Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Is there a simple way to disconnect the governor arm from the carborator? I've removed the bolts that hold the carb on but it won't slide off (It needs cleaned big time) because the of the linkage to the governor arm (wire rod and spring).  The shop manual says to remove one of the two screws that hold it on, but I'm not sure which one should be removed or what will happen to the governor if I do remove them.  I have heard that governors are really hard to adjust and I was trying to avoid that agrevation.  I've labels the two screws "A" and "B"  (one of them is really a bolt).

friiy wrote:

Yes mine is 8hp.  Nobody can find the service manual for the 8hp, but the specs for the 6hp is often very close.  The maximum torque (HP?)  for the 6hp is rated at 2800 rpms.  The max RPM is 4000 rpm.

 

My first big splurge on the Yamaha.  (it's earned a little pampering after all these years).  I found a see-thru filter at Volkswagen shop $2, a piece of 1/4 fuel line (not sure what size I needed) $3 and some BJ weld (they give you a black tube and a red tube to mix together) $4. .  Oh, and I picked up a multimeter with a clamp for a spark plug.  I'm storing the snowblower outside until I know it does not leak gas. I have started storing my plastic gas tanks outside too.  Just a little piece of mind. 

 

I hooked up the mutimeter's tach clamp and  got a  reading on the rpms.  The multimeter did not give me just one number, it was more like a range of numbers so I just took the average. The idle RPM has been adjusted and is now running at 2000 and sounds much quieter and calmer that it did before.  I cannot reach the limiting (high) screw with my short screwdriver so I could not adjust it. But I did get a sense of where 4000 rpm is on the throtte.  I was running it higher that that for a few intermitten moments before, I hope I didn't wreck anything.  The motor does still shake more that I think it should at idle but at idle it is now quiet enough to easily talk over.

The snowblower started right up without and issue (electric start) and it was cool out tonight (34 F).  The oil was changed and has remained clear ( the engine has a viewing window for the oil reservoir that is really interesting to watch)  Should tachs give a range or just one number?

Not sure if I'm reading the spec sheet correctly but the snow thrower is a Yamaha with a side valve engine?  Honestly, I've never heard of nor seen a Japanese side valve engine.  Not that they don't exist.  I just haven't seen one in all of my years.   Japanese have been techno leaders in engine design.  I'm curious how old the snow thrower is?  

Borat,  The old Colman generators back in the early to mid 80's were all Kawasaki l head engines ( the first Powermate's) ,  John Deer had on all its large mowing tractors a separate 5 hp L head Kawasaki vaccum/ blower motor to drive clippings up the bag chute...   Also the first Honda mowers I worked on were L head on the HR215..

honda made for a time a 2.5 hp motor (L head ) that went on the Mclane edgers which was real sweet.  My dad has a EM3000 honda generator with the first CDI ignition that is L head.

The stuff really flurished out west back in the early 80's and stayed until California started enacting smog and noise requirements,   That's when the OHV started to take off for us. 

The L head stuff that was made was great,   It was like they took all the features the mechanics liked and placed it in a Aluminum block,   Big ball bearings,  unboltable rewind,  quite muffler,  chrome sheilds over the muffler,  float carb, CDI ignition standard. oil alert / shutoff.  IT was like they took motorcycle engineering and put it lawn mowers with high gloss paint...

I think you were able to get so much more because the doller was worth so much over in Japan.

Things I miss :

Kawasaki TD24d motor (2 cycle)

Echo CS280   saw

Echo PB210E blower

Echo 2 stroke mower (4 hp) .  Borat,  thats what you have right?

Toro 2 stroke commerical lawn mower with the Suzuki engine

Wisconsin Robin 5 hp (L head)

Oh well,  

Friiy

borat wrote:

Yes, those valves are on the side.  They are covered with small tin plate and are easy to get to. I opened it up to look in there not knowing what I would find.  There are two of them.  I think that this Yamaha snowblower was manufactured in the mid 1980's.  Isn't "overhead valve" considered a far advanced/improved  design over the side valve or L-head?  While trying to find parts for this snowblower I met a Yamaha snowmobile dealer that used to sell the Yamaha snowblowers in his store.  He said they were really nice but pricey and hard to sell for that reason. 

