Need help Fast Please

[AceMan]

Hi people, I am having trouble with my 96 Harley killing Vmax. It has developed a strange knocking sound from the right hand side rear cylinder area somewhere. I have had a reputable mechanic go right over the bike and not only service but did the cam cain, lifters etc and also checked the clutch and put a camera in and around the gearbox and we still cant find anything. The sound is a ticking type of sound that follows the rev range and gats faster with higher revs. It settles down when holding it around 5000rpm but comes back when revs increase. Mechanic said next thing is to pull down the motor but will cost me "more than the bike is worth" as he put it, apart from that let it develope. I have put around 500km on it since the noise started and it hasn't gone bang yet, but no more. I need to get this sorted. The bike has 47k on it and has been very well looked after.
Any info would be appreciated and will go along way thank you.

 

[tugla]

guess basic stuff which im sure your mechanic looked at, oil level or chg it out, exhaust leaks. how about checking valve clearance, at 47k due for a check. have all these been done?

 

[AceMan]

mate all that has been done for sure. I am thinking I might have to pull engine down but I would like to go straight to the problem with out having to replace everything when I do pull it down

 

[TURBOVMAX]

Hi people, I am having trouble with my 96 Harley killing Vmax. It has developed a strange knocking sound from the right hand side rear cylinder area somewhere. I have had a reputable mechanic go right over the bike and not only service but did the cam cain, lifters etc and also checked the clutch and put a camera in and around the gearbox and we still cant find anything. The sound is a ticking type of sound that follows the rev range and gats faster with higher revs. It settles down when holding it around 5000rpm but comes back when revs increase. Mechanic said next thing is to pull down the motor but will cost me "more than the bike is worth" as he put it, apart from that let it develope. I have put around 500km on it since the noise started and it hasn't gone bang yet, but no more. I need to get this sorted. The bike has 47k on it and has been very well looked after.
Any info would be appreciated and will go along way thank you.

The Vmax is weak in the wrist pin dept. When the pin and connecting rod develop a little too much clearance you hear that noise. Can't tell by not hearing it in person... but I would suspect that it's the noise. I agree with your mechanic just ride it and don't beat it too bad. It will last a long time before you need to pull it down completely for rebuild. That way you can ride while you collect parts for your newly rebuilt engine : )

 

[one2dmax]

Agreed, The rods as delivered lack a little. We bush them to get a better lubricated surface and reduced wear. I've seen them sloppy in as little as 1000 miles. BUT, check your starter clutch bolts as they tend to get loose and the clutch can rattle causing strange noises too.

We ran one easy for about a year then said the hell with it. Started running it hard again. Finally reworked them 3 years later.

Sean

 

[Rusty McNeil]

Sean, how about piston slap?

Don't know if the vmax is susceptible to it or not?

Mines got 42,000 niles on it now, it for sure has more "character" noise than it did when I bought it, but I think it's mostly in the valve train.....

 

[richwrench]

What about carbon build-up on top of the piston ? It takes up all the clearance between the piston & cyl head & will sound like a metallic knock. If that cylinder is running rich or burning oil that could also be a cause. I've seen it in a number of autos, but I don't know if a VMAX has close enough tolerances. Running some top end cleaner or slowly drizzling water down that cyl while holding the rpm's up is a quick & easy way to find out if it's carbon. And by drizzling I mean pouring a SMALL amount of water or cleaner - too much at once will cause a hydrolock & bend a rod. Just my 2 cents...

 

[one2dmax]

The OEM pistons sit about .050 down into the bore so you have to have a ton of build up to get into anything. Seafoam and BG44K both clean that stuff up (BG stuff more so then the other). You can also dribble auto trans fluid into the carbs while it's running which will do the same thing.

Unless you built the engine yourself Yamaha usually does a good job of setting the bore to piston clearance. I have seen issues with not enough ring gap but by the time you figure that out it's smoked the engine.

Sean

 

[tugla]

mate all that has been done for sure. I am thinking I might have to pull engine down but I would like to go straight to the problem with out having to replace everything when I do pull it down

i hear ya man, was just checking. Did this just come about one day or did you slowly hear it coming on, just curious?