CRF450x hit max revs at 6000rpm

[landysi]

Hi sorry if I'm posting this in the wrong place. I have a 2010 CRF450x and it is only hitting 6000rpm before what feels like the rev limiter. I have been thorough the checks in the manual for the coil, exciter coil, ignition pulse generator and as long as I am doing them correctly they all seem fine! However the bike hits 6000rpm and it feels as though it's hit the rev limiter! Any help as to the cause would be appreciated.

[Jim Dettman]

<<However the bike hits 6000rpm and it feels as though it's hit the rev limiter! Any help as to the cause would be appreciated.>>

One thing you didn't mention; the setup for the tach<g>

Actually, what's tripping you up is that the CRF's use a wasted spark system, so you've got two firings for every revolution (fires at TDC every time, not just after compression). 

What your really doing is pulling 12,000 rpms.

Jim.

 

 and just as a double check (and so your not hitting the rev limiter!), you should be seeing an idle of 1,700 rpms.

 

Jim.

[landysi]

>
One thing you didn't mention; the setup for the tach
Actually, what's tripping you up is that the CRF's use a wasted spark system, so you've got two firings for every revolution (fires at TDC every time, not just after compression). 
What your really doing is pulling 12,000 rpms.
Jim.
 
 and just as a double check (and so your not hitting the rev limiter!), you should be seeing an idle of 1,700 rpms.
 
Jim.

Thanks for the response Jim. The reason I looked into the revs and added the vapour computer to check it was that I noticed I was topping out at 45mph on standard gearing and not the usual 70.mph. So the vapour needs
Setting at Ppr 2? If that is correct and it is revving to 12000 rpm why am I only hitting 45mph?
Simon

[MSFIT]

I thought rev limiter was 10k, or like 10,800.

 

What's your carb setup? Maybe your needle is too far down, try raising it up one clip (moving the clip down a notch).

[Jim Dettman]

Simon,

PPR1 should be correct.  If that's where you were then you've got something else going on.  What do you get at idle?   Should be 1,700.   If that's what you have, throw in some more details on what's going on.

As far as the rev limiter, I'm pretty sure it's 12,500 rpms, and another 500 if you have the pink wire disconnected.  But that may vary by year.

Jim

Edited March 29, 2017 by Jim Dettman

[landysi]

Simon,
PPR1 should be correct.  If that's where you were then you've got something else going on.  What do you get at idle?   Should be 1,700.   If that's what you have, throw in some more details on what's going on.
As far as the rev limiter, I'm pretty sure it's 12,500 rpms, and another 500 if you have the pink wire disconnected.  But that may vary by year.
Jim

Yes it's set to ppr1 and is idling at around 1700rpm I believe as that 10500 rpm is max and 11000 with pink wire mod which I have done. I seem to have a normal amount of power at low revs and it pulls hard but it 6000 it and it pops and splutters as thought the rev limit is reached. Clearly it's only hitting 6000 though and hence why I'm only hitting 45-50 mph as nowhere near all the rev range is being reached. Is it possible there is a fault with ICM?
Simon

[CRF DOC]

Check for a loose ground on the coil or metal shaving buildup on the pulse trigger coil.

[landysi]

Check for a loose ground on the coil or metal shaving buildup on the pulse trigger coil.

Ok will check that out thanks
Simon