Can't get it running

[454MRW]

Sorry, but the manual does not list the slide information other than part # 22-746/1. is the o-ring at the top of the carb that seals the lid in good shape? Bing has them. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[brian kirby]

Im running

165 main
283 needle jet
45 pilot

Brian

[Andreas Piepke]

OK so the 283 needle jet seems to be what people are using. I already sent an email to Bing Agency to inquire about availability. My main jet seems right. The number 40 pilot jet is probably close enough. I might get a number 45 too, as used by Brian, once I order from Bing.

Thanks for your input!

Andreas

[Gordon Brennan]

Since you have gone this far with the carburetor, I would replace the brass float bowl seat, float needle, float itself, clip and pin as well. I have done this on my Penton, 73 Husky and 74 Can Am Bing carburetors, and it made a big difference. The float that was in the Can Am was old and heavy. It actually sank when I put it in a separate larger bowl of gas. Try to find a new black one. Bing doesn't have them, but they work the best. But the white ones will work.
If all the carburetor re-building doesn't work, I would remove that silencer, just to see if it makes a difference.
Actually, I would have done that first.

[VICTOR MONZ]

1990 KTM 125 - Del Orto Carb


Cannot get it to run start and need help.   Any ideas ?

Thanks, Victor

Or an offer ?

[Andreas Piepke]

Hi Victor,

Any luck yet with your bike? Does it have spark? Is there gas in the bowl? Is the spark plug dry? Did you try a new spark plug? Sometimes starting issues can be caused by plugged air channels in the carb connecting to the pilot jet. Obviously I have no way to diagnose your problems just a few shots in the dark.

Good luck

Andreas

[Edd 44k]

GB was correct in suspecting the float. The foam (white) float get heavier with age. they can be checked with a gram scale , I am out of town at present and can't recall correct weight. Bing no longer imports the Black 310 floats. I don't know if they are no longer made or that this completely cures the white float problem and you wont be buying replacement foam ones. I ran 310 floats on all my Pentons 125/250 and they ran great. Talk to anyone riding an Airhead BMW and they will all tell you that the white floats are a common issue. DON"T TRUST OLD FOAM FLOATS PERIOD!

Lot of Penton parts for sale.  Inquire via email.

[Andreas Piepke]

Hi All,

Here a picture of my assortment of carb components:



I also tried a size 2 slide (left), a size 0 slide (right) was installed in the carb:



I tried some 12 different combinations of components and settings. The size 2 slide didn't work at all, the bike ran way to rich. After my experimentation I found a combination that works much better than what I had initially:

40 pilot jet
170 main jet
2.80 needle jet
46-281-01 jet needle
size 0 slide

I further moved the ignition "time" from 2.55 mm BTDC to 2.25 mm BTDC.
I'll post a video of a test run for you to critique once it stops raining here. It seems I am making some progress!

Cheers

Andreas

P.S.: Yes I did install a new rubber ring on top of the carb. I don't know what to say about the float issue. The job of the floats is to maintain a consistent amount of fuel in the bowl. I took the bowl off multiple times during tuning and always found approximately the same amount of fuel in there. This indicates that the floats are doing their intended job. I don't know how else to diagnose this short of replacing the floats. This is not that easy as they don't seem to be sold any longer. Is the "black type" the hollow air filled kind?

[Daniel P. McEntee]

Heavy floats would tend to make it flood out. As they become more fuel soaked and heavier, the level has to get higher to shut off fuel. You could re-adjust them, but the same thing would happen over time. If you could fins the proper type of foam, I guess you could carve new ones and replace them on the old yoke, or fabricate some from sheet brass. Just depends on how much work you want to do.
   I still say you are the king of photo posting here! I've been following the thread just to see the photos you post of the work along the way. May come in handy some day!
  Good luck and have fun,
  Dan McEntee

[Andreas Piepke]

Thanks for the input Dan! I think I addressed the issue of the float position earlier. Have a look at the carb after adjustment:



I set the floats at a slightly upward angle. I determined the angle such that the desired fuel volume of 40 ml is in the float when the float needle shuts off and not such that the floats are parallel to the carb body. This method allows fuel level adjustment independent of the buoyancy of the floats. I think this is a good method, however, there seems to be no data out there to tell me what a good amount fuel in the bowl is. The carb is not flowing over so I think heavy floats submerging into the fuel too deep isn't a problem.

I really appreciate the input!

Andreas

[454MRW]

Throw that float in the trash and don't think twice about it! Send me your address and I will ship you a good used black one. The float should be level just as the lever contacts the spring loaded pin on the float needle, not with the full weight of the float resting on the needle valve, which would actually depress the spring loaded pin into the needle giving an incorrect setting. [email protected] Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Andreas Piepke]

Thanks Michael, this sounds like a great suggestion! I just sent you an email.

Cheers

Andreas

[SouthRider]

As Mike says the float should be un-weighted when setting. Put the carb on it's side & it should be level just as the needle touches it's seat.

Also - in the pics above the slide on the right looks worn out. Bings were famous for having "soft" slides. As they wear they flop around forming the oval shaped ridge that you see in the pic, allowing air to leak around the slide. In worst case scenarios the slide will eventually jam partially or wide open.

_____________________________________________________________________________________

"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."

1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax

[454MRW]

Float is shipping to you today. Another thing to make sure is that the float pivot pin does not have any burrs on it that could cause erratic function. If it feels rough, sand it with some emery paper to smooth it out. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Andreas Piepke]

Thanks a lot! I'll let you know once I received the part. I inquired at Bing about the availability of a type-0 slide for my carb, let's see what they have. I also asked for info regarding the location of the custom seat of my carb, relative to the float needle position of a standard carb of this type. I'll condition the pin that seems like a good idea.

Cheers and thanks again!

Andreas