copemech

I would nt be concerned with that exposure, yet at the same time I would not sniff the pipe!

I do not think there are too many variables here, as it seems to me the majority, or at least a fair amount of the oil is condensed in the lower end of the motor to provide contact protection of the surfaces. As the rpm and velocity of the mixture are slowed in low rpm operation, more oil accumulates in the bottom.(oil migration time slows) Now with an increase in throttle openings and rpm, this condensed oil is indeed put back in motion through slinging and increased air velocity getting tossed up top(the only way out) and eventually making its way to the combustion chamber. Some of the incoming mix may still be atomized with the fuel charge, and may be fairly well burnt with the ignition process, yert the part which is now syrup that makes it there is still exposed to the flamefront yet is not ignited. Not its purpose really, it is there to lubricate, not burn. The oil in the squish area of the combustion chamber has low flamefront exposure as well, long story made short it eventually gets spat out with the flow of things and will then accumulate in the exhaust.(oil migration time is lessened and it makes its way out, partially) Thankfully, modern oil does not burn well, doing its job, and continues to flow for the most part rather than produce a partially burnt carbon deposit in the motor. It is in that state that it will lay up in the exhaust unless one can keep it flowing with some velocity or actually manage to get enough heat in the exhaust to light some of it off and burn it out. Or both! It seems to me that both rpm and engine load are required to develop enough exhaust temps to either light off the grunge or keep it flowing, which is eventually spat out as smoke(as the case of the hillclimb) or spatter(oily mess that does eventually occur) and fings its way. Anything less is still laying up in the exhaust and once again, one does not want any more of this accumulation than need be, no more than he wants the smokey riders in front of him in the que.

Point of the entire thread being that many could indeed find comfort in using the higher ratios as a well proven element here. A bit more modern, yes, add the fact you would want good oil. Billy will lead us to the fact that for the most part the oil is indeed NOT consumed in the combustion process on a trials bike as it has a very high flashpoint and we run very low exhaust temps with the slow running. At the same time it brings me back to the original concept of all the accumulation in the exhaust, which for your average rider is not good. The charred remains of the oil that has passed still needs to migrate outside and be expelled eventually one would hope. The less accumulation at the other end, the better!

Yea, but don't take me long!

I answered your question, Billy! Is there anything else you need to know?, Then go away now like a good lad!

My vial is calibrated in 10ml increments, so I know. Then I flush it with the fuel to return the clinging remains, so should be close!

Yes you are correct here in soo many ways! And just that being the point of the discussion. You see we have already found some running way too much, and even though I feel 80:1 is conservative enough, there are still those that doubt that number, although well proven.

Mind you I do not totally disagree with the logic here. Therefore I just run the strimmer and saw on the bike mix!!!! Don't run the saw too hard though.

Seems about 50:1 would be the accepted standard for the air cooled trials bikes nowa. No idea about the Metrella, depends on just how hard one is running it, but I would not think any more than 32:1.

I think I would throw the little fecker off the bike!

I have posted this before as well in another thread, yet not in the general forum. This was written by an oil engineer at Maxima, and if you read through the last paragraph you can kinda follow the logic on a trials bike application.

Ok Jon v8 here is an example of an oil manifacturer that is soo sure the quality ot the product that they are willing to stake their reputation onit! Run your strimmer and saws as hard as you like at 100:1. And it ain't no old style blend!

Well, a few good responses here and all over the board as I would expect. Not picking on anyone here as this is an educational exercize!(m) A lot does depend upon what you are doing with the bike, and the TYPE of oil! I am referring to modern full synthetics here primarily. No chosen manufacturer, as the industry all share most of the basic technology and I would think similar accross the board with differences in their own additive packages. I am sure there are indeed some semi-synthetic(blend) oils out there that work well in a trials environment too. Soo in looking at responses, Spenser seems online with the higher ratios! And running them hard as well! Pete is confused? Toothandnail seems to be somewhere about the factory Ossa recco, yet seem Borus posted it at 110:1? Add he also stated that the mains were lubed by the gearbox oil on the Ossa I believe, similar to a Gasser. I have no idea, yet it all goes to show they are taking them lean and finding it sufficient! Billy T- Yes that oil fire is hotter, takes more to set it off yet when going? Flashpoint on high synth is up there with castor oil, which requires a lot of heat to burn off, yet the castor carbons up badly in a cold motor and exhaust. Jon v8- Your bike ain't a strimmer!!!! That is the point! Since when do you rev the bike like that? It is a different animal, treat it accordingly! Baldi- Yea, well, safe side being what it is, seems 80 is still safe as we are indeed going far beyond now. It ain't yer dads old oil! Dirt is the enemy, and oil cannot overcome that! Godzilla- Good conservative recco, use any crap oil at that ratio, yet better oil, less ovit , and good practice is the point here!!!! And NO- A747 is a bean oil blend as I recall. Smells great yet carbons up badly in a trials bike, less than ideal!

