No More Blue Exhaust?

[Twinpots]

Some time ago I mentioned a product that spray coats the inside of the manifold/exhaust to supposedly reduce heat absorption.
This weekend I finally fitted a pair of brand new front pipes to my 67 Bonneville and thought this was the perfect opportunity to test the product as trying to coat the inside of used pipes might be an unfair test. Using the long tube and spray fan nozzle supplied I had given the inside of the pipes a good three coats and used about half the can. I did this some weeks ago so they have certainly had plenty of drying time. I did my usual Sunday morning cafe ride up Mount Tamborine yesterday with a few fast blasts just to get things cooking a little.
The result? When hot there was maybe a very slight colour change but it was so slight I could be imagining it. Certainly no Blueing. Initial results would seem to suggest this product does exactly what it says on the tin and prevents the unsightly discolouration of the Triumph exhaust. As you may have discovered already using chrome polish does restore the look but it does also quickly wear away the chrome if done a few times. Certainly interesting to see if this product works long term. I will keep you posted. For anyone who fancies giving it a try its Eastwood High Temp Internal Exhaust spray. I can see one disadvantage though as the previous colour change was a great way to gauge any mixture imbalance between the cylinders as it was surprisingly accurate by comparing the colour.

 

[OldRider48]

Some time ago I mentioned a product that spray coats the inside of the manifold/exhaust to supposedly reduce heat absorption.
This weekend I finally fitted a pair of brand new front pipes to my 67 Bonneville and thought this was the perfect opportunity to test the product as trying to coat the inside of used pipes might be an unfair test. Using the long tube and spray fan nozzle supplied I had given the inside of the pipes a good three coats and used about half the can. I did this some weeks ago so they have certainly had plenty of drying time. I did my usual Sunday morning cafe ride up Mount Tamborine yesterday with a few fast blasts just to get things cooking a little.
The result? When hot there was maybe a very slight colour change but it was so slight I could be imagining it. Certainly no Blueing. Initial results would seem to suggest this product does exactly what it says on the tin and prevents the unsightly discolouration of the Triumph exhaust. As you may have discovered already using chrome polish does restore the look but it does also quickly wear away the chrome if done a few times. Certainly interesting to see if this product works long term. I will keep you posted. For anyone who fancies giving it a try its Eastwood High Temp Internal Exhaust spray. I can see one disadvantage though as the previous colour change was a great way to gauge any mixture imbalance between the cylinders as it was surprisingly accurate by comparing the colour.

I've used the Eastwood product on a 98 HD Fatboy. It certainly helps but it isn't a cure all. The only cure I've seen work is a Ceramic high temp polished coating like from Jet-Hot. I had a set of headers done on a Chevelle and they looked good for years until I sold it. Not quite Chrome but it does look nice.
https://www.jet-hot.com/coatingsoverview

 

[Twinpots]

I'm sure it won't be perfect and I am 100% certain the rate of discolouration will depend on how hard you ride the bike.
I ride fairly gently so hopefully it will last for a while. It is asking a lot of a spray can product to withstand the heat coming directly out of the exhaust port but we shall see.

 

[OldRider48]

I'm sure it won't be perfect and I am 100% certain the rate of discolouration will depend on how hard you ride the bike.
I ride fairly gently so hopefully it will last for a while. It is asking a lot of a spray can product to withstand the heat coming directly out of the exhaust port but we shall see.

I'm not a hard rider either and the Eastwood product definitely makes a difference, also depends on how spot-on your air fuel mixture is. All that said, I would use it again on new pipes.

 

[Twinpots]

I'm not a hard rider either and the Eastwood product definitely makes a difference, also depends on how spot-on your air fuel mixture is. All that said, I would use it again on new pipes.

You make a good point regarding mixture. I recently fitted a brand new pair of Amal Monoblocs and I am still experimenting with settings/jetting/idle. It is running really well but without the experience of a having another similar bike as a benchmark its hard to know exactly how it should run. So many variables with a carbie bike even down to how its ridden. Plugs are now brown on the insulator and a little sooty around the edge. This is probably the best I can hope for, it is not a modern fuel injected motor after all. It is fast throttle response up I am working on.
i.e faster downshifts if the motor blips quicker without a hesitancy. I get the impression these twin carbies had issues in this regard. I dropped the needles one notch (leaner) and this did improve pick up and had less sooty plugs. Wary of going any leaner and running too hot which is what you mentioned. I'll be honest I am yet to do the standard flat out, cut throttle and check plugs test for the main jet size. I rarely ride like this anyway. I am running all standard jet sizes as fitted by Amal which are the same as originally fitted when this bike was new. As I am not worried about fuel economy or see much risk in choking a Polar Bear I prefer to run on the rich side and have a slightly cooler engine. I did try fitting a Cat but it wouldn't fit then it scratched me so I gave up.

