what did you do to your motorized bicycle today?

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fatdaddy

New Member
May 4, 2011
1,516
4
0
San Jose, Ca.
Today I learned that ALL these brand new Chinese made engines need to be examined carefully, before installation!

My brand new engine kit, had 2 base gaskets installed from factory.

Ive learned that others have experienced cylinders that were installed backwards, and other engines with 3 head gaskets!
I found out the hard way that the factory will use mismatched parts. If they got the wrong cylinder or a piston rod too long they'll just add gaskets to keep the piston from hitting the head. ALL they care about is getting yer money out of your account. EVERYTHING ELSE is YOUR problem. And yeah, ya gotta inspect everything.
Red.usflg
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Replaced throttle and clutch cables on customer's bike and readjusted clutch, added a few more coats of grabber green to the specialized frame's front triangle, then I will redo the rear triangle in semi flat black, I've also stripped the original yellow paint off the rear spring so I can powder coat it lime green.
Got the presta valve adapters in the mail today so I could put air in the fixie's tires, and hopefully this weekend I can have an engine installed in that one so I can have something to ride while I'm redoing the mountain bike.
 

knightscape

Member
Jul 29, 2013
340
1
16
Maine
Only changed the name of my ride --- sorry, Shan.....

Xseler, can you tell me about the direction your head is facing? I thought slant heads were supposed to have the plug facing forward for some reason? I don't know it if matters and I realized I don't have any idea why I thought that. Does it not actually make any difference?
 

Greg58

Well-Known Member
May 1, 2011
5,353
2,575
113
65
Newnan,Georgia
You can run the head either way, I found on one of my engines that it runs better with the spark plug to the rear. I don't know if the head mates the cylinder better or what the difference is but I can tell it.
 

fatdaddy

New Member
May 4, 2011
1,516
4
0
San Jose, Ca.
I've done it both ways. It doesn't seem to make a difference. I did it usually because of the CDI and where I wanted it mounted. To keep the plug wire off the head. But performance wise I could tell no difference at all.
fatdaddy.usflg
 

knightscape

Member
Jul 29, 2013
340
1
16
Maine
Took a sanity ride after work today. Bout 12 miles to my folks' and back. Gorgeous summer evening here in Maine. Just what the doctor ordered after a nutball week. First long ride since jetting and intake mods. Defintely added mid range power. I think I'll try up another size on the jet and see what happens.

 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
that's a really nice looking bike you got there...
All I've done today so far was air up the tires on the road bike and flip the rear wheel around so it runs off the freewheel side, but I'm still at the shop so I'm getting ready to put a rear sprocket on the fixie side of the hub and hopefully get an engine together and installed before I run out of steam for the night...
 

xseler

Well-Known Member
Apr 14, 2013
2,886
151
63
OKC, OK
Xseler, can you tell me about the direction your head is facing? I thought slant heads were supposed to have the plug facing forward for some reason? I don't know it if matters and I realized I don't have any idea why I thought that. Does it not actually make any difference?

I've ran it both ways. However, I've got a theory --- the bike runs slightly faster this way because of less air resistance.



:D xct2
 

Panhead

New Member
Mar 20, 2015
74
1
0
Michigan U.S.A.
Took a sanity ride after work today. Bout 12 miles to my folks' and back. Gorgeous summer evening here in Maine. Just what the doctor ordered after a nutball week. First long ride since jetting and intake mods. Defintely added mid range power. I think I'll try up another size on the jet and see what happens.

The John Deere paint scheme is cool. I think I need to hike my jet size, too. Thank goodness I ordered a carb that came with an entire box of different sized jets! Kind of like playing Jeopardy, one day I'll hear >ding< and Alex Trebeck will smile and say, "Panhead, you're today's winner!" dance1
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Tonight I actually made some decent progress with the road bike project... first I had to decide how I was going to install the rear sprocket so I decided to open up the center hole just enough to fit the flange of the fixie cog in thru the hole then made sure everything was centered up, clamped the 2 together then welded the 44 tooth sprocket onto the fixie cog. Problem solved, no rag joint, no adapters, perfect chain alignment, no complaints here...

I was just going to do that and go home but decided to choose an engine for the bike, temp installed the super rat then decided to go with a Dax engine instead. Grabbed a brand new Dax bottom end from the stock room, got a cylinder I previously ported, did a quick hone job to get the right cross hatch pattern, and put a piston on with the rings removed, trial fit the cylinder and the piston was protruding by about 1.5mm... I definitely didn't want to stack head gaskets so I grabbed the degree wheel and some copper base gaskets as well as a .040" thick spacer.
Stacked the gaskets and spacers until I got a 0.6mm squish clearance using a .025" thick copper head gasket, then checked the port timing to see if I needed to cut any more on the jug or not. After setting up the degree wheel I ended up with 164 degrees of exhaust duration, 122 degrees of intake and 132 degrees on the transfers so no piston ramping or cutting of the skirt will be needed or done.
I still need to take the top end back off to put the rings on the piston and then do a final assembly. The pipe of choice for this one will be a kx65 pipe since it fits really well with minimal modification and should hit where I want it to for a good combination of acceleration and top speed. For the carb I'm leaning more toward the mikuni vm18 for this engine since it's still fairly easy to tune and I want this bike to be not only fast but able to get up to speed quickly as well.
here's a pic of the progress I've got so far... this frame makes it a lot easier to work the engine without having to take it out of the frame so I've been able to set up the port timing and squish clearance, the head is temp installed so I could see what it's going to look like and to protect the internals until I can finish everything else I'm doing to it...

 

Tony01

Well-Known Member
Nov 28, 2012
1,729
1,721
113
sf bay area
It's running good! Like scotto said plug n play... Changing the oil..

Davezilla that should be a screamer... Watch out for those road bumps laff
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Yup... this one's gonna scream but after a short ride in the parking lot I'm already looking at a shock absorbing seat post, cloud 9 seat, and shock absorbing stem for it... this one does ride just a bit rougher than my other bikes but luckily I got lots of smooth pavement to ride on
 

DRBS

Member
Jun 22, 2014
269
3
18
Westland MI U.S.A
i took my cylinder off today and added the third transfer port boy did that add some more power!!!!! now i can really notice the reed valve working no more burb burb out of the carb my air cleaner is dry and it feels better at mid to high range cant wait to build my own expansion chamber next weed getting some .035" sheet metal and going to use my pressure washer to expand it out should be pretty good for a home built expansion chamber ill post pics of the finished exhaust when im done with it