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Cafe

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Hey. I'm 72 years old. I started with a Cushman Super Eagle when I was 14 and went through eight more bikes. I got off of them for the past three years, but decided to ride again. I recently bought a '83 XS400Maxim built into a café racer. After 20 miles I already have a problem which I will post under another thread. I look forward to looking at everyones bikes and watching what goes on around here.
1983 Yamaha 400 CafeRacer2 sharpened.jpg
 
Welcome to the forum. If you run those type air filters directly on the carbs you will have problems. Uni foam filters will help but stock is best. But with your mods that can't happen.
 
High idle, off idle stumble, mid and or high rpm's break ups. Lean conditions also could happen. These type carbs use vacuum to operate the slides. Aftermarket filters especially short pleated type ones create turbulence in air flow making changes to the vacuum. These bikes came with air boxes and used foam type filters along with a cross over and crank case vent line. The air flow was smooth and balanced to the motor. Did you build this bike?
 
No, I did not build it.
I can understand what you are saying, but I don't have those symptoms. It is very cold natured on start up. Is that normal?
 
All my carbed bikes run rough when theyre cold and need to use the choke/enrichment for a while before they settle. Some take 5-10 minutes of warming up. Your issue could be heightened with that air filter setup.
 
It takes five minutes to warm up nicely, turn off the choke and she runs great. Reckon I'm lucky so far. I do have a problem though. I went for my first ride, twenty miles, and everything was great. Then the engine started spittin'and sputterin' like it was running out of gas. Then it died. The battery is dead. It is an Antigravity 8 cell and had been working fine. I let it sit a few minutes and it made a very short effort to turn over. There is not enough juice to blow the horn. If this were a car I would suspect the alternator and/or battery.
 
Re-charge the battery and start the bike. Put a volt meter on it and if your not getting the volts stated in the other post your charging system has issues.
 
I found this at the Antigravity battery website for my battery.
"Custom builds like cafe racers or small bore customs up to 800cc. (Please note if you use older classic bikes from mid 1980s and earlier you should update the charging systems to a modern voltage regulator.)"
I will ask the builder if he did this upgrade.
 
Builder says bike has modern regulator/rectifier.
I'll get it charged and test as you recommended.
 
Heres mine bought it a few months back was stock am making into mildly modded cafe - love these bikes tons of fun to work on and tide - i had not had a bike since dirts bikes 25 yrs ago - im bit bad now - want to get another
 

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