Over the past year i have spoken to many 2 stroke engineers about my bike. They all have diffrent opinions. but before i tell everyone who said it. One of the top engineers in the country said this....

"NO 2 STROKE SHOULD SEIZE IF THERE SET UP CORRECTLY NO MATTER THE CONDITIONS." when i ask what about top end rebuild etc he said "YOULL KNOW WHEN IT TIME TO REBUILD THEY JUST GET SLOWER"

So what do the techy boys think of that? TRUE or FALSE iv never spoken to an engineer/Mechanic who said that so just wondering what you guys think?

Define "correctly".

If you mean set up with a big enough margin of error (i.e. rich enough, low enough compression and retarded enough timing) to be on the safe side at -10*c at sea level with a sea mist then that is definately true. But take that bike into Death Valley at 40*c and 10,000ft and see how it runs.
But to be fair not many people seize totally standard NSRs.

Or if you mean set up correctly for the conditions at the time the same is true.

The problem comes when you play with the settings in a quest to improve either power, ridability or both. Then you ride it in 20*c colder conditions than you set it up or at wide open throttle for miles or both.

A good demonstration of the margin manufacturers build in is shown by the power the bikes produce;
Most of the full power 250's claimed 55 bhp, this will be an at the flywheel figure and they can be ridden hard anywhere within reason.
A carefully set up NSR on standard pipes and carbs can make 60-65bhp.
That's near 20% more power basically from running it leaner.

And the ridabilty factor, I've spoken to RGV and RS250 boys who've run proper UK full power settings and they can't believe how tractable my bike is (was ), in mid summer it really did pull totally cleanly from 3000 rpm at pretty much any throttle opening.
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fontyyy wrote:

And the ridabilty factor, I've spoken to RGV and RS250 boys who've run proper UK full power settings and they can't believe how tractable my bike is (was ), in mid summer it really did pull totally cleanly from 3000 rpm at pretty much any throttle opening.

Exactly! I'd rather have a 55bhp MC21/28, or a 3XV, than an 65bhp RGV/RS...
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NSR300R - Why did i ever have a 250...

Exactly! I'd rather have a 55bhp MC21/28, or a 3XV, than an 65bhp RGV/RS




at least the nsr wont dump its powervalves and eat the engine.
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faster-faster-faster-faster+pop. oh sh*t its fecked again.

Yes, I think the chap was talking about a mild tune not a serious balls out modified barrels and heads but basic jet and chambers, Actually the bike that was in question was a rgv500, well a rg 500 with rgv125 barrells straped on, The bike was claiming (i did say claiming) an extra 20bhp and i though that was alot for straping barrels on and thought it had seize potential but thats when the statment came out and i was suprised. Ill have the final results of my bike saturday but it seems itll be on the mild side around 60hp so im hoping if micks done his stuff right ill have a fairly reliable bike wich will just need routine rebuilds, one which is due around 6000kms
But intresting guy's i thought the first reply would have been False they all sieze??? MMMMM maybe this guy knows his stuff!! will wait a bit longer and see if anyone else has comments. Alot of mechnics said it would just happen sometimes others said climate but Like Fonttyy says were talking a alround setup!

When my 21 was stock all bar a KISS delimiter for the ignition, I never had a problem. I reckon that was in the low 50's.

I rode it 100 miles flat out (and I mean flat out - it was like a 100 mile plug chop Fontyyy!!!) to Thruxton and back one year, and it never missed a beat! The journey up was fairly mild for March, and the way back was freezing cold and almost torrential rain... not a single splutter!

It's only since messing around trying to get the few HP over 60hp with stock bits that I've had issues, and two of the three issues have been my own fault/stupidity! 10 years of total reliability, 1 year of destruction! Doesn't take a brain surgeon to work that one out!!

We've discussed this before, and come to the same conclusions! Using the RGV as an example, as it's probably the most common full power 250 that was sold in the UK: do you think Suzuki would've released a bike onto the market that they knew would be neglected and thrashed in equal quantities, if they didn't think it was reliable?

I say "true"; if set up conservatively, I don't see any reason why a 2-stroke won't ever seize, but you also won't be getting the most out of it, and that's what they're all about - screaming, stinking, and tinkering!!!
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fontyyy wrote:Define "correctly".. But take that bike into Death Valley at 40*c and 10,000ft and see how it runs.

Er mate, Death Valley is actually 329 feet below sea level. I was there six months ago...

But I wholeheartedly agree. The two of the three siezures I've had were my own fault - modifying and not rejetting, Going from 25c to 10c and not rejetting.

The third was a coolant pipe coming loose, which would kill any water-cooled engine on the planet.
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Mate it's a valley and indeed it's lowest point is below sea level but, it's highest point is 11046ft above sea level. I did look before I posted. I just wanted to choose somewhere everyone knew was hot and dry.

As Andy says you've got to get the most out of it or you may as well buy a diesel....55 squidgy horse power? No thanks.
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As Andy says you've got to get the most out of it or you may as well buy a diesel....55 squidgy horse power? No thanks.

Ive had many modded 2 strokes in the past and ALL have been pretty unreliable in one way or another .
The MC21 i have now will be getting a set of pipes and a re-jet to suit and thats about it (standard pipes are far too quiet for my liking ) as i just want to be able to go out for a blast and not be worried that it might not make it home ,Im not afraid of getting my hands dirty as i work in a garage so its my job to tinker ,But its taken me a good few years to find a nice NSR and be able to afford to have an NSR as a second bike/toy so i am going to try and look after it as its got to last me a while .
The other thing is im pretty skint at the MO so standard 55 squidgy H.P = safe in my book
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