engine rattle

[wvspeedfreak]

I have my buddies sons drr air cooled 50 here and it has a rattling sound coming from the right side of the engine.It is very noticable when you first start the engine and it comes and goes until it is warmed up then it is considerably quieter but still there.
I pulled the fan cover and fan off and started it up to eliminate it being something about the fan making the noise because it sounded like the fan possibly hitting the cover.Noise was still there.Any ideas?

[wvspeedfreak]

What will a bad crank bearing sound like?It doesn't have any up and down play in it but the noise is very pronounced on the right side in the flywheel area.I also pulled the flywheel and didn't see anything wrong.

[Logan #34's Dad]

Is the oil injection still on it? If so the gears on the pump my be grinding.

[wvspeedfreak]

The oil injection has been removed.The quad seems to run fine and he said it started doing it shortly after he had the top end replaced.I guess I need to just open it up.Figured I would pick some of your minds before I started on it ;) It is strange how noisy it is when it is cold but almost goes away once warmed up.

[bulldogfallon]

Originally posted by wvspeedfreak
It is strange how noisy it is when it is cold but goes away once warmed up.


What's my wife have to do with this?

LOL


:devil:

[wvspeedfreak]

:D

[forgiven]

You sure it is not the springs holding the head pipe and back portion of the exhaust pipe together?

[wvspeedfreak]

I checked to make sure the pipe itself wasnt hitting anything because it runs pretty close to the engine but didn't actually check the springs.I will be sure to look at that but is sounds like it is internal.He will be happy if that is all it is.

[forgiven]

I have actually gotten radiator hose cut and sleeved them because it is so annoying to me.

[rmuscle]

had a wierd rattiling noise on my sons 70 turned out it was the bolts came loose that hold the pipe to the motor. it was driving me crazy cause i could not find where it was coming from , finally found it was the bolts loose tightened them up and it went away

[mudder700]

I had the same thing happen, the bolts on the head vibrated loose and it rattled, once it warm up it wasn't nearly as loud, check there first, make sure they are tight....

[qcitytile]

I think I have the same problem. We put a koso cylinder on a polaris and ever since its made a ticking noise. Im still trying to figure it out. We have run it a few times and it runs strong but its very annoying. I thought the same thing maybe a bearing but hard to tell without splitting the case. If I figure something out Ill post and if you figure it out please let me know. Thanks

[wvspeedfreak]

That is how this quad is.The noise is most noticeable as soon as you fire it up for the first time and gradually gets quieter as the engine warms up.It will actually stop doing it for a second and then start again.The fact that he said it started doing it shortly after the top end was replaced really has me wondering.
I haven't had time to mess with it much yet but did pay attention to the things mentioned in the above posts and all that checks out.
I should have some time tomorrow evening to check it more.

[Nick's #1 Fan]

I don't know if it is the same sound but I had the same issues with my sons Kasea some time back.

Make sure to check the squish for head clearence and you also may need to check the piston and the top end bearing to make sure there is no play between the rod and the bearing.

We had an ovalled out rod that caused a clanking sound at low rpms and ultimately destroyed the cylinder once the bearing gave way. We had to replace the crank since the rod was garbage.

Hopefully you can find the problem before the damage is done.

May not be the answer but another suggestion

[wvspeedfreak]

I am inclined to think that something like that is what is going on.I am going to pull the top end this evening.

[Nick's #1 Fan]

Let us know what you find, I am curious to know what it is...Good luck.

[wvspeedfreak]

Got it apart this evening.All I can see is a nice scratch on the cylinder wall on the intake side and it appears that part of the pin that keeps the top ring from turning has chipped off and is missing.This may have been the noise but I am trying to check everything else while I am there.It sounded pretty noisy...
Can anyone tell me what the allowable range of movement is for the rod side play at the thrust washers?