« previous next »
Pages: [1]   Go Down

Author Topic: Strange problem  (Read 1207 times)

0 Members and 2 Guests are viewing this topic.

Offline emilios

  • Enthusiast
  • **
  • Posts: 153
Strange problem
« on: January 26, 2010, 08:43:14 AM »
Hi guys..
A friend of mine came yesterday and told me that he has a strange problem with his cb100n(sohc too)
Well...the bike start easy...it runs little(about 3km) and then suddenly engine die...he start it again easy(one or two kicks)and after a couple of km engine die etc...
He bring bike to several mechanics but they only got his money..the problem is still there...someone told him that some parts are from cb125...
Can you tell me where the problem should be?
Thanks
Logged

Offline City Boy

  • Hot Shot
  • ***
  • Posts: 689
Re: Strange problem
« Reply #1 on: January 26, 2010, 08:46:43 AM »
Hi.From your description a good place to start would be to look for a fuel restriction slowing the flow .   Rock On
Logged
'52 Kiekhaefer Mercury Rocket Hurricane KG4H
'70 750/RC 1000 Original Owner
'83 1100F

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,301
Re: Strange problem
« Reply #2 on: January 26, 2010, 09:16:28 AM »
+1 NO FUEL!

vapor locked gas tank?  try running it with the tank cap on loose.
carbs gummed up and floats not operating float valve properly.
Logged
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline KB02

  • Take it easy there, Sonny, I'm an
  • Old Timer
  • ******
  • Posts: 3,760
Re: Strange problem
« Reply #3 on: January 26, 2010, 10:13:52 AM »
+2

That was my first thought as well. Also pull off the fuel valve and make sure it is clean. My old F1 would run fine with the valve in the ON position, but ifg you put it on reserve, I would only last a mile or two before it starved out. A noce little cleaning took care of the problem.
Logged
1978 CB750K Project
2000 Ducati ST2
...and a pedal bike

Join the AMA today!!

My project thread Part I: K8 Project "Parts Bike"
My project thread Part II: Finishing (yeah, right) touches on Project "Parts Bike"

Offline sangyo soichiro

  • Tuck
  • Master
  • *****
  • Posts: 2,167
  • ☢ the atomic playboy ☠
Re: Strange problem
« Reply #4 on: January 26, 2010, 10:16:14 AM »
Quote from: emilios on January 26, 2010, 08:43:14 AM
Hi guys..
A friend of mine came yesterday and told me that he has a strange problem with his cb100n(sohc too)
Well...the bike start easy...it runs little(about 3km) and then suddenly engine die...he start it again easy(one or two kicks)and after a couple of km engine die etc...
He bring bike to several mechanics but they only got his money..the problem is still there...someone told him that some parts are from cb125...
Can you tell me where the problem should be?
Thanks


I agree with the rest that it sounds like a fuel problem.  But what did your friend's mechanic say it was?
Logged
1974 CB 750
1972 CB 750 http://forums.sohc4.net/index.php/topic,57974.0.html
1971 CL 350 Scrambler
1966 Black Bomber
Too many others to name…
My cross country trip: http://forums.sohc4.net/index.php/topic,138625.0.html

Offline emilios

  • Enthusiast
  • **
  • Posts: 153
Re: Strange problem
« Reply #5 on: January 26, 2010, 10:33:10 AM »
He didnt told me... only that they fix it but the problem is still there...
Logged

Offline Industrial Cafe

  • Like a well oiled
  • Really Old Timer ...
  • *******
  • Posts: 6,372
  • [Brian] I've got something to say about that!
    • Undead Asphalt
Re: Strange problem
« Reply #6 on: January 26, 2010, 02:52:28 PM »
it's gotta be a restriction in the fuel system, go over there and help him.
pull the line off the tank and see if it drips out the petcock.
put the line back on the petcock and check for any loops or horizontal lines in the fuel line between there and the carb.  turn on the fuel to see if any comes out at a good rate of flow.

If that's good, pull the bowl.
   with the bowl removed and the fuel line attached to the carb you should be able to open the petcock again and get a good dribble of fuel pouring out.
 If not, check the float valve for debris.

that's all I got for ya.
« Last Edit: January 26, 2010, 02:54:08 PM by Industrial Cafe »
Logged
everything I say is pure speculation and
I have no idea what I'm talking about  ._.

                                    Marla              .:71CB750:.CAFE

Offline Frankenkit

  • Industrial Strength
  • Really Old Timer ...
  • *******
  • Posts: 6,525
  • 2012 CBR250R, 72 CL350, Member #4600
Re: Strange problem
« Reply #7 on: January 26, 2010, 02:56:54 PM »
Try using some brake kleen or spray carb cleaner to blow out the vapor passages in the gas cap really well.  it really sounds like tank vapor lock to me... or maybe a clogged or dirty (or backwards?) inline fuel filter?
Logged
"Moderation in all things - especially moderation. Too much moderation is excessive. The occasional excess is all part of living the moderate life."
2012 CBR250R "Black Betty"
1980 CB650c- (sold) Delilah
1973 CL350- Lola?
Quote from: The_Crippler on July 19, 2010, 07:58:02 PM
Sweet, bubbly, Buddha - Say it ain't so!!!
Stuff for sale

Offline emilios

  • Enthusiast
  • **
  • Posts: 153
Re: Strange problem
« Reply #8 on: January 27, 2010, 08:33:41 AM »
Well...today i went to my friend and found that the problem is not in fuel system...also he told me wrong things...
Bike it was hard to start and he took it to a mechanic...the mechanic solved the problem(but he didnt told him what was the problem)...
My friend took the bike from mechanic and for 2,3 days was running good..but after..at high speed..bike wasnt running good and he found that spark wasnt good enough....
Another mechanic told him that the bike has cb125 parts and it cant run good..
Iam wondering if the points get loose on high speed cause vibration?
Logged

Offline mystic_1

  • Really Old Timer ...
  • *******
  • Posts: 6,071
  • 1970 CB750K
Re: Strange problem
« Reply #9 on: January 27, 2010, 08:47:52 AM »
Quote from: emilios on January 27, 2010, 08:33:41 AM
Iam wondering if the points get loose on high speed cause vibration?

Quite possible.  Time for a full tune-up (don't just do the points, do it all).  That will eliminate many potential sources of problems.

mystic_1
Logged
"A ship in harbor is safe, but that is not what ships are built for."
- John Augustus Shedd

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0
Pages: [1]   Go Up
« previous next »