1975 CB125 Tracker project

Back when I was in the bike business we had a bunch of the honda 200cc singles in the atvs with carb issues. It turned out that the vibrations would cause the needle and needle jet to wear. If you knew where to look you could see the wear pattern. The needle would have a frosted looking area right where it passed through the slide and the needle jet would be slightly ovaled if you pulled it out and looked through it. The plugs would look just like yours since the needle couldn't seal in the jet and fuel would be pulled through the main at all throttle openings.
 
I read that about the XL185's too. I'll take a look and see if there is the same wear and if so order up a needle and jet! no sense chasing my tail if they are bad. Thanks!
 
Only available kits Keystar don't have a seat. Found 1 NOS on ebay but they want $45 for the needle and seat!
 
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There is a little wear on the needle. Does it look enough to be an issue? Seat looks round.
 
I'm going to put that back in with the clip moved up one notch and see if it leans it out enough. If still too rich I will order replacement parts.
 
I had one seat on Hunley that was wallowed out. Ended up replacing it with a '79 seat (I'm a bad boy) and she ran great after that. The errosion on the seat was evident from the top.
 
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ok I re-installed the carb and it is still crazy rich. Ordered the NOS Honda needle and seat. The aftermarket carbs were sketchy and I wanted oem. $42 was hard to swallow but I want a good running bike.
 
That needle shows the classic wear pattern for a worn needle and needle jet. I would replace them. Lowering the needle doesn't help since the jet is worn oval and allows fuel to leak past even the lowered needle.
 
ex119x said:
That needle shows the classic wear pattern for a worn needle and needle jet. I would replace them. Lowering the needle doesn't help since the jet is worn oval and allows fuel to leak past even the lowered needle.
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Yep. Thanks for telling me. I ordered a NOS needle and seat last night.
 
Maritime said:
Ok floats were 26mm reset to 24mm per spec. Cleaner comes out of all the air circuit. I found a newer cleaner 105 main jet and swapped the. Set the needle one leaner than if was. Will check valves tomorrow eve and see how they sit. One a side note the pla printed speedo disk warped in the sun and is shot. Will need to reprint in abs
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Update on the PLA-ABS reprint. tried 2X to get it printed in ABS first warped bad during print. we built a carboard enclosure and it helped some but still warped enough in printing we can't use it. Hopefully if we put a top on the enclosure the temps will stay high enough to get a flat print. if not it will be re-decal the steel plate.
 
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finally arrived. Installed and will be firing up tomorrow to see how it runs. Comparing old and new seats you can see how bad it was deformed. Very oval.
 
Always nice to get OEM parts for the carb internals as it seems the aftermarket ones always seem to have mixed quality. These should do the trick.
 
Yep. Put them in. Ran great for 10 min then started acting up. I was like wtf. Went to pull the plug to read it and.....
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So a quick trip to Napa and a new plug and cap and we're 90% there. Wot works and I can redline it in 1-4 5th isn't redline but it holds top speed at 7K so I think thats right.
 
So did another ride, about 50KM round trip to and from work. I managed to get it up to 9500 RPM and about 95 KPH on a flat section so it's pretty close to running right. Top speed is rated at like 105 KPH at 10K RPM and I'm not sure it should be run that strung out for long periods. It seems to like to settle in at 7K RPM in 5th which I think is about 75-80 KPH. The bent front fender rubs a bit on the front tire, the wheel is ever so slightly out of true so you feel it pulse and rub at the higher speeds. I tried bending it out, we'll see if that worked. Now all we need is to get Magoo into the next MSF and get his license. We'll go take it to the lot we teach and put it through it's paces first as well though.
 
You've put lots of time and effort into it and it sounds like it's worth it. Junior should be able to get lots of happy and safe miles (sorry, klicks) out of the little beastie.
 
Hope so. Came home tonight to a puddle of gas under it even though I shut the petcock off. Dammit.
 
SO petcock has gone bad somehow. Not sure I can fix it, may have to try another one. also the float is set too high as the gas is coming out of the overflow tube. Have a catch can under it until I can drain the tank and sort it out. Every time the bike is done, it's not. I found 1 made in Japan replacement that looks as good as OEM vs. the made in China one I bought. 3x the price but if it lasts longer than tank of fuel it's worth it.
 
pidjones said:
Some Chinabay parts need to be purchased in threes so you can combine and make one that works.
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Yep, I got the inline in last night, drained the tank and will open it and see if there is a replaceable o-ring or gasket. I will also adjust the float to stop the leaking out of the overflow.
 
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