The WS7 3 is several years old, if you really like these engines go with the WS9 as it is just like all the WS7 engines you are used to only it has a turbo plug and uses the MES exhaust system that gives it a little more power as well. If you want the most powerful you want the B9 or soon to be B10. The Shark9/Cross10 are basically the same engine and offer almost as much power as a B9/10 with better fuel economy. Any of the other engines are really just sport engines and probably would not satisfy you if you have raced before.

I have not had a chance to use the engine protector yet so if you get it to fit with the Losi clutch I would like to know. As far as runtime, thats a tough question that has a lot of other variables. For me when I go down in nitro I usually get worse gas mileage as I find myself in the throttle more because I am missing some power I am used to. the Shark gets better mileage than the B9 so just add the shim and go with 30% and see how it does. Remember it's going to take a good gallon before it'd fully ready to race and lean out for max performance and mileage.

Hey Chris, the B9 and B10 are the same, they are 5+2 intake ports, and 3 exhaust ports, the Killer 9 is 5+2 exhaust and intake and 1 exhaust port, the Shark 9 is 3 intake and 3 exhaust port,

Yes, B9 and B10 are the same engine with cosmetic changes. The crankcase is now coated like the WS line of engines and the case it's self is reinforced a little around the main bearing. The B10 also has an extra fin on the cooling head. I have honestly never even bothered with a K9.

Also not sure if you were a WS7/9 fan but if you were you may want to pick one up as they are doing away with the entire line of square stroke engines, and replacing them with the Cross10.

Yes, I saw that, I like the WS7 line, to me it's more linear than the C6 line, and more top end, I'm a big fan of the WS7 line, the B9, B10, and the cross 10 seem to be the same as the C6 BBT line. I do like the mileage the C6 line gets. I did see that they have a WS9 engine also.

Hey Chris, have you been able to get any track time on your Shark yet? I am trying to decide on a fresh mill for this season.:tire:

B9 and B10 are really just the old school C5's with updates thru the years, so they went to C5BB, then C6BB then C6BBT and so on. The Cross10 is not the same tho, it is actually the 2010 version of the Shark9. The WS9 is honestly an awesome engine as it's the first time they incorporated the 3 exhaust ports (MES) into that engine line. Unfortunately the ones that have already been made are all that there will be.

Ran it for a few practice tanks in AZ last month, it ran awesome but it was a pretty limited amount of time and still not fully broken in. I think you should get either the Shark or the B9, the WS engines are sweet but you really have to coax some extra bottom end out of them at our altitude.

Finally got some runtime tuning with the Rally 9.
Very nice smooth engine and a whole lot of run time.
In my Hotbodies D8T 15.30min of run time from one
tank. 7mm restrictor, Werks 2013, and Sidewinders World 30%.
Plenty of power and not lacking anywhere.

My race partner with WS7 III with OS 2050 got 13.30min out of his Kyosho MP9 on a full tank. Plenty of power all around. 7mm restrictor and same fuel.

does anyone know how the pros break in there motors, and in details.

Found out the engine protecter dosnt come out until april:(. I well be trying it with a losi clucth and ill let you know when i get it im about 99.9% sure it well work. The shark is waiting on a competition heater and ill start breaking her in Nice and Slow should be ready for late spring i know its going to be a beast. I heat cycle my motors alot and take my time never rush Your motor. I always get a good 10+ gallons from my Rbs with all the power i need. Ill report how everthing going with the shark for you guys. Thanks for the info. Speedyrob

Anyone know where I can find a piston and sleeve for my RB WS7III?
If anyone has anything just shoot me a PM. What plug have you guys ran back in the day with the Ws7? It's a standard plug.

Part number RBD01143-WS7M will work for you and it looks like A-main has it in stock. This is the P/S/R set for the WS9 so it has 2 extra exhaust ports and probably the reason it cost more than the set for WS7.

Was trying to look for a p/s set without rod. If I can't find that I'll just put my RB back on the shelf. I was just going to dust it off to see if it has a smoother power band than my Werks engine.

Rb ws7
 

Sounds like you have a new conrod if you dont you may need one so i would buy the new P/S/R . If you are looking for a cheap way i would send your old p/s/r off to rayaracing.com it well be about 90% brand new but may need a new rod. Hope this helps im sure the ws7 is smoother than the werks. Speedyrob

C6 VS C6 USA
 

What is the difference between the c6 t7 and the c6 usa edition???

There are two things, first is the the crank shaft. The C6USA has a ballanced modified crank that has a hard coated pin. The Turbo button on the C6USA is also modified and has what looks like a turbo cut in it that faces the exhaust port. The USA has quite a bit more power but does not get quite the fuel mileage of a regular C6.

I'm having a time trying to get the tune on my S5 just right. I know it's hard to help tune over the net, but any help is appreciated. I can normally tune most any engine great, I just can't get a handle on this one.

Top end seems great, and I can get it to idle good. But when I'm running on the track, the bottom end just seems like it's not there. It's not very peppy. I can get a video of it if it will help

Can a bad bearing cause this? Even if it runs great everywhere else? I'm not having problems with temps, it's just that low speed problem.

To anyone running the S5, where are you needles at now from fully closed?

I would try leaning your bottom end a little more. What is your engine doing when you come off a full speed pass. What pipe are you running? I have a backup souped up S5 with turbo button and WS7 crank that I run with a Dynamite 007. It is nasty!

I went from a JP2 to the RB 2020 and it helped the bottom. I tend to run the bottom a bit fat, it seems to lean out after its heat saturated.:)

I'm running a O.S. 2050 on it right now. I have noticed that too kat.

