engine knocking

[therustyaxe]

Ok, A few hundred miles back I got this knocking from the lower end (crank case).

From a locals experience it turned out to be the bearings for the crank.

Please don't tell me it is a bearing for the crank or connecting rod!

I really don't want to split the case after the build I just did.


Paul

[Rebel]

What else could it be? You could just ignore it and if it is a rod bearing it will let you know in no uncertain way, you know, if will expose itself to you by coming out and saying "hello, we are not doing this anymore". If somebody is knocking you just got to open the door and see if you want to let them in.

[kuzikood]

the old phrase dig a hole and push it in comes to mind but hey ill pay the shipping if ya decide to give it away lol

[therustyaxe]

Arent you ganna send me that free carb? HeHe.

[shiftless]

Before you sweat the crank, ya might wanna check for the piston toppin out
I put a 61mm kit on mine and after about 150 mi I heard a new knock (def wasn't valve tap)
Took the head back off and the piston was barely hittin the ex valve
I'm gonna double or triple base gaskets to stop it (hopefully)
The smallest spacers I can find are 2mm
Too big for me..
Fortunately I have another engine I'm running while I remedy this
I ride mine daily

[Rebel]

I know a guy that had his piston shaved/milled off to get the clearance.

[therustyaxe]

The funny thing is this started way before the new build.

I talked to Carlos and he gave me allot of info about the china cranks.

He is going to hold on to a Japanese crank for me until I can get some money together.

This China bike is becoming an expensive mode of transportation lol.

[kuzikood]

hey expensive but way cheaper than a lot of hobbies i.e. hunting,golf, r/c cars airplanes boats helicopters, full size autos, and best part is you can drive it to work woohoo now thats satisfying

[kliff]

May 28, 2009 23:13:35 GMT -5 shiftless said:

Before you sweat the crank, ya might wanna check for the piston toppin out
I put a 61mm kit on mine and after about 150 mi I heard a new knock (def wasn't valve tap)
Took the head back off and the piston was barely hittin the ex valve
I'm gonna double or triple base gaskets to stop it (hopefully)
The smallest spacers I can find are 2mm
Too big for me..
Fortunately I have another engine I'm running while I remedy this
I ride mine daily

How did you fit the 61mm cylinder to the case? If you "dremmelled" it, while still assembled, with the crank, then most likely, there is your problem.

I know I sound like a broken record, but that is no way to clearance an engine for cylinder fit. If on a budget, and the dremmel is you only means of getting the job done, then split the cases. Otherwise, sooner or later, parts will start failing. From past experience, if your oil pump isn't already scored internally, and it don't take much, it will be. Then rocker arms pivots, cam bearings, and the entire top end will start seeing progressive wear and failing parts, as the lower end continues to wear, unless, the rod bearing just cuts itself loose, or a main locks up.

If I'm wrong, I apologize shiftless. But I've seen the "dremmel scenario" on sooooo many different egines over the years.....it just ain't funny. The dremmel is a great tool, I use it religously, but it's simplicity, cheapness, and convenience, DO NOT over ride proper procedure when building an engine.

Again, I apologize, if I'm wrong...that's just sorta my soap box, and I always wanna see newbs at least get a chance to read it... so about twice a year, I'll pick on someone's post to make a statement....that is unless Doug wants to gimme a sticky, for my soap box...then I can say what I gotta say, and just shuddup!

BTW... I got me a 2mm Japanese crank from Carlos....it is BEAUTIFUL! can't wait to use it.

I also sent Jeremy a link on "toolage needed" to do BBKs the right way. So you guys up in his neck of the woods will have a local shop capable of boring cases the way it should be done.
Start bending his ear, I'm sure he'll buy the tools, if'n he see's he can get a return on his investment from you locals.

[Rebel]

Jeremy has in the past been more into doing 50cc motors, is he shifting gears now?

[shiftless]

May 31, 2009 8:34:21 GMT -5 kliff said:

May 28, 2009 23:13:35 GMT -5 shiftless said:

Before you sweat the crank, ya might wanna check for the piston toppin out
I put a 61mm kit on mine and after about 150 mi I heard a new knock (def wasn't valve tap)
Took the head back off and the piston was barely hittin the ex valve
I'm gonna double or triple base gaskets to stop it (hopefully)
The smallest spacers I can find are 2mm
Too big for me..
Fortunately I have another engine I'm running while I remedy this
I ride mine daily

How did you fit the 61mm cylinder to the case? If you "dremmelled" it, while still assembled, with the crank, then most likely, there is your problem.

I know I sound like a broken record, but that is no way to clearance an engine for cylinder fit. If on a budget, and the dremmel is you only means of getting the job done, then split the cases. Otherwise, sooner or later, parts will start failing. From past experience, if your oil pump isn't already scored internally, and it don't take much, it will be. Then rocker arms pivots, cam bearings, and the entire top end will start seeing progressive wear and failing parts, as the lower end continues to wear, unless, the rod bearing just cuts itself loose, or a main locks up.

If I'm wrong, I apologize shiftless. But I've seen the "dremmel scenario" on sooooo many different egines over the years.....it just ain't funny. The dremmel is a great tool, I use it religously, but it's simplicity, cheapness, and convenience, DO NOT over ride proper procedure when building an engine.

Again, I apologize, if I'm wrong...that's just sorta my soap box, and I always wanna see newbs at least get a chance to read it... so about twice a year, I'll pick on someone's post to make a statement....that is unless Doug wants to gimme a sticky, for my soap box...then I can say what I gotta say, and just shuddup!

BTW... I got me a 2mm Japanese crank from Carlos....it is BEAUTIFUL! can't wait to use it.

I also sent Jeremy a link on "toolage needed" to do BBKs the right way. So you guys up in his neck of the woods will have a local shop capable of boring cases the way it should be done.
Start bending his ear, I'm sure he'll buy the tools, if'n he see's he can get a return on his investment from you locals.

Kliff,
I measured my case opening with some cheapo hf calipers and it was a hair over 62
I shot Carlos an email with measurements and asked him to send me the biggest sleeve that would slide in w/o machining, he sent me a 59mm setup with a 61mm jug and piston, that he sells for carts
I have an odball P engine that measured head height and stud lengths that were the same as a standard QMJ
He had never heard of a P with my measurements, so I sent him detailed pics of the engine with calipers on certian parts

No dremel action I have opened em up with a dremel on qmb to make an 82cc fit (I know it's not recommended)
On the clearance issue, Ive ordered aluminun shims from KS to remedy that
I wasn't thrilled about the multiple gasket thang
Since I've got to build it (again)' I'll take the time to get it right ;-}