Engine knock

[BrileyR]

I have a knock coming from the lower end of the engine, on the right side, in the water pump area. It's usually heard at idle and up to around 1500 rpm. I found some other threads about a similar problem, it has been recommended to sync the carbs, I checked them and they are spot on. I have fresh Rotella synthetic in it with no change. The coolant is full as well. Is it possible that the pump needs rebuilt? The motor has 70k miles. I'm really concerned about the knock, I just bought the bike and don't want to rebuild the motor already.

 

Any ideas would be appreciated.

 

Thanks, Briley.

[massey130]

I assume it did not knock when you bought it. I don't want to offend, but can you call the seller and ask what he did to make the knock go away?

[MasterGuns]

Is there any difference in the knock when cold? If knocking only when at normal operating temp, I would suspect the water pump. Does the rhythm increase with engine rpm? Not to discourage you, but I too had a knock. I ruled out the WP, a loose cam chain which could be attributed to a bad chain tensioner, and clutch. I decided to replace the entire motor... no more knock. With only 70K on it, I doubt it is serious. Check out the WP.

[chabicheka]

I have a knock coming from the lower end of the engine,

 

Any ideas would be appreciated.

 

Thanks, Briley.

 

 

 

Methinks you are supposed to say...."WHO'S THERE?"

[BrileyR]

I assume it did not knock when you bought it. I don't want to offend, but can you call the seller and ask what he did to make the knock go away?

 

 

I guess I was too excited when I was checking it over to notice. oops!

 

The knock can be heard when it's hot or cold, but more noticable at normal temp. I got out the stethoscope out, and I can't really say it's coming from the WP, but that's where it is heard the loudest. I switched to 20w50 dino oil tonight, and that made no difference at all. Could the valves being out of adjustment cause the bottom end to make noise?

 

Methinks you are supposed to say...."WHO'S THERE?"

[dingy]

Could the valves being out of adjustment cause the bottom end to make noise?

 

 

 

Valve adjustment won't produce a knock.

 

When you changed the oil, was there much debris on the magnetic pickup on the end of the drain plug?

 

Something else to try is to pull one plug wire at a time and see if one cylinder affects the knock more than other 3.

 

Gary

[jasonm.]

This exact thing happened to me. If your carbs are sync'd. Then you have a cylinder or two running much richer than the others. ME, my chioke plungers were leaking. And made the idle uneven. All along I thought she was tuned great. I fixed this and EGA'd the bike...now it's the smoothest ever been in the last 20 years. To check choke plungers you need a good digital tach. After the choke is off but still not fully warmed up. And one by one press on the plungers and read for changes in the tach. Plungers have rubber seals and can go bad. Or the aluminum they seat against gets pitted. The play in the water pump gear is quite noticable. when things are not smoothest. That and the clutch basket.

[Drreb]

Well I'm not the best wrench on this site, but it would seem to me if you are hearing it the loudest at the water pump. I would start there.

[BrileyR]

The drain plug was clean, but I only had 1 week on that oil. I'll try pulling one plug at a time and see what that does.

 

I'll also check the choke plungers, it does smell really rich when idling.

 

Thanks everyone for the help.

 

Briley.

[Grisolm1]

My 88 sounded like a bucket of rocks was being shaken in the clutch area. Carb rebuild and a good synch cleared it up. These bikes seem to do weird things when the carbs are out of whack.

[jasonm.]

Well I'm not the best wrench on this site, but it would seem to me if you are hearing it the loudest at the water pump. I would start there.

Don't touch the water pump unless the seals leak at the weep hole @6 o'clock.

And with clean carbs, the low speed screws like it somewhere around 2 turns CCW +/- a half turn.

[BrileyR]

I took the bike to Lancaster Sport Cycles in Lancaster OH. This is where the previous owner had it serviced for the last 8 years. Joe in the service department is supposed to be very good with the old Yamahas, he said it could be the WP and it doesn't sound bad enough to worry about right now. Maybe this winter while the bike is apart I'll rebuild th WP just to be sure.

 

By the way, If anyone is looking for a place to take their older Venture for service, the guys at Lancaster Sport Cycle were very helpful. and it sounds like Joe really knows his stuff.

 

 

So for now I'll just ride it and try not to notice the knock.

 

Briley.

[a1bummer]

just a little FYI. When I thought I had a knock in my engine, it turned out to be the baffles in the exhaust collector rattling.

[BrileyR]

just a little FYI. When I thought I had a knock in my engine, it turned out to be the baffles in the exhaust collector rattling.

 

 

That's been added to my list of checks for this winter. That list is getting longer and longer.......

[jasonm.]

How loud is it? Mine could be heard after warm up more easily than cold. The knock was simply the water pump gear rocking on the pin it sits on. From the right side of the engine easily heard. But standing on the left ...hardly. Clutch baskets on these also make a mild knocking. Same side as water puump. Noise due to uneven idle. Nothing to worry about. A perfect tune up on an EGA could cure this. DO NOT go to anyone that does not have an EGA machine(exhaust gas anylizer aka CO machine). Don't waste your money on a noise...98% of the shops and mechanics have not a clue because they are trying to do things AS FAST AS possible. ANd only know what they have seen or heard. I have been thru most everything in the last 20+ years with mine. ANd found out things others were not aware of. And there are others out there like me...Many of them here.

[BrileyR]

Mine could be heard after warm up more easily than cold. The knock was simply the water pump gear rocking on the pin it sits on. From the right side of the engine easily heard. But standing on the left ...hardly.

 

This is exactly what mine sounds like. Does the gear wear on the pin after a while? Would replacing the gear cure this?

 

Thanks for your input!

 

Briley.

[jasonm.]

Replacing engine parts will not fix this. No, the parts will not wear out. You need to get a true tune up with and EGA machine. Again, it could also be the clutch making this noise too. The clutch has a "lower" toned rattle than the water pump gear. But either way a tune up is needed.But you say this Lancaster place serviced it. Just wonder how much service? And do they have an EGA. EGAs were common at all Yamaha dealers in the 80's. But now they don't seem to have them. But by me, the Dyno places that power tune the sport bikes , most all have EGA capability. And that's how mine was done. BUT they have to connect to the exhaust ports. Located on each header pipe. Look for a 10 mm head bolt on the underside of the front pipes and in the rear cylinders just a few inches down the head pipes. Use a 6 point socket to remove and use never sieze when putting the bolts back in. The adapters needed are the same as carb sync adapters for Kawi's 5mm thread. Mine was set to ~ 1.5% CO which was about 13.5 : 1 air / fuel ratio at idle. It took a $15k dyno system to do this. So check around. Expect to pay $50 to $100.

[Shorty]

. Use a 6 point socket to remove and use never sieze when putting the bolts back in. The adapters needed are the same as carb sync adapters for Kawi's 5mm thread. Mine was set to ~ 1.5% CO which was about 13.5 : 1 air / fuel ratio at idle. It took a $15k dyno system to do this. So check around. Expect to pay $50 to $100.

 

My 88 also has the same problem and will be getting the fuel ratio test also. Would it be a good idea to have the Valve shims checked out first, considering it's never been done... I've got 116,000 on it.

 

Can you really get the bolts out without breaking them?

 

Also the "Knock" in my engine is much less when I pull in the clutch lever.

[Squeeze]

The "Knock" which disapears when pulling the Clutch Lever is the 6003 Ball Bearing in the Clutch Pressure Plate.