Well are you? How much is enough? What oil do I use? These are all questions that are commonly asked here. You may find many answers, Some old school, some conservative, some safe. Yet for the most part is seems that many tend to err on the old school rules here that no longer apply and in fact is is costing you money in both higher maintenance and wasted product. I will not even get into environmental concerns here, as it is a secondary issue, yet not forgotton. Now we are talking trials bikes here, mostly putting about, revving a bit on occasion, then you gotta doo the BIG hill and the bike starts smoking like a chimney! Why, you ask? Because it is fully loaded in the motor and exhaust with all the wasted oil that you have accumulated from the day, or more that has accumulated in there and may never get out really, just turns to grunge that stops up your mid box and muff because it does not move. It cannot because it is lacking in two respects, these being air Velocity, to which the motor has not maintained through large throttle openings during the ride, the average here being not over half throttle at best, and the other being Heat transferred into the exhaust under high engine loads such as the hillclimb(at half or more). Fact is that most simply do not even grt the bike into a mode of operation to use the oil that you put in! The rest as bogging waste! Now, I shall start off by example of the fact that our(Sherco) Pro riders here have used the mix of 80:1 of high quality synthetic for over a decade now I believe, and without issue.Now these lads do get some revs in the bikes on a regular basis and tend to keep some heat in the motor and exhaust. Do you ride at top level? Most do not even come close! Ok, so I can be like them and run 80:1!!! Well, y'hat is a start for some! Mind you we are not doing consistant high revs and road work here at speeds. Just normal passages between sections and such with some hills and vals and some hard running, yet even hard runs up long hills and things are fine. You got any long runds up a mountainside? Few again! Comment as you will. I shall get back on this later!

Them fork bootie things work well at keeping crud out. Specially if you ride in the mud a lot. Ck outer rubber on MC for tears due to rocks and debris. If it is grunged up inside there is likely a hole. Once repaired, pack the inside with silecone grease as a preventer. It is inert to the rubber components.

I would tend to agree with the above comments. The clutch should free up on its own yet may take a bit of rididg. Try rocking the bike in 4th gear with engine off for a bit. If carb is correct and all, the intake tract is ok, the crank seals are indeed suspect. There are some quick tests for this that may apply. Ck rear brake master cyl for leakage. pull the pedal off and inspect inside the boot(torn) for fluid and debris.Seal kits were in short supply for a bit. ontact me if you cannot find one.

Short of a few major issues, I figure one can keep that bike in good nick on an annual cost of 3-500 quid, possibly less for a punter.. Just how does that compare to the depreation expense of a new one? Seems to me anything out there built in the last decade is competitive enough.

Rob Toole is in the Ft Smith area I believe. Great guy and good rider. Surely there is some place to ride and practice including Keenans, within a couple hours drive.

Yea, she will spit when topped off, likely normal.

Just a joke of sorts. Michael obviously knows, I figured Phillip!

I have seen the Techno's do well and hold up in modern competition. Take a beating and keep on ticking!

In a way this is no different than trying to detune a 2.9 Sherco, Wayne. I do not think them that bad nowadays actually, not like the '03 bike persay, which was very peppy. In answer to your question, and having run the 24mm carb on the bike for a while now, it seems to me that the smaller carb is only marginally more gentile, as one is actually opening a smaller hole with a given amount of throttle. Now this may indeed limit the top end power limits, but in the mid range of things where most of us mere mortals find our limits, well, they will still put you on your ass! The decieving thing about the big 300 bikes, being docile on the bottom end of things, is the fact that it seems they can rip your arms off if you get into the mids and better. Do not be fooled , they can be brutal!

Razorback, did you buy that bike from Mexico?

Jon, have you seen Keenan lately? Is the ATR doing anything? Who else was it over there accross the border?

At least it is hotter than hell so it evaporates quickly! In the winter when the vapors lay low near the ground and accumulate this could be more of an issue!