When I make a wide open throttle pass, it takes a minute before it comes down to the actual idle. when I gun it afterwards, its like it hesitates, then it goes great.

When it hesitates it's not bogging, or cutting out, just sounds real flat and doesn't have the bottom I think it should have.

My cousin has a WS7 and I can tune his with my eyes closed.

The S5 will seem a little slow on the bottom if it's lean or rich on the LSN. The best way to know what the engine needs is to recognize when the bottom end seems soft. Does it start out with good snappy bottom end then lose the snap as you run longer? If so that means your LSN is too lean. If you never seem to have good response from the bottom end then you are probably too rich on the LSN. Remember that when you lean the LSN you will need to lower the idle, and if you richen up the LSN you will need to raise the idle.

Thanks Chris. On the box the LSN seems fine, it's when I put it on the ground to take it around the track it seems to lose power. I'm running an Odonnell 99 in it now, with the 2050.

I think I may have had the idle a little high as well. I just lowered it and I'll give it a shot tomorrow.

Also checking for leaks, the front bearing seemed to leak a little more than I'm used to seeing. I'll work with it tomorrow, and if I can't get it I'll order a bearing and see if that helps it

The front bearing on the S5's only have one rubber seal so they will leak a little more fuel especially if your still runnin rich. If you can find other pipes try them if you can, I have never had any luck with JP or OS pipes on RB's. Another thing to try if you have the option is maybe 1 tooth bigger on your spur gear, you won't even notice much of a difference in top speed.

I normally use a McCoy 59, you may want to try one or a Odonnell 77. If you can find a RB 2020 or a RB 3002 pipe to try I think you'll like how it "feels".:)

anybody know rear bearing size for a RB S9?

13 X 25 RB part #01150-13s

RB Shark 9 update
 

Update on the Shark 9 guys this things coming ALIVE:sneaky: not leaning on it much. Im still using a 1/10 faom to keep it around 210-215F it been leaning itself out alot. Im about a quart away from a gallon trying to get some fuel thru it before my points race on march 27th. I have been using the compitition heat to help preheat before start. It feels like its going to have something for my C6 i have my motor for my 2010 points series. Ill keep everyone posted about how everything goes. Great motor as aways from RB. Running byrons 30% nitro 11% oil .40 shims Thanks Speedyrob

Thats good to hear!!! If anyone is considering one of these I know a main still has them on sale. The new Cross10 is going to be the replacement for the Shark9 but it will not be quite the performer the shark is as the Cross10 will not have the balanced crank like the Shark has.

I thought I posted this..guess I was wrong... how does the K9 perform with a 9853? lmk guys thanks

K9 has good bottom end, the 9853 is for more bottom, I would try a9886, before the 53, the 86 is for mid to top end, and probly get better fuel mileage with the 86 over the 53. I'm using the RB 2045 with the 192 header, and it works great.

Howdy.

I am new to nitro and I recently bought a used S5 L2G and it is doing something strange.

The motor starts and idles fine. When I run it around the track it has good bottom end and high end with plenty of smoke. The tuning seems fine. Once in a while when I hit a jump wrong (not a hard hit, just a small one will do it also) there is hardly any power at all. The car will move but just barely. After 10 or so seconds it will start working correctly again. Then I take a jump wrong or jar it in some way and no power again.

I have had a couple of guys that are good at tuning try to figure it out but they haven't had any luck so far.

It does it in two different vehicles with different clutches, etc. We have done an air leak test and it doesn't appear to be leaking anywhere. We have went back to factory settings a few different times and re-tuned and it still does it. The carb doesn't appear to be sticking closed.

Has anyone seen this happen before?

Thanks!!

I have..2 different times for 2 different reasons.
Check the head shims on the head button,since it was a used motor a shim may have been taken out and or your running a fuel the the nitro and oil combination is creating to much compression in the motor...try different fuel and or a different ...cooler glow plug...
On my Nova after a big jump or small one after about 2 minutes after motor was warm it would bog down after landing....LIKE a lean bog starving for fuel...,,,my fuel was creating to much compression once motor was warm.
Also on my 8.t 2.0 truggy the piece that the throtle linkage goes through thats attached to the servo horn was installed backwards and this was causing the carb to bind at about 1/3 open .

thanks

I've been out of racing for a few years now and went last weekend. I threw a rod in my S7 and I'm looking for a new RB. I've read several pages back in this thread and had a few questions. I noticed that RB is going to stop producing square stroke engines, whats the reason for this? I liked the power of my S7, it had been worked on alittle but it was very drivable. Is the S9 basically the same engine? I'm running it in a RC8 with a 2035 pipe. Is the Cross 10 replacing the S9? Thanks for the input.

Well I am not exactly sure on the reason for eliminating the square stroke engines but it could be that they are just old technology. Novarossi doesn't have any more square stroke motors so maybe it was an extra cost for RB to keep these engines in production as they are the only engines with 13mm cranks.

The S9 that is still available in some shops is the same as the S7 you are running. The WS9 will be an even better choice if you like your S7, the WS9 will have a little more power on the bottom end and more top end than what you have now but it will still be very smooth and very controllable.

The Cross10 is actually replacing several engines, the S3/Junior9, S5/Hobby9, S7/S9, WS7/WS9 were all square stroke engines and they are all going away. The Cross10 is the Novarossi based replacement for these engines, the K9/K10 is the Taiwanese engine in the lineup that is designed to give a good performing engine at a good price. (I personally prefer Nova quality)

Thats 2 of us!:nod:

Check your battery connections also, maybe a servo, or receiver too. ya never no with this stuff.