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Thread ID: 87621	2008-02-27 21:06:00	2 stroke motorcycles	Thomas01 (317)	PC World Chat

Post ID	Timestamp	Content	User
644518	2008-02-28 22:04:00	Hi Thomas. Thank you for also recalling the use of the small sand-blasting machines. The ever knowledgeable surferjoe almost caused me to doubt my memories.......... obviously American plugs were different to European plugs in the days before they all became Japanese plugs.... :rolleyes:	Scouse (83)
644519	2008-02-28 22:25:00	I remember that smell of Castrol R when the boy racers on their Ariel Arrows used to hoon around our village. I learned to ride on a BSA Bantam 125. Still remember it as an exhilarating experience. The first time in your life you could go fast without having to pedal!	Fishb8 (484)
644520	2008-02-28 23:59:00	I remember that smell of Castrol R when the boy racers on their Ariel Arrows used to hoon around our village. I learned to ride on a BSA Bantam 125. Still remember it as an exhilarating experience. The first time in your life you could go fast without having to pedal! Well sort of boy racers in their single cylinder dungers.	XRNZN (13406)
644521	2008-02-29 00:16:00	Well sort of boy racers in their single cylinder dungers. The Arrow was a 250cc 2 stroke twin. If you have to have a car to be a boy racer, how about this bit of madness A Lotus 23 powered by Ariel Arrow - Six of them! utahlotusmuseum.com	PaulD (232)
644522	2008-02-29 00:26:00	Sandblasting a plug to use on a 2-stroker was a no-no as the porcelain would then have a "tooth" or opened surface from the abrasive that would allow burned deposits to embed themselves into it and allow for much earlier flash-over of the spark . That made the plug useless as a spark traveling down the porcelain instead of across the electrodes was not conducive to ignition . And . . . yes . . . motor oil not actually designated for use in a 2-stroke engine is also counterproductive . It has not been designed to go through combustion and just leaves a nasty deposit on the plug . . . again with shortened life . Ask about the ports and the exhaust too . . . as a 4-cycle oil will build up some marvelous amounts of ceramic-like deposits all the way through them and they will put a crimp in performance too . Many 2-strokes however still run 32:1 with impunity . . . IF the oil and the compression and a slew of other designs and variables are observed . Back-pressure in the exhaust is one of the designed-in components of 2-cycle theory . Without it, the power band is too narrow and likely to cause lean-outs at certain on-the-pipe situations where extraction is more efficient because of Doppler and waveform/counterform values in the pipe . Positive/negative sonic and pressure waves in the pipe cause the performance to drop off excessively or to improve by what factor the engineers wanted . Modifying these shapes (bells, cones, recombinant platforms, "pea-shooters" and expansion zones) are all very counterproductive without some real seat of the pants or slide rule experimentation . . . not to mention time/money or personal frustration . A good streetable pipe has a rather broad range or "sweet-spot" power band and is not at all "pipe-y" for the driver . . . necessitating him to keep the RPM in a narrow range for max power and efficiency . Some very early designs . . when pipe tuning was not well understood . . . had some very complicated gearboxes with many ratios to keep the engine on the boil . . . for just that reason . The Yamaha YDT Series 1/250 Roadracer was one of these that had that famous "ripping canvas" sound that had the Isle of White roadracers all aghast . It was there in the very early 1960's with a little Japanese pilot on it who must've only weighed 65lbs/30kg and was all over the rider's seat to get it around the turns met the likes of some "serious" iron in the form of the AJS, Norton, BSA, Triumph pilots and crews who were laughing at the sound of the engine and the clouds or blue smoke until it ripped them a royal one in speed records and times . *I need a citation for this info . . I distinctly remember it well . . even the description of the engine sound in a magazine I was reading at the time . I have THIS LINK ( . yamaha-motor . co . jp/global/product-history/mc/1950/yds-1/index . html" target="_blank">www . yamaha-motor . co . jp), and THIS LINK ( . motorbike-search-engine . co . uk/classic_bikes/1963_yamaha_classic_racer . jpg" target="_blank">www . motorbike-search-engine . co . uk), but alas, it is not what I want to find . The Suzuki X6 Hustler ( . wikipedia . org/wiki/Suzuki_T20" target="_blank">en . wikipedia . org) was another one such bike that required (gasp!) a 6-speed transmission just to make it streetable and useful . It WAS very fast and powerful when it was