I've have a 1977 MC5 250. I'm using Spectro and mixing at 32:1. I've got a lot of oil coming out of the pipe. Is anyone going leaner on your mix?
Your jetting is too rich
Bob
1986 ISDE Italy
1987 ISDE Poland
1989 ISDE Germany
I think Bob's right; it's jetting. Today's oils burn pretty clean but I haven't done 32:1 since the early 80's. Shoot I'm currently running 40:1 (Maxima 927) and that is considered rich by today's standards. I'm about to move into the 50:1 arena.
Pete Petrick
175 Jackpiner
Slow but Good
I have used yama lube at 32:1 for years.I race my Berkie and Six Days hard.If you want these old engines to last you need to be on the rich side.If you have oil coming out of pipe I would say your to rich on your jetting.You want to see some smoke.PLug should be a chocolate brown.
Spectro 40:1 for me
Just to show how the mixtures have changed, we used to run 20:1 back in the 60's..
Donny Smith
Paragould, AR
I have always used golden spectro concentrate mixed at one 12oz bottle to five gallons of gasoline with no problems whatsoever.which is 53.3 to one. I have used this oil since hi- point went away in every bike i've had.I also used the same ratio with the hi-point oil (sine 1972) I also use the old gas out of my bike in my powered lawn equipment.In my opinion if you are using the spectro concentrate at 32:1 it is way too rich,however if you are using the spectro s/x i believe it calls for a richer mixture.
I'm with John B.
Thanks everyone, I'm currently running 1 bottle to 4 gallons, I was thinking the bottle was 16oz. So it's actually 42:1. Sounds like I can go a little leaner in the mix. I still have 20:1 stuck in my mind. Thanks again.
If you go leaner on the oil mix, your bike will get richer..
Bob
1986 ISDE Italy
1987 ISDE Poland
1989 ISDE Germany
Quotequote:Originally posted by Bob Bean
If you go leaner on the oil mix, your bike will get richer..
Bob
1986 ISDE Italy
1987 ISDE Poland
1989 ISDE Germany
and with the cost of 2T oil, if you go leaner you'll be richer too! ;)
Pete Petrick
175 Jackpiner
Slow but Good
The oil burns when the combustion chamber temperature is high enough to reach the oil's flash point. Reducing the oil to fuel ratio is not a fix.
Gasoline is what cools the engine and oil provides lubrication.
If you have excessive oil coming out of the pipe your combustion chamber temperature is not high enough.
I've seen dyno test where an engine made its best power at 16:1. The down side is excessive carbon build up. But lubrication makes a difference.
When your jetting is to rich the excess fuel is cooling the combustion chamber temperature below the flash point of the oil and raw fuel and oil is going right out into the pipe.
Most people understand jetting, so you don't seize at wide open throttle, but don't consider that most of us don't stay wide open for very long.
Quite often its the low and mid speed range (closed to three quarters throttle) where we ride most of the time and jetting in those ranges is just as important as high speed jetting.
Just having a pilot jet that is to large can cause excess oil coming out the pipe over time.
Checking the plug color at 1/4, 1/2, 3/4 and wide open, will control excess oil with any oil or ratio you choose.
Ron is exactly right, excess oil at the exhaust really has nothing to do with the oil type or ratio, its completely a result of too rich jetting, almost always too rich on the needle/needle jet.
Here is a picture of my modern Honda CR500 running 32:1 Maxima 927 castor.
(http://i1177.photobucket.com/albums/x348/kartwheel68/540939_4265561911648_1010271807_n.jpg)
Absolutely zero smoke at any throttle setting other than idle, and its because its jetted perfectly. If you look right at the tip, you can even see the heat mirage, but no smoke.
Brian
Quotequote:Originally posted by wfopete
I think Bob's right; it's jetting. Today's oils burn pretty clean but I haven't done 32:1 since the early 80's. Shoot I'm currently running 40:1 (Maxima 927) and that is considered rich by today's standards. I'm about to move into the 50:1 arena.
Pete Petrick
175 Jackpiner
Slow but Good
I have used OPTI in 1962 at the ISDT with a mix of 50-1
In 1970 OPTI came to Canada and since then I ( we ) use it mixed 100-1. Yes times have changed.Oil and materials are so much better.
I use SHELL Super,the only company in Canada who does not have methanol in his high test gas.
In any case,proper carb adjustmend is a must.( easy with a Lectron) Lolol
Speedy
Have you seen these?:
http://www.powerapt.com/smartcarb.php
It's like a Lectron on steroids.
Pete Petrick
175 Jackpiner
Slow but Good
That's what I meant to Brian. Just smoke at idle.
Exactly Mickey.
Brian
I rode the bike yesterday, it really wanted to bog at the low and mid ranges. The top end ran good. I moved the clip on the needle up 1 notch, got noticeable improvement but I'm on the top notch. The plug is still black. Does that mean I need to look at the needle and/or needle jet?