 

[OldRider48]

You make a good point regarding mixture. I recently fitted a brand new pair of Amal Monoblocs and I am still experimenting with settings/jetting/idle. It is running really well but without the experience of a having another similar bike as a benchmark its hard to know exactly how it should run. So many variables with a carbie bike even down to how its ridden. Plugs are now brown on the insulator and a little sooty around the edge. This is probably the best I can hope for, it is not a modern fuel injected motor after all. It is fast throttle response up I am working on.
i.e faster downshifts if the motor blips quicker without a hesitancy. I get the impression these twin carbies had issues in this regard. I dropped the needles one notch (leaner) and this did improve pick up and had less sooty plugs. Wary of going any leaner and running too hot which is what you mentioned. I'll be honest I am yet to do the standard flat out, cut throttle and check plugs test for the main jet size. I rarely ride like this anyway. I am running all standard jet sizes as fitted by Amal which are the same as originally fitted when this bike was new. As I am not worried about fuel economy or see much risk in choking a Polar Bear I prefer to run on the rich side and have a slightly cooler engine. I did try fitting a Cat but it wouldn't fit then it scratched me so I gave up.

I agree, a little rich is always better & cooler. As long as the plugs don't foul, who cares. I did a run and shut off on one of my bikes when I added a CV Carb. 1/4 throttle, 1/2 throttle and full throttle, shutting off and pulling the plugs.
I had never done it before and just wanted to check. You know, old guys have the time to do such things, HA! I've never done it again.

 

[Twinpots]

In total agreement. Being totally honest I have a whole stack of Champion plugs (my favourite for the Triumph) that I continually clean and have ready to swap out. I do this after almost every ride. I haven't taken the plugs out since yesterdays run with Castor oil so it will be interesting to see how they look.

 

[Marks]

Blued pipes were always a badge of honour. Like back tyres with no chicken strips.

 

[speedrattle]

I'll be honest I am yet to do the standard flat out, cut throttle and check plugs test for the main jet size.

theres another way that works if youre close already. find a long straight stretch, a bit uphill is better. run the bike at wide open throttle for a few seconds to stabilze the mixture, then roll off tbe throttle 1/8 of a turn. carburetors go slightly rich when you do this.

if the motor speeds up a bit-- not a lot really- when you do tjis then the main jet is slightly lean. if there is no change then the jet is okay or a bit rich.

you can also just increase main jet size until the motor finally starts to blubber on WOT. then back off either one or two jet sizes. that will generally be right, but you can then do the 1/8 roll off thing to make sure

 

[robjones]

Twinpots,
Having just bought a new set of pipes myself I thought what the heck, I'll give it a try.

Pulled a rag with thinner on a coat hanger through the pipes a few times first to clean any manufacturing oils. Yes, it was a little messy but wiped right off the pipes. Initial drying time was pretty quick. Says to let it sit for 8 hours or so but that's not a problem as I'm waiting on a throttle cable.

I'll report back eventually...

robj

 

[Old Coot]

Some time ago I mentioned a product that spray coats the inside of the manifold/exhaust to supposedly reduce heat absorption.
This weekend I finally fitted a pair of brand new front pipes to my 67 Bonneville and thought this was the perfect opportunity to test the product as trying to coat the inside of used pipes might be an unfair test. Using the long tube and spray fan nozzle supplied I had given the inside of the pipes a good three coats and used about half the can. I did this some weeks ago so they have certainly had plenty of drying time. I did my usual Sunday morning cafe ride up Mount Tamborine yesterday with a few fast blasts just to get things cooking a little.
The result? When hot there was maybe a very slight colour change but it was so slight I could be imagining it. Certainly no Blueing. Initial results would seem to suggest this product does exactly what it says on the tin and prevents the unsightly discolouration of the Triumph exhaust. As you may have discovered already using chrome polish does restore the look but it does also quickly wear away the chrome if done a few times. Certainly interesting to see if this product works long term. I will keep you posted. For anyone who fancies giving it a try its Eastwood High Temp Internal Exhaust spray. I can see one disadvantage though as the previous colour change was a great way to gauge any mixture imbalance between the cylinders as it was surprisingly accurate by comparing the colour.

Hi if you do the Malaney Imbil Gympie and back down through Kin Kin you will heat the pipes a lot better and have a blast. hahahah. I've also tried a polish which is supposed to help called "Blue Job" heheheheehe. Living in FNQ now and having to put up with the Gillies Range.

 

[OldRider48]

theres another way that works if youre close already. find a long straight stretch, a bit uphill is better. run the bike at wide open throttle for a few seconds to stabilze the mixture, then roll off tbe throttle 1/8 of a turn. carburetors go slightly rich when you do this.

if the motor speeds up a bit-- not a lot really- when you do tjis then the main jet is slightly lean. if there is no change then the jet is okay or a bit rich.

you can also just increase main jet size until the motor finally starts to blubber on WOT. then back off either one or two jet sizes. that will generally be right, but you can then do the 1/8 roll off thing to make sure

I've got one I'm fiddling with. I'll give it a try.
wide open throttle for a few seconds to stabilize the mixture, then roll off the throttle 1/8 of a turn. carburetors go slightly rich when you do this.
What is the mechanism of why the mixture enriches when you roll off of the throttle 1/8 of a turn.

 

[speedrattle]

i believe its because the air flow slows immediately, while the fuel already in the jets continues into tbe venturi, hence a bit rich.

but im guessing here

 

[OldRider48]

i believe its because the air flow slows immediately, while the fuel already in the jets continues into tbe venturi, hence a bit rich.

but im guessing here

Works for me! I'll give it a try.

 

[speedrattle]

its noticeable even with a single change in jetting up or down. because its a fine-tuning mechanism, its something you can do seasonally as the weather warms in the spring and cools in thefall. the factory jetting was always a compromise, and if you dont mind a bit of fussing you can often improve it for your own situation, elevation, and season.