[olNick]

Greeting to all from a new member,

I’ve come across this site while googling for tech info from Larry Widmer and David Vizard, and have wound up here with a wealth of additional info.

I’m planning on rebuilding my bike motor in the fall, and looking for info on performance.

Suzuki Intruder
1400 cc 45* v-twin
45* crank
chain driven 3 valve OHC
9.3:1 CR
94x98 bore x stroke
33mm intake, 40 exhaust
0.31 lift intake, 0.35 exhaust
272/276 duration intake/exhaust
71 hp (52 kW)/ 4.800 rpm, 112 Nm/ 3.200 rpm.

While the engine pulls like a tank, I feel these hp/torque figures a very low for an engine of ~700 cc/cylinder. I would like to do something about that. From what I’m seeing claimed, many 88 inch Harleys are approaching the 100 hp zone. I’m jealous!!

While the bike is fairly conventional, I think maybe the hemi style head could use some improvement. Below are pics of this head, first one from the manual which shows it’s bowl clearly, and the second an actual head

1400_head.GIF

valves111sf.jpg


Notice there is no particular squish band in this head, so I would think it’s only depending on swirl from the intakes for charge mixing. IIRC, at the time of introduction, Suzuki was touting its TSCC, Twin Swirl Combustion Chamber although I thought that all well designed dual inlets should promote good swirl.

On this next pic, I’ve outlined a bit where I’m considering welding up the chamber to add add a primary squish at 3:00 o’clock and a secondary one at 8:00 o’clock, resulting (hopefully) resulting in

Copy of valves111sf.jpg

Raise CR w/o milling or dome pistons
Improve combustion due to enhanced swirl
Drop timing requirements due to shorter flame front travel
Lower heat loss due to smaller cc surface area

I know I need to look up and understand squish band percentage, and squish velocity, but comments are welcome wrt to these issues.

If we believe in progress, the below pic is from the 1500 Intuder that came out 10 years later, with a more traditional pent roof and added squish. Albeit with dished pistons to drop CR to 8.5:1

1500_head11.jpg

Can you guys give some input. Do you see any pitfalls by going this way…
I will clean up and try to flow the heads after building the flowbench on this site.

Anyway, great site, and am looking forward,

Regards,

nick