If it is a Bing and you did not personally put a brand new needle/needle jet in it, before you go any farther you need to get them. Working on jetting a Bing is a waste of time unless you know absolutely for certain that the needle/needle jet combo are good. You can not tell by looking at them if they are good or bad, and it will save you massive headaches just getting new ones.
Brian
+1 on what Brian said.
It wouldn't hurt to order more than one jet needle. I spent a lot of time and money on the 24mm Bing for my Mudlark. The needle is important and they aren't all the same. I ordered one and it didn't even feel right when I ran it through my fingers. There was a step in it. I tried it in the carb and it didn't work well. I ordered another one and I couldn't feel any steps in it with my fingers and the bike ran very crisp.
Bing parts wear out fast. At least that has been my experience with the Penton and the Husky.
Pete:
Maybe I am just a glass is half empty person. Cast carb is $375.00 and billet is $775.00. Sounds like just another bunch of hooey. Not even one decent picture of inside of carb. No photo of floats, no cutaway, no parts break down and yet they want to have consumers pre buy before some models are available? No information on why this new carb is better. The 2 videos show me nothing that any 20 year old carb can't do. My guess is they won't be around 3 years from now. Just my opinion.
Ted
Ted,
It is a direct copy of a Lectron in billet. Nothing special, and its not worth the money when you can buy 2 Lectrons and a handful of needle for the price of one of those "Smart" carbs.
Brian
Yep. I've been following a long running thread on KTMtalk.com about the APT carb. I understand what they're saying, but I just am not buying the whole APT phenomenon. IF I were to ever updrade my the carb on my 08 KTM 250XC, it would be a Lectron. I'm okay with my stock carb. The only thing I've done my bike is put in a JD jetting kit and set up the suspension for my size, weight, and riding style -- the bike is good to go! I just need to ride more!!;)
IF I were a Pro licensed/AA/Expert racer, I could understand the rationale for the need for speed. I understand buying a new FMF/PC pipe, new VF reeds, or even changing out the cylinder head, ignition, and getting some porting work done, etc etc.....I've done it in the past, but realized in the end I just need to ride more!!;)
To each his own...
Just like John I run one bottle of golden spectro in my 5 gal gas can and fill it just to the 5 gal line. I never notice much smoke once it warms up. In the 3 season's I've been running the bike no engine problems besides an exploded stator which had nothing to do with my gas mix.
Also what has been said about jetting is spot on. I rebuild my carbs every winter and sit them on the shelf for the spring. I've never updated jets and started having similar issues with my triumph this spring. Ordered new needle jets and it seems to have fixed my problem. Looking at the new ones to the old ones I can not tell a difference but sure notice it when they are in the carb and working.
74 250 Hare scramble
73 CMF 6day
68 6day V213
Thanks for all the responses. I have a much better understanding of what is happening. The jets and needle were all replaced when I put the bike together, and only have a couple seasons on them. I don't think wear was an issue, just too rich. I ordered new jets from Bing last week and a new needle as well, just to make sure.
We seem to have many different posts on jetting spread out over the years that we crawl through, but never get a definitive answer on what worked.
What is required is a page or link on the website that:
a) lists the stock Bing setups (ie 36 or 38 etc, type 1 54 or type 2 54 etc) and associated jetting for Pentons/KTM's. including info on your elevation and air temps etc, slide number, needle jet, needle, pilot etc.
b) lists modified setups that guys run, ie Mikuni and associated jetting for Pentons/KTM's.
Like a one stop shop for people to check out and work with as a good base line starting point.
Cheers,
Adrian
Quotequote:Originally posted by t20sl
Pete:
Maybe I am just a glass is half empty person. Cast carb is $375.00 and billet is $775.00. Sounds like just another bunch of hooey. Not even one decent picture of inside of carb. No photo of floats, no cutaway, no parts break down and yet they want to have consumers pre buy before some models are available? No information on why this new carb is better. The 2 videos show me nothing that any 20 year old carb can't do. My guess is they won't be around 3 years from now. Just my opinion.
Ted
I understand. I've been watching some of the threads too. From what I've heard the Lectron guys pretty much focused on the drag racing crowd for years and didn't improve the carb for off road use & this is where the Smart Carb guys jumped in. I'm just sitting on the sidelines watching it all pan out...or not.
Pete Petrick
175 Jackpiner
Slow but Good
Quotequote:Originally posted by adrian_goold
We seem to have many different posts on jetting spread out over the years that we crawl through, but never get a definitive answer on what worked.
What is required is a page or link on the website that:
a) lists the stock Bing setups (ie 36 or 38 etc, type 1 54 or type 2 54 etc) and associated jetting for Pentons/KTM's. including info on your elevation and air temps etc, slide number, needle jet, needle, pilot etc.
b) lists modified setups that guys run, ie Mikuni and associated jetting for Pentons/KTM's.
Like a one stop shop for people to check out and work with as a good base line starting point.
Cheers,
Adrian
Great idea!