A rider ...

[Ricks]

So far , the Cushman coil has produced as much as maybe 20 seconds of run time . Disappointing .

Or , is that what the rest of you have experienced ? Maybe I'm doing something wrong ? It would be the very first time in my life .

Pete .

I run a cushman coil in both of my wico bikes.  I think you need to tear down that motor and find out what is wrong.  What is the compression?  What is the ring gap?  Have you measured rotator valve clearance?  With the new carburetor and coil, there must be something else going on.

[pd]

I've been wondering the same thing , Rick .

The last compression reading was at about 80 pounds and when I installed the new rings there was a fairly snug .014" gap . And , I set them at about 120° . I don't know what the rotary valve clearance is . That would have more to do with vacuum , I'd think .

The bike ran better with the OEM coil in place .

Pete .

[oil-lamp]

I would step back and check the fuel system just for grins. Check to see if there is flow from the tank and the gas is good. Is there fuel build up in the crankcase is the crankcase sealed good? Have you check the carburetor?

[Ricks]

I've been wondering the same thing , Rick .

The last compression reading was at about 80 pounds and when I installed the new rings there was a fairly snug .014" gap . And , I set them at about 120° . I don't know what the rotary valve clearance is . That would have more to do with vacuum , I'd think .

The bike ran better with the OEM coil in place .

Pete .

80 lbs is good.  The factory spec on the rings is .008-.010, but this brings up another point.  One of the old timers at Portland thought this was too tight.  I would also check the crank seal.  Maybe your vacuum is way down, and you are sucking air around the crank instead of through the carburetor.

[pd]

The one thing I can't seem to get a handle on is what keeps changing .
One day it runs good enough for me to ride a couple miles , the next it won't run for a minute .
I'm thinking that maybe points and condenser , but   Nova II ?
The crank seal is new , installed 2 years ago . I have not tested vacuum .

Pete .

[pd]

I spent a little time studying .

I re-learned what I once knew and had forgotten : Ignition coils are matched , by the manufacturer , with condensers ( capacitors ) for maximum performance and system balance .

That fact could explain why my motor runs and then not . I have used the same condenser while trying different coils and getting a multitude of results . I'll pick up a new and hopefully good condenser tomorrow .

If that doesn't do it , I'll likely be tearing the motor down to threads .

Pete .

[pd]

Dang . The motor runs less than 10 minutes and then quits . It gets enough RPMs to move the bike and that's it .
It seems to have vacuum with my hand over the breather method . No carb blow back at all .
That's with a Carpenter carb , Cushman coil and condenser . Fresh premium with Opti2 mixed .

Tomorrow the motor gets pulled and taken apart .

I'll do a compression test before .

I've never had a motor do what this one is doing , but then , I've not had a Simplex motor , other than this one , before .

Pete .

[pd]

I was waylaid . Other stuff had to be done . Like a new battery and brass cable ends for the Monaco motor and the wiper motor on the Jeep decided it needed attention . And , 'someone' left my shop ( actually it's just a shed I took over for the Summer ) a total mess . I'm taking a break right now from cleaning it , in prep for the Simplex motor tear down .

Hopefully , getting there .

Pete .

[pd]

So far this morning :

A compression test showed only about 65 pounds ... A few weeks ago , it was at about 80 pounds .
 The spark plugs are burning clean , a light tanish coloring . Both plugs are clean , even though the inside plug is insulated from it's wire .
I removed the compression plate cover and plate . I found very tiny bits of what at first looked to be carbon in the bottom of the crankcase  , black , but a bit too shiny . Then I took the cylinder off . The bore looks pretty good with a couple places showing a bit of what seems like blow-by and a couple of very light scuffs .
The piston showed much the same as the cylinder , but the scuffs are deeper .
The connecting rod both top and bottom are way too loose . Loose to the point of what looks like the back corner of the rod contacting the crankcase . Neither were loose when I put the motor together a couple years ago . That looseness is most likely due to the lower rod bearing being poor quality .

All that leaves me thinking I'll need a new piston / rings and pin ; bore job and a new rod with QUALITY bearing(s) .

I'm glad I quit running the bike when I did . Much more damage would definitely have followed , otherwise .

Pete .

[Ricks]

Pete, post a picture of the rod bearing please.  Is it a double row bearing?  Is the cage intact, or did it come apart? 

A couple of the old timers at Portland are always preaching about replacing the roller bearing with a needle bearing, as they say they have seen many rod bearing failures.

[pd]

Rick ,

This bearing defintely failed . It is a double row bearing and the outside ball cage is no longer there . That's what the bits were that I found in the crankcase , as far as I can tell . I'll post a pic after I get back out there this afternoon .

I'll be installing that roller bearing you posted about .

Pete .

[Ricks]

Make sure you get one with an inner ring!  The one I ordered did not have one, and I wound up having to order one separately.  I will update with part number when I get it.

[pd]

I'd appreciate that .

About the billet rods you're running : where did you get them and are they still available ?

And , what about the over sized piston ?

Pete .

[pd]

Here is a pic of the failed bearing :



Here's a pic of the rod where I think it contacted the case .



I checked the case and it shows where the rod 'bumped' . Just a mar , with no evidence of anything more .

Pete .

[Ricks]

That is pretty discolored.  Looks like it got really hot. 

Wayne is the source for the billet rods and pistons.  He can also bore your cylinder for you.

Bob Kerr also does the billet rod with the needle bearing conversion.  His uses a custom size bearing and he must have your crank to fit it.  Here are a couple of pictures of his rod.