2 Stroke Unreliability.

[Itchy]

Why are they so unreliable ? , ie GSX Mick at squires looked worried his NSR250 might seize at any moment, erm why is this? .

4 strokes generally only seize with no oil or if they over heat, last few months I must have seen
5-6 'blown up' RGV250s tempting but I was put off by the perceived unreliability issues,

surely if you give them plenty of 2 stroke oil , and don't over heat them they'll be fairly reliable
right RIGHT? .

Any thoughts?

Thanks.
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Spain 2008France 2007Big one 2009 We all die. The goal isn't to live forever, the goal is to create something that will. In the end, your life will flash before your eyes. Make sure it is worth watching.

[st3v3]

I would of thought, as is mine, as long as there is a nice amount of oil, petrol and water(not to mention general usual maintenance) any 2t would be Ok.
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[Finglonga]

They are mega reliable until they are tuned by people who don't know what they are doing or don't know that once they are tuned they need a stripdown every X number of miles.

Many Many moons ago I had a trusty GP100 (with a tuned 125 lump in it) never let me down as it was looked after. Sold it to a friend who I warned it needed stripdowns to keep it sweet . . . . 2Weeks later it was seized up . . . then again, then again. He sold it in the end as it was unreliable.
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Andy Sez....
F.Y.Y.F.F.

[MarJay]

[brooky]

Bikes like yer NSR, RGV's and TZR's were already in a high state of tune when they left the factory, And as such they wont be as reliable due to the performance they deliver.

When it comes to things like this you cant have it all. You either have the performance and lose some reliability, or you have the reliability and loose the performance.

Just the way two strokes are, I Love 'em!
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Suzuki GSX-R 750 K6.

[mattgirv]

I wouldn't go so far as to say a 2 stroke engine is unreliable.

Compared to 4 stroke engines they need more maintenance. A lot of bike owners I know aren't exactly vigorous with maintenance anyway, let alone with a bike that demands more attention.

Yeah tuning would affect life of the engine, but usually it is because one thing has been changed, which causes something else strain because it cannot cope with the change. Especially people on a budget. One person I knew bought a race can for his NSR. Lovely, but he didn't rejet his carbs or do any sort of adjustment to cope with the change. His bike ran like shit for it. I'm sure it didn't help with the overall life expectancy of the engine.

[JakeyR]

In 6 months i've gone through 3 head gaskets (yes, 3!) and the engine has seized once due to the oil pump failing, and its an 05 model, wouldn't expect this many problems but it's all sorted now

[stinkwheel]

I must say that anything that has caused one of my 2-smokes to let go would have done the same on a 4-stroke.

Err. Had a crack in an inlet manifold, ran lean and holed a piston. Points shifted, ignition retarded and holed a piston and I had a CDI pack in.

There again, I had the conrod fail on what is supposed to be an ultra reliable 4-stroke single. Big ends collapsed on my mates GPZ305.

An important consideration is that when a 2-stroke lets go, you open it up to see how you're going to fix it. When a 4-stroke does so, you open it up out of morbid curiosity to see how many bits the inside of the engine is in before fitting a new one.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Al]

I do about 6k a year on my vespa commuting and its fine, Ok it probably does preduce less power then a 4 stroke 125 but still...
I keep the oil topped up, change the plug every few months and a little bit of self servicing . kept it going up fine so far.

In fact the motor is about the best bit, the rest of the vespa is starting to fall apart
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Yamaha FZR400RR 3tj
My Instagram Thingy

[cagiva gezzer]

My two stroke is running at 280BHP/L.

You have to expect any engine making that much power to let go with very little warning.

Each time it's had a fit it's given me warning, but only now am i able to realise it's on the way out.

Get a 2T that's making 4T power/L outputs and they're the most reliable and much loved engines in the world. i.e CRM250.
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"because one stroke isnt enough and four strokes waste two"

[iooi]

Never ever had any issue with my old 2 strokes, be that a AP 50, TS100, 2 x X7'S, LC350 or a DT125.
All the 250's & 350 did at least 10,000 miles a year on nothing more than std service and i never had to have a head off on any of them apart form the AP 50 when i stripped the thread on the spark plug Was learning at the time.
Fair to say that all apart from AP 50 were new, but apart from free 1st service never saw the dealer again.
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Just because my bike was A DIVVY, does not mean i am......

