RM370 Cylinder head volume ?

[micko]

Does anyone know the volume (cc) of a standard head or a recommendation  for a 76 RM370, thanks in advance

[oldyzman]

Cant help you with the cc volume in the chamber, I think you need to adjust the squish first then measure the cc's with a burette or even with a syringe, then calc the effective comp ratio, if you need to read up on this stuff then get the book:
A Graham Bell Two Stroke performance tuning
it helped me a lot.
I think most peolple who are really fair dink about building a fast old two stroke reshape the chamber, over my head though.

Brett

[micko]

Getting it welded up and reshaped etc, just wanted to know the original volume as this one has been played with (butchered) before. Cheers

[Tomas]

Are you going to keep the old suzuki shape or going to shape it more modernish? I did one head for rm 125T folowing this man's blog http://www.southbayriders.com/forums/threads/116608/page-5. Head works well but I have not noticed any power increase.  I only ride bikes for fun. Was just experimenting a bit. It may work beter for open class motors since they are harder to jet and they also ping a bit I have heard.

[micko]

Going for the modern shape and centre spark plug Tomas, hopefully get rid of the dreaded ping !!!

[KTM47]

Just something to consider. 

I received a bulletin from MA saying the government is going to phase out the use of leaded fuel of any type for racing.  That means it will be come impossible to get avgas etc.

I know that part of making two strokes work with unleaded was reshaping the heads.

[sleepy]

Just something to consider. 

I received a bulletin from MA saying the government is going to phase out the use of leaded fuel of any type for racing.  That means it will be come impossible to get avgas etc.

I know that part of making two strokes work with unleaded was reshaping the heads.

Kevin. What is MA's view on oxygenated race fuels. There are several brands out there make make good HP improvments.

[Momus]

Going for the modern shape and centre spark plug Tomas, hopefully get rid of the dreaded ping !!!

How badly is your bike pinging?

My 370 has a 400 barrel with the 370 head. I set the squish at about 050" and enlarged the combustion chamber slightly more than pro rata to maintain or drop the CR. I run it quite rich and have never heard more than a tiny, momentary ping running in deep sand on a hot day.

[LWC82PE]

The spark plugs were on an angle for a reason. The single down tube frames would block air flow to the central plug so they tilted them out the left so they stick out past the frame and recieve more/better cooling.

[Davey Crocket]

But all the DG heads etc had the plugs straight up and down and in the centre Leith. What about the heads that had the combustion chamber more to the intake side to stop pinging and to run a higher compression. They tried all sorts of things.

[Lozza]

Just something to consider. 

I received a bulletin from MA saying the government is going to phase out the use of leaded fuel of any type for racing.  That means it will be come impossible to get avgas etc.

I know that part of making two strokes work with unleaded was reshaping the heads.

There will never be a phase out avgas for piston engine aircraft. So we will always have leaded race fuel if you want it. Unless expensive and extensive testing starts for lead how will that ever be policed?

Reshaping the head for unleaded in a myth, the head will work the same with leaded and unleaded. The fuels require different carburetor and ignition settings.

Does anyone know the volume (cc) of a standard head or a recommendation  for a 76 RM370, thanks in advance

About 12:1 is the highest comp your going to get away with on a air cooled engine before the diminishing returns set in. 

[Momus]

The spark plugs were on an angle for a reason. The single down tube frames would block air flow to the central plug so they tilted them out the left so they stick out past the frame and recieve more/better cooling.

l reckon the plugs were on an ange so they could be easily accessed with the chamber in nice and tight.

[KTM47]

Just something to consider. 

I received a bulletin from MA saying the government is going to phase out the use of leaded fuel of any type for racing.  That means it will be come impossible to get avgas etc.

I know that part of making two strokes work with unleaded was reshaping the heads.

Kevin. What is MA's view on oxygenated race fuels. There are several brands out there make make good HP improvments.

The MA homologated fuels are on this page =homologation]http://www.ma.org.au/index.php?id=1984&no_cache=1&sword_list[]=homologation

[sleepy]

Just something to consider. 

I received a bulletin from MA saying the government is going to phase out the use of leaded fuel of any type for racing.  That means it will be come impossible to get avgas etc.

I know that part of making two strokes work with unleaded was reshaping the heads.

Kevin. What is MA's view on oxygenated race fuels. There are several brands out there make make good HP improvments.

The MA homologated fuels are on this page =homologation]http://www.ma.org.au/index.php?id=1984&no_cache=1&sword_list[]=homologation

I had a look and only 3 homologated fuels. One being VP Roo 100 but there are a stack of other VP products that aren't. Is MA or MQ doing any fuel testing at meatings or is it a free for all?

[GD66]

That joint is out of control with their compliance, political correctness, racial equality, land rights for gay whales etc. Why stick their nose in on that subject when they are flat out administrating their gradually-disintegrating sport ? Who is going to do a fuel test on a 30-bike club day miles out in the sticks ? Idiots.