50 pm

This project is going to slow down a bit over the Christmas period, but for now I'm still cracking on.

I have stripped all the paint off the swing arm and will make a start on the frame tomorrow.

I picked up the forks for the bike the other day, so here's a pic of them in the frame.

JanBros · Post by **JanBros** » Sun Dec 16, 2012 12:47 pm

are you gonna leave the supports for the subframe single sided ? I would put one on each side to avoid twisting forces on them

Luders · Post by **Luders** » Sun Dec 16, 2012 1:30 pm

I'm not sure what you mean Jan, but the sub frame is complete as you see it.

I based my design on the Yamaha TZ.

Here's an OEM one for sale...

www.ebay.co.uk/itm/260699199161?redirect=mobile

daz680 · Post by **daz680** » Sun Dec 16, 2012 1:42 pm

i think Jan means so that at each fixing point the subframe sits between 2 lugs rather than just one at each fixing point

Luders · Post by **Luders** » Sun Dec 16, 2012 2:13 pm

Ah I get you, thanks Daz.

So in answer to the original question, no, because I believe that adding additional mounting points would be over engineering.

Each of the lugs is 8mm thick.

scooble · Post by **scooble** » Sun Dec 16, 2012 5:17 pm

phwoarr!!

Luders · Post by **Luders** » Sun Dec 16, 2012 5:41 pm

I will be getting the frame etc anodized black, so have been cleaning up the swingarm in prepartion.

daz680 · Post by **daz680** » Sun Dec 16, 2012 5:44 pm

That yam looks stunning, i take it from the intakes it runs a pressurised airbox, any advantage to this on a 2 stroke?

Luders · Post by **Luders** » Sun Dec 16, 2012 6:13 pm

Yes Daz there are advantages, but they can be tricky to get right and setup in my experience.

I was thinking of running one with this build and pinching more ideas from our beloved TZ.

Not sure if anyone has noticed the forks, but they too are TZ

Rocket · Post by **Rocket** » Sun Dec 16, 2012 6:51 pm

I run pressurised air box and it helps alot, when I post the 2013 race bike build you should be able to see it in place, quite alot of work to make and fit but worth it I think.

Post by **500bernie** » Sun Dec 16, 2012 7:15 pm

I will show my stupidity by asking.....
How do you stop rain etc filling up the air box

Luders · Post by **Luders** » Sun Dec 16, 2012 7:47 pm

I don't think you truly can Bernie, I would say you just have to clean it after each race.

Rocket · Post by **Rocket** » Sun Dec 16, 2012 7:54 pm

there are drain holes at the bottom of a standard air box which allow any fluids(water/excess fuel) to drain, but rain can get in the system like any other ram air system and I don't worry to much about this as the carb/airbox rubbers are quite away up the airbox which allow for alot of water in there before it gets in the rubbers, over a 10 lap race it would need alot of rain to fill the airbox to this point, at the October Auto 66 race meeting it was very bad weather with hail at times but this didn't cause any problems with water in the airbox.