why do bikes run better after a thrashing?

[Cosmik de Bris]

Some days the bike just runs nicer, smooth and zingy rather than lumpy and unzingy, I guess the humidity, temp of the day etc have an influence on how nicely the motor runs. But, the motor always feels really nice after I've thrashed it a bit, i.e. zingy.

So what is it that does this, what changes in the motor to make it feel like this?

Cheers

[caspernz]

Removing the cobwebs will do that :laugh::laugh:

[Moi]

Many years ago there used to be a Jaguar/Daimler service agency on the corner near the Domain - some will now guess who I'm talking about. Due to people I knew I used to get to see and chat with the owner and the talk was about cars. He once said that Monday morning the cars would be parked outside the workshop and the owners in the office moaning about how awful their Jag/Daimler ran while they were out on their Sunday drive...

The cars were left for the day for the garage to fix them... someone was assigned the "job" and would take each car for a blat down the southern motorway to about Papatoetoe and back which would blow out all the "cobwebs" as caspernz so nicely put it. The owners collected their cars at the end of the day and were pleased with what the garage had done. I never did ask how they charged for it!

[Ginge09]

Cool air helps. It's more dense so you get more oxygens into the engine per induction stroke.

Bike runs better in the early morning.

[roogazza]

Many years ago there used to be a Jaguar/Daimler service agency on the corner near the Domain - some will now guess who I'm talking about. Due to people I knew I used to get to see and chat with the owner and the talk was about cars. He once said that Monday morning the cars would be parked outside the workshop and the owners in the office moaning about how awful their Jag/Daimler ran while they were out on their Sunday drive...

The cars were left for the day for the garage to fix them... someone was assigned the "job" and would take each car for a blat down the southern motorway to about Papatoetoe and back which would blow out all the "cobwebs" as caspernz so nicely put it. The owners collected their cars at the end of the day and were pleased with what the garage had done. I never did ask how they charged for it!

Mid sixties I did my time as a mechanic for Shelly's (Jaguar Agency at the time). I recall taking Jags out for a tune up !!!! Down the motorway all sorts of shit flying out the exhaust.
Owners would come back and say how great the car was running and what did you do ? haha.
Pottering around town in them did no good whatsoever.

Sometimes I'd say yeah, cleaned the plugs !!!!!

[Grumph]

Sometimes I'd say yeah, cleaned the plugs !!!!!

You've got it...unburned deposits on the plugs raising the resistance across the electrodes.
A good thrash getting them up to optimum heat removes most of the crud.

Plugs have got a lot better since those days - in a Jag, ideally, you'd have run a hot plug around town and changed to a cold one for a trip.
Remember that the specified heat range was supposed to cover use on the new motorways - so was probably a bit colder than ideal.

[Swoop]

The cars were left for the day for the garage to fix them... someone was assigned the "job" and would take each car for a blat down the southern motorway to about Papatoetoe and back which would blow out all the "cobwebs" as caspernz so nicely put it. The owners collected their cars at the end of the day and were pleased with what the garage had done. I never did ask how they charged for it!

I had a mate at a big BMW dealership in Auckland, who went through exactly the same process...

[slofox]

Cool air helps. It's more dense so you get more oxygens into the engine per induction stroke.

Bike runs better in the early morning.

Wot 'e said. Cold air is the cats whiskers. Which is why I really like riding in frosty conditions...apart from frostbite, hypothermia and paralysis due to freezing your nuts off. :whistle:

[Moi]

Wot 'e said. Cold air is the cats whiskers. Which is why I really like riding in frosty conditions...apart from frostbite, hypothermia and paralysis due to freezing your nuts off. :whistle:

Not to mention ice on the road... :shit:

[george formby]

Wot 'e said. Cold air is the cats whiskers. Which is why I really like riding in frosty conditions...apart from frostbite, hypothermia and paralysis due to freezing your nuts off. :whistle:

Cold, damp air on me 2t's. Noticeably perkier in rain and damp conditions. More motor, less grip.....

[Drew]

Sometimes I'd say yeah, cleaned the plugs !!!!!

Which either needs done every 1000ks or not at all on a jag. Fuck they strip the threads like a cunt.
Nice easy head to get off though, with a clever cam chain system and heaps of room.

[ellipsis]

...dunno...this is good tho..

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[Cosmik de Bris]

Cobwebs? Yes but what are they? Cool damp air, yes, but that doesn't suddenly happen after a fast ride. The plugs seem to be the best answer.

Cheers

[caspernz]

Look at it in terms of the human body maybe? Prolonged periods of inactivity have an obvious result, performance goes down. Prolonged periods of activity, performance goes up.

Same for a mechanical device, use it the way its maker intended. It just feels more alive...

[Drew]

Look at it in terms of the human body maybe? Prolonged periods of inactivity have an obvious result, performance goes down. Prolonged periods of activity, performance goes up.

Same for a mechanical device, use it the way its maker intended. It just feels more alive...
No. Just no.

