what did you do to your motorized bicycle today?

GoldenMotor.com

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
so i layed it down yesterday as stated above, i rode it today and it runs like **** i just got home so i haven't taken it apart yet (still too hot) any ideas what may be causing it to run like garbage? it doesn't seem to hold idle anymore and when i throttle on it runs and then almost bogs out completely.
My first guess is the carb took a hit and disloged the assembly. Check for air leaks at the carb to manifold and manifold to cylinder.
 

tgaydos

New Member
Jul 16, 2015
108
1
0
astoria oregon
i think it was as simple as an air leak, i went to pull the fuel line off and the whole intake manifold was super loose, not sure if it was this morning or not, i didn't check.
and i think i got the leak around the petcock (hopefully).
 

tgaydos

New Member
Jul 16, 2015
108
1
0
astoria oregon
i'm going to take it out again here in a bit to test it and see if that was in fact the issue, i took the head off and there was a bunch of un-burned gas/oil on the piston and in the cylinder so my bet is that the loose intake was indeed the issue.
 

DRBS

Member
Jun 22, 2014
269
3
18
Westland MI U.S.A
it could also be that the float is stuck open and the fuel is just overfilling the float bowl and just running into the crankcase and the cylinder
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Just did some more transfering parts off the old mountain bike frame to the new one... I still need to get a wide 3 piece crank set for this one and I'm going to need to make a set of billet mounts since the frame tube is too wide. I'm also going to need to get a few more spacers for the head unit since this one is a little shorter than the other one and the stem won't sit all the way down like it's supposed to, but a 1/4 or 3/8" spacer should make it fit just right.
This frame is a little bigger than the old frame but space will still be pretty limited. I did a test fit by setting an engine in the frame so I know it'll have a little more room than the other one but not much, There shouldn't be any problems using a shorty intake and an 18mm Mikuni or a 21mm Dellorto. I'm going to try and use the Super Rat engine I built in this frame but the front mount bolts are too close together for the frame tube to fit in between so I'll either make a billet mount or see if I can open up the billet mount I already have enough to go around the frame tube, the one I got is about 1/16" too small so I'm going to try and use it before making a new one.
This one will get the Super Rat engine I built a few months ago along with a CR80 pipe and a 21mm Dellorto PHBG carb since that's what I got sitting around at the shop. I may try and get an Arrow reed and do the necessary cylinder and piston mods but I can still make this one plenty fast as a piston port. This one may go back on hold as I get closer to finishing the road bike, but I got some good progress on it tonight.

Here's an idea of what this one's going to look like...





 

xseler

Well-Known Member
Apr 14, 2013
2,886
151
63
OKC, OK
Not so much what I did to the bike --- there's really not a lot needed anymore, it's what I did to 'accessorize' it........




My helmet shell will now match the accent colors on the bike.

"He's so vain, you know he'll think this song is about him." Yeah, I was hum'n Carly Simon as I was spraying! :D
 
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DRBS

Member
Jun 22, 2014
269
3
18
Westland MI U.S.A
well i just raised my exhaust port 2 mm and added a extra base gasket to raise my timing and i got it up to 56MPH whoo hoo now to get the 18mm delloroto carb on there and hope i break 60MPH
 

xseler

Well-Known Member
Apr 14, 2013
2,886
151
63
OKC, OK
I just got back from a ride on mine. Personal fastest speed on this bike happened this evening. Saw an indicated 42.5 mph on a very slight downhill! This is more than fast enough for me.

The 36 tooth hub I got from mzmiami does the trick. Also, the NT Speed carb has got more chops than the CNS V3 that was previously on the bike. My homemade exhaust is also a great addition to the mix. Quite satisfied.


Makes me wonder what this little Skyhawk would do with a little internal massaging.....
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
did pretty much nothing to mine, but customer rode it with a top speed of about 15mph and tufts of hair missing where he'd been pulling it for a week trying to figure out what was wrong

he had the slide in upside down and it actually ran, but was slow
 

tgaydos

New Member
Jul 16, 2015
108
1
0
astoria oregon
i discovered that my base gasket is kaput so i made a temporary one out of a PBR can, hopefully it'll hold for a bit until i can get a new one. but it looks a lot better than what i pulled off (a homemade gasket by me from car head gasket material). i will be ordering a whole new gasket set when i can, until then i'll run this makeshift gasket until it pops and then take it completely down because i want to paint the frame.
 

DaveC

Member
Jul 14, 2010
969
1
18
Boise, ID
Been shopping around for a rear wheel drive electric set-up. Got my eye on several. I do want one of the newer generation drives. I'm moving to Oregon and they prefer that a bike be electric so no gas engine ;)