Engine noise on 95" with gear drives

[R.Bingham]

Is this rattle something new or has this been happening since the new build ? If it is the latter I would say its piston slap. Most builders recomend cast pistons for street because they run quieter. If it is something new I would check every bolt on the bike. It may be something as simple as a loose heat shield.

 

[BUBBIE]

I used keith black pistons and yes they are forged, only have 6500 miles on them, just built the motor in may this year

I had used a set of KB's and loved them...... If the Bore and Hone was done correctly to their Tight specks, You should have a good motor!!!

If oil pressure is good and checked with a gauge, I would RUN the bike normal and NOT lug it down.... I never liked lugging.

The noise Could be a bad crank.... I did have one AFTER I installed the upper end rebuild. Running my New KB's and needed to be completely re-done AGAIN.. BUMMER..... went with 10.25/1 SE teflon pistons, Good but NOT the same as the KB's
The crank(rod) noise would show up as a Ticking upon acceleration and not just at idle or lugging, but also at higher RPM.

metal on the magnetic oil plug (bright flat pieces of metal) not just fuzz

signed....BUBBIE

 

[Hoople]

Compression is higher? Can the octane your using support it.? It's probably too much spark advance at the low RPM.

Have you checked what the cranking PSI is just to get an idea what your dealing with. Do you know what # your tune file is? If still Delphi, it's easy to look up what your spark curve is. Do you have a SEST? If so,, do a VCI recording and see if your spark curve is too deep.

I bet it's your spark curve.

 

[kmcnabb]

Had all my work done by a repitable motor builder in the states,tolerances were tight on cylinders, I dont lug the motor but sometimes it happens, oil looks fine just serviced it, can't seem to hear the niose at higher rpm.

My compression is not as high as it should be according to the guy how did my machine work for me, right now it is 170 and he said it should be 190 - 200, don't really understand the spark curve thing but I put in a powercommander 3 usb and had it dyno at a shop in Grand Forks so I hope they would of check this.

 

[TQuentin1]

I'am a new member and been reading this forum for quit some time and have a question I would like to put out there. I have 06 street bob and recently put a 95" kit in with K.B. piston, andrews 32g gear drive, s&s lifters and adjustable pushrods and powercommander usb3 and done head work as well. My concern is I have some low rpm knocking/rattle when I take off or lug the motor, and also some valve train noise. I realize I will have more noise with the gear drive set up but anybody have any ideals where to start? Bike runs and performs good.

Hard to interpret the description of a sound without being there to actually witness it. But here are some key steps in the Andrews Products procedures for installing the gear drive:

13. After new cams and gears are installed, backlash for inner cam drive gears (34T) must be checked. Using a wooden rod, press down on the front cam through the exhaust lifter bore and hold the front cam from rotating. Gear backlash can be checked by turning the rear cam back and forth. Some backlash must be present. Recommended operating backlash for cold gears is .0005 to .001. Cams should roll freely with NO binding. Cams with 0.000 backlash (too tight) may whine when running. Backlash greater than .002 is too much and can sound like noisy lifters at lower RPM. Either of these conditions must be corrected before continuing. Undersize rear cam gears (33-4272RX-S) or oversize rear cam gears (33-4272RZ-S) are available from Andrews.

16. At this point, it is very important that the crankshaft gear (31 teeth) and the rear cam drive gear (62 teeth) be checked for proper backlash. Before installing pushrods, rock the rear cam gear forward and backward with your fingers. Backlash can be felt as "freeplay" between the two gears. Gear backlash must be checked at four different crankshaft positions by rotating the crankshaft 90 degrees and checking the backlash at each position. Minimum of .0005 to .001 backlash must be present at each position. Gear mesh must show that some backlash is present.

If checking cam gear backlash as described
above shows no backlash, a smaller 31 tooth
crankshaft gear MUST be used! This is a very
important step; Do not skip it!
Cam gears operating with no backlash can
cause gear tooth failure and / or engine damage.

Undersize pinion gear (to increase backlash):
Andrews Part #.................... 33-4160X-S

Oversize pinion gear (to reduce backlash):
Andrews Part #.................... 33-4160Z-S

TQ

 

[kmcnabb]

Thanks for the response, did all that when I did the install and seemed o.k. but checked the compensating sproket on the weekend and it was fine so it has to be something else. I hate to say it but it sure does sound like piston slap to me i just don't want to beleive it and why is it with only 6500 miles, unless rings didn't seat good or something. My next step is to pull off exhaust and check cams out as I want to re-adjust my push rods. The guy that did my machine work for me said you turn them another 1/2 longer if need be.

 

[BUBBIE]

Thanks for the response, did all that when I did the install and seemed o.k. but checked the compensating sproket on the weekend and it was fine so it has to be something else. I hate to say it but it sure does sound like piston slap to me i just don't want to beleive it and why is it with only 6500 miles, unless rings didn't seat good or something. My next step is to pull off exhaust and check cams out as I want to re-adjust my push rods. The guy that did my machine work for me said you turn them another 1/2 longer if need be.

When you fit the cyl's to the pistons OR when they were fitted TIGHT,,,, They need to be bored under,,,,THEN HONED to fit... The pistons call out for 000.0005 (That is 1/2 Ten's)on the clearance....AND a proper torque plat used... If this is NOT done correctly the pistons will CLANK...... If it is this I would Not Worry about the piston slap,,,,, warming engine before giving it the Gun... IT will Last for a LONG Time....Just will be noisy,, so you'll sound like a BSA.... People will WONDER what you have...

If your builder Knows this and did it right , you should not have piston slap...(.)

signed....BUBBIE

 

[Jack Klarich]

When you fit the cyl's to the pistons OR when they were fitted TIGHT,,,, They need to be bored under,,,,THEN HONED to fit... The pistons call out for 000.0005 (That is 1/2 Ten's)on the clearance....AND a proper torque plat used... If this is NOT done correctly the pistons will CLANK...... If it is this I would Not Worry about the piston slap,,,,, warming engine before giving it the Gun... IT will Last for a LONG Time....Just will be noisy,, so you'll sound like a BSA.... People will WONDER what you have...

If your builder Knows this and did it right , you should not have piston slap...(.)

signed....BUBBIE

Im with Bubbie on this, were Torque plates used, if not you could have piston slap

 

[kmcnabb]

I know he bored them honed them to fit the piston as I was going to doing the bore job my self as I'm a machine shop supervisor at the mine here but he strongly recommended he do it for those reasons. He has a professioal race team in the NDRA and builds his own motors and has set records so I'am sure he does. I will check the cams out and if nothing I'am drive like I stole like I always do.

 

[BUBBIE]

I know he bored them honed them to fit the piston as I was going to doing the bore job my self as I'm a machine shop supervisor at the mine here but he strongly recommended he do it for those reasons. He has a professioal race team in the NDRA and builds his own motors and has set records so I'am sure he does. I will check the cams out and if nothing I'am drive like I stole like I always do.

GLAD you have that Ability and Understanding.....!... You probably will Teach ME something....


When I went to SS570 gear drives on my 2000 FXDS, I did the things that TQ1 mentioned, checking all the tolerances, ordering the right gears .. I had click noise but Not Too Loud.. I went with the fueling oil pump and delkron plate and THEN after the build, Fueling lifters... I did have More noise Clank with the HD lifters(new) than Normal..
That is when i changed out to the fueling and IT Did quiet down a Lot.

Glad to have you on board!

signed....BUBBIE