That fails as an analogy. Since biological things are tuned through use and repetition, and mechanical components wear with the same treatment.

A motor that goes best after a thrashing is likely tired. Once things get proper hot they seal better perhaps. Though one would think as soon as it cools down it all needs to be done again.

[Ginge09]

Agree with Drew. No comparison between the human body and a mechanical device in this context.

Giving a bike a good hard run may or may not improve it. Depends on the bike.

A highly tuned 2 stroke used in commuter mode will foul and clog. A good hard run should clear that. It's not designed to run in stop/start low rev mode.

A mild 4 stroke is designed to tug all day across a wide range of riding conditions. It won't complain too much, but a good thrashing occasionally will clear its lungs.

The cobwebs are a whole bunch of stuff like the engine mapping in your electronic gubbins if you have them ( coz some of them "learn" your riding style ), the carbon build up in your head and plugs, the various mechanical tolerances of 250 hot whizzy bits of metal, your own mental state on a a Sunday morning when you head out for a thrape with the lads.

It's a piece of machinery. Learn to get to know how it responds to external influences and keep it maintained. It'll let you know when it's unhappy.

...and that's why these guys talk about thrashing Jags to improve the state of tune. They were an expensive high performance car used as cruisers. A 20 minute squirt up the motor way gets them back in the comfort zone they were built for.

[Grumph]

A highly tuned 2 stroke used in commuter mode will foul and clog. A good hard run should clear that. It's not designed to run in stop/start low rev mode.

...and that's why these guys talk about thrashing Jags to improve the state of tune. They were an expensive high performance car used as cruisers. A 20 minute squirt up the motor way gets them back in the comfort zone they were built for.

Mmmh, not only Jags - and some of the 2 stroke comments hold...

A shop in ChCh was well known for the "5 minute tune up" on commuter 2 strokes.
It consisted of the foreman taking the bike out into the alley and revving the tits off it for the 5 minutes...
What this did was break off the carbon deposits that had built up on port edges - most noticeably the exhaust port top edge....
Full timing resumed, you had full power back again.

The same foreman - who is still around - was noted in the trade for his ability to charge out 16 hours in an 8 hour day....

[Daffyd]

I had a P76 back in the day. I had to take it for a thrash about once a month. For the first 10-15 km you couldn't see anything but smoke and crap in the mirror. It was a different car after that.

[Cosmik de Bris]

No. Just no.

That fails as an analogy. Since biological things are tuned through use and repetition, and mechanical components wear with the same treatment.

A motor that goes best after a thrashing is likely tired. Once things get proper hot they seal better perhaps. Though one would think as soon as it cools down it all needs to be done again.

I don't think tired is the answer, both my bikes are pretty new. Hot though maybe the answer because yes, once it cools down it does seem to go back to unzingy, except for those days when the temp and humidity are ideal.

Cheers

[old slider]

I had a P76 back in the day. I had to take it for a thrash about once a month. For the first 10-15 km you couldn't see anything but smoke and crap in the mirror. It was a different car after that.

They made great little jet boat engines.

My old girl has an awesome 3 litre v6 from the late 60s early 70s even though it is a blue coloured motor it has been an amazing power plant for many years.

334916

[caspernz]

No. Just no.

That fails as an analogy. Since biological things are tuned through use and repetition, and mechanical components wear with the same treatment.

A motor that goes best after a thrashing is likely tired. Once things get proper hot they seal better perhaps. Though one would think as soon as it cools down it all needs to be done again.

You're overthinking it.

Take a high performance 2 stroke, potter it around town for a week and it'll be asleep. Give it a decent run, remove the built up carbon or soot and it comes alive.

Take a couch potato, send him to boot camp for a couple of months and he'll come back more lively.

But yeah take it to the long term and mechanical stuff wears out, look at it in terms of well within normal service life, and I stand by my analogy.

Since you like mechanical comparisons, take a high horsepower truck that's never been held wide open on a decent climb at max payload, then compare it to the same version that's been "worked" hard and a blind man can tell the difference. One is "asleep" and the other one is well and truly "awake" :laugh:

[rastuscat]

A guy I knew in the navy in 1983 was away overseas and had left his RD350LC sitting idle.

He contacted me when they were on the way back, and asked me to get it running for when he was back.

Basically it was seized. No electric start, it just would not kick over.

Took out the spark plugs, sprayed in some CRC, left it to sit for a couple of days. Charged the battery during that time too.

When it started first pop next time, the smoke was incredible, as it burnt 6 months of oil and CRC sitting above the pistons.

Took it for a blat (a colloquial term for a vigorous ride) down the Southern Motorway. Bingo, sorted.

When he got back it was running like a charm.

[rastuscat]

My mechanic gave me a lecture a while back about being too polite to my bike. I rode it generally in the lower rev ranges.

Since my tune up (by my mechanic) I'm giving it more stick.

Mechanic said it was something to do with our low quality fuel. Needs to be flogged from time to time to clear out the gunk.