Reliability of middleweight sportbikes

[oscar777]

Ive been wondering since these machines are so high revving, are they also generally fairly unreliable? I know there will be loads of anectodal evidence and it all depends on maintaince.

What Im interested in, is what is the highest milleage 600cc supersport, youve seen with stock motor?
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Push bike with a 80cc jerry rigged 2 stroke---> CBR125R ---> GSXR600 ---> Ducati 1098SF

[qarka]

A friend has a 1996 CBR600 with 70,000ish on the clock, seems to go ok.
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[MCN.]

GSXR600'S eat cranks faster than most 2 strokes, sorry about that.

[stevo as b4]

It's an interesting question but there are a fair few factors:

1, You don't see very many 600cc sportsbike's with enough mileage on them to have major engine wear.

2, Maintenance will be the biggest single factor. If oil and filter changes are strictly adhered to, and servicing, but especially monitoring and adjustment of valve clearances. (over time valve seat recession/wear will occur and keeping accurate checks of clearances over time and mileage will show this as it becomes noticeable)

3, Modifications. For years people used to bung on race cans and systems onto their bikes and not re-jet to suit. It varies and depends on the bike too. Some are set up to run richer than others from the factory, especially as there was never any Catalytic converters to keep happy on bikes until very recently.

But over a long period of time any motor that's set up to run too rich or too lean can cause damage, in the case of being too rich by carbon deposits forming in the combustion chambers leading to pre-ignition etc.

4, Owners.

Some owners are sympathetic towards their machines, some are not. For example over a long period a bike that is started and raced to 5000rpm on choke and or had the choke left on too long, could have more serious engine wear than a bike that was treated differently. The same applies for those that always bang into the rev limiter when accelerating, or downchange at high rpm a lot of the time etc. Also some folk would ride out onto the main road with a cold engine and then race off, whilst some owners will ride gently until coolant and oil temps are up to normal running levels.

5, There's always the potential for a manufacturer to have made an engine with a built in defect, a porous casting, incorrect clearances, or a bit of machining swarf left in an oil pump or something etc.

Then there is factors such as bikes that are crashed and suffer damage and ingestion of dirt or grit into the engine that way too.

How long is a piece of string?

But the notion of say a 14000-15000rpm 4stroke engine being highly strung and long term unreliable or having poor longevity due it's high performance for the capacity is not really an accurate correlation either.

Sure many bike engines will never manage car engine levels of mileage, but then many bikes never see serious miles enough to totally wear out an engine or for it to grenade due to wear, before the bike is scrap or been smashed up beyond repair.

[oscar777]

I know its hard to generalise things like longevity.

Whenever I look at bike milleage I always double it to get an idea of car milleage equivelent. So Id be impressed if my bike lasts somewhere near 50k

I know car engines have a much easier life in general, but the service intervals are much less frequent so it gets fresh synthetic every 3 months or so.

[Wafer_Thin_Ham]

[Wafer_Thin_Ham]

Generally speaking they're pretty damn reliable. You don't hear many horror stories of Japanese 600's consistently blowing up.

First generation 675s can drink a bit of oil, first generation R6s can shit their second gear, CBR600Rs can eat reg/recs, but these are not problems isolated to 600s.
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[monkeybiker]

When ever I buy a car/bike I do so on overall condition. Mileage means very little to me and sometimes low mileage can be worse than high mileage with lots of short journeys not warming up and start stop town traffic.

My Z1000 has about 30k on it and is far from dead. I would like to hope I can get 100k out of it. I've heard of someone with a Z750 with over 70k on it still going strong.

[MCN.]

[Wednesday Biker]

I know the ninja 250 isn't a 600 sports but I did read some blog about a guy who had done over 70k on his and read other stories of ones with decent mileage.One guy did 88k before it died.
Considering you have to take them past 10k before they even start to move, that mileage seems pretty good.You basically have to thrash them every minute of riding them
You will thrash a sports 600 but not every minute of riding it like a 250. So I'd imagine the engines could go way past 70k too.