Note: I also found this very useful information on the web (the high throttle position on the "adjust bolt" leads me to believe mine is way out of adjustment) :

You are correct.  Over head valve design is more efficient than  L  head (flat head).  It provides superior gas flow and head cooling.  Which in turn extends the life of moving parts in the head and has better opportunity for generating more power for the same displacement and runs smoother.  I'm just surprised to see a Japanese engine manufacturer actually building L head engines that recently.   In  1981, I owned a 750 cc Yamaha Seca.  It was very sophisticated for the day.  The engine on that thing was dual over head cams with four carburetors, four into two exhaust.  It's hard to imagine that they'd be building state of the art engines on bikes yet building near stone age engines on other equipment. 

Actually, I find it unusual that many Japanese manufacturers are building any kind of push rod engines (ohv).  Their specialty in small ATV, scooter, and motorcycles is generally single overhead cam engines which are stone axe reliable but technologically  more advanced than push rod engines.  Could be some cost savings with the push rod design.  I don't know.  It's very unusual to find overhead cam engines in OPE.  I know that Honda does provide a few engines for that purpose.   I bought a Craftsman lawn tractor for my camp in 2005.  It has a V-twin single overhead cam engine in it.  However, almost everything else I looked at  when I was shopping was push rod.    The Husqvarna machine I have at home has a push rod V-twin Kawasaki engine in it.  Can't say that there is any noticeable difference between the two. 

The problem with going to a overhead cam  on a smaller engine is the need for a chain of smilar size,  the cam gear would have to be twice the size of the engine crank gear,   The crank gear would be at LEAST the size of the PTO shaft,   The head would have to hold the cam gear and it's bearings + cam .  plus a chain tensioner- maybe a ajustment setup or a spring loaded mechanism... Then you would have to seal it all up... That is a lot of gasket / o-ring surface..   Now that lawnmowers are price shopped items and the rpms between  the diffrent power equipment needs are pretty standard.   There really is no need to go crazy with a small engine lawnmower arms race..  That is what the Honda rep told me back in 93,   That's why he said you don't see tuned mufflers , ohv cams and timing advance on most small engines...

Borat, Bikes have always had a arms race going on,  look at the rpms  they run at and the HP and torque they produce.   All that and small CC's.

Borat.... When you gonna post some pics of your bikes?  What sweet projects have you got going on now?

With grease under the nails,

Friiy

Do motorcycle engines ever end up on OPE?

I'm presently doing the brakes on a '74 RD350.  It has front disk and rear hub brakes.  I pulled the calipers off, separated them and blew out the pistons with compressed air.  That was a bit of a chore.  The brake piston look as though they'd never been removed in 34 years.  Internals are good.  No rust or pitting.  I'm waiting for a shipment of parts.  Lots of parts for the entire project.  I need to re-seal the calipers, put on an new stainless steel front brake line (with built in micro-switch - sweet), and install new brake shoes in the rear wheel.  I spent a good week re-doing the wiring.  The way the bike arrived, it looked as though a colour blind chimpanzee with set of wire cutters and a roll of tape did some "repair" work.  It was a major mess.  Thank God for schematics.  I still have the headlight & gauges all apart.  That's where the wiring lives.   My next job is to take the forks off and refurbish them with new seals, oil and whatever else looks like needing replacement.  I have numerous parts in getting powder coated and my engine apart as well.  I need to get the new pistons before I can take the cylinders in for re-bore and honing.  I also have the heads going in to get the squish step reduced.   I could go on all day, the list of things to do is sooooo long.  Fortunately so is the winter.  So I'm taking my  time, doing a few hours a day. 

Despite the condition of the wiring on this bike, the machine is fairly fresh for it's age.  Just over 9000 miles on the bike and the engine (not original) looks even fresher.  Before I pulled it apart,  I did a compression test.  It had 120 lbs. on each side.  That's freaking remarkable because the engine has it's original pistons!   The heads had virtually no carbon build up.  This engine appears to have never been apart.  That's a good thing.  There are signs of blow-by on the pistons but that's the norm for those old two strokes.   I'm completely rebuilding the top end so new pistons and rings will be installed in the fresh cylinders.

My '76 RD400 that I built earlier this year turned out to be a lovely little rocket.  Just an amazing machine.  Even by today's standards, that bike hauls serious ass and is a delightful handler.  It does have a number of go-fast goodies on it though.  The '74 RD350 will be as fast if not faster.   It will be making similar power but the bike will be around 40 lbs. lighter.  I'll post some pics when it's done.  Here's a couple pics of the RD400 (red) in finished condition and the 350 I'm working on.