My Lawnmower Forum banner
1 - 8 of 8 Posts

· Registered
Joined
·
140 Posts
Discussion Starter · #1 · (Edited)
Hi everyone,

I have a question regarding the residential V-twins used in the lawn tractors and residential ZTR's.

Back in the early 2000's my mom and her boyfriend at the time bought some land and wanted to build a new house. So the boyfriend bought a new Huskee (Tractor Supply) with a Briggs twin but not sure of the model.

I used the Huskee once or twice and it had such a good sound, at idle it made a BWAP-BWAP-BWAP... sound kind of like a Harley twin but not as harsh more throaty, steady and quieter.

So this year I decided to get a new LT for my mom's place (they never sold the old house, my childhood home and never built a new one and the boyfriend is no longer there). Anyway I decided on the new Cub XT2 Enduro with the Kohler 7000 KT725 "twin" (note the quotes, I'll explain).

So I got the machine and it performs well, tons of power and blows grass into the next township it seems but something didn't seem right, It doesn't sound like I thought it should, at idle it sounds much like the L-head singles I've used for the last 36 years but quieter.

When I got the tractor I downloaded the parts manual from the Cub site and they have the parts illustrations for both the Kohler and Kawasaki FR engines and I was surprised by what I saw.

For both engines the crank has only a single crankpin, both cylinders are in phase not 180 deg out as I expected. At first I thought the diagrams used a generic crankshaft drawing but the Kohler one shows two oil ports slightly offset by a few degrees from each other as one rod is "flipped" over relative to the other.

Now I don't know if both cylinders fire simultaneously or alternate every other cycle but I wonder if this is the reason why I don't get the impression of smoothness where a 180 degree crank would cancel itself out on firing but in these engines both cylinders push in the same direction on firing

In my research before buying the machine I'd read that twins are smoother and quieter but to me it seemed kind of the same as the old singles I'm used to.

But one thing I know is that I miss that BWAP-BWAP-BWAP...!

Anyone have any thoughts?

Thanx.
 

· Premium Member
Joined
·
1,596 Posts
I can sort of see where your coming from... I currently have a Cub with a Kawasaki and it makes a nice growl when it starts up and once it's idles it sounds really nice. Closer to the sound you describe than the newer Twins. Like you would think their supposed to make. I'm not really up on engines like your explaining with the cylinders are in phase. I know sound of an engine. Briggs vs Kohler vs Kawa. Each have their own unique sound and characteristics!

I'm sure the resident motorheads might be able to explain a more detailed answer :)
 

· Registered
Joined
·
140 Posts
Discussion Starter · #3 ·
Yeah, I always thought the twins had the cylinders 180 deg off each other but I checked out youtube and there was a nice sounding Briggs ELS that someone rebuilt and it's the same as my Kohler with both connecting rods sharing one crankpin so I guess I have learning to to. This is my first twin so I hope it holds up, It seems to be made half decent and is supposed to be based on the Command Pro design. runs great so far after 9 mowings (only about 4 hrs!) but we'll see down the road.
 

· Premium Member
Joined
·
9,020 Posts
This the sound you like?? I love opposed twin Briggs and Kohler Commands.

Kohler Command opposed twin.

 

· Premium Member
Joined
·
9,020 Posts
My favorite engines are these opposed! Reason I kept both types now!
 

· Registered
Joined
·
140 Posts
Discussion Starter · #7 ·
The Huskee also had a kind of smooth diesel-like sound at higher RPM. I'll try and find out what engine that Huskee had next time my mom's ex comes around but seem to remember it was 18hp or so and pretty sure was a Briggs but don't know if V twin or opposed. Maybe the newer engines have quieter mufflers I don't know but the Kohler KT725 I have doesn't sound much different than a single to me except maybe the exhaust pulses happen twice as often so might sound a little smoother but certainly not deeper.

Yesterday a local municipal crew unloaded a couple big ZTR's and started them at idle, they too didn't sound like that Huskee by what I could tell from 100ft away.
 

· Registered
Joined
·
3 Posts
If its a 90 deg. V Twin I can offer some input.

My Husqvarna GTH2248XPC has a Kawasaki FH641V BS15 90 deg V Twin.

In this configuration 1 cylinder fires then rotates 270 deg and fires the other cylinder then rotates 90 deg then firers the other cylinder.

This configuration gives perfect primary balance.

Just like my Moto Guzzi Motorcycle and Ducati etc.. 90 deg configuration.

An opposed engine think BMW Motorcycles 180 deg crank so its balance is perfect secondary balance.

A Harley Davidson is a 45 deg V Twin . I cant explain the balance for this type .

There is also Vertical twins with both 360 deg cranks and 180 deg cranks.

Others may chime in

TOM B

Although this input is motorcycle based some of this info applies to our lawn eq.
 
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top