Forum Navigation
Please or Register to create posts and topics.

477 Racing Head - Status: canceled

PreviousPage 4 of 4

interesting idea  if i had a working sample i could hand it to the indian head guy who would copy it by carving a oem head.

OK, here is the result and it meshes with Dools dyno.

I made a mistake at transfering data from the graph yesterday - the corrected value is 13 sec - unfortunately due to this mistake 2 further data points became unusable which kind of cuts into the reliability of the value as average. Because the result is less than surprising I let it slide (I would have to re-do the head mount - too much work!) - todays average with the OEM head turns out to be 14.6 sec and with a bit of wiggle room this is more or less what the dyno says - 1.5 hp = 5% over stock.

Case closed I think. the head is not worth playing with, at least not in an unprofessional manner that is payable by mere mortals.

It should also be mentioned that there are issues with the quality of work of my head guy. He seems to be OK when it comes to standard refurbishing work but like a brainless drone he does not think even a bit about what he is doing and what effect it could have. Peter was emailing me the results of his BH inspection and they are not encouraging. Appart from the fact that his logic is sound: any effect will be only due to head room increase, not valve size increase, the usage of USED valves (re-ground probably with an electric drill and sandpaper) is a big no-no and indicative of the "I give a shit" work ethics here. If they can get away with it they cut corners wherever possible. Quality is an unknown thing.

I quote his email here:

This (picture) is the condition of the Valve after a 150kms, impossible to adjust Tappets correctly. Not my opinion, Fact. Feeler gauges can not set that gap, it must be done by feel.

Having been reground from an old Valve, the Hardening is gone.

Second Pic shows the measurements of the vital dimensions of the BV, the number on the Inlet Valve is 40, the number next to the Seat is 34, okay the Valve is Bigger than original at 37.5mm but the seat is still the same size, so yes it has Bigger Valves but the Hole that the gasses go through is the same as OEM. As the Seat is 3mm thick , there is not much that can be done to enlargen it without seriously compromising its integrity.

Improvements from de Shrouding and the change in combustion Chamber are what your getting although I don’t know if there is a  name for that, perhaps there is but I doubt it sounds as good as Big Valve.

and he is 100% spot on.


Uploaded files:
  • valve1.jpg
  • valve2.jpg
PreviousPage 4 of 4