Ando the huricane heads for 120" I looked at had 12.1 comp coated Pistons  the cam's have 675lift & 270 duration @ 50.  You sure that's the cam you have?

 

Krash, you might be thinking of the S&S 675, the RX cam is more like 660 lift and 278 ?

No speedster these are new HD performance heads best heads for HD i have seen, out flow the 120R heads by a long way the superflow flow bench could not measure how much air as they flowed more that flow bench. these heads will kick s&s butt. i would like to build a 113 put a set on it just for fun.

they have huricane riveted to outside in normal spot. for HD

 

Another chapter begins with the RX

the other day noticed that at about 5500rpm the bike just nose dived( everywhere else was sweet and to anybody else they would have never noticed the issue as big ran good up till 5500rpm)

after trying new plugs and leads that didn't make a difference I put it on the roller where it was noticed that the AFR's just fatted up after 5500rpm, after several VE and map changes with the same problem still present it was worked out that there was an efficiency problem.

when I got it home it was discovered with a leakdown test that front and rear exhaust valves are passing major air.

Also whilst stripping it down I noticed the front intake valve has a busted spring

Got quite a few things to check out Hilly hopefully I won't be off the road to long

All is good as one has to understand that when you have these things highly strung there will be these bumps in the road

Very lucky your on to it and running double springs could see a dropped valve happening there ,hopefully it will be as you said this is good thing
About keeping a eye on things with a leak down good catch there that's for shore

Very lucky.

I can't pick any think up with straight edge but will have the shop check them out

WTF damaged that exhaust valve guide in pic two Ando.

That's not good to read Ando, do you think it's tunned right? Looks on lean side to me but the fuel probably different to what i'm used too. what was AFR under load when you reved it WOT?

 

Thanks Ando, that does not look too lean, but i would probably have a map closer to 12.5 under full load if i was racing.

The exhast valve would be hottest part in motor when runing so has a hard job.

was the head as it came with 120R from factory?

But not too bad these things can happen just on rebuild you try to make sure that don't happen again. 

When you mentioned you would like to shave a bit off the head for a bit more sqeeze, i love that myself!!! but i would check what swish clearance you have now, then take it off bottom of barrels to rais piston in bore for a tighter swish, but don't go tighter than 40 thou for street, if you can't find someone who can machine from bottom of barrel i know someone who can.

 

Krashhere are my target AFR's pretty consistant with what the gragh indicates, I will take your advise on board and try a 12.5 AFR

The heads are the stock 120Hurricane heads Untouched just bolted on

With the bigboyz calculator if the heads are 95cc as advertised and the 15cc domed pistons it coms in at 12,42/1 static compression and with the RX 267 (67* Close) cam its 9.7 corrected.

The heads will be CC'd to confirm actual chamber size before I take any of them

[URL=http://s307.photobucket.com/user/Ando1450/media/2015-09-29_184652_zpse3bvvg8q.png.html][/URL]

Ando How much cranking pressure has it got?

Also can you show me the timming your running?

Had 196psi before head issues, will post up timing tonight when get home

Hilly all good points, the head Temps don't get over 270*F and quite cool at speed like around 220 to 230, had the same thought about timing tables but it doesn't pull timimh according to the power vision ( I have mounted up on the bars)

I might throw it out there on HTT and see what they think, will have a yarn to Lushy aswell

Hilly Valves are straight, seats will be cut to 45* and valves ground to 45* this will help with durability

it looks like apart from the busted spring (which could be just one of those things) that I have not done any damage, seats look firmly in place and will just get cleaned up, I am waiting on the Chamber volume to work out if I want to up the comp some more

Timing I got hold of a RX tune of some one else and the timing table are very different so I will dig a bit deeper there

This is from another 120RX in a wide glide with V&H Longshot staggered

[URL=http://s307.photobucket.com/user/Ando1450/media/2015-10-02_210734_zpsqthorzr8.png.html][/URL]

This is from another 120RX in a wide glide with V&H Longshot staggered

[URL=http://s307.photobucket.com/user/Ando1450/media/2015-10-02_210734_zpsqthorzr8.png.html][/URL]

Hilly wouldn't it be nice to have a roller and just play around and then develop your own methodology and system around timing, you could base this on info and see what works.

But for me if you have an efficient build then it should require less timing, but that's just my pea brain theory on it

Hilly's right, timing is such a complex issue, so many variables to consider.

Ando, along with the roller, a vacuum gauge would be good to use to monitor the best volumetric efficiency at any given condition or scenario whilst hooked up to the tuner.

You could then create custom advance curves that would suit each engine and it's condition, based on that best volumetric efficiency.

Food for thought.