Triumphrat

speedblastr · 06-22-2007

I think the bike is a little more snappier running Hi-Test (premium)or at least it feels that way.IMO. I caught an earlier thread and I thought I'd bring it up on the table to see your opinions. 8-)

odatbob · 06-22-2007

I run 92 at the chevron station...no more stalling from take off and runs a lot better..glad I switched.Millage is the same but immediate response!! :-D

dazco · 06-22-2007

According to everything you'll find on the subject it should be just the opposite. the higher the octane, the worse the power because it makes the fuel burn slower. It's the lower octanes that should give you better performance, tho with the possibility of knocking which is why higher octanes exist in the first place. usually the manufacturer will recommend the lowest octane the vehicle can use w/o knocking. You should feel better performance with 89. Thats what i have read many times, tho i'll admit to never trying premium. I think i also read It may also lead to excessive carbon buildup too, but not sure about that one. I'd do some reading up on the subject if you intend on using it regularly.

Silverado57 · 06-22-2007

My understanding is that higher octanes make the engine run hotter.
Not such a great idear for an air-cooled engine in the summer.

I've tried high test on occasion with no discernable difference in power or MPG. The bike is designed to run on 89 and seems to do so nicely.

oldroadie · 06-22-2007

The higher the octane, the slower (actually the more uniform) the burn. Higher octane is preferred in high compression circumstances where you want the fuel to burn at a more controlled, therefore slower, rate. You should strive to use the lowest octane rating possible without knocking to prevent carbon build up from the slower burn. That said, only you can know which rating makes your engine run the smoothest and knock free. For my 04 TBA that's 89.

speedblastr · 06-23-2007

I pulled the plugs tonight ,was running a little sluggish. cleaned UNI filter helped a lot. Pulled the iridium plugs (sitting on the motorcycle) left plug had quite a bit of carbon build,not excessive but more than the right side which was tan with traces of carbon.Well this premium thing must be in my head then,ya learn something new everyday,must be my imagination running away with me.................... I think the real seat of the performance problem with my bike lies in the balance of both carbs which by the way my poly-carbonate mercury sync carb. balancer came post delivery today from newspeedmaster.I need to get this done.I'm powering one cyl. more than the other.Something I didn't know was they sent me the mercury in a separate vial. I know I don't want to become mercury poisoned. Must read directions very carefully,don't want to draw it into bike,first I need to figure out how to get it in the tester, haven't read directions as of yet.I know this is not rocket science but is trippin' me out a little.I'll shoot for tomorrow. 8-)

[ This message was edited by: speedblastr on 2007-06-23 00:34 ]

dazco · 06-23-2007

Don't worry about it. It's easy to pour it in. I was a bit apprehensive too, but it was simple. As for the engine sucking it in.........ain't gonna happen.You'd have to rev the heck out of it which you don't do when balancing.

Once you get the merc in it, tap it a bit to make it settle and it's even good to allow it to settle a while before using it to avoid air bubbles and whatnot. Mine was a bit flaky till it settled a bit. Anyways, heres what i did to get the best accuracy. Make sure the bike is well warmed up first, then attach any one of the hoses to a given cylinder, say the right one for sake of argument. turn the idle know up to the point where the merc is staying pretty much in the same place. (With low idle it bounces up and down a lot) take note exactly where it's staying on the gauge. then remove the hose and attach any other to the same cylinder. Start it again and see where the merc sits. If it sits exactly in the same place, mark that hose and the first one you tried with a black marker. If it doesn't, try another one. the point here is to find the 2 hoses that are as close to each other as possible. The little plastic restrictors that go in the tops of the tubes have pin holes in them to allow just enough suction to allow the merc to be accurate w/o getting sucked into the engine or being to low to not pull up into the tube. unfortunately, the variance in the hole size in the restrictors can result in each hose showing slightly different measurements at the same given amount of vaccum the cylinder creates. So you want to use 2 hoses that are closest to each other in that respect. And f you cannot find 2 that are close enough, you can adjust the restrictor hole in one with a pin.

Hope that was clear. Good luck. Oh, and make sure to check those plug gaps......maybe the richer plug's gap is a bit too wide or the opposite and isn't burning efficiently.

Gregger · 06-23-2007

Quote:

On 2007-06-22 20:53, oldroadie wrote:
The higher the octane, the slower (actually the more uniform) the burn. Higher octane is preferred in high compression circumstances where you want the fuel to burn at a more controlled, therefore slower, rate. You should strive to use the lowest octane rating possible without knocking to prevent carbon build up from the slower burn. That said, only you can know which rating makes your engine run the smoothest and knock free. For my 04 TBA that's 89.

Agree totally with oldroadie. Our engines are low compression and have fixed ignition timing (Correct me if I'm wrong). Detonation/pinging shouldn't really be an issue. On a high compression 904 BB units, I would definitely use premium to slow down the combustion process to prevent knock.

On performance autos equipped with knock sensors that retard ignition timing when detonation is detected, you will notice a difference in performance between premium and regular gas.

enginuity · 06-23-2007

Quote:

On 2007-06-22 19:13, dazco wrote:
According to everything you'll find on the subject it should be just the opposite. the higher the octane, the worse the power because it makes the fuel burn slower.

I think you (or someone you heard) made some wrong assumptions there. The point of higher octane is that it is more resistant to predetonation. Predetonation is when the compression heats the cylinder charge enough that it explodes, and the explosion (as opposed to a spark induced, controlled burn) is the problem. No matter the octane, when there is a spark, it will burn.

So... Basically, if a low octane isn't detonating, there's no advantage to using a higher octane, unless it means you can tune more aggressively, but that's not the point of this thread.

speedblastr · 06-23-2007

Look,not trying to make an atomic bomb here.I can pour gas on the driveway and light a match to it and it will burn too.For some pre-anticipated reason I thought I could get more bang for a buck using premium....not.However ,I'm not trying to make a swiss watch here,but do appreciate all of you guys input, will tune and adjust accordingly.Speed. 8-)

[ This message was edited by: speedblastr on 2007-06-23 17:09 ]