Light hammering sound w Vboost normal?

[wayne z]

Hi all, keep in mind that I am riding with a half helmet and windshield, so I hear a lot more sounds than most, prolly.

First, when I nail it, around 6k up I can hear a light high pitched hammering sounds from the engine.
Not that loud, but loudest thing this normaly quiet running engine is doing at the time.
I wonder if this is normal Hi power combustion sounds, or maybe the dreaded detonation? I am running 87 octane non-ethenol. Maybe I should try 92 oct and see if it still hammers?

Second, the stock exhaust has had the holes drilled out to 1/2 ". The right can emits much louder and higher pitched sound than the left. Is this unusual or just nature of the beast?

 

[one2dmax]

Try a sync. Should not affect it but just curious.

 

[wayne z]

Just did carb overhaul and sync about 100 miles back and a follow up sync about 75 miles back. Idles fine and runs smooth everywhere from idle to mid to full power.

 

[wayne z]

Think I might fix the throttle partly open and check the butterfly/venturi clearence with drill bit butts, like we did to sync UL plane carbs back in the day.

 

[dannymax]

Messed up gears in the servo motor? :confused2:

 

[MaxMidnight]

Think I might fix the throttle partly open and check the butterfly/venturi clearence with drill bit butts, like we did to sync UL plane carbs back in the day.

Suggest a sync with vacuum gauges will be more accurate.

 

[wayne z]

ause

Suggest a sync with vacuum gauges will be more accurate.

Done that twice with a 4 tube mercury manometer. Thought I would double check with drill bits, in case of some vacuum anomolies within the engine might cause throttle plates out of sync when guages show correct. Foe instance, I can adjust sync to perfect at idle and it's way off at 3000 rpm. I can sync at 3k then it's off at idle. So that's why I want to physicaly guage them to see what's going on.

 

[Rusty McNeil]

Terribly difficult to get a stock motor to detonate so I'm betting it's not that. Think you would have to have temps near boil over point to get detonation no matter how hard you hammered it.

 

[wayne z]

Terribly difficult to get a stock motor to detonate so I'm betting it's not that. Think you would have to have temps near boil over point to get detonation no matter how hard you hammered it.

Yes, the noise I'm hearing is probably normal for hi power, never noticed it when I was riding with 3/4 helmet and no windsheild. With 1/2 helmet and windshield, you hear every little noise from the engine and tranny.

Still have to chec sync ect. and try to find out why the right exhaust is louder.

 

[XXXMAX]

I get a stronger sound from the rt side of both of my Gen 1 Beasts. Don`t know why and have tried sync at a higher RPM. Still the same, louder on the Rt. I then had my hearing checked and about deaf on my left side from years of high pitch noise. I set backwards on my bike and the left side was louder than the rt. Problem solved.

 

[SpecOps13]

I have 2 Vmax's, one is high compression. I run 93 octane Non Ethanol in everything I own just because of that bike. Total, I have 3 bikes and 4 Cages and store 37 gallons of Non Ethanol here. I don't want to have the chance of putting the wrong gas in the 89. My 89 sounds and runs like crap even with 89 octane Non Ethanol and barely runs on 93 octane Ethanol. The 94 will run fine on 87 but also runs terrible with any octane of Ethanol. In fact all of my vehicles run pretty bad when I have to put Ethanol of any octane in and the mileage goes down. I'm happy to hear that you run real gas. Try a higher octane and see, as it won't cost you much and if you are a little lean on the mixture it may be causing some detonation. I believe it's worth a shot.

How many miles are on the bike?

 

[sdt354]

ause

Done that twice with a 4 tube mercury manometer. Thought I would double check with drill bits, in case of some vacuum anomolies within the engine might cause throttle plates out of sync when guages show correct. Foe instance, I can adjust sync to perfect at idle and it's way off at 3000 rpm. I can sync at 3k then it's off at idle. So that's why I want to physicaly guage them to see what's going on.

I sync off idle for that reason.

 

[SpecOps13]

I sync off idle for that reason.

I sync at 3,000 rpm (using fans directed at the radiator) and let the idle fall where it may. If it's too far off to idle, the carbs need work.