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Old 08-15-2011, 11:49 PM
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mapbike mapbike is offline
Motorized Bicycle Elite Member
Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: what did you do to your motor bike today?

Hey rustycase,

Below is a link to motion Industries web site and these links are for better wrist pin bearings that will fix a top end rattle caused by the soft wrist pin bearing getting flat spots on the needles.

( Bearing Link ) Motion Industries - Product Search --

These bearings are very good quality and will stop the wrist pin bearing issue for good.

( Seal Link ) Motion Industries - Product Search --

Dont pay any attention to the pic on this seal link, the seal is correct but they have the wrong pic on here, I have several of these seals for my engines and they are a gray Nitrile Material just like it says in the description, the pic on the web site is wrong, but the link is correct so you can order better seals here and they are very reasonably priced too.

Best wishes...

Peace, map

Originally Posted by rustycase View Post
Yah, when I was working I always did that, Happy...
Now I'm just scraping for pocket change! lol
a china ht is just abt my speed!

Well, that guy murphy has caught up with me again. (I really need a faster MAB!)

My tiny number drills are labeled incorrectly from the local source... figgers, they are china made, too! When I check em with my mitutoyo caliper they all come up precisely one number increment off... no biggie, I just gotta run the next one in line...

My basketcase came dismantled, for a taco'ed rear wheel and the carb off and partly dismantled.. Seller said he'd had mid-range probs...
It was a #71 main jet and four stroking... so, on the conventional wisdom advice, I took it to a #74 and it fell on it's face. no go. Opened to #73 and it motivated a little but mostly with the choke worked feverishly...
Back at #71, (which is REALLY #70 !!!) it's still lacking for any speed at WOT and four stroking most of the lower rpm throttle settings...
I opened to #69 today, headed towards #68 which another fellow advised who has a small flock of them... a little bit of power back, but will only gain speed when headed down a hill.

I checked the burn on the ngk plug and it's WHITE! lean lean lean!

Got a drip of oil at the lowest mag cover screw... so I popped the cover off and there IS oil in the bottom of the case forward of the front screw boss, mostly... the seal probably isn't the best and I SHOULD replace it, but I got bigger fish to fry... or maybe rescue from the coals???

...rocking the engine at tdc with the plug removed, to get an idicator mark on the mag rotor, in advance of any tear down, as Alf has said, I'm getting more rattle from the top end than I would like to hear... Bad wristpin bearing or a rocking piston, I guess... Compression is still 'thumb OK' so I've put it all back together. It starts easily and does motivate...

Guess I better start comparing the price of parts against a replacement motor!

Does anyone know?
Did Murphy ever travel to asia?


Gonna open up that main jet again this afternoon... pretty soon I'll be pouring the mix in from a bucket! lol
I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!
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