More Berkie bad luck

[Ed Chesnut]

Still haven't heard whether we are talking about a Bing or a Mikuni.

If you are lean on the pilot jet . . . well, you are lean on the pilot jet . . . and that is a bad thing.

I reckon I could go along with your tuner's theory . . . but it seems simpler and cleaner to simply note that it is lean on the pilot jet and you should go richer so it won't be lean any more.  (IF that is indeed the problem.)

Can't say as I've bumped into seizing an engine on an MX track by rolling off the throttle then rolling it back on.(or snapping throttle off then back on)  You can certainly sieze one up by running for an extended period, say 30 seconds or more, at 1/8 throttle on a lean pilot jet though.  You can maintain surprisingly high road speed (or high track speed) at very, very low throttle settings while "on the pilot jet" if there is a slight down grade.  And if the pilot jet is lean, that could cause real problems.  (example, a 100cc engine with road gearing can maintain 50mph cruise on the pilot jet with a good tail wind or a slight down hill . . . but not for long if the pilot jet is lean)

Ed

Keep the rubber side down!

[Larry Perkins]

I never saw a Berkshire with any bigger pilot jet than a 45 and I can not imagine that the difference would cause a bike to seize but I learn something everyday.  The main on a ported 100 might be as big as a 150 and I could see that difference causing seizure.  Not sold on the seizure breaking the ring either but again I am not the biggest technical wiz either.  Fun to learn and curious to see the outcome.


Ed,
He mentioned it as a Bing.

 
Larry P

[Mickey Sergeant]

The 45 and 150 was what I was thinking for my starting point. Not sure if the next size on the mahle piston will work,that would be a 49.0. gouged good.Buehner doesn't show a 49.5. Is there a wiseco piston for this bike that they make.

Thanks Mickey

[Mickey Sergeant]

Sorry were talking about a bing

[john durrill]

Mickey,
B engine  , 100 cc ( 48mm standard bore) , 27 mm type 53 Bing ?
Jetting you had was 135 main , needle # 4 , needle jet 276 , pilot jet
#40 ? Cable choke on or disabled and sealed up? Pipe type? Milled head?
 Larry brought up some very good things to look at . If it were me would measure the exhaust port width and look at the corner radius.
     The 100 is a very good design and not prone to what you had happen. I have a good friend that rode a Factory Herc 6/D 100 in 2 Day Trials here in the US. With the cylinder the Factory folks modified for him Rick said he would get right at 7 miles before the piston failed.
He went back to a slightly less wild cylinder and had great luck with it.
 Best of luck with it Mickey,
john d.

 

[brian kirby]

Its highly unlikely, but not impossible, that a seizure caused a snagged/broken ring. Broken rings come from worn out top ends, unchamfered ports, or too big ports. Of course, your bike could have too big ports and be too lean at the same time.

Ed is also right about the pilot feeding fuel at all points. I believe the Bing works the same way, after all, even at WOT the pilot/idle jet is still exposed to vacuum so it will flow fuel.

On my 100 it had a 35 idle jet (28mm Bing model 28) and a 145 main. The pilot was super lean so I went to a 40 and have not touched the jetting since. At its first race, the ISDT Reunion Ride in Tulsa '08, there was a road in a test section and I had it WOT in 6th gear for about 25 seconds and it didnt lock up.

Brian

[Mickey Sergeant]

Like I said I only had a 135 main in it.Don't know what I was thinking.I just order some main jets all the way up to a 150. Start with the 150 where I know it should be rich and work backwards. I knew it would be risky with the porting i've done, I'm competitive when I get on the track.Ive allways been an over rever and hard on engines.I have learned my lesson on trying to over ride the bike.I need to just go out and have fun and finish the races. Lg is going to have to keep me under control:D

[brian kirby]

I know where you are coming from, I'm a bit of an over-rever myself but you have to try to resist that urge because these old small bikes only have so much power to give. On a modern bike like my YZ125 you can just over-rev it sooo hard and it keeps making power, these old bikes sign off so even though its a 100 you almost short-shift compared to a modern bike.

Brian

[checkcrew]

Mickey,

the Wiseco part # for the 100cc alloy Sachs motor is #162P
do not use a Wiseco piston that is in the old light green and white boxes, these were the early pistons that had problems, the red,white and black box is what you want,

if you are currently at 2nd OS with a Mahle that should equate to 48.40mm
Wiseco pistons are measured at .025 entervals, so a #162P2 would measure at 48.50mm
many guys are mislead thinking that the number after the letter is in .010 thousands, it is .025 thousands
so a #162P8 would measure 50mm

these pistons are out there but you will need to hunt for them,
i bought a P8 a couple years back for a highly ported EC Birt cyl and it worked out fine, but that is the end of the line, after that you need a new liner,

hope this helps,

keep us posted,

quote:Originally posted by Mickey Sergeant

The 45 and 150 was what I was thinking for my starting point. Not sure if the next size on the mahle piston will work,that would be a 49.0. gouged good.Buehner doesn't show a 49.5. Is there a wiseco piston for this bike that they make.

Thanks Mickey

Mike Gallagher, NJ.
[email protected]

[sixdazed]

Anybody want to buy a bunch of nice wiseco pistons in green and white boxes?

ric emmal

[checkcrew]

sure Ricky, i'll use them in my old Lawnboy mower [8D]

quote:Originally posted by sixdazed

Anybody want to buy a bunch of nice wiseco pistons in green and white boxes?

ric emmal

Mike Gallagher, NJ.
[email protected]

[joe novak]

How do you mix your gas and oil?  Specifically, what type of gas, oil, and what ratio?   joe

[OUCWBOY]

Joe,
I am shocked that no one else has asked that question before now.....

Donny Smith
Paragould, AR

[Mickey Sergeant]

I use a non blended ethenol free premium gas octaine rating of 92 with torco gp7 premix at 32:1 I get it at a farm agriculture store

[Mickey Sergeant]

Just called the store where I get the fuel. They also have a 110 octaine rated fuel.The fuel I use has been in the back of my mind if it's ok.I know ther's another pog member by me that uses it that told me about it.Boat marinas are plentifull by me, I will check out there fuel also.