wristpin needle bearing question
- Thread starter Thunderhead289
- Start date
Davezilla
New Member
Agreed... 2 grams really isn't worth swapping parts out for... even on a new build.
rogergendron1
New Member
I did not read all the post here but let me give you my opinion ....
You can run a stihl chainsaw bearing and drill out the center of the wrist pin it cheap and it works flawlessly and lightens it up a bit
You can run a moped needle bearing and a super light titainium wrist pin... A lot of racers go this way and it works the shiat... I have never herd of a problem once from a titainium wrist pin
Or you can go with a stock drill wdist pin and a bronze bushing and run a mix of 32:1 and never ever worry about a damaged top end again or a bering failure... Bronze bushings are used in super high rpm drag motor just for this reason
I ran a titainium wrist pin and cause I had nothing else I made a brass ... Yup you heard me BRASS bushing and ran that on a 9,000 + rpm 13:1 comp drag bike for nearly 1,000 miles without a single problem but swapped it out with a stihl saw bearing latter on a rebuild ... When I chexked it with my micromite I fount it only had worn less than .0005 on the outside and it had worn only .001 on the inside were it rode on the wrist pin !!!! That is hardly any wer for that kind of abuse and that soft of a metal . I ran that drag bike at a mix of 30:1 to 32:1 at all times with lucas oil semi synthwtic race oil .
Now that I know juicemoto sells bronze bushings I do not think I wil ever eun a needle bearing on the top end ever again on any china girl build .
I just know feom lots of ezperiance that a well tunned high comp motor running a good 32:1 mix will run perfext for thousands of miles at wide open rpms and under race conditions on a bronze bushing and I will never ever have to worry about bearing failure .
You can run a stihl chainsaw bearing and drill out the center of the wrist pin it cheap and it works flawlessly and lightens it up a bit
You can run a moped needle bearing and a super light titainium wrist pin... A lot of racers go this way and it works the shiat... I have never herd of a problem once from a titainium wrist pin
Or you can go with a stock drill wdist pin and a bronze bushing and run a mix of 32:1 and never ever worry about a damaged top end again or a bering failure... Bronze bushings are used in super high rpm drag motor just for this reason
I ran a titainium wrist pin and cause I had nothing else I made a brass ... Yup you heard me BRASS bushing and ran that on a 9,000 + rpm 13:1 comp drag bike for nearly 1,000 miles without a single problem but swapped it out with a stihl saw bearing latter on a rebuild ... When I chexked it with my micromite I fount it only had worn less than .0005 on the outside and it had worn only .001 on the inside were it rode on the wrist pin !!!! That is hardly any wer for that kind of abuse and that soft of a metal . I ran that drag bike at a mix of 30:1 to 32:1 at all times with lucas oil semi synthwtic race oil .
Now that I know juicemoto sells bronze bushings I do not think I wil ever eun a needle bearing on the top end ever again on any china girl build .
I just know feom lots of ezperiance that a well tunned high comp motor running a good 32:1 mix will run perfext for thousands of miles at wide open rpms and under race conditions on a bronze bushing and I will never ever have to worry about bearing failure .
rogergendron1
New Member
I think my current build will be a driled stock wrist pin and a bronze bushing, though I am thinking that I may be able to run just a over sized titainium pin on a drilled and reamed crank and piston, no bushing or bearing at all .
mapbike
Well-Known Member
Juicemotoparts now recommends that only a bushing is used on the titanium wrist pin, I have one that just failed big time after only about 50 miles but I was running their experimental aluminum bushing, and I hav seen pics of other titanium wrist pin failures when someone ran a needle bearing on it, I know that at least one of them that failed was running a used needle bearing that haf been run on a steel pin previously which could have been an issue, but I think a bronze bushing on the titanium pin will probably be ok, nothing to gain by using a titanium pin and bronze bushing over a needle bearing and steel pin in the weight department because the titanium pin and bushing actually weighs 2 grams more than a steel pin and bearing.
I wont buy another titanium pin I dont think, and im not sure if I'll ever use the two bronze bushings I have or not but I may try one at some point.
Whatever anyone does I highly recommend staying away from the aluminum bushing.... not a good Idea, emailed juice with my results so maybe they will pull that part from their web site before anyone else trashes a piston, wristpin and possibly the jug.
Map
I wont buy another titanium pin I dont think, and im not sure if I'll ever use the two bronze bushings I have or not but I may try one at some point.
Whatever anyone does I highly recommend staying away from the aluminum bushing.... not a good Idea, emailed juice with my results so maybe they will pull that part from their web site before anyone else trashes a piston, wristpin and possibly the jug.
Map
Ya I read some stuff on the older juice moto bushings and it was no good. The reason I wanted a bushing was to lighten up, for less vib. I ended up getting a new needle bearing, pin, piston and rings, clips and a nu cylinder. Basically a nu top end from piston bike for 88.00.the cylinder was worn out. I need to pick up a jetpack cdi. That's all I can afford right now.anyone know where I can pick one up??
mapbike
Well-Known Member
youll be waisting your money on that jet pack CDI..... Dont fall for the hype my friend, that CDI wont do a thing for your engine.
Best bang for the buck is the stock unit.
If you want to get an aftermarket unit that wont lower performance the HD'S Lightening is the one to get, but dont expect a huge power or speed boost with it either, I can say it is made very well, it will do anything the stock unit will do, it does have a bigger coil and it has a useful key switch, all the other aftermarket CDI's are snake oil and will limit rpm potential in my experirence.
mapbike
Well-Known Member
Quickest place I could think of to get the set up is
http://www.sickbikeparts.com/catalog/product_info.php?cPath=22&products_id=184
OR
http://www.pedalchopper.com/hd-lightning-cdi-kit/
If you just feel you have to have a after market CDI and coil setup this is the only one I would recommend from personal experience.
Map
Davezilla
New Member
I bought one of those CDI's last summer just to see if it was any good and to tell the truth, the stock CDI outperformed it. Not to mention the engine wouldn't fire until I reversed the wiring because they were soldered in the wrong place on the board.
Now the HD lightning is a good CDI if you have to have an aftermarket one... I don't have one myself, but from other's experiences I can say it's a good quality unit. I may buy one to experimant with on my next build since I'm plenty happy with the stock unit on my current build.
Now the HD lightning is a good CDI if you have to have an aftermarket one... I don't have one myself, but from other's experiences I can say it's a good quality unit. I may buy one to experimant with on my next build since I'm plenty happy with the stock unit on my current build.