When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
1971 Harley sportster. Got my bike from California had it shipped to me in Colorado my altitude is about 5500, the bike losses power in fourth and kind of just runs crazy thinking its jetting but not sure about this carb looks like a mikuni vm34 but no markings? Any thoughts on what to do ?
Elevation is likely your issue, but the carb may need a full rebuild regardless. Not a complicated task, just your time, some parts and patience. Do it yourself and learn your motorcycle:
Most likely as already said elevation can cause issues, most carburetors are effected. In general you jet a little leaner when going up in elevation. Just to see what happens, see if you can lower the needle one groove and see what changes running wise. Also I'd get a hose clamp on that fuel line.
Most likely as already said elevation can cause issues, most carburetors are effected. In general you jet a little leaner when going up in elevation. Just to see what happens, see if you can lower the needle one groove and see what changes running wise. Also I'd get a hose clamp on that fuel line.
yeah got one on there now I pulled the carb I think its one of those Amazon carbs so got a real mikuni will start with stock jets and will move down from there thanks!
Elevation is likely your issue, but the carb may need a full rebuild regardless. Not a complicated task, just your time, some parts and patience. Do it yourself and learn your motorcycle:
In my world, 99% of time, suspected carb issues are really mis-diagnosed ignition problems.
For me, carb troubleshooting always, always starts with ignition / ignition timing. Ignition timing can be off a bit but it is still critical if your bike is to meet your expectations in all 4 gears.
Points ? or electronic ignition ? Regardless, when was the last time you had a timing light on it ?
So, from where I sit:
step 0 --> address the air cleaner. You need one.
step 1 --> crawl thru the ignition, (if points, set @ 0.018" (both lobes)) & verify with a timing light
then and only then
step 2 --> mess with your carb
Ignore ignition timing on a '71 motor & you'll be chasing smoke indefinitely. Good luck with your new ride.
Years ago I pulled over for a guy broke down on the side of the road. Of all things it was a panhead. The guy was running it with no air cleaner. He had a velocity stack on it. I saw a thin line of sand grains running all the way through that velocity stack and figured the sand would chew up his motor pretty fast.
I'm running a VM 38 on my 75. I don't know squat about older ironheads but maybe you're starving the engine for gas with a slightly smaller carb.
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.
Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.
Carb trouble need help!