boiling . The driver was constantly stirring the gears looking for the right combination of throttle and RPM though . Very busy! It had a new-unique "rotary shift" that allowed the driver to come to a stop in 6th gear and just pull up two times to hit first . The shift pattern was 1-2-3-4-5-6-N-1-2-3-4-5-6-N . . . and so one . Spark plug heat range, is of course, tantamount to performance, and the wrong heat range can hole a piston on the hot end of the scale or foul the plug(s) and engine on the other end . E85 fuel . . by the way . . is not to be run in a 2-cycle engine . Does anyone remember Castrol Caster "R" Racing oil? Or "Torco"? I ran them both in my Yamahas and early Kawasakis . Yummy smells and great performance . Torco smelled like hot peanuts . . . and Castor "R" was more like nitromethanol . I owned a Suzuki X6 Hustler in 1967 . Mine was red . http://www . t20suzuki . com/ :)	Trev (427)
644523	2008-02-29 00:52:00	In the early 60s I had a BSA A7 500 twin, which I thought was a marvellous bike. A fellow student offered me a ride on his new Yamaha 2 stroke (forget whether it was a 250 or 350) and I took it for a wee banshee howling trip along Rolleston Ave in ChCh. Strewth, it stripped the lining off my teeth. My Beezer never seemed the same after that. Why did the early racing 2 strokes seize up so often and unpredictably? I recall reading a book by one of the racing lads who said if he was following a 2 stroke he tried to keep part of one eye focused on its exhausts - he learned that a telltale puff of smoke would signal a seizure of the bike ahead, so he knew to take quick evasive action to avoid the collision. Apparently there had been quite a lot of casualties amongst following riders.	John H (8)
644524	2008-02-29 01:23:00	A couple of points there . I am puzzled your comments on sand blasting of plugs . I follow the logic OK but do remember that it worked extremely well and no way caused problems . In those days plugs were too expensive to replace and sand blasting gave them a new life . I and my friends used the process regularly on both 4 and 2 strokes . Never remember being disappointed by the results . And Castrol R . Yes of course I remember . In fact it is impossible to forget . What a glorious PONG . The only industrial smell that was extremely pleasant . Do people still use it ? Tom Castrol still has it listed on it's website . . so I imagine it's still available . I was using NGK-Racers in the aluminum cans . . . and they didn't at all like to be blasted . Another thing . . . . SOMETIMES you would leave a small piece of sand in the nook 'way up in the shell and it would become dislodged when you cranked the engine . . . Presto! Instant ring and cylinder damage . But . . . . . . sandblasting was OK on many engines . . . we had Champion plugs that were the worst for sandblasting, but the ol' A/C Delcos and the Autolites (which could actually be installed with a hammer) were pretty bullet proof for blasting . I've never like a cadmium-plated sparkplug shell . . . we had a lot of trouble with them removing the threads from the heads if we didn't use an anti seize compound . . . but that wasn't the technology of the day then either . NGK and Behru were exceptional in almost all fields . British engines were the worst for losing their threads . . . even when you took all the precautions . Ever try to pull an E-type Jaguar straight 6 head? Nasty!!!! I think the threads were cut in Londonderry fog that had congealed and they carved into an engine of sorts . Lodge and Prestolite and most Bosch plugs were junk as were the aforementioned Champions . I had a few of them blow out the porcelain from the shell in a high performance engine . I could destroy many of them when they were freshly installed in an engine by customer's request and then make a dyno run on the car . The plugs started out at about 5KV at idle, and after just a few minutes on the dyno, they needed about all the coil could put out just to idle . . never mind when you hit the loud pedal . We called those brands: "one-run-specials" as you changed them after every 1/4 mile run for new plugs . I think the pits in most of the drag strips in the US were paved by Champion spark plugs .	SurferJoe46 (51)
