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[snowrider13]

I hear talk of cams with Longer duration ex. numbers as being "cooler" running. Is it strictly the ex. duration or does the overlap have a part in this? Looking at the mr103 for use in a 110. Do the Easy start cams produce more noise than the standard chain drive models?

[HD Street Performance]

As far as cooler running a proper tune cures that for the most part. Heat needs to be defined. Radiant heat from pipes is worse with some pipe designs and will interfere with motor cooling as well as rider comfort. Sure a longer duration cam with associated lower cylinder pressures will cull some motor heat but I wouldnt be changing cams for that if you want to retain the low end punch the stock cam offers. Pipe choice and tune are very important and first regardless of the cam choice. There are haters of the se255 and I am sure they will speak up but it works fine for my ride and what I do. I have added wards fans which with a good tune keeps the heat under control. There isn't any downside to the ez-start feature but your motor has acr solenoids to lower cranking pressure no need for that feature.

[Jswerve]

There are haters of the se255 and I am sure they will speak up but it works fine for my ride and what I do. I have added wards fans which with a good tune keeps the heat under control.

I agree. Next time I buy a CVO (IF) I will add an air cleaner and pipe and have it tuned by a competent tuner and call it a day.

[Steve Cole]

Lots of internet stories out there. There is no one stead fast rule that works when it comes to running cooler. Let's for a moment think about what really happens in a running engine. Fuel and O2 are burned in the cylinder and the expansion from that burn is pushing the piston downward. It is really all that counts. The bigger the fire the more power you produce. So if you increase power you have to increase the heat, there is no way around it. Now how much of the heat that comes from the cylinder do you feel? If you try to increase the amount of O2 entering the cylinder which is what you are doing when you change the camshaft, port the heads, ect. you are trying to increase power output and therefor are also increasing the heat produced. Now changing the exhaust to try and get the heat produced out and away from the engine does not reduce the amount produced, it just attempts to move it away sooner. The only issue on a HD is you sit very close to the exhaust pipes so you feel all that heat on your right leg. Some pipe designs get the pipes closer and some further away but the heat is still the same coming from the engine. A typical HD engine produces about 950 deg exhaust temperature at idle and about 1400 deg under load, so one has to ask themselves how close to you do you want all that heat and is that worse than a 250 deg engine?

[HD Street Performance]

Exactly, radiant heat perceived as engine heat.

[willyB]

My understanding of the 255 is that the exhaust valve timing closes too early there by re burning the non-exhausted exhaust gas a second time to reduce emission levels.

Am I thinking correctly?

[Steve Cole]

You can only burn combustible gases. If you close the valve early and hold back some burned gases it displaces what can be filled into the cylinder the next time around. What happens is most people do not spend the necessary time to get things setup properly. A 255 camshaft just needs a little more understanding when tuning but it's a damn nice camshaft for what it is supposed to do. I have not had any heat related issue with a 255 camshaft when tuned properly.

[snowrider13]

Thanks for the info, the reason behind the use of the mr103 cam, just looking for a little more carry to the right. I love the grunt of the 255, don't want to lose to much down low. Currently running Fullsac D, with 2" and screens. this helped noticeably with right side heat. Going to see Steve about a TTS this winter, just need to find a tuner in CNY that will work with this unit. Has anyone used this cam in a 110?

[HILLSIDECYCLE.COM]

Thayer's Sales and Service, in Corfu, NY, (Batavia area) has tuned clients bikes our ours that have that brand of tuner.
An S&S .570 WILL tame engine heat even at 10.0 cr.(which carry's less ccp than an untouched engine with the 255 emission grind)
Have a client in Binghamton, NY, that his wife actually rides with sandals, now....drove up here 90 miles one way to alert us to that this summer.
Scott

[snowrider13]

Steve, do you have the dyno sheets available on the testing you did on all the cams? I am very interrested in a 255 vs Andrews 48. The numbers caught my eye. Curious to what the graph shows.

[Dr.D]

Steve, do you have the dyno sheets available on the testing you did on all the cams? I am very interrested in a 255 vs Andrews 48. The numbers caught my eye. Curious to what the graph shows.

Yes Steve I wan to see the se255 and andrews54.

[owl893]

A 255 camshaft just needs a little more understanding when tuning but it's a damn nice camshaft for what it is supposed to do. I have not had any heat related issue with a 255 camshaft when tuned properly.

Thank you Steve Cole........
OWL

[Dr.D]

I agree. Next time I buy a CVO (IF) I will add an air cleaner and pipe and have it tuned by a competent tuner and call it a day.

To quote a prominent member here, bawahaha! I've ate them words too.

[Jswerve]

To quote a prominent member here, bawahaha! I've ate them words too.

Hehe