Head flow testing.

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comnoz said:
I have tried to use aluminum rockers before- not on a Norton- They worked great for a while and then started breaking one after the other.
Aluminum rockers would need to be very large to avoid flexing and the fatigue factor. I would only consider steel or Ti in the limited space available in a Norton head. Jim

That's the conclusion we came to for this service duty and space available.

We need to start talking about the next shortstroke build.
 
One of my friends used to modify Honda XL125 heads back in the '70s. He would take out a bunch of metal and then just chop off the guide flush with the port. Of course he did that by just leaving it in there while he did the porting job and it ended up flush with the aluminum hole. The resulting guide was about 5/8 of an inch long. Sounds crazy but it lasted ok for racing and he won a lot.
 
Just tossing out stuff I've come across and applied accidently. If no vanes to turn air flow then next best is vortex generators. Might try the 1007 head with a saw tooth or wire thread fiber gasket at the entry. Might try with just the lower half of gasket projecting VG's into flow - say 1/32 to 1/16" to get most the way out of boundary layer. Large scale aircraft/car size, orient the vanes 15% to the streamflow. That's why ya see V shapes in wide flat flow areas like the center of roofs but straight along body lines near roof edge because air flows up and back diagonally on its way to the lower pressure center flow. This draws fast air energy into the thickening boundary layer to get it moving further down steam bend, and against the high pressure back wash eddies formed on the down slope bend of rear window or short radius of intake.


Head flow testing.


Other shapes work too like sharp scales they not think even add thrust by increased back pressure.
Head flow testing.


Inside the head there's a thumb size patch I see inlet flow blasts against and then seems to ricochet to miss the exhaust valve. I wonder about trip tumble ridges or dimples there. One wants to see head surfaces all blasted clean of carbon.
 
Hi again, did mislead you a touch bike# 1 has a RH10 and bike # 2 has a RH4 head. Is the RH10 with a decent valve job the way to go with the JS keihins?
Regards Mike
 
Brooking 850 said:
Hi again, did mislead you a touch bike# 1 has a RH10 and bike # 2 has a RH4 head. Is the RH10 with a decent valve job the way to go with the JS keihins?
Regards Mike

Gooday Brooking 850,

The Rh10 should outperform the RH4 in every situation. Mine runs away from the 2 RH4s I ride with. There are many better qualified than me to comment.

I woud run the RH10.

Cheers
 
Brooking 850 said:
Hi again, did mislead you a touch bike# 1 has a RH10 and bike # 2 has a RH4 head. Is the RH10 with a decent valve job the way to go with the JS keihins?
Regards Mike


Yes, The RH10 is the better head both for power and durability. Jim

[too bad the RH4 isn't an RH7- you could put it on e-bay and buy a couple more Nortons from the proceeds}
 
comnoz said:
Yes, The RH10 is the better head both for power and durability.

Could a knowledgeable machinist/engineer port out the RH4 head to match the RH10? Seems a simple upgrade...
 
grandpaul said:
comnoz said:
Yes, The RH10 is the better head both for power and durability.

Could a knowledgeable machinist/engineer port out the RH4 head to match the RH10? Seems a simple upgrade...

The RH4 ports are already larger than the RH10. You would have to un-machine them. :)
 
So the smaller ports on otherwise identical heads are better?

Can the RH4 then be welded up and ported to match the 10?

I would think the additional welding would fix and/or help prevent typical head cracking on the RH4 also...
 
grandpaul said:
Could a knowledgeable machinist...

I never claimed to be a knowledgeable machinist, ESPECIALLY on heads.

There's one category I can't be listed in: people who have destroyed Norton heads (and there are MANY in that category)
 
mikegray660 said:
ludwig said:
grandpaul said:
Could a knowledgeable machinist/engineer port out the RH4 head to match the RH10? Seems a simple upgrade...

???


I would like to post a cartoon here , but ..
:


haha good one- and i think i know which cartoon! :shock:

How old are you two guys? Do your parents know you're using their computers?
 
I think it starts with MONKE and ends in Y :mrgreen:

mikegray660 said:
ludwig said:
grandpaul said:
Could a knowledgeable machinist/engineer port out the RH4 head to match the RH10? Seems a simple upgrade...

???


I would like to post a cartoon here , but ..
:


haha good one- and i think i know which cartoon! :shock:
 
I believe there was a past discussion about using epoxy to reshape intake ports, which could be done that way (per the thread) because the temp was low enough to allow it. I will see if I can find the thread and post it here.

Russ
 
rvich said:
I believe there was a past discussion about using epoxy to reshape intake ports, which could be done that way (per the thread) because the temp was low enough to allow it. I will see if I can find the thread and post it here.

Russ

Epoxie can be used to build up the intake port and make it flow better. With modern pump gas it will only last for a while until the epoxy starts failing. It seems to last ok with race gas. At least long enough for racing. Welding in the middle of an intake port is pretty much out of the question.

That will not solve the cracking problem in an RH4 head. Fullauto cured that one. Jim
 
bill said:
I think it starts with MONKE and ends in Y :mrgreen:

mikegray660 said:
ludwig said:
???


I would like to post a cartoon here , but ..
:


haha good one- and i think i know which cartoon! :shock:

"Ludwig", "mikegray660" & "Bill",

First time around this stuff might have been considered mildly humorous by the easily amused, but by now it just seems like mindless persecution.
 
rvich said:
Jim, I found the thread, and you gave the same comment there:

fullauto-head-combat-head-standard-head-t8478-30.html?hilit=intake epoxy

And I believe it may have been discussed in the earlier pages of this thread as well. My memory was that it got higher marks. It was another member who swore up and down it was the solution. :oops:

Russ

Well I have certainly done a lot of JB weld port jobs- both on my bikes and other peoples. It is a lot easier and cheaper than welding or installing inserts. On my streetbike I would get one season out of it before pieces started flaking away. Usually around 8000 miles. I only consider it for racebikes anymore. Jim
 
thanks guys, will do a swap after giving the RH10 a thorough inspection and valve job, any advantage in changing the valve/seat size, or just leave them std and a good valve grind/lap?
Regards Mike
 
Brooking 850 said:
thanks guys, will do a swap after giving the RH10 a thorough inspection and valve job, any advantage in changing the valve/seat size, or just leave them std and a good valve grind/lap?
Regards Mike

What I usually do for a good strong stock street bike is just a good 3 angle valve job. Keep the seat width down to 1mm intake and 1.5mm exhaust so they don't pack up with carbon and burn. Make sure the short side radius is steady -without steps as it turns down toward the seat.
Reduce the valve guide size to 1/2 inch where it protrudes into the port so it looks like a 750 guide to the airflow. Use Black Diamond valves and hard bronze guides.

On the 850 the best mod for the buck is to raise the compression up to around the 750 spec. 9.5 to 1. 10 to 1 will be ok if you ride solo most of the time.

There is a lot that can be done beyond that to raise the RPM level and make it more racy but for most street use I wouldn't go there.

Stick with a stock or very mild performance cam. Race cams get their horsepower from increases in RPM. Often times they end up with less torque in the RPM ranges enjoyed on a street bike. It takes a lot of time and money to make to make a Norton dependable when it's used at high RPM regularly. Jim
 
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