KR-1S.co.uk Forum

The KR1s has now done some miles and I have a slight problem. Starting is perfect, pickup is fine, midrange is fine I can feel the kick as it gets on the pipe at about 8,500 but at 10,500 I get a bit of a splutter as though I'm hitting a rev limiter and it wont rev any harder.

I tried , new plugs, new HT caps, new air filter but it made zero difference. Cabrs have been in the US cleaner for hours. Fresh fuel. Carb rubbers OK, no air leaks, good battery, PV's mechanism moves. This is the 1st time I have ridden the bike properly so have nothing to compare it to.

Engine, carbs, air box exhausts, everything is completely std, apart from the rectifier which is an electrex unit.

Any suggestions ?

just a thought ,check the block connector to the ignition switch ,and clean the pins

What type of plug are you using?

Cheers

It had iridium (not sure what make but not NGK) and I swapped to BR9ES. Should I try BR10ES ?

Know somebody who had a top end misfire. Bike did everything fine just went flat at the very top of the rev range.

He said he had tried new plugs so we tried new ignition, coil, rotor even fitted another crank.
In the end I fitted an old set of EV plugs and it ran fine. He had been using ES.
Never really figured out what the cause was but suspect that ignition as it got older wasn't producing the same sort of spark and with a better plug it could get the required spark.
Electrical problems I have seen are the HT lead connection to the coil is poor, the windings on the high voltage coil start to fail but that usually affects starting. CDI faults are usually it works or it doesn't. The other thing might be to check the power valves are opening correctly and are adjusted correctly.

Having said that a stock KR can feel a bit bunged up at the top end - but that is by comparison with my engines which were never stock.

Not sucking coolant in ?

Changed the plugs and plug caps (again). No change. It gets to 7,500 then starts to go then when the KIPS should be opening it is just really flat all the way to 11,0000. Not it's not sucking coolant, spark is good, plugs good, dry not oily. Pipes are clear and not clogged. Don't know what's wrong

Is there a way or holding the KIPS valves fully open ? I know it would be pretty un-rideable at slow speed, but at least I could tell if them not opening is the problem ?

Cheers

Phil M

If you've a nice long straight road nearby (a private road obviously) I left the left hand side fairing insert panel off, then wound it on in 3rd with my fingers on the end kips lever. Was easy to feel that the valve opened as it came onto power.

with the ignition switch switching on, cycle the KIPS to the open position and than switch it of again.
disconnect the connectors to the KIPS motor and they stay open

JanBros wrote:with the ignition switch switching on, cycle the KIPS to the open position and than switch it of again.
disconnect the connectors to the KIPS motor and they stay open

Cheers

bozbridge wrote:If you've a nice long straight road nearby (a private road obviously) I left the left hand side fairing insert panel off, then wound it on in 3rd with my fingers on the end kips lever. Was easy to feel that the valve opened as it came onto power.

Might try it in 1st gear !!!!

Cheers