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High comp..high heat


HWB

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Bike is all done finally, very happy today. Went for a test ride, 70kms or so, for those who dont know, it has a do t head, skimmed a bit as well, full port, no guides in the runners cams degreed 105°/105° full exhaust, mikuni flatslides 38, had to cut and weld the tanks for clearance. Everything is so damn tight on this bike now, pingel lever barely opens to 3/4 but thats more than enough. Anyways i felt alot of heat today while riding. Rode hard, the whole ride took about 30 minutes, when i stopped at a light i felt insane heat. I know its due to the higher compression. What can i do to bring the heat down? Any bigger coolers ? Cooler fans ? What do you gjys do to fix the heat issue. Im afraid if i dont address the issue the engine wont live long. Cheers

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From your Bio - you aren't exactly in the coolest part of the world are you ! ! !  You are sailing very close to the edge using a skimmed DOT head (i'm guessing static CR may be about 11.5+ : 1 or more) and I'm unsure of the quality of your petrol as it would be advisable (in the UK at least) to be using 98 / 99 RON fuel. But back to cooling - a head cooler is pretty much a requirement with that climate & engine spec IMO and / or a bigger / more efficient main cooler wouldn't hurt either!

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A skimmed DOT head is bonkers in my opinion, they are already such a low profile combustion chamber that when you skim them you can seriously screw up the squish band, not to mention the extra increase in compression which as mentioned above by Gixer1460, will not be great on pump fuel in your part of the world where it's toasty warm :)

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2 minutes ago, dupersunc said:

If you arent getting detonation the compression ratio isnt anything to worry about.

Head cooler definetly needed though. Bigger the better.

Aye it's a fair point... if it works, it works :D(y)

Out of interest, what's the typical size (width / rows) used for a head cooler when tuned?

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3 minutes ago, dupersunc said:

Look at period racebikes. They have as much cooling as they can fit

True indeed, I just wondered if there was a common "go-to" size that people often use, Similarly to how it seems to be fairly commonplace to replace the stock cooler with 19row wide / extra wide. (y)

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98 octane fuel, head was 0.4mm skimmed so i guess it isnt much, definitely interested in a head cooler or a bigger main cooler, im planning on keeping the stock fairings, any big main coolers you reccommend ? Also where would you fit the head cooler.

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12 hours ago, dupersunc said:

If you arent getting detonation the compression ratio isnt anything to worry about.

Head cooler definetly needed though. Bigger the better.

Its a big 'IF' !

Its a new build with 70kms total running & its unclear as to new / used bottom end, set-up status of the carbs / ignition and whether the package was ragged around or ridden sensibly? Its the detonation that you don't hear that kills engines and most of the time you won't!

'Bigger' cooler doesn't automatically mean larger frontal area - depth or thickness needs to be considered, as this allows longer contact time so transferring more heat. They will be equally 'draggy' for airflow but thicker may be easier to package within bodywork!

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32 minutes ago, Gixer1460 said:

Its a big 'IF' !

Its a new build with 70kms total running & its unclear as to new / used bottom end, set-up status of the carbs / ignition and whether the package was ragged around or ridden sensibly? Its the detonation that you don't hear that kills engines and most of the time you won't!

'Bigger' cooler doesn't automatically mean larger frontal area - depth or thickness needs to be considered, as this allows longer contact time so transferring more heat. They will be equally 'draggy' for airflow but thicker may be easier to package within bodywork!

Well the whole build is 'used' the dot head obviously used cranks used valves used, bottom end used, pistons everything.. i broke it in a bit before kicking the shit out of it to be honest, ran hard for a good 15 minutes, high rpm low gear, might be foolish of me but considering all parts were already married before. I did change all seals and gaskets as ine should, fresh oil and thats about it. Carbs are rs38 stock main jets and stock everything except for 50mm velocity stacks with no filter as for the time being cz i need to see the accelerator pump nozzle and dial accordingly. I tried to give an ear for detonation by riding on 5th at low speed all i could hear was the crackling of the slides. Can anyone point me to a good cooler that WORKS and FITS with my fairings ?

 

I will do a spark plug check later and post pics hoepfully no indication of knock will appear, or at least if knock is occuring i would like to be able to see to confirm

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9 minutes ago, HWB said:

Well the whole build is 'used' the dot head obviously used cranks used valves used, bottom end used, pistons everything.. i broke it in a bit before kicking the shit out of it to be honest, ran hard for a good 15 minutes, high rpm low gear, might be foolish of me but considering all parts were already married before. I did change all seals and gaskets as ine should, fresh oil and thats about it. Carbs are rs38 stock main jets and stock everything except for 50mm velocity stacks with no filter as for the time being cz i need to see the accelerator pump nozzle and dial accordingly. I tried to give an ear for detonation by riding on 5th at low speed all i could hear was the crackling of the slides. Can anyone point me to a good cooler that WORKS and FITS with my fairings ?

 

I will do a spark plug check later and post pics hoepfully no indication of knock will appear, or at least if knock is occuring i would like to be able to see to confirm

I did point you to one that works and fits :)

IMG20210911122332.jpg

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1 hour ago, dupersunc said:

No. It's a gsxr1000 k5> oil cooler. Takes the same fittings as a slingshot oil cooler, which is handy.

Oh nice, that's definitely a piece of info I'll be storing in the brain vault for later:D

1 hour ago, Gixer1460 said:

Its an oil cooler off a water cooled bike! That is actually a neat solution if you are keeping the fairing and if the fittings are freely available?

It is a really neat solution, even on a naked bike. Although I'm kinda amazed it doesn't get grit blasted and pebble-dashed to death so low down and in direct line of the front tire (y)

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3 hours ago, dupersunc said:

No. It's a gsxr1000 k5> oil cooler. Takes the same fittings as a slingshot oil cooler, which is handy.

Dup, do you know if other 1000s models have also the same fittings or is it just a k5 thing

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