rb 22

[Darrell Taylor]

who out ther running a rb 22 with avanit head!!! and how much cooler do ther run.please,and who selling them,price

this May or not help. I have an RB20 with an Avanti head and it does appear to be running cooler. think I may have to go to a B7 as it's very rich downstairs. The head is the only change to the kit well apart from new piston and crank and it was running fine before. pretty unrideable with the b9

dont change the plug to a 7 or 8 even youll kill it the 9 or even a 10 or 11 would run fine i reckon you have an oiled up plug

if not oiled up the cooler running head has probably just tipped over the edge over rich jetting into too rich jetting

[Darrell Taylor]

Ok, Darrel, thnx, just that I use centigrade and the sensor is under the plug. When I had my tuned rb 236 std cyl head, using a tto gauge at 65 - 75 mph it would go as high as 220 degrees. With my steel lined rb 260 with ron moss head at 65 - 75 mph its only ever been as high as 187 degrees. So it runs a lot cooler than before. this is on the road not a track so maybe thats making the difference?? What do you reckon?


cheers

think ur old 236 may have been a touch lean or too advanced or too high compression or had a bad fan/cowl clearance and was u running different pipes ,too many differences between the 2 motors to make a fair comparison really
also diff plug grades will show diff temps ,the ones im quoting are on a 10plug

[jonashford]

Darrel,

It was running a franspeed race, close fly cowling, cutaway head cowling, mikuni 35tmx carb, n3 plug, af rb cyl head, not sure of comp ratio but done by afs, agusto 7000, set at 24 degrees

current one is close fly cowl, same agusto set up, ron moss head and cowl, dont know comp ratio but again done by afs, same mikuni carb, n3 plug, was with the same race pipe and then franspeed tourer now super tourer, done thousands of miles this year with this set up so it must be somewhere near, Its just I thought the temps are low!

Im getting a new gauge soon so maybe they will differ again?

cheers
Jon

[Darrell Taylor]

Darrel,

It was running a franspeed race, close fly cowling, cutaway head cowling, mikuni 35tmx carb, n3 plug, af rb cyl head, not sure of comp ratio but done by afs, agusto 7000, set at 24 degrees

current one is close fly cowl, same agusto set up, ron moss head and cowl, dont know comp ratio but again done by afs, same mikuni carb, n3 plug, was with the same race pipe and then franspeed tourer now super tourer, done thousands of miles this year with this set up so it must be somewhere near, Its just I thought the temps are low!

Im getting a new gauge soon so maybe they will differ again?

cheers
Jon

youll be richer now on the bigger motor ,and effectively more retarded timing as bigger bores req more advance,the avanti head has a full squish band design and generally run a tighter squish for improved cooling where the std rb head 1.5 sq runs a bit hotter too ,sounds like u have a nice set up
r u going to dans dyno shootout

[jonashford]

Im running it with a 340 main, 25 pilot, 57 needle 2nd clip down, Ive tried a 56 needle but its boggy mid range so went back to the 57, I run a powerjet on it as well but i prefer to not rely on it, rather the jetting be right. Ive yet to try a 345 or 350 main cos of the crap weather, with the tourer on it ran ok with a 350 in but it hardly ever got on to the main jet probably due to the cyclone box and big crank, I prefer to do my jetting and experimenting when I go on the rallies, a 690 mile round trip to woolacombe usually gives me plenty of time to iron out any problems lol, so I wont be visiting the shoot out day. Hope it all goes well for everybody

Thanks for your time Darrell

cheers
Jon

[rbgaz]

So what is the danger zone ?


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