[phil_DT]

[stinkwheel]

The solution to the problem is fuel injection.

Yamaha make, V5 2-stroke outboard motors which put out 250bhp. Reliable as you like.

EDIT: Also my classic project bike is a Suzuki T500. Injects the oil directly along the crank, which is sleeved for this purpose. They were very popular with amateur race teams in their day because you could do a whole season without having to strip the engine. Just change gearbox oil and plugs.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[firefox]

ive done 7000 miles on my dt stroke in 4 months and its still going strong
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bye bye gti <^>( ' . ' )<^>
*officer* what caused the crash ? *firefox* you see that wall up there sir ?
*officer* yes what about it *firefox* i tooted my horn but it refused to move i had to teach it a lesson.

[Ariel Badger]

[cagiva gezzer]

125cc running 35BHP - 35 x 8 =280.

The highly strung 125's / 250's will always have short lives.
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"because one stroke isnt enough and four strokes waste two"

[st3v3]

[Ariel Badger]

[Jack_Cheese]

They are reliable as long as you keep with the service schedule. They generally don't tolerate abuse as well as 4-strokes do, though.

Not warming them up is a sure fire way to kill them too, but when they do blow up, it costs feck all to rectify compared to a 4-stroke. If a 2-stroke seizes, you need a barrel re-plate, new piston, rings and gaskets. If a 4-stroke does it, you may need valves and timing mechanisms, too. then there's the added labour of timing it all up again.

As for not doing a 100 mile trip, i did a 280 mile round trip up round delivs bridge and god knows where and my Cagiva YES, CAGIVA didn't miss a beat the whole way.

Jack
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www.bikepics.com/members/jackcheese <--- NOW FOR SALE! 51 Plate Cagiva Planet 125
Quacker_boy: "Jack, you really are a dick!"

[Ariel Badger]

I rode a 250 RD LC all over Zimbabwe in the 80s, thrashed it on the blacktop and took het into the dirt a lot. I did thousands of miles and only problem I had was a worn gear selector fork.
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Bikers make great organ donors, get 115 on your licence today.

[Pte1643]

Owned an RGV for 2 yrs, way back when.

Done 30 miles a day, work and back, (Yes, I used it as a commuter ), everyday in all weathers (didn't have a car then).


She NEVER once missed a beat.

[JakeyR]

[bish777]

My MZ was perfectly reliable.

Its just demented wasps like RS125s when ragged by wannabe racers that explode every five minutes.
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GSXR1100J

[MementoMori]

I had a little RS50 for a year and a bit, and used to rag it around town and also to get me to college and back and not once did I have a problem with it, only menial electrical faults. It was a perfect little bike.

Then again, I am a girl so probably rode it like a fairy.
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The tiger who came for a pint

[Diggs]

I rode my AP50 from Wakefield to Ipswich one dark, cold, long lonely night as a teenager and it didn't miss a beat. Only problem was I had to wait till 8 in the morning for petrol halfway down. 6 hours in the dark by the side of a road in the Fens is no fun...

Two strokes can be reliable if you remember to top up the oil and you clean the plugs every 500 miles of so, plus decoke and get handy with the circlip pliers.... They just need more maintenance, thats all!

I stripped the plug threads on my AP50 too... the 'bang!' it made when I tried to pull onto a roundabout and the plug hit the underside of the frame was quite impressive! Well, it impressed me... lol
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Now - Speed Triple, old ratty GS550, GSXR750M
Gone (in order of ownership) - Raleigh Runabout, AP50, KH125, GP125, KH250, CBX550, Z400, CB750FII, 250LC, GS550, ZXR750H1, Guzzi Targa, GSX750F, KH250 x2, Bimota SB6R and counting...