Guys I think I have a crank seal problem. I already post this about a month ago that my bike sometimes idle at 1500 then sometime it goes up at 4 to 5 thousand RPM. But my question is how can I be sure that its a crank seal problem? Could it be blocked jets cause I dont have fuel filter and the last time I opened by carbs it full of dirt in the bottom. could a block jets cuase this? I want to be sure because oil seal are quite pricey plus the trouble of opening the crankcase. any suggestion? or how to be sure what the problem is?

Thank to all..

If you suspect the carbs are dirty, then clean them. And fit a fuel filter - remember all that dirt is being sucked into the crankcase and into the bearings. Not good.
_________________
MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Ill fit the filter right away, but could dirt cause the inconsistent idling?

any more opinion guys? please anyone? matt?

get your spanners out and start stripping it down its not hard to pull a nsr motor apart or put in back together !

Start by pulling the carbs off and having a look inside. If they're dirty then that may be your problem.

Sounds like an air leak of sorts though.

Can you get the motor leakdown tested?

How will I do that leakdown test? i have no idea about that.

leak test: you have to fabricate some plates that can close the intake holes, where the carbs are and a sparkplug insert that will allow you to send pressurized air into the cylinder and then close it off. Then you wait to see if the pressure disappears again, indicating leakage.

Before you do this or take the crankcases apart, you can run the engine and spray some dieselstart aroung the crank seals to see if the rpms change when you do it. This will of course not check the middle crankseal, but that one does go bad very often.
You can use it for checking air leaks in other places on the bike too.

Don't spray it all over the place though as its highly flammable.


google is your friend
http://vmaxoutlaw.com/tech/leakdown_tester.htm
http://www.google.dk/search?sourceid=navclient&ie=UTF-8&rls=GGLG,GGLG:2005-38,GGLG:en&q=leakdown+test
_________________
Poul
"If Life Gets Boring, Risk It!"
MC21SE, KISS box
MC21SP, HRC box, racing loom

Thanks man