644525	2008-02-29 01:57:00	Why did the early racing 2 strokes seize up so often and unpredictably? I recall reading a book by one of the racing lads who said if he was following a 2 stroke he tried to keep part of one eye focused on its exhausts - he learned that a telltale puff of smoke would signal a seizure of the bike ahead, so he knew to take quick evasive action to avoid the collision . Apparently there had been quite a lot of casualties amongst following riders . Poor oil . . and tight tolerances coupled with heat were the baddest killers of 2-strokes . I have seized a couple . . . but really I think it was the plugs that were holing a piston that caused the ultimate coup . Getting the right heat range for a plug is a hit-or-miss thing and usually trashes a few plugs along the way . If when reading your spark plug (you DO read your plugs . . right?) and it is shown to be running too hot ( . lambretta . co . uk/downloads/image/plughot . jpg" target="_blank">www . lambretta . co . uk), the reason behind it is probably a major cause of most holed pistons, seizures and loss of power and performance . An engine running too hot can be caused by quite a number of things, but the main problem is once your plug shows signs of this, it is normally too late and some damage has already occurred . The reason for reading the plug is to stop it happening again! 2-cycles are notoriously damaged by any of the following: Too hot of fuel grade (premium "anti-knock-types or higher octanes) selected for type of journey, speed and/or load . Lean air/fuel mixtures . Ignition timing too advanced or counterweights are frozen (only on centrifugal advance types of distributors) Too high compression ratio . Change in Ambient air conditions, altitude, humidity . WATCH THIS PROBLEM!!! If your engine is running on the ragged edge of self destruction, just having the sun go behind a cloud can grenade and otherwise healthy engine . Remember that the 2-stroke uses the piston as an exhaust valve and if the fuel is retarded in the burn rate and flamefront propagation values, as a higher octane fuel is . . . it'll still be burning as it goes past the piston . That equals a lot of plasma-cutting heat and velocities and it can easily destroy the piston making it appear to seize up . ( . kenoconnorracing . com/htmlpics/backwards%20piston . jpg" target="_blank">www . kenoconnorracing . com) To confirm that, just drop the header pipe and see if it's got little balls or a spray coating of piston aluminum on the inside . . . a sure tipoff that the piston was dying from too much heat and just couldn't take it any more . If you notch the piston for increased port timing . . . then remember too that the piston has now been relieved of some of the heat-sink metal that is important for the integrity of the ring(s) and the top of the piston . Horses cost fuel and reliability . A good vegetable-based lube oil . . turn the oil injection 'way up if it has it and use REGULAR fuel that runs cooler with the right heat range of plug and at least try to tune the carb(s) to whatever exhaust system you had on them . Be careful here with TOO MUCH oil . . . it is displacing fuel and therefor running the air:fuel ratios all amok . Keep the ratio near as you can to 13 . 5:1 . That's the optimum ration for all-around 2-strokes in general use . Again . . . READ THE PLUG!!!! The little guys like to wing it 'way up in the RPM ranges . . don't lug them and for the sake of your pocketbook, make sure they get good airflow over the fins .	SurferJoe46 (51)
644526	2008-02-29 03:08:00	hi joe.......while on the subject....... any ideas on how to cure 2 stroke oil smoke after its been left to idle a while? it has a habit of running like crap and even stopping if its left to idle. oil fouled? runs fine when given a bit of use.	tweak'e (69)
644527	2008-02-29 05:14:00	Define "IDLE" from your perspective for me...but if I assume the act of having the engine running slowly anticipating a burst of power demand..then the following applies: Some engines just have a propensity to collect oil in the crankcase...and that's why the crankcases are so tightly stuffed with castings. The fact that the crank and the lower end of the rod take up just about all the space in the case, leaves little area for oil to collect. Some Schnerle designed engines CANNOT run clean off-idle...no matter what you do. These typically have a five-port design and they are cold cold cold in the crankcase with very low velocity and mixing of the oil (entrainment) at idle to about 3,000 RPM..then all hell breaks loose and the oil gets entrained and out the exhaust it comes. However, all things being equal..and if we are talking a relatively new design-good designed engine, the extra smoke from an extended idle might be minimized by a better quality oil in the mix. What mixture are you using? What brand of 2-cycle oil? Is it a water-cooled or air cooled engine? (It makes a BIG difference). If it's oil injected, then the pump might be stroking too far at idle..check the twin cables (likely that have a splitter in the main throttle cable) and make sure that the injection pump returns to minimum position at idle. Give me a hint what the engine application is and the job it was originally intended to perform...maybe I'll have an epiphany and be able to help.	SurferJoe46 (51)
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