More Berkie bad luck

[Mickey Sergeant]

Went to my first race of the season. Riverdale raceway,Hammer tongs series. Signed up in the vintage int125. Gated with 5 exp.6 or 7 int's. With one lap to go 1st in the int 3rd in the exp, bike quit running. Piston stuck. Got home took apart top end, found broken bottom ring. Half of ring sucked into bottom end. Gouged cylinder good. Will need board.Maybe I will get luckey and get ring to come out without having to take bottom end apart AGAIN.With my luck I dought it. It's just more time and money!

[brian kirby]

This might be obvious, but did you chamfer the ports if you did a fresh bore? If not, that will snag and break a ring.

Brian

[Larry Perkins]

If GS style port widening is done and there is not a GS piston run or ring pins relocated that can happen also.  Has extensive port work been done?

Larry P

[Mickey Sergeant]

Yes the cylinder was ported by a qualified person that had penton specs.Looks like all the ports were chamferd.The piston was a mahle piston on its 2nd bore.

[checkcrew]

Mickey,

i recently read on the Monark site about the GS porting and the bulliten states the ring locating pin has to be relocated to prevent what has happened to your engine,
i am sure your porting was properly done but the piston still most likly needed the ring-pin relocated to avoid this misfortune,
keep your head up, you will get it right,

regards,

Mike Gallagher, NJ.
[email protected]

[gooddirt]

Not sure but I think he add a extra boost finger port some where in the rear of the barrel; might have caught on it?.

[Mickey Sergeant]

Thought some of the ring went into the bottom end. piston was at bottom stroke. turned upside down spun free a good 100 revolutions.. the other half must of went out the exhaust. I will flush out goode:Dto make sure.I will talk to my guy about the pin relocation thing. Thanks for the info.

[checkcrew]

Larry,

if that is the case, ring-pin location is critical !!!

hopefully he can save the liner with a single bore,
Mickey stated it was already at 2nd OS,
i know you can go up to 8th OS using a Wiseco

tough brake, but very fixable !!

Mike Gallagher, NJ.
[email protected]

[Mickey Sergeant]

Just double checked to see were ring cought or broke.Looks like dead center on the exhaust port.

[Mickey Sergeant]

Showed my cylinder to my engine guy. Said it siezed first.Said plug looks way to lean.. He says to go to a bigger pilot jet first before assuming its the main. A bigger pilot will cool down qicker allowing more fuel as you close throttle off main he says. So what is the pilot jet considered on the bing. They use different terminology in my parts manual.

[Gordon Brennan]

The pilot jet is the idle jet. Not sure that's the problem though.

[Larry Perkins]

Mickey,

If you are running a Bing the pilot jet(or idle jet) is the one that comes out with a little screwdriver but it controls starting only is my understanding.  Not to cause trouble but are you sure your engine guy knows his stuff?  I would question your engine guys knowledge or perhaps mine.  Pilot jet controls starting, needle jet from almost nothing to barely 1/4 throttle and the main the rest on a Bing anyway.  I can not imagine that a pilot jet could cause a seizure or that you could ever get a plug reading at idle.  I think regardless of carb you would have to be off considerably in needle jet or pilot jet to cause seizure.  I have seen Bings on 100 and 125 Pentons with everything from a 25-45 Pilot jet and a 270-283 Needle jet without ever seeing a seizure with those.  If it was a seizure and not an airleak I think the main jet would be suspect.  I have not seen your cyclinder but I still suspect a snaged ring in a port.  Just my opinion but the only seizures I ever encountered in 40+ years of racing were from air leaks and never jetting so I guess I jet okay.

One other thing, if he is off on this advice I would rethink anything else he has done.  Others here with a bigger brain can confirm what I am saying on jetting or possibly correct me.  I am always open to learning.

Larry P

[Ed Chesnut]

I don't know much about Bings, but I'm pretty familiar with the Mikuni.  So if that is what you've got . . .

The pilot jet is the idle jet BUT . . . it flows fuel at ALL throttle settings.  It is the only jet providing fuel at zero to 1/8 throttle, but it is still providing a bit of fuel at 1/4, 1/2, 3/4 and full throttle.  That is why (on a Mikuni anyway) it is important to NOT change the pilot jet without checking jetting at all throttle positions.  (If you were already borderline lean at full throttle and went to "clean up" a blubbery idle by changing the pilot jet one size leaner, you would ALSO end up leaner at full throttle . . . which could be disasterous).

On a Mikuni, the combination of the needle jet and needle has significant effects from about 3/8 throttle to about 7/8 throttle.

It sounds to me like the ring snagging problem and the possibility of an air leak have to be eliminated before messing about with jetting.

Ed


Keep the rubber side down!

[Mickey Sergeant]

Ok let me try to explain better how the pilot jet thing was explained to me.I'm positive I dont have an air leak'I didn't have the main jet I thought was in carb.It only had a 135. I thought I put in a 140 to start with.Pilot jet is a 40.I need to keep better records.With the porting on the engine I know that is way to small.
 This is how it was explained to me.You still need to be in the ballpark on the main. If you are running it hard on the top end and you would blurp the throttle closed quick and then back on by having a bigger pilot would help give a little extra fuel to help cool the plug and piston.It's more like an extra insurance policy to help keep cool.Sorry I'm all over the place,Just had surgery on my right hand this morning to remove some scar tissue thats been giving me problems. I'm still a little loopy, so be a little gental on me. Hope that will make more sense

[checkcrew]

Mickey,

your there on the pilot jet being to small and causing it to seize,

KTM has a bulliten out on the 08 and up 300 2/strokes to go up 1 or 2 sizes on the pilot jet to prevent poss piston seizeure from high speed closed throttle,

i believe your friend hit it !!

good luck,
keep us posted,

regards,


Mike Gallagher, NJ.
[email protected]