Project Clapped out 1998 KX250... What works? Turbo Crank?

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Sandblaster
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Re: Project Clapped out 1998 KX250... what works?

Post by Sandblaster » Wed May 09, 2018 10:58 pm

Lazy roll on 5th gear wheelie..

https://youtu.be/c-t4_qovPcI

I think we are ready for a dyno pull...
If bikes are for kids I'll never grow up.

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Re: Project Clapped out 1998 KX250... what works?

Post by Sandblaster » Wed May 09, 2018 11:06 pm

Turbo cranks are completely different to jet then a standard crank...
We went round and round before we started dialing it in..


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If bikes are for kids I'll never grow up.

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Re: Project Clapped out 1998 KX250... what works?

Post by Sandblaster » Mon May 14, 2018 3:51 am

On 5-11-18 Jason and I loaded the bike up and took it to one of the dyno's we already had numbers from.
Remember, we tested this bike before the turbo crank on two separate dyno's.
We did that because we wanted verifiable evidence one way or the other that this mod works, or it does not work.


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Remember, we rebuilt the bottom end only.
The top end is the same worn out nasty dirty top end.
All we did was rinse it out and dropped it back on, carbon and all :o
It's not how we normally build engines but we had to keep the test as accurate as possible under the circumstances we are working with.


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As you can imagine we were very nervous.
But let me tell you this, after run no. 1 it was clear we had a winner....
We gained a verifiable 15% over a broad range of the RPM... 15%!!!!!
Here is a graph showing our initial results..


dyno day.jpg
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We have a little jetting to dial in.
A bit on the needle and one step down on the main and we should be close.
I am not showing HP numbers as those don't mean as much as you might think.
Later this next week we will be taking the bike to the second dyno, which is newer and will show the entire RPM range.
I can't wait to see what it says.
But here is the deal, don't run out and buy a Turbo crank just yet....
Let's see what the second dyno says...

Next up I will take my good running all stock KX500 and run it on both dyno's.
I will take it home and replace the crank with a turbo crank and try it again.
If we get similar results I will be very happy but remember, the KX500 does not react to crank mods like the smaller cc's do.

But for now, we are going to rebuild the top end and start trying different combo's to see what the upper limit it for a broad power out put that will be guaranteed to put a smile on your face :D
If bikes are for kids I'll never grow up.

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Re: Project Clapped out 1998 KX250... what works?

Post by Sandblaster » Wed May 16, 2018 12:02 am

Looks like Monday the 21st will be Dyno day... Ugh... I can't wait that long :(
If bikes are for kids I'll never grow up.

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Re: Project Clapped out 1998 KX250... what works?

Post by Sandblaster » Mon May 28, 2018 9:27 pm

Jason Tanner rode the Turbo Crank KX250 yesterday with a buddy riding a 01 YZ250. Starting at a low RPM and rolling the throttle on the KX was a tiny bit faster, but once the power came alive especially in the upper mid range to top end the KX just walks away. It's as if he had another half a gear on the YZ. Which of course put a huge smile on his face. We need to get some new needles as I think there is improvement to be made on the bottom end. Of course putting a new top end on it will also improve things a bit :lol:
If bikes are for kids I'll never grow up.

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Re: Project Clapped out 1998 KX250... what works?

Post by Sandblaster » Mon May 28, 2018 9:28 pm

Jason Tanner also has another 1998 KX250 that is in awesome condition. After we get the top end rebuilt on the Turbo Crank KX250 I want to get out for some woods riding and compare... It should be a fun day. 8-)
If bikes are for kids I'll never grow up.

long_av8r
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Re: Project Clapped out 1998 KX250... What works? Turbo Crank?

Post by long_av8r » Wed Nov 21, 2018 7:08 am

So, whatever happened with the tale of a turbo crank?

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Re: Project Clapped out 1998 KX250... What works? Turbo Crank?

Post by Sandblaster » Wed Nov 21, 2018 3:46 pm

On the 250 we are waiting for Jason to get the top end plated and put a new piston in it...
Then we will go back to the dyno to see where it is at,
Next we will start making compression and porting changes to enhance performance further with dyno results at each point.
So for now it's a Jason show...

On the 500 we need to swap out our crank for a newer design and take it back to the dyno...
It's only time and money :lol:
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long_av8r
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Re: Project Clapped out 1998 KX250... What works? Turbo Crank?

Post by long_av8r » Sun Nov 25, 2018 4:30 pm

Funny thing, now I have all kinds of money, no kinds of time - I may not even make it to the desert this season, but I'm going to try. Still really interested in seeing what happens with this, especially since it seems to be a viable mod at this point. What is the cost for one of these cranks?

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Re: Project Clapped out 1998 KX250... What works? Turbo Crank?

Post by Sandblaster » Sun Nov 25, 2018 10:50 pm

long_av8r wrote:
Sun Nov 25, 2018 4:30 pm
Funny thing, now I have all kinds of money, no kinds of time - I may not even make it to the desert this season, but I'm going to try. Still really interested in seeing what happens with this, especially since it seems to be a viable mod at this point. What is the cost for one of these cranks?

For pricing, Steve Parris is the man to speak to.
406-600-9451

Yeah, I'm in the project for the long haul :lol:
If bikes are for kids I'll never grow up.

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