desperate help! 83 heritage hardtail.

dstroy12

dstroy12

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Hey guys!

Sorta new around here. I bought a heritage special 83 about a month ago and hardtailed it. This is my fifth build of the season, but I have to admit my first xs650/yamaha. I'm just lost with this. Carb. I put pods on it. Rejetted to 145 main and a 45 pilot. Adjusted idle set and turned mix to two turns. Fired her up and ran like a champ. No bogging but will admit smelled a bit rich. Toook her for a 30 miunte test drive. Ran perfect. Then when sitting at a light she just died. Outta nowhere. Tried to start and nothing. Turned her off and Pulled over. Sat there a sec and tried again. Then it was fine...

Drove some more then it happened again. I've got it home and I'm lost.

Ideas?
 
What pods do you have? Some of the cheap ones have a lip on the inside where they mount on the carbs, this can block of the holes in the carb bell.
The 145 mains sound a bit big. The 83 has the BS34 carbs. Even with short open pipes and good pod filters a 140 is plenty. The 45 pilot is ok.
I have the BS 34's on my 750 kitted engine. I have uni-filters with 1.5 inch head pipes and straight through shorty mufflers. I have 137.5 mains, 45 pilots with the mix scews at 3 1/4 turns out. Runs strong. I may try the 140's but it runs good now.
The idle speed should be 1200-1500 rpms.
Have you read www.amckayltd.com/carbguide.pdf It explains how to clean and tune these carbs.
Leo
 
@Leo - your correct it does have a lip. But wouldn't that suffocate the engine to fail even when I start it? As for cleaning yes totally went thru them. My total confusion is why it would take a long time for this symptom to come up. And then when I let it sit its fine.
 
The carb guide explains tuning too.
Could be your gas cap. The gas cap needs to vent the tank. Being a chopped up bike you probably don't use a stock tank. If your cap isn't vented then air can't get in, no air in = no gas out.
Try riding for 15 minutes stop and open the cap, does it make a sucking noise?
No gas cap is air tight. So after it sets a few minutes enough air bleeds in so gas can flow again, till it vaccum locks again.
Leo
 
YEah, Electrical is sorta my thing. Everything is good. and as for fuse holder. that wouldnt explain why it would happen 30 mins later, plus itll try to start just wont.
 
Do you have an in line fuel filter on it? It could be that after that period of time the float bowls are running dry and then as she sits for a little while they fill back up again.
 
I'm still in favor of the fuse or fuse holders. Have you checked/replaced the brushes? The TCI is rather fussy about having enough volts, bike goes much below 12 and it says the hell with it no more sparks. Could be something intermittent in the TCI too.
 
No fuel filter. And the battery is sitting at a nice 12.86 but unfortunately I do have something to report... I changed the oil cause I was thinking maybe its overheating. The oil reaks of gas. I'm afraid the would mean a ring issue. Correct? Am I fucked?
 
Well it may not be rings yet. You most likely need new o-rings on the float valves. How far into the carbs have you been?
 
5th build of the season? You should be telling us what's wrong by now. Since you're not, I guess you're right - you're fucked. Custom bikes are a wonderful thing if done right but most people can't build a whole custom bike in their garage (right or otherwise). I threw the towel in on helping a local guy build one. His entire tool set is contained in one little blow-molded case, lol. That means he thinks it up and I do all the work with MY TOOLS. Fuck him - but at least I see now he has company, lol. I don't feel so bad any more (not that I ever did).
 
when it dies at idle it sounds like a bad battery and/or charging system. that's how mine acted when the battery was going bad, and again when my charging system was weak.
 
So a little update. Bored the vent hole larger. Took off the pods that were blocking the air jet. Changed oil. Ran wonderfully. Only thing is now I have a hang in the idle. I'm assuming its air leak on the intake manifold. In my test run this time much less back fiirng when engine breaking. Battery reading when running is 13.45. Still have no idea about gas smell in oil. This things fun but I miss harleys. Lol
 

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