Another alternator hits the dust and not under warranty

[TheCowboy]

OH - me likey!!! I've already wrapped my exhaust with heat wrap BUT wow this has potential.... I would like to try it for sure!!!

TheCowboy

[Astolfo]

Originally Posted by ebrabaek

Carbon fiber would be a great isolator..... But we would need some input from the know how's...... That this would in fact work..... Before making a shield.......

Erling

this should be a very easy part to make....I will look into it. and keep you posted. how hot do you think it gets? i just need to find the correct resin

[JRWooden]

Since the oil cools the cover, and the coolant cools the oil, I would hope that whole mess should never exceed 200F?

As a high-side estimate I would guess (hope?) that the side cover never exceeds ~250F / 120C.

There is going to be some radiant heat gain from the exhaust which is going to be hard to estimate.

Maybe someone with an IR temperature gun could shoot a reading on the bottom-side of their stator cover after a good hard ride?

[JoelWisman]

Originally Posted by JRWooden

Since the oil cools the cover, and the coolant cools the oil, I would hope that whole mess should never exceed 200F?

As a high-side estimate I would guess (hope?) that the side cover never exceeds ~250F / 120C.

There is going to be some radiant heat gain from the exhaust which is going to be hard to estimate.

Maybe someone with an IR temperature gun could shoot a reading on the bottom-side of their stator cover after a good hard ride?

Hi JRWooden. An IR gun isn't going to tell you squat about the surface temperature of the stator cover owing to the subject of emissivity. It also won't tell you squat owing to laws of reflectance.

I know IR guns look neat and have a pleasant number of buttons and big lCD digits that seem all high tech, but they are perhaps the most grossly misused tools on the planet.

IR thermometers are for highly trained professionals and novices that have studied hard to take QUALITATIVE readings of prepared surfaces that can not easily be measured by direct contact. IR thermometers are never for taking QUANTITATE readings unless the instrument costs thousands of dollars and the user has a masters or better in thermodynamics.

In addition to the laser pointer, stun-gun, and torch lighter, IR guns are fun toys, but thats all they are unless you know a hell of a lot about how to use them.

I don't say this to be arrogant, but because I see IR guns cause needless worry when they are continuously misused.


An ir thermometer reads emitted infrared energy in a given portion of the EM spectrum. Cheepo IR guns are not well calibrated and read outside of the bandwidth of heat. In addition, different substances radiate at higher and lower bandwidths at the same temperature. Thickness of a substance also affects the radiated wave length. this is just for starters.

The biggest affect to an IR guns reading is going to be how the surface differs from a black body. Chepo IR guns are usually calibrated loosely and inaccurately to an emissivity of 0.95. This works well with many organic objects but won't be accurate at all for our stator cover surface which is glossy enamel paint usually having an emissivity of around 0.8.

Further, there is reflectance. The surface of our stator is reflective and is going to reflect a lot of IR energy from near by emitters such as the exhaust down tubes.


Back to the subject at hand which is the stator cover temperature. Using an accurate CONTACT probe after a hard ride in a 36 F ambient, the surface of the stator cover was 213 F and varied just 4 degrees in the 8 places I measured it.

Back to the subject of IR guns, using my upper end toy IR gun it varied from 189 to 257 degrees. The IR gun is not wrong. I have little doubt that it is accurately measuring emitted IR, but emitted IR is of no relevance to the question of the stator cover temperature nor most of the other things people use IR guns for.

Heres an accurate surface probe http://www1.mscdirect.com/cgi/NNSRIT...-SearchResults

1/4 the price and reads temperature, not emitted IR :)

[Astolfo]

Originally Posted by JRWooden

Since the oil cools the cover, and the coolant cools the oil, I would hope that whole mess should never exceed 200F?

As a high-side estimate I would guess (hope?) that the side cover never exceeds ~250F / 120C.

There is going to be some radiant heat gain from the exhaust which is going to be hard to estimate.

Maybe someone with an IR temperature gun could shoot a reading on the bottom-side of their stator cover after a good hard ride?

so...a 400F resin should be good enough? I do not want to end up with a bunch of melted resin on my bash plate....

[JRWooden]

Originally Posted by JoelWisman

... Back to the subject at hand which is the stator cover temperature. Using an accurate CONTACT probe after a hard ride in a 36 F ambient, the surface of the stator cover was 213 F and varied just 4 degrees in the 8 places I measured it.

Heres an accurate surface probe http://www1.mscdirect.com/cgi/NNSRIT...-SearchResults

1/4 the price and reads temperature, not emitted IR :)

213 F sounds about right - thanks!

Likewise ... thanks on the surface probe vs. IR... I just ordered a surface probe!
I don't own an IR gun and ... don't think I'll buy one ...

Astolfo - I'm just guessing, but yeah I would think that if the carbon fiber part is going to be attached to (or even better yet) spaced slightly away from the bottom of the stator cover that 400-degree resin should be fine.

I'm curious - Is the higher temp. resin more expensive? Harder to work with?

[Astolfo]

Originally Posted by JRWooden

Astolfo - I'm just guessing, but yeah I would think that if the carbon fiber part is going to be attached to (or even better yet) spaced slightly away from the bottom of the stator cover that 400-degree resin should be fine.

I'm curious - Is the higher temp. resin more expensive? Harder to work with?

mix ratios are very important as curing temp and time, and air. vacum bagging and oven although not a must, is better. I will see if i can get the a mold out of my bike and make one. but it will not happen until next year. besides it is cold around here

[ebrabaek]

Originally Posted by Astolfo

so...a 400F resin should be good enough? I do not want to end up with a bunch of melted resin on my bash plate....