Maybe other parts don't last as long and bikes do tend to rust quick if not really well looked after.I think sometimes the engine outlasts the rest of the bike because it would take many riders 20 years to put 100k on.

[oscar777]

[monkeybiker]

[P.]

I abused my 2008 Varadero 125 but had regular oil changes and it got to 77,000 miles before selling.

I bought a Ninja 250, 59 plate. Shat it's internals at like 15 or 16k.

It all depends on luck.

[Slacker24seve...]

[Polarbear]

It's not uncommon to see 10 year old sports bikes with 5,6 thousand miles on them. they are just toys.

My bikes do a few thousand miles a year and most of that will be in one good romp around Europe. My wifes ER6 will probably have done no more the 500 miles between MOT's.

Toys, just like 98% of sports bikes are.
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[MCN]

[monkeybiker]

[Polarbear]

[monkeybiker]

[quote="MCN"]

[stevo as b4]

The only instance that I can think of where 600cc sportbikes engines do seem to regularly grenade, or expire quietly is in TT side car racing.

This is not a typical usage, the motors are always tuned, and the TT is a bike killer generally due to the rough surfaces and the hammering, bumps and jumps etc that bikes get. There's probably more bikes die at the TT each year from electrical faults, or things like coils, ECM's, or wiring looms/connectors breaking or getting shaken around too much, than from internal engine issues.

But engines do sometimes let go, and sidecar racing a 599cc engine on a circuit like the IOM course is about as hard a punishment you could inflict on a motor, especially one that's had the last few % of easy to find power wrung out of it, by gasflowing, breathing and fuelling mods etc.

Road riding generally cannot push most car or bike engines that hard, as your never really flat out for very long if at all, and speed limits and stop start traffic use don't really tax motors very much. The most strain you could probably put on a bike or car's engine on the road is the testing of the coolant system when sat in slow/stationary traffic for hours on a hot day etc.

Dyno's and even 1/4mile drag racing don't strain motors that hard either compared to other forms of useage.

Straightline top speed chasing over 2miles of runway might be about as hard as you can push an engine, but it's over in a short time, not like an industrial or marine engine where it could be worked under full load and full throttle all day long in an enclosed space etc.

[MCN]

[MCN]

[stevo as b4]

Sort of agree to an extent, and constantly varying loads and speeds do put more strain on things than a steady cruise condition would.

Though a lot of car's/engines that are used soley in heavy traffic it's normally the clutch that takes the brunt of the abuse, but over time things like riding the clutch, and not replacing it in time etc, can cause crankshaft thrust bearings to wear out, and even wear the crankcase/block out if left for too long too.

Mum's taxi probably does not get warmed up on each and every drive, probably suffers mayo build up/condensation in the breather's/ under cam covers etc. And probably does not get serviced or the oil and filter changed nearly as often as it should. Add to that many cars rarely get the oil level or coolant level's checked as routine maintenance, with the often quoted line: ' hell isn't that what the dealer is for at service time?'

[Serendipity]

I’m sure there’s higher out there, but my ’94 CBR600FR has 85673 miles on the clock.

Works as good as it ever did, still on stock motor and not much work beyond maintenance carried out, but… and it’s a fairly big but…

…it’s started making a noise that makes the mechanically sympathetic part of me wince. Consequently I’ve not used it much the last couple of years. I rode it to work a couple of times last summer, but the noise concerned me so it’s been laid up since.

The noise is hard to describe. It’s sort of a slightly different note of whirring in the engine, like a higher pitch accompaniment to the normal engine noise. It’s not the typical CBR camchain noise, but it’s quite possibly the camchain that’s behind it. I plan eventually to crack it open and replace the chain and guides. My fantasy is a modest engine strip down and rebuild to check wear and put my mind at rest. Time, money, tools and experience have put me off so far.

Most of my miles were done over a fairly short period of time between 1997 and 2002 when I commuted on the bike every day. My maintenance record wasn’t perfect, but I tried to keep on top of it. Unmolested mid-nineties CBR600s are known for high levels of reliability, but can’t speak for more recent models.
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2016 CBF1000F - Commuter heaven | 1994 CBR600FR - Awaiting defibrillation

[oscar777]