should i fit a big valve head?????

I told he it was for road use only that I like to shall we say use it not cruise it. That I did not want all top end but as much spread of power as possible so I could do overtaking with having to drop gears an whined it up first (had 350YPVS Yamaha but I've grown up now honest I have) I told him to give me a reliable useable motor an that i would except his advise as to what parts where needed an work to be done. He said my motor was not in to bad a state an he would rework the ports to suit my needs. he is the kind of man who you just trust as he carefully lessens writes down what is to be done an shows you the parts etc that will be used. He talks to you in a modest way an doesn't try to sell you things instead reminds you of the fact politely that this will not be a small budget job an if you don't want to spend the money he will not mind an understands. He reassured me the work will give me the engine I want an with his knowledge an reputation you can't realy not trust him to deliver. He did not say he would open the ports as I asked if that was his intention by he would improve there flow and that the motor would respond well to the work with bottom end being done to an it would all work together as a whole package.

jseng1 said:

Those forks on the bottom of that crank are never going to work as a bob weight.

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That is just what you end up with when you have an old Maico front end laying around and you need something to align a two stroke crank. Jim

Sheeze Jim and me are in a bit of a quandary as boosted engines respond better to bigger exhaust valves than intakes to flow more but can then have more heat flow issues, ugh.

I just thought that Mick is undeniable an expert an so let him do what needs to be done he has the knowledge skill an long track record to back up his claims. Both he and his wife are very pleasant to deal with an leave you feeling happy you have done the right thing and as someone else says in another thread on here Nortons long stroke an low balance factor means these engine behave in an unusual way compared to other engines so experience counts with them. When the motor is back in the bike an run in then we shall see but I have no doubt it will have so power an he assured me it will pull on the road an be very useable so know its wait till work is done after Christmas an then we will see.

Glen,when the fullauto head is used with the raised floor of the exhaust port, does it work better with big or small diameter pipes, or is the effect unchanged whatever diameter pipe is used ? Does it work differently when a 2 into one system is used compared with separate pipes? Do you have a link which describers the reversion effects ? I feel that the results of using the fullauto head with a different configuration exhaust system might give unanticipated results, and it is an expensive exercise buying the head. In a lot of these things the effect of the combination is often different from the sum of effects caused by the individual parts.

STEVE ; here topic-t12069.html?hilit=hogslayer young T. C. s machine is stated to have 1 5/8 intakes & 1 7/16 exhausts .

Generally one would assume the throat was opened appropriately , AC . or we could put a 2 in valve on a 1 in port , to block it comprehensively .

The Ancient Alfa straight eight 2300 had interchangeable valves & heads , fore and aft . As it was Supercharged . Impeding exhaust flows not a good idea .
The Intake largely takes care of itself - Blown . The tight lower radius , if present , shouldnt present to much of a problem . but good gnomes get the garden hose full tit ,
put a finger over the end , and squirt the water down the center of the intake . Observeing at various valve lifts , for stalling or eratic behavior . good fun on a hot day .



appears to be the Sierra Cosworth TURBO valves from their site . Nimonic etc & oversize available there .
Might pay to have Hi Duty Ex valves in there , thatll handle the heat . Talk of Alumn Bronce preferable
for guides in heat to .

I like the Weslake Rickman 4 valve heads used on the Nourish engines. Are the Nourish engined bikes quicker than the commandos when raced in the US and the UK ? Generally speaking a 4 valve head usually gives a 10% power boost over a two valve motor of the same capacity. Although it is possible to get a two valve Jawa speedway motor going almost as fast as a four valve one. Perhaps a big twin doesn't rev fast enough to get full advantage ?