Pinging

[RagingMain]

Might be a silly question but....
With a helmet on & ear plugs in how would one tell if the engine was pinging???

Just wondering. Sean built a 1300 venture for me and put the high compression pistons in. I have been running 89 but not sure if I need to run 91.

Thanks in advance.
Cheers

 

[maleko89]

I suppose remove all that and listen at idle? What's your compression? Hulign's bike has over 200 psi compression and he runs 87 w/o troubles. You could look at your plugs too. Look for peppering on the center porcelain below the center electrode.

 

[Neil-3446]

Might be a silly question but....
With a helmet on & ear plugs in how would one tell if the engine was pinging???

Just wondering. Sean built a 1300 venture for me and put the high compression pistons in. I have been running 89 but not sure if I need to run 91.

Thanks in advance.
Cheers

You should be able to feel the chatter. Might try braking it without your helmet and ear savers in when warm, and bogging the engine down trying to do a 2nd gear burnout.

Are you running a dyna 3000?

What is your cr at now estimated???

Anything over 10.5:1 and I would run a higher grade.

Neil

 

[RagingMain]

I suppose remove all that and listen at idle? What's your compression? Hulign's bike has over 200 psi compression and he runs 87 w/o troubles. You could look at your plugs too. Look for peppering on the center porcelain below the center electrode.

When we did the compression check after the build it was 175 psi. I will pull the plugs and take a look at them. Idle sounds fine, just feels funny when down shifting and hitting the throttle to pass, I can feel a different kind of feeling coming through the foward controls. Then again it could be because of the solid engine mounts.

I am running the dyna 3000 on curve 3 advance.

Estimated CR from the piston manufactrurer is 12:1

Thanks for the help

Cheers

 

[maleko89]

Mine is starting to exhibit the same vibrations. I noticed my stock pegs are worn down to the metal in places so that's on possibility. Next going to make sure everything is tight and maybe buy a new ME880 up front. It's definitely getting old.

 

[Thevmaxrider]

I am running 12:1 comp pistons in my 1428 and it still runs just fine on 87 octane gas. Check the plugs on a routine basis and have seen no sign of detonation yet so I would say that you should be fine. Changing to solid motor mounts will definately change the way the bike "feels". Every vibration that was absorbed by the rubber mounts is now going to be transmitted directly for you to feel.

 

[Jayhawk]

If it were mine, I probably spend less time analyzing this one, and more time riding. Just run the 91.

 

[Thevmaxrider]

If it were mine, I probably spend less time analyzing this one, and more time riding. Just run the 91.

And carbon up the valves due to incomplete combustion........

 

[Jayhawk]

And carbon up the valves due to incomplete combustion........

With mid-grade in a bike with higher than stock compression? Okaaayyy...

 

[Thevmaxrider]

Mid grade is 89 octane here in Canada, not 91. Have seen the results from running 91 in an engine that doesn't need it..... it ain't pretty. I run high compression pistons in a non-stock engine and run 87 octance, as per the motor builder's instruction, with no problems. The Vmax engine, stock or modified, has a cold combustion chamber unless you change the squish band by making it smaller. Most motor builders use the stock chamber dimensions even with a higher compression piston. To adjust this they use copper head gaskets to ensure the proper chamber dimensions and volume. If the motor builder decked the block and used thinner gaskets then yes you could have a detonation issue, but if the builder brought the volume to stock or even close to stock then no you will not have complete combustion, regardless of compression ratio. Given that he says his motor has 175psi compression, which is bang on for stock, yes you will carbon up the valves.

 

[one2dmax]

I run 87 in my 1500 with 12:1 - usually knock is first seen in plugs if it is light. A loud knock (under the hardest load) will be audible even over a header.

I don't know if i've seen the need for premium yet other then one of the 14:1 engines. These engines have incredible heat absorbtion in the cylinder heads.

Sean

 

[Jayhawk]

Well, perhaps an octane increase is not warranted. I stand corrected. However, if the guy suspects pinging, it seems a safe move is to move up a grade of gasoline and then look for any signs of carbon buildup. Pinging is a known engine destructor, and the risks of missing it are fairly substantial.

Premium here, FWIW, is 93 octane. I'm at 12.5:1, and running it in my bike everyday.

 

[RagingMain]

Thanks for the help guys. Didnt mean to start anything, just worried about the new motor. Sean put a lot of hard work into it. Dont want to destroy it. I will check the plugs

Cheers

 

[fasterlapdunn]

Mid grade is 89 octane here in Canada, not 91. Have seen the results from running 91 in an engine that doesn't need it..... it ain't pretty. I run high compression pistons in a non-stock engine and run 87 octance, as per the motor builder's instruction, with no problems. The Vmax engine, stock or modified, has a cold combustion chamber unless you change the squish band by making it smaller. Most motor builders use the stock chamber dimensions even with a higher compression piston. To adjust this they use copper head gaskets to ensure the proper chamber dimensions and volume. If the motor builder decked the block and used thinner gaskets then yes you could have a detonation issue, but if the builder brought the volume to stock or even close to stock then no you will not have complete combustion, regardless of compression ratio. Given that he says his motor has 175psi compression, which is bang on for stock, yes you will carbon up the valves.

Explain more please. I thought the higher the octane rating the better the air/fuel mixture will burn leaving less carbon build up. I know with the higher compression that you have= you need an octane level less susceptible to exploding twice (knocking). I have owned a bunch of bikes and have always used the highest octane available at the pump...now 93, just because I want LESS carbon build up. I can kind of see your point though. The 93 has a high anti knocking characteristic, thus, without high compression the engine will not burn it efficiently/entirely...????

 

[Thevmaxrider]

The problem lies with the thought that higher octane somehow equates to cleaner burning. High octane fuels burn slower and colder, this is what helps control detonation (spark knock, et al) along with the "anti knock" additives. There is a finite amount of time that the fuel/air mixture has to combust during the power stroke of a 4 stroke engine. Slower burning fuel coupled with the cold combustion chamber in a Max can cause carbon build up.

Know, having said this, help your engine by taking it up to high rpm which will raise the combustion chamber temps and "blow out" the carbon. The problem lies with the fact that most folks operate their engines in "cruise" mode (~4k rpm) for long periods of time which allows carbon build up.

 

[fasterlapdunn]

I cruise some days and some days the VMAX is WFO! I'm leaning toward 87 is good enough...until you here a KNOCK! WTF! Thanks Mr. Rodgers :rofl_200:

Sorry had to do it :eusa_dance:

 

[Thevmaxrider]

Been living with that name for 40 years and have learned not to take offense LOL.

 

[gtotiger1]

Ok - so what do we all run for octane in a stock vmax - i have been runnibg 91 for years , am i wasting my money????

 

[Thevmaxrider]

87, no more, no less.

 

[maxcruiser]

Ok - so what do we all run for octane in a stock vmax - i have been runnibg 91 for years , am i wasting my money????

I run 87 octane as recommend bu the manual and no issues - but like Jim says, need to blow the carbon out every once and a while - that never seems to be a problem tho!

Mike