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!
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
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
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.
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]
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?.
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.
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]
Just double checked to see were ring cought or broke.Looks like dead center on the exhaust port.
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.
The pilot jet is the idle jet. Not sure that's the problem though.
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
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!
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
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]
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!
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
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
Sorry were talking about a bing
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.
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
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
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
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,
Quotequote: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]
Anybody want to buy a bunch of nice wiseco pistons in green and white boxes?;)
ric emmal
sure Ricky, i'll use them in my old Lawnboy mower [8D]
Quotequote: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]
How do you mix your gas and oil? Specifically, what type of gas, oil, and what ratio? joe
Joe,
I am shocked that no one else has asked that question before now.....
Donny Smith
Paragould, AR
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
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.