Topic: higher compression

[James360]

I have a CL360 considering boring it 2mm also raising the compression,
original compression is 9.3 how high do you figure i could go on the static compression still run 93 pump gas ?. I'm considering just forgetting
pump gas going to 12.5 compression pistons how much extra torque/hp
do you think i would gain by going to 12.5 comp.

[mlinder]

10.5 is about as high as you should go on an old street bike, James. It depends, of course, on combustion chamber design, piston design, etc, but 10.5 is a safe bet.

[James360]

Hello mark

If I keep the stock cam keeping the revs down not trying to do 13,000
rpm road racing it I assume this what they try to do in racing
will the stock rods, bearings handle the 12.5 compression.
This bike is to small to be a real road bike i have it stripped of all the lights, gauges anyway. I'm fixing to tear it down send the head to mike reick,
if i'm going to spend this kind of money can't seriously go long distances on this bike anyway the 12.5 compression would give me a lot more torque everywhere and obviously torque times rpm = hp.
I might still talk myself into the suzuki pistons, but im thinking about losing the starter going high on compression. I have a gram scale and could order some pistons light enough as long as i can keep the total weight no higher then the counterweighting or lighter. I'm not wanting to spend money for carrillo rods
to turn big rpms, I could be wrong but i'm thinking the stock rods could handle
the compression. But if i'm wrong say something before i pull the trigger on any parts lol.

[mlinder]

12.5:1 will cause pre-detonation without some serious work on the combustion chamber, though Mike will fix most of that for you. Also, the pistons will require some shaping to reduce hot spots which cause pre-detonation.
I'd consider 10,5 to 1, honestly, for street use. 12.5 is just too high.
 12.5:1 will also likely require heavy duty engine studs.

[James360]

12.5:1 will cause pre-detonation without some serious work on the combustion chamber, though Mike will fix most of that for you. Also, the pistons will require some shaping to reduce hot spots which cause pre-detonation.
I'd consider 10,5 to 1, honestly, for street use. 12.5 is just too high.
 12.5:1 will also likely require heavy duty engine studs.

No i would not even consider pump gas with 12.5 compression if i go that far
i was already planning on having to use higher octain race gas.

will i have to try to modify to bigger dia studs, what do you mean on the studs
just higher quality ? I suppose i need a copper head gasket.

[mlinder]

Heavy duty studs, the ones that hold the jugs and head and the crankcase together. Dunno what they make for the 360, but the ones for the 350 are in the 300 to 400 dollar range.
Dunno why you want to make the thing unridable without lots of work and race gas, though....

Why don't you follow PJ's lead abs go with the GS pistons. Had some pretty good power with stock cam. Then you could ride it all you want on pump gas.

[tbpmusic]

You may have picked the wrong bike for all this.

Even stock engine parts for 360's are hard to find - particularly the top end stuff.
There were never many performance parts for them, almost non-existent now. The aftermarket people pretty much ignored this bike (so did Buyers, for the most part).

[James360]

Heavy duty studs, the ones that hold the jugs and head and the crankcase together. Dunno what they make for the 360, but the ones for the 350 are in the 300 to 400 dollar range.
Dunno why you want to make the thing unridable without lots of work and race gas, though....

Why don't you follow PJ's lead abs go with the GS pistons. Had some pretty good power with stock cam. Then you could ride it all you want on pump gas.

If i have to spend that much just for studs i will give up on high compression
go back to the suzuki pistons. Forged pistons, rings, pins,clips any size or
comp.i want would be $400.00, the suzuki stuff will end up about $200.00.

[James360]

You may have picked the wrong bike for all this.

Even stock engine parts for 360's are hard to find - particularly the top end stuff.
There were never many performance parts for them, almost non-existent now. The aftermarket people pretty much ignored this bike (so did Buyers, for the most part).

I haven't had much problem finding any parts for it, before i bought it i called
couple honda dealers they said about 50 percent of new parts are still available for it, by comparison my 67 CL 77 that they sold a lot of very popular bike in its time worth way more money then any of the 350s 360s or 450s there is almost no parts available for it through the honda dealer. The 305 honda after it quit being imported into the US (1968 350 showed up) was sold new for a lot more yrs down in mexico but there still is almost no new parts for it now through honda. In the early eighties when I bought the CL77 i bought a lot of new parts for it that it did not need still have them on the shelf did not take much to fiqure out the parts would soon not be there for it anymore. I'm not going to list all the spare parts i have for it and there not for sale lol.
    

[bwaller]

To backtrack a bit, the top end studs on the 360's are both shorter and more stout (10mm) than the 350 twins (8mm)

[James360]

To backtrack a bit, the top end studs on the 360's are both shorter and more stout (10mm) than the 350 twins (8mm)

This is good to know seems like i did notice something mentioned somewhere
about the studs being shorter but if there 10 mm and the 8 mm stuff was working for the stock 350s that should make them for sure stouter, its hard for me to think this small being used to playing with SB, BB chevies. someone did mention the 360 oiling system was a litte better i think it may be a different oil pump not sure what changes were really made.
   This engine of mine seems to be in good shape no reason to redo it other then a want for more power. I have just been trying to look at all the options
i could do to it within some reasonable amount of cost. Sure glad you told me this I may still consider the high compression. Thanks

[mlinder]

HD studs are not necessarily about their diameter. It's about what they are made of.

[James360]

HD studs are not necessarily about their diameter. It's about what they are made of.

No doubt about it, but if i were going to try it id sure rather try it with 10mm studs then 8mm.

Whats the name of the company making studs for the 350.

[mlinder]

HD studs are not necessarily about their diameter. It's about what they are made of.

No doubt about it, but if i were going to try it id sure rather try it with 10mm studs then 8mm.

Whats the name of the company making studs for the 350.

Dunno who makes em. A few companies sell them. look at m3racing.