Yep... Post heat cure for sure.... I use a good mix from a alchemist in Mid CA....... It holds up to about 450F...... Good stuff...With a post cure that is easy to work.... I made the Bash plate from it........ and have made countless side covers....etc. with it. I just meant that before making one...... I wanted to make sure that this would benefit the stator.... Ie... the header is in fact a catalyst. You will also effectively stop any heat transfer out from the stator cover...... So if someone stepped in and stated that this is an issue.... I'd whip up one in a heart beat... I'd make it from Kevlar (Aramid) though.... better protection...and heat isolator....... Could even make'em pretty...like this.....




Erling

[Astolfo]

Originally Posted by ebrabaek

Yep... Post heat cure for sure.... I use a good mix from a alchemist in Mid CA....... It holds up to about 450F...... Good stuff...With a post cure that is easy to work.... I made the Bash plate from it........ and have made countless side covers....etc. with it. I just meant that before making one...... I wanted to make sure that this would benefit the stator.... Ie... the header is in fact a catalyst. You will also effectively stop any heat transfer out from the stator cover...... So if someone stepped in and stated that this is an issue.... I'd whip up one in a heart beat... I'd make it from Kevlar (Aramid) though.... better protection...and heat isolator....... Could even make'em pretty...like this.....




Erling

Good, how much for one cover for the startor, with alternating kevlar, carbon?

[ebrabaek]

Originally Posted by Astolfo

Good, how much for one cover for the startor, with alternating kevlar, carbon?

...... Before we go there.... I would like to hear Joels opinion on this.... I seems to have caought someone stating that the "most toasted part" was around the header area..... Like fwd lower.... You guys think this would help..... I like the protection it would offer armoring the side.... But I really want the warm and fuzzy....so as not to offer a snake oil like fix... I don't have an idea...what it would cost. I need to look at attach points.... coverage...etc. If you want stiffness.... then yes....a mix of CF/K....say 3 of each...total of six..... would be about 3-4mm thick....and offer plenty of heat protection....and make that case....just about bullet proof.

Erling

[Astolfo]

Originally Posted by ebrabaek

...... Before we go there.... I would like to hear Joels opinion on this.... I seems to have caought someone stating that the "most toasted part" was around the header area..... Like fwd lower.... You guys think this would help..... I like the protection it would offer armoring the side.... But I really want the warm and fuzzy....so as not to offer a snake oil like fix... I don't have an idea...what it would cost. I need to look at attach points.... coverage...etc. If you want stiffness.... then yes....a mix of CF/K....say 3 of each...total of six..... would be about 3-4mm thick....and offer plenty of heat protection....and make that case....just about bullet proof.

Erling

yeah I was not talking about the side. I was thinking of some king of bracket around one of the "headers" or even the vash plate...
maybe we can exchange ideas here and see what we can come up with

[ebrabaek]

Originally Posted by Astolfo

yeah I was not talking about the side. I was thinking of some king of bracket around one of the "headers" or even the vash plate...
maybe we can exchange ideas here and see what we can come up with

Yeppers.....The thing that sucks though.... Is we have to ride for several thousand miles to see if the mod works..... And although I like the idea....I'm not 100% sold on that it is the solo culprit..... For aesthetics... I think a plate that conforms to the case in the area of the headers...will look best......But I will need to study it a little more....

Erling

[vtbob]

[QUOTE=JRWooden;17507394]Since the oil cools the cover, and the coolant cools the oil, I would hope that whole mess should never exceed 200F?

As a high-side estimate I would guess (hope?) that the side cover never exceeds ~250F / 120C.) end quote


I believe most water / oil cooled engine design try to keep oil tempature above 225F so it is above the boiling point for water. This make any water in the oil, water is a combustion by product, boil off and vent. I believe the top temperature is around 275F. Synthetic oil can tolerate higher. The temperature range between these is normal.

This makes sense in a water oil cooled engine as the water temp(under pressure so it is higher) is limited by venting/blow off at around 230F.

It is clear that the oil is always (nearly anyway) hotter that the water so the water cools the oil.


In reading all these post it would seem ( but not enough facts to say for sure ) that the problem is in failing regulators and the burning of the stators is a symptom of that failure.

The write up on the SCR (fail short) and FET(fail open) failure modes ring true to me. Does any one know of a FET based regulator as a replacement for the stock unit?

I'm planing on a taking my 17K mile bike on a 10K mile trip to alaska next spring....so that replacement regulator may be prudent

[JoelWisman]

I'm confused vtbob.

I've only ever heard of 3 regulators failing on one of these bikes, this thread is about stator failures. As to the failure modes of FET versus SCR, same experience here, but the SCR doesn't fail closed for very long as it burns up. In any case, failing open is the worst possible outcome, once open nothing shunts current to ground, voltages go through the roof, all lights burn out, then all 7 of the onboard ECU's.

There is some interest in a series regulator rather then the parallel one that comes stock, but the difference between SCR or FET in either one has nothing to do with reliability.

What is your thinking on a FET R/R making your bike more prepared for a trip?

[vtbob]

I must admit, I do not understand this stator failure problem. I've been trying to glean a better understanding from all the posts and the article in the MOA mag.

My, admittedly uninformed bias has been toward an electronics failure..ie the regulator. the Stator is a lump of metal and some type of insulation polymer. It seems to me that it is so easy to design the stator to withstand over currents and over temps...with essentially no cost penalties....that is would be so dumb not to have huge design margins...it would not be the root cause.

Over my experience Iv've replace several regulators and a few alternator diodes....never had a stator problem. Yep I know this has no direct mean to this problem...but my bias is there till I understand the root cause.

Thanks for the additional info