Not quite sure which newsgroup to post this in, but since I am building
a mini chopper, I thought this would be appropriate.

I just purchased a 6.5hp Briggs motor, model# 121332 from harbor
freight . It is a single cylinder OHV engine. The first thing I
noticed is a big note right on the box that said "For go carts, use
only model # 136200". Here is the link to the engine:
http://www.harborfreight.com/cpi/cta...emnumber=92785

I downloaded the manual for this 130000 series model, and it is quite a
bit different. The 130000 sereis is a single cylinder L head engine.
The cylinder sits straight up and down, vs the 120000 model where the
cylinder sites at about a 45 degree angle from the base.

Does anyone know why B&S recommends to only use this136200 model for go
carts?

I don't see any problem with using the 120000 model engine I purchased,
but I just want to make sure before I fire it up and start taking it
apart to fit it into my chopper.

Thanks for any info.

On 4 Feb 2006 22:07:51 -0800, "Terry" wrote:

Not quite sure which newsgroup to post this in, but since I am building
a mini chopper, I thought this would be appropriate.

I just purchased a 6.5hp Briggs motor, model# 121332 from harbor
freight . It is a single cylinder OHV engine. The first thing I
noticed is a big note right on the box that said "For go carts, use
only model # 136200". Here is the link to the engine:
http://www.harborfreight.com/cpi/cta...emnumber=92785

I downloaded the manual for this 130000 series model, and it is quite a
bit different. The 130000 sereis is a single cylinder L head engine.
The cylinder sits straight up and down, vs the 120000 model where the
cylinder sites at about a 45 degree angle from the base.

Does anyone know why B&S recommends to only use this136200 model for go
carts?

I don't see any problem with using the 120000 model engine I purchased,
but I just want to make sure before I fire it up and start taking it
apart to fit it into my chopper.

Thanks for any info.

Most likely lubrication- the 120000 is recommended for fixed
applications (pumps, gensets) and it's possible it won't lube the
valve train if it's bouncing around a lot.
Also, the 120000 looks to be a fixed-speed engine and may not have
enough bottom end to get a kart moving or have too high an idle speed
for a Comet clutch.

-Carl

The Intek engine series is the one that Briggs reccomends for their
racing program. The label may refer to some class racing restrictions.
We use the 10 hp hp version (well, actually 9.3hp on the dyno) for the
Mini Baja competition.
http://students.sae.org/competitions...st/2004pix.htm


Terry wrote:
Not quite sure which newsgroup to post this in, but since I am building
a mini chopper, I thought this would be appropriate.

I just purchased a 6.5hp Briggs motor, model# 121332 from harbor
freight . It is a single cylinder OHV engine. The first thing I
noticed is a big note right on the box that said "For go carts, use
only model # 136200". Here is the link to the engine:
http://www.harborfreight.com/cpi/cta...emnumber=92785

I downloaded the manual for this 130000 series model, and it is quite a
bit different. The 130000 sereis is a single cylinder L head engine.
The cylinder sits straight up and down, vs the 120000 model where the
cylinder sites at about a 45 degree angle from the base.

Does anyone know why B&S recommends to only use this136200 model for go
carts?

I don't see any problem with using the 120000 model engine I purchased,
but I just want to make sure before I fire it up and start taking it
apart to fit it into my chopper.

Thanks for any info.

The engine is not a fixed speed, it has a throttle lever on it. I
looked it up at small engine warehouse
http://www.smallenginewarehouse.com/....asp?PN=121432 and it is
designed to work with the troy built horse tillers. So I don't think
bouncing around is a problem since tillers will bounce around a lot
more than a mini chopper on the street.

Here is a .pdf file of my engine
http://www.smallenginewarehouse.com/...ngs/121400.pdf and a
..pdf file of the 'go kart' engine
http://www.smallenginewarehouse.com/...ngs/135200.pdf. These
are a 1 page drawing and description showing hp curves.

The RPM range looks to be the same on both 1800 to 3600. My Comet
clutch enganges somewhere between 1800 and 2200. And my engine has a
lot more HP at the lower RPM range than the go kart engine. But I am
not sure if the 1800 is the minimum RPM. Sounds kind of high.

As Roy mentioned, he uses the Intek engine series, which is what my
engine is. Maybe B&S has qualified their go kart motor to be legal in
go karts for resellers.

I'll probably give B&S a call tomorrow and see what they say. But as
of now, I can not see any reason why the 120000 series engine I
purchased would not be a good choice for a mini chopper.

Thanks.

I think I may have just figure out a difference. I went to your mini
baja link and found the model of the engines you use. I looked it up
at small engines warehouse and their was a note that said a spacer is
required on the Intek engines to make the shaft height the same as the
L head engines.

