Posts
1250
Joined
7/19/2018
Location
Wildomar, CA
US
Edited Date/Time
11/8/2018 6:33pm
I have a 1980 YZ250 that smokes more than the Marlboro man. I am using Maxima K2 at 32:1. I just put a new clutch side crank seal in it and it still smokes just as much. It also spews oil out the exhaust pipe and dirties up the spark plug with burnt oil deposits. I'm thinking that it may be sucking trans oil from between the cases, but maybe the K2 just smokes a lot at that ratio which is one of the main things I am trying to determine. I called Maxima and didn't get a definitive answer.
What oil do you use?
What ratio?
Does your bike smoke a lot?
What is your bike?
Thanks in advance for any info.
What oil do you use?
What ratio?
Does your bike smoke a lot?
What is your bike?
Thanks in advance for any info.
50:1
No
85 ATC250R and 78 RM125
The Shop
maxima did say i can definitely run their gear oil in the gas for a while without doing damage other than carboning up the system, so i guess if it is leaking from the trans into the engine, i could probably run 60:1 at the moment and be safe, lol.
Do they smoke some all the time at all speeds?
Are you ever holding them wide open very long like in a desert race or a gp with some long straights etc?
I am racing in the elsinore gp in a week and they have two long 70 mph straights and the race is 30 minutes long.
i have been running shell 93 e10 with 25% vp street blaze, and the street blaze has ethanol too. i just bought some ms109 today and will try that at 20% with the shell. i can't get non ethanol gas where i am but a little ethanol is not a bad thing like some people think it is. the biggest drawback is that it can attract moisture under some conditions. vp says the 109 makes the most power out of all their fuels because it burns the fastest but of course that doesn't mean it is the best for all apps which is why they have a bazillion different fuels but i think they could whittle a few out. i'll find out soon if the new master brew makes any difference in how it starts which isn't very easily at the moment but i am still working on that. the ms109 has 10% oxygen, but the odd thing about the ms109 is that it has the lowest rvp by a huge margin, which isn't good for starting at all but i will soon find out.
Then in the late 70’s I ran HiPoint at same.
After that Spectro at same ratio.
Never any top or bottom end failures due to oiling.
I can only dream that my pipe will ever look like that. Mine looks like the exon valdeze, lol..
I repacked my silencer before i changed the seal and it immediately got oil soaked again and it smokes the same after i changed the seal. The silencer packing does not get hot enough to cause this amount of smoke even if the packing is soaked, plus it smokes from the second i start it which is long before the silencer gets hot.
The last race i was in 4 weeks ago with calvmx, i entered the novice class, and was in second place in front of i think scott burnworth and 15 other experts, intermediates and novices until some clown behind me went wot into a turn and centered punched me, so i am definitely floggin it reasonably hard, but certainly not as hard as warren reid on a 1974 fmf or dg built cr125, lol.
Today I am attempting to find the parts i need to do a leak test. If i find them i will post the results.
I used to run 50:1 but felt a lot of pressure from engine builders to run more oil in my 125s at 32:1. Since I ride 125s, 250s, and an Open bike I just split the difference and run 40:1 in everything.
My bikes are jetted well and I don’t have the smoke problem you describe. The K2 doesn’t have that great 927 smell...but it’s way cleaner on powervalves.
If they are water cooled it makes a significant difference.
Pit Row
79 YZ 400
83 Cagiva 125
88 Cagiva 125/250
90 KTM 125
95 KTM 250
Many people riding trials bikes run 80:1 and sometimes leaner with no problem.
The results are that there is a small air leak of 1 lb per minute, however, the tester was leaking a tiny bit so that accounts for a little bit of the leak, irregardless, 1 lb per minute is not remotely bad enough to cause the amount of smoke I have. The piston also looks like new and there is zero blowby past the 2nd ring, therefore, it seems to me that the majority of the smoke is from running the oil a bit rich, so tomorrow, I am going to elsinore to test it with 38:1 and 80% 91 octane e10 shell pump gas and 20% vp ms109 oxygenated fuel then will do some high speed runs.
I will post as to whether it blows up or not, lol.
More oil than necessary can also reduce hp and slow the rate at which rpms build but it seems that some of the people that believe a little more oil will make a measurable difference in ring seal seem to either not know that or think an insignificant increase in ring seal is more important. Some also seem to completely miss the fact that compression can be increased by simply reducing the size of the combustion chamber.
Some also miss that fact that there is no way they are capable of riding their bike as fast is it can be ridden, so even if they got another hp by better ring seal, it ain't gonna get them around the track one bit faster and they should simply practice more to go faster instead of worrying about something so insignificant.
More oil also reduces the amount of power (btu) in the fuel.
Some people that worry about less ring seal with less oil on a 2 stroke don't even think about it on their 4 strokes, lol.
I have never seen a scientific test that showed this. If you have, please post it.
didn't have to re-jet with my new fuel blend and new 38:1 oil ratio and there is very little smoke now so i will leave it there for now or maybe just go 40:1 to make it simpler. Might try 1 size bigger main when i get time as well. May put it in this week then try it at practice on friday before the elsinore gp race. i have 2 hours after practice before my race so i can change it back if it is too rich.
thanks for the replies, they were useful.
PS - It pulls slightly harder now too so it's a win win all around, plus i got to smoke a guy on a 2001 250 suzuki.
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