Author Topic: carb issues  (Read 1530 times)

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rosedog

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carb issues
« on: June 19, 2010, 07:20:40 pm »
been way too busy of late renovating my house to be working on my bike, but finally i got the old girl aside and decided to have a look at her.. the bike in question is a 1976 model honda xr 75, having not been started for atleast 6 years that i can remember, and not being looked after as she deserved things were a little sad..

the fuel in the tank had gone off, the carb was full of crystalized fuel, and the fuel tap was completely blocked.. 

i cleaned the tank out, although is still a bit rusty looking, so i will need to treat this with something, pulled the fuel tap apart and dug the brown gunk out of the holes and the slide of the tap, pulled the carb apart and cleaned the slide and jets, aswell asgiving the inside of the carb a bit of a spray and wipe with carby cleaner..

with high hopes, i filled the tank with fresh fuel, made sure there was filling the bowl, the give the little beast the kick of her life...    shockingly, the bike fired for a couple of seconds, then stopped, a few more kicks and it did the same again.. i tried a bit of areostart with the same reults....     i figured that this would be pilot jet issues????, so i pulled the carb again, and cleaned the pilot jet again... was definately bloody blocked... 
back together, and heap of areostart and the old girl is a runner... still cant wipe the smile off my face..
now here starts the problem, the bike idles fine, but when i raise the revs, i get to about 1/4 throttle and the bike starts to die.. back off to idle again, every time i increase the throttle past this point it does the same.. anybody got a solution for me??? obviously i havent cleaned somethin well enough, would just like to know what it is..
cheers, rosedog..

Offline frostype400

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Re: carb issues
« Reply #1 on: June 19, 2010, 07:22:25 pm »
how about your spark plug?? could be failing.
1971 tm400 and PE's

rosedog

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Re: carb issues
« Reply #2 on: June 19, 2010, 07:31:53 pm »
true, i guess due to all the bad fuel issues i have dealt with i just guessed it would be carb orientated... cheers, will be replacing it as a just in case anyway, once i have it running, il restore the old girl...

Offline Mike52

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Re: carb issues
« Reply #3 on: June 19, 2010, 07:33:37 pm »
Did you pop the stand pipe out and clean the tiny holes?
Woops better call it by its right name.
Needle jet.
« Last Edit: June 29, 2010, 02:38:47 pm by Mike52 »
85/400WR,86/240WR,72/DKW125,Pe250c,TC90,TS100,XT250,86/SRX250,XR400r
Friend  struggling up a hill on a old bike at MTMee .http://www.youtube.com/watch?v=cjj6E2MP9xU.

rosedog

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Re: carb issues
« Reply #4 on: June 19, 2010, 07:43:26 pm »
Did you pop the stand pipe out and clean the tiny holes?
sorry mate, what is the stand pipe???  i cleaned the little holes in the pilot, if this is what you are referring too..

Offline Mike52

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Re: carb issues
« Reply #5 on: June 19, 2010, 08:07:25 pm »
Yer mate take the slide out then undo the main jet a bit then gently tap the jet. Gently I said. ;)
The brass tube that the jet screws into should slide up into the slide area.
Undo the jet and gently push the pipe up and out.
If you look all along the pipe you will find a lot of small holes.
Clean the suckers out. Oh and clean out the hole that the tube came out of.
When replacing the pipe note the pin in the carb body and line up with the slot in the brass tube.
Screw the main jet back in.
Assemble the other bits and with a bit of luck :)
« Last Edit: June 19, 2010, 08:09:09 pm by Mike52 »
85/400WR,86/240WR,72/DKW125,Pe250c,TC90,TS100,XT250,86/SRX250,XR400r
Friend  struggling up a hill on a old bike at MTMee .http://www.youtube.com/watch?v=cjj6E2MP9xU.

rosedog

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Re: carb issues
« Reply #6 on: June 19, 2010, 08:25:23 pm »
cheers mate, will have a crack at this in the morning, didnt even know you could seperate the two..

rosedog

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Re: carb issues
« Reply #7 on: June 20, 2010, 03:58:20 pm »
well, problem found.. pulled the carb apart again and did a bit more thorough job of cleaning it, found the main jet blocked again... must have still been some crud i had missed..
put her back together, and decided to check out the air filter  before i tried starting her.. what a mess, i guess 20 years of no maintanance  doesnt do foam air filters so good.. the biggest piece of foam i could collect was about the size of a 10c piece.  with that lot cleared up i gave her a kick in the guts, first kick she fired, no areostart, full throttle response, i even took it for a burn around the yard... the old girl lives...
now to pull it apart and restore the little gem...