So most likely, the Intek engines shaft, if mounted on a flat surface,
will not accept a standard Comet style clutch, or it may be to close to
the mounting surface.

This is just a guess, but the Intek engine you are using in the mini
bajas looks exactly the same as the Intek 6.5hp engine I am planning on
using. So I don't think their will be any reliablity or performance
issues using this motor in my mini chopper.

I have a very old L head on my kids gocart that has seen well over the rated
RPM for many long runs, I'll here him in woods just waiting to hear the POP,
but it just keeps going. When it does go I'll just reach into my junk pile
from the dump and put another on it.
"Terry" wrote in message
oups.com...
I think I may have just figure out a difference. I went to your mini
baja link and found the model of the engines you use. I looked it up
at small engines warehouse and their was a note that said a spacer is
required on the Intek engines to make the shaft height the same as the
L head engines.

So most likely, the Intek engines shaft, if mounted on a flat surface,
will not accept a standard Comet style clutch, or it may be to close to
the mounting surface.

This is just a guess, but the Intek engine you are using in the mini
bajas looks exactly the same as the Intek 6.5hp engine I am planning on
using. So I don't think their will be any reliablity or performance
issues using this motor in my mini chopper.

The Intek engines idle at 1800, makes it tough to get the machine to
idle, then engage and still have some rpm range left. We have been using
Polaris or IBC clutches, the Comet clutches are too wimpy, not to
mention no tuning parts.

Clutch tuning is a LOT of sciece and a LOT of art. There are something
like a dozen variables to play with. You can get some anomilies like
raising the final drive gear ratio (higher numerical ratio) and it
REDUCES your acceleration. Exactly opposite of what happens in a car or
truck.

Terry wrote:
The engine is not a fixed speed, it has a throttle lever on it. I
looked it up at small engine warehouse
http://www.smallenginewarehouse.com/....asp?PN=121432 and it is
designed to work with the troy built horse tillers. So I don't think
bouncing around is a problem since tillers will bounce around a lot
more than a mini chopper on the street.

Here is a .pdf file of my engine
http://www.smallenginewarehouse.com/...ngs/121400.pdf and a
.pdf file of the 'go kart' engine
http://www.smallenginewarehouse.com/...ngs/135200.pdf. These
are a 1 page drawing and description showing hp curves.

The RPM range looks to be the same on both 1800 to 3600. My Comet
clutch enganges somewhere between 1800 and 2200. And my engine has a
lot more HP at the lower RPM range than the go kart engine. But I am
not sure if the 1800 is the minimum RPM. Sounds kind of high.

As Roy mentioned, he uses the Intek engine series, which is what my
engine is. Maybe B&S has qualified their go kart motor to be legal in
go karts for resellers.

I'll probably give B&S a call tomorrow and see what they say. But as
of now, I can not see any reason why the 120000 series engine I
purchased would not be a good choice for a mini chopper.

Thanks.

On 5 Feb 2006 08:57:40 -0800, "Terry" wrote:

The engine is not a fixed speed, it has a throttle lever on it. I
looked it up at small engine warehouse
http://www.smallenginewarehouse.com/....asp?PN=121432 and it is
designed to work with the troy built horse tillers. So I don't think
bouncing around is a problem since tillers will bounce around a lot
more than a mini chopper on the street.

But tillers don't go from idle to full power to idle- they run at one
speed, no?

The RPM range looks to be the same on both 1800 to 3600. My Comet
clutch enganges somewhere between 1800 and 2200. And my engine has a
lot more HP at the lower RPM range than the go kart engine. But I am
not sure if the 1800 is the minimum RPM. Sounds kind of high.

It's not- a lot of small engines have high idle speeds- the carb may
not have a traditional idle circuit, or the idle is a fixed jet.
Thanks, EPA.

1800 RPM will have the clutch starting to engage (most are spec'd to
be fully enagaged at 2000- 2200 RPM).

Some engines have a speed-sensitive decompression feature (Easy-Spin)
that holds the exhaust valve open until the engine is turning X RPMs,
X being about 1000 RPM , IIRC.

As Roy mentioned, he uses the Intek engine series, which is what my
engine is. Maybe B&S has qualified their go kart motor to be legal in
go karts for resellers.

Maybe- one of my coworkers crews a quarter midget and the rules are
pretty strict.

-Carl

I have used the large self drive walk behind tillers, and they always
go from idle to full and back to idle. You have a throttle on them and
when you want to dig, you go full throttle, and when you stop or turn
or lift the blades, you go to idle.

But my main question is how is this motor different from the "go kart"
version that they recommend to use?

I know clutch tuning will be something I will have to do once it is all
running. Just want to make sure the motor I have will work before I
put oil in it and fire it up.

Thanks.

