Metal-on-metal noise @ high RPM

[Dockspa1]

What version of motor do you have? Dac's, Kings, Simpson etc.

 

[srdavo]

Just a small install note;take your connecting rod and put it in your frezer and the new needle bearing in your oven at home,heat the bearing to 300 and freze the rod over night use good gloves and a small bench press to install the bearing ,If you dont have a press use a c-clamp and some peices of plywood as a hand press to insert the bearing

Seems to me, freezing the connecting rod will make it smaller. (harder to press in the new bearing/bushing)
Cold=Contracts
Heat=Expands
& I didn't have to completely remove my connecting rod to replace my bushing.

Hi put your wrist pin bushing in the freezer, and it will shrink a little then press it in, Mike

Somebody also suggested using dry ice to shrink the bushing.

 

[ducky]

I have a King's motor. I'm certainly regretting it to some degree. Wish I had gone for Dac's or Simpson. But I live in the Great North. We don't seem to get everything as good in Canada

 

[dave1490]

Seems to me, freezing the connecting rod will make it smaller. (harder to press in the new bearing/bushing)
Cold=Contracts
Heat=Expands
& I didn't have to completely remove my connecting rod to replace my bushing.




Somebody also suggested using dry ice to shrink the bushing.

ya that,s right heat the small hole in the rod and freeze the bearing.

 

[Patch]

My engine seems to be making the same metal on metal noise but all of the time. It still seems to run fine but very noisy...deafening almost! Its almost like a very strong vibration but ive inspect the all the parts i can without total dissassembly. So do you think my con rod to piston bushing is shot?

I will go inspect right now PS I have a dax 70 has anyone else experienced this?

 

[srdavo]

Patch....check this http://www.motoredbikes.com/showpost.php?p=72111&postcount=3

the constant noise sounds like this.

 

[Patch]

tHANKs Srdavo Unluckily that was the first thing I tried... Not a solution. This is much noisier It sounds like the piston is hitting something or something in the transmision is clicking but in a very loud metal clicking sort of way. To be more in-depth... Its a very resonant metal pinging/rattling sound. I could record it on video and post it somewhere?!?!
And I have checked to wrist pin...seems to be fine
Any other Ideas?

 

[Patch]

OK so Im swamped...my bushing looks fine, but I really don't know what a bad bushing looks like or feels like.

The bushing does have some twisting room for motion but its pretty small. IE I can twist the piston head just a tiny bit...would that much matter?

I don't have the guts to go in and check the crankshaft bushing but that too has a little room for movement which makes me think they're 'ok'

Could someone show me what a just barely worn but inoperable bushing looks like? or just tell me if I should Post pictures of mine and start a new thread>? Any help much apreciated!

 

[ibeenjammin]

Hey Patch-

I am having the same problem. I have recently had my motor apart and couldn't find anything wrong with my bushing as well. Have you noticed a loss in power, mainly lower end torque since you have been hearing the metal on metal noise? I am trying to problem solve for myself as well. I have lost a noticable amount of pull and I want it back. I would love to know if anyone has some input on when to replace the bushing as well. Obviously once it is shredded or cracked it needs to be replaced, but is their a way to tell if it has been worn too much and needs to be replaced? Thanks for all your help

 

[azvinnie]

i personally have had the lower bushing go, on me. which really means that you need a new bottom half. that is of course, if you know how to take these little engines apart with out hassle, ohh yaa puting back together without leaking(cracked case). still pains me, when l see it sitting on my bench