The specs are exactly the same as the K9. It looks like RB just wanted to update the heatsink logo to reflect the new year 2010.

When they originally started to use the MES it was to help with overall power and fuel economy. In theory you can use the new P/S/R set with a turbo button to get a WS9 performance but that's if the older crankcase is milled out to open the 2 extra exhaust ports to be functional. I will look at my old WS7 later to make sure.

Thanks for all of the quick responses! This is really cool stuff. I am not the best driver around, but I love messing around with engines and car setups.
Another question: When is the crank pin on a WS7 considered worn out? The spec sheet calls out crank pin specs but what do you look for? I use digital calipers measuring in quarters (12/6 o'clock, 3/9 o'clock) around the pin in addition to visually looking for “slop” between the con rod bearing and crank pin. What is the “average” service life assuming the engine was not abused? I know with “cheaper” engines this can be a major wear/problem area. No need to rebuild engines if cranks and crank pin are worn out.

The average service life has a lot of factors in it, I can say I have a WS7 that has almost 16 gallons of fuel on it and the crank pin is still in great shape. The WS7 engines have the hard coating on the pin so they will last longer than normal. As for when it's worn out... brand new the pin should measure 5.02, once it gets down to 4.99 at any of the angles you measure it at I would say your better off replacing the engine.

Rick the best way to save the crank-pin from premature wear is to keep good air filtration, and replace the conrod as soon as the motor is fully broken-in. For me that's usually the 2-3 gallon mark, or whenever I loose mechanical pinch at TDC.

What wears the original brass conrod bushing is a combination of dirt, over-revving a tight fit, and overheating. Once that brass bushing get's too oblongated, the rod then dances on the crank-pin, instead of just snuggly rotating. It's a chain reaction because next the p/s will wear out prematurely, while the crank pin is losing diameter.

After replacing the rod you can then turn that baby loose on the track, without worrying about rod bushing and ensuing crankpin damage. Your motors will then last indefinitely, with good air filtration.

Hey Chris, could you tell me what size the rear bearings are in the shark 9 and the c6?

Shark9 and C6 engines are both 14x25.8x6 for the main bearing. If you are unable to find a replacement RB bearing they are the same as the Novarossi bearings. You can also get the Novarossi ceramic in that size if you want.

Ok, I need some help with my Killer 9. The motor has a little over 2 gallons on it, I run nitro juice 25%. I'm running it with a 7mm restrictor and the dynamite 053 pipe and a 97T glow plug. Motor has been sealed and bearings were recently changed, put a ceramic in the rear. Motor rips and is fast, but I can't get the bottom end dialed in. It feels rich on the bottom all the time and loads up quickly when idling. I keep leaining the LSN and it get's better, but never get's right before it's too lean. I do the pinch test and it idles right at 3 seconds before it starts to increase in RPMs. I'm starting to think that the 3 second test just isn't sufficient for this motor. When I'm waiting on the start of a main, I'm always concerned it's going to flood and die. When we take off, I smoke everyone out. Should I just contiune to lean on it or what?

It does sound like your LSN is too rich if it loads up while idling like that. When you are leaning the LSN are you also lowering the idle of the engine?

first thing to do is remove 1 of the head shims....... it has 4 in it, and it really only needs 3....with 4 shims the compression is very low, which is what is making the low end hard to tune...what kind of clutch are you using ? what type of vehicle and gearing ? also you may find the Jp3 to offer a much better powerband then the 053....

I have removed 1 head shim but have only run it once since. I do have a JP3 pipe but it seemed to be a gas hog for me so I haven't messed with it in a while. I haven't touched the idle at this point.

Forgot to add, the motor is in an XT8 09 spec with standard gearing13/47
clutch is answer aluminum shoes with medium springs.

RB has so many engines out now. Can someone do a run down? Just looking to get back to RB just to see what they got goin' on. Thanks.

I would also say lean the bottom out more, with the 7mm carb restrictor you have to cut the fuel to match the less amount of air coming in. I ran a 7mm restrictor in my K9, my low end needle was turned in quite far to get the tune right. You will know when your low end is too lean. Fatten up your highend a little to be safe and tune in your low end first. Also Don't try tunning these engines until you get heat in them also. Preheat it to about 200* with a hair dryer or heat gun. Try the JP-3 again, my experience with it on my JL .21 (same engines) is that it really wakes these engines up thru the entire powerband!

Cool, I'll keep tweaking on the lsn. I was wrong, I have a JP2, not 3.

Thanks for the help

Thanks Chris.

Hey pickle, make sure your idle isnt too high. I see alot of people have the idle turned up too high and it causes the same effect. Try lowering your idle some and jus see if u notice a difference.