One source I've read mentioned that B&S vehicle engines have a spring
for the throttle so that when the throttle lever or peddle is let go,
the engine returns to idle, ala car gas pedal. Most are intended for
applications like lawnmowers where when you set the throttle, it stays
set. One parts list had the callouts for what was needed to convert one
particular engine to a kart engine. It might even have been on the
Briggs site, I was looking for governor linkage diagrams at the time.
There's a lot of differences in the different series of engines, some
minor, some major, like cylinder material. I've got a book that
details some, but not all, the differences. Some models have just
sleeve bearings, some have partial ball bearings, some have full ball
bearings. Some are splash oiled, others have partial or full pressure
oiling. Without a catalog or some other factory-supplied material, I
don't think it's really possible to just look at an engine and tell
what's inside.

Stan

Thanks for that info. The spring return makes sense for go kart use.
And if it already comes on the 136200 model engine, that could be a
good reason why B&S say to only use that exact model for go kart
applications. But that is not a concern for me. I will be stripping
all the accesories off the engine, and fabricating my own air cleaner
assembly, exhaust, gas tank, and throttle setup.

It looks as if this engine will work out fine. It's for a fun project
that is not going to be used in any type of racing environment, or even
on a regular basis.

If I come across anything unusual that would prevent me from using this
motor in this type of applicatoin, I'll post it for others to know.

Thanks again for all the info.

I just spoke with B&S tech support. They told me that none of their
new engines are recommended for go kart use. B&S wanted to get away
from that market for liability reasons and stuff like that.

But I did ask what the differences were between their older go kart
model. Besides the obvious tilted cylinder, and OHV setup, the main
difference for not using them on go karts is the throttle setup. All
their new engines have a stiff throttle setup that does not return to
idle. The older model 136200 (for go kart use) had a return spring.
One other difference is that the new engines have a float bowl
carburetor design.

The engine can be mounted up to a 15 degree angle front or back and
still get proper lubrication.

They also stated that any B&S engine used in a go kart application
would void the warranty. Just repeating what I was told.

Sounds like this new engine will work out great for my application once
I modify the throttle assembly to work properly with a return spring.

Kinda hard to square your tech support answer with the B&S website:
http://www.briggsracing.com/display/...p?docid=101243

It shows clear references to the kart world.

Terry wrote:

I just spoke with B&S tech support. They told me that none of their
new engines are recommended for go kart use. B&S wanted to get away
from that market for liability reasons and stuff like that.

But I did ask what the differences were between their older go kart
model. Besides the obvious tilted cylinder, and OHV setup, the main
difference for not using them on go karts is the throttle setup. All
their new engines have a stiff throttle setup that does not return to
idle. The older model 136200 (for go kart use) had a return spring.
One other difference is that the new engines have a float bowl
carburetor design.

The engine can be mounted up to a 15 degree angle front or back and
still get proper lubrication.

They also stated that any B&S engine used in a go kart application
would void the warranty. Just repeating what I was told.

Sounds like this new engine will work out great for my application once
I modify the throttle assembly to work properly with a return spring.

Ya, I know this. He answered my questions about the differences
between the 120000 and 130000 series motors, so I didn't want to take
up any more of his time. But my only explanation to that was he was
refering to their standard line, not their racing line of motors. It
could be a complete different division, and thats why they are going
away from go karts in their standard line. They will leave it up to
their racing line to supply those motors. But who knows what he was
thinking!

We use the Intek 20 units and run the h**l out of them. Stupid air
filter covers tend to come off under high vibration, running flat out in
dust so thick you can only see 50' is tough on motors.

Terry wrote:
Ya, I know this. He answered my questions about the differences
between the 120000 and 130000 series motors, so I didn't want to take
up any more of his time. But my only explanation to that was he was
refering to their standard line, not their racing line of motors. It
could be a complete different division, and thats why they are going
away from go karts in their standard line. They will leave it up to
their racing line to supply those motors. But who knows what he was
thinking!

Ya, I was looking around on the B&S racing engines. They look pretty
nice. But for now, I'm just looking for a fun play motor to stick in
my mini chopper. I'll probably gear the thing so it won't ever hit
over 35 mph since my butt will only be about 10" off the ground! But
at least I know I will have plenty of power with the 6.5hp engine.
This engine will have no where near the abuse of any type of racing
engine, and most likely less abuse than the average 2 seater go kart
you can pick up at the local sporting good store.

I have learned alot about these 4-stroke engines from the research I
have been doing. I used to run a KT100 in my Emick go kart back in the
80's. Thing would easily to 70mph. But I haven't really been into
this scene since back then. Got into racing 2 stroke dirt bikes.

Anyway, I'll be building myself a go kart after I finish this mini
chopper. I'll have some fun picking out and modifying a nice race
engine.

Thanks again for all the info.