noise

[maxape]

Hello all, after some advice, gave my max a blast on the way to work today and as i shut off the throttle from a high rpm 4th gear run, the engine made a massive bang and started to shudder making loud whirring sounds, but kept running. I idled into work . Started it up at lunch no problems or noises. Going to trailer it home to check it over. Just wondering if the vboost could be the reason for the drama. Any ideas would be welcome, thanks.

 

[jfeagins]

Is all your front/rear tread still intact & OK? A partially busted U-joint could also make those kinds of noises. A friend of mine had a drive shaft shell out on him while under decel, but a broken shaft would not have allowed you to idle on in to your work place.

 

[sdt354]

Hello all, after some advice, gave my max a blast on the way to work today and as i shut off the throttle from a high rpm 4th gear run, the engine made a massive bang and started to shudder making loud whirring sounds, but kept running. I idled into work . Started it up at lunch no problems or noises. Going to trailer it home to check it over. Just wondering if the vboost could be the reason for the drama. Any ideas would be welcome, thanks.

V-boost? Not likely. Are you talking Back fire type noise?

 

[maxape]

Hi, thanks for the replies. I am thinking maybe the vboost stayed open just long enough to cause a backfire with the large amount of fuel/air mix. Are there any known problems with the system I should look at.

 

[tinman22]

what is high rpm? How high?

 

[maxape]

Hi, on the red line or more, just holding it open till I run out of room. Started it today to see how the oil pressure was, seemed ok. Bike seem to run ok, no strange noises. I am going to pull the belly off to make sure there's nothing bouncing around in there before I run it too much, just to ease my own thoughts.

 

[sdt354]

Hi, thanks for the replies. I am thinking maybe the vboost stayed open just long enough to cause a backfire with the large amount of fuel/air mix. Are there any known problems with the system I should look at.

Some of us run open boost all the time. So, not that.

 

[maxape]

Hi again, not getting much time to fix my problems, but bit the bullet and took it for a ride. Seems to go ok but has a loud whirring noise somewhere in the motor area. Pulled the alternator cover off just to have a look in there . The 3 flywheel bolts look tight and secure, but the big starter gear moves back and forth on the crank about 1.5 mm, i don't think this is the cause of the noise but would that be normal movement ?

 

[Miles Long]

Does the sound increase/change pitch with the rpm of the motor, Mr. Ape?
You can use a mechanic's stethoscope to try to pinpoint the area where the noise is originating, or (oldschool), use a screwdriver with your ear next to it.
Also, post a video of your bike with the noise present. Do a walk around.....walkabout?......to give the viewers a better chance of diagnosing the issue.
Cheers!

 

[blaxmax]

Walkabout historically refers to a rite of passage during which Indigenous male Australians would undergo a journey during adolescence, typically ages 10 to 16, and live in the wilderness for a period as long as six months to make the spiritual and traditional transition into manhood.:eusa_dance:

 

[Miles Long]

Walkabout historically refers to a rite of passage during which Indigenous male Australians would undergo a journey during adolescence, typically ages 10 to 16, and live in the wilderness for a period as long as six months to make the spiritual and traditional transition into manhood.

Yup. Was aware of that, Blax. Just trying to inject a little Aussie flavor into my post.
Cheers!
Gotta run. Can hear my Billie starting to boil upstairs......

 

[blaxmax]

Walkabout historically refers to a rite of passage during which Indigenous male Australians would undergo a journey during adolescence, typically ages 10 to 16, and live in the wilderness for a period as long as six months to make the spiritual and traditional transition into manhood.

Yup. Was aware of that, Blax. Just trying to inject a little Aussie flavor into my post.
Cheers!
Gotta run. Can hear my Billie starting to boil upstairs......

Well done Miles-Well done.

 

[maxape]

Hi, got myself a center stand and that made things abit easier. The noise is coming from the rear of the gearbox as some of you were thinking. Almost silent in neutral but noise gets louder and higher in pitch as you go up through the gears. I will try to workout how to get some video up. Thanks. Stay safe over there my American friends.

 

[Miles Long]

Others with more experience will chime in, but a common issue with the final drive assembly is a loosening of the pinion nut, easily corrected. I hope your problem is as simple as this.
Cheers!
Miles, your Canadian friend:biglaugh:

 

[sdt354]

+1 to checking the pinion nut. After, check the u joint for play. They can get noisy when they're bad, even at slow speed. From there it gets more involved, checking out the shaft & final drive.
Steve-o

 

[1967vmax]

I had a whine on decal about the same gear 4th. I found that my pinion gear was shot in the final drive i think the torque killed the rear end the gear was like a Knife edge . I had a spare venture diff and installed it love it with the 1500cc

 

[maxape]

Hi , finally got to pull the drive out. The uni was just flopping around because the end of the middle drive shaft has broken off. Anyone had any luck just replacing the shaft so you don't have to pull the motor out?

 

[sdt354]

Hi , finally got to pull the drive out. The uni was just flopping around because the end of the middle drive shaft has broken off. Anyone had any luck just replacing the shaft so you don't have to pull the motor out?

Three bolts and it comes out as a unit. The will most likely be shims in there also. A used unit will save you time & money. Lash needs to be checked
upon install. PM sent.

 

[one2dmax]

***MAJOR CAUTION NOTE***
The ujoint is bolted to one part of a two part matched assembly. The pair of gears are matched at the factory and designed to be replaced as a pair. Also, setting the shimming it not super easy without all of the case numbers and numbers on the gears. Usually some of the numbers are missing from the equation.

Having said that I have seen (and done) just a replacement of that output gear portion with no problems. You may have some possible increased gear noise but it should be minimal. I've got plenty of spares from junked engines i'd sell cheap if you want one.

Another repair I have seen was to take the broken gear (easily removed without taking the engine out as was mentioned earlier with the three bolts and a tug). Take the gear to a machine shop, have it drilled and tapped out then either use a bolt or have a stud installed for the nut to tighten back on to.