24HP V-Twin B&S - Fault driving me CRAZY!

[bertsmobile1]

Ordered.

And you cut out all those holes (large and small) with a nibbing tool?

Yeah,
It is one of those punch & anvil types that fit on the end of an electric drill.
Cuts a slot about 2mm wide.
For commonly cut ones I made a wooden template and because the punch runs inside a static tube, you can use the tube as a guide.
Anything smaller than 5mm gets drilled then dressed to exact size with a dremel tool.

Got sick of having composite gaskets for vintage motorcycles crumble then leak .
I still get some made by Lanni at CopperGasketsUS but the hike in postage has doubled the price so I only put an order in if there is 5lbs of gaskets needed so the freight can get amortized over 20 or more gaskets.

 

[bertsmobile1]

Yes Bert is right ..... That is a very good price. Dealers don't have a lot of mark on that stuff.... If I order that kit by itself I would have 15 bux in shipping and package materials..... My customer could go to another dealer that has it in stock and pay cheaper there...........

People always think we make a killing on parts..... That's Bull Butter......

Plus Tard Mon Ami ~!~!

Yes , sucks big time.
have to order in $ 200 lots to get free delivery from one supplier or pick up at the warehouse which is a 2 hour round trip from the other.
Briggs demanded that I keep $ 20,000 of parts in stock in order to open an account with them and then I have to spend a minimum of $ 10,000 pa to keep it open.
Kohler were a bit easier, they still required I keep $ 20,000 on the shop floor but did not care abut the annual spend.
However their "wholesale" prices to me were dearer than the retail from a lot of the bigger online warehouses who give free delivery.
Allmowers give me free delivery but only on prepaid orders of $ 50 or more.
Thus my workshop is full of aftermarket parts, genuine parts only ordered in at customers request.
Even then I have to charge parity pricing on parts because 1/2 the customers will put the invoice on feaces book to see if they got ripped off and there is always some keyboard wizard that comes up with a silly price.
So a lot of parts end up going out under cost price.
OTOH I allow the contractors free access to the store room and they pay my full price for the priviledge of grabbing some oil & blades at 3am on the way to their first job.
And these bloke use enough parts to warrant bulk purchases of blades & filters so it is a case of round-abouts & swings.

 

[Boudreaux In Eunice La.]

Thus my workshop is full of aftermarket parts, genuine parts only ordered in at customers request.
Even then I have to charge parity pricing on parts because 1/2 the customers will put the invoice on feaces book to see if they got ripped off and there is always some keyboard wizard that comes up with a silly price.


Ok what is parity price Definition ??? What is feases that the wizards use ??? I am not keen on the lingo in your part of down under ... Please excuse my ignorance.... How can anyone get your wholesale prices... That is protected by our distributors for dealer only only eyes...........

Oh yeah I know all about the stock up cost to start a dealership... Back in the very early 80's. It cost us 10,000 to start the Simplicity dealership for lawn tractors...... They had bought out Allis Chalmers lawn and Garden division.... My biz partner's Dad owned the Allis Chalmers dealership in my area.... Farm equipment from combines on down to Hydrostat mowers...... That was a million dollar operation right there........

 

[bertsmobile1]

Same price as from dealers on the web for the same products.

 

[Boudreaux In Eunice La.]

Same price as from dealers on the web for the same products.

Gotcha .........

 

[Neo7]

Stay away from throwing parts inside the engine..... Backfiring usually means that the valve train is the issue..... Whether it be a slipped guide a bad or dirty valve that needs to be lapped or a cam that's bad not moving the valves as they should be moving.... Or a bent push rod >>>>>>>>>

Let us know Mon Ami ~!~!

Ok here's the update....

Took both heads off today. Valve seats were in place, valve / valve stems were all straight and they seemed to be well bedded in and sealing well. Minimal carbon deposits on the the valves, pistons head and inside the cylinder head. Both inlet ports did have a thin layer of carbon, which just wiped out with a rag. I'm assuming that's from the backfiring, but both exhaust port were very clean.

I then pulled off the crankcase cover... You could eat your dinner in there!!!... It was that clean, no slime, sludge or metal deposits in the oil either. Tappets were also in perfect condition.
Measured the cam lobes and each tappet (with a small ball bearing in the seat and digital vernier calipers) for each lobe ....

• Inlet 2 - 31.2mm, Tappet 41.1mm
• Inlet 1 - 31.1mm, Tappet 41.1mm
• Exhaust 2 - 31.2mm, Tappet 41.3mm
• Exhaust 1 - 31mm, Tappet 41mm

1 is the Left Cylinder and 2 is the Right Cylinder.


Each cam lobe has a good shape point and is consistent the other lobe. The two inlets lobes are identical in shape and the two exhaust lobes are identical in shape too.
All this is kinda great news .... Except!!! .... WHAT the HELL IS WRONG WITH THIS ENGINE?!?!?!?

My many thanks to Boudreaux for talking me out of buying parts I hadn't properly confirmed were faulty.
Tomorrow I'll buy some Grinding paste and a Lapping tool to lap the valves in but it will be another week before the Gasket set arrives.

I am still open to more ideas gents? ... Including gently tapping the crankcase.... with a very large sledge hammer lol!!


All the best.
Neo

 

[Boudreaux In Eunice La.]

Did you ever check your flywheel key ????? That just came up on another engine question today..... They will shear if you get backfire........

might as well check that when the engine is back together............

 

[Neo7]

Yes ... three times!... over the many months I've had the popping.
And I've substituted both coils/plugs (from a working B&S V-Twin I have) and replace the diode lead. Substituted the fuel pump replace the carb and resealed the inlet manifold gaskets.... All to no (or minimal) elavil :confused3:

But I WILL NOT be beaten!! ... :anyone:

 

[Neo7]

Need lots of brain power here ... Ideas and HELP!!! :laughing:

 

[bertsmobile1]

Need lots of brain power here ... Ideas and HELP!!! :laughing:

I will still go with a cam defect.
The figures quoted with the tape test definately show one cylinder lagging behind the other.
Measure the circumference of the flywheel to convert the mm into degrees ( divide by 360 )
As the cams are pressed onto the shaft on a spline I am guessing , and this is a wild guess yours are out of time.
If the local B & S dealer is a nice guy take your cam and ask him to compare it to a new one.
Most dealers keep a few cams in stock.
Check all of the pushrods for length & straitness.
Also check that the alloy ones do not have a worn ring & are hanging on the shoulder of the worn area.
Also double check the valve spring length and spring rate.
Cheap & nasty way is to put a bathroom scale on the deck of a bench drill ( a press is better ) then compress till the spring is 10mm shorter.
Read the "weight" shown on the scales.
They all should be within 10% of each other or better.
Spring rates for Briggs engines are expressed as lbs/inch and there are plenty of on line converters from kg/mm to lbs/inch.
I use a kitchen scale against the chuck of a lathe and pop the spring against the tool holder so can read off the compression of the saddle travel.