The title about sums it up... I've got this 2000 Honda Ace Shadow Deluxe, which is a 750 twin-cruiser, with a pair of Keihin 36mm carbs on it.

The history is not good (it's my sis's bike)

It developed some issues, and she took it to a shop. This was a couple years ago, but it hasn't been ridden but once since then... They cleaned the carbs, charged her $400 and sent her home.

The problem was a stumble or flat-spot midway up the RPM range, such that the bike would actually quit running just about when you wanted to shift. The shop did not fix the problem.

So, it sat at my house (outside, but under cover) for a year at least, when I tried to start it again. Sure enough, it would start on the battery! Wow! It needed some "choke" to idle though. I have since learned that the choke on these carbs is not really a choke, but an enrichment circuit...

About two months after I started it, we went to send it home and... no start. Would fire nice on ether/carb cleaner though.

After trying the pour-in carb cleaner stuff, I gave up and pulled the carbs, which was not as bad as I anticipated. There was crystalline gunk in the float bowls.. one had a lot and the other had a little.

I removed the jets, used a piece of fine copper (soft... ) wire and a lot of carb spray to clean the two removable jets (big one, little one), generally sprayed the heck out of the rest of it and found that there were four small holes near the throttle plate, cleaned those off. These being covered with goo is probably why it wouldn't idle w/out the enrichment/choke earlier...

Anyhow, now it's all back together and it starts and idles like a dream.

But it bogs fatally with any throttle at all... even if I try to run it up really slow, it dies around (guessing, no tach) 3000 rpm.

It's BAD.. not rideable at all.

I've searched far and wide, and can't find any information about tuning/setting these carbs other than how to swap jets etc.. Obviously I just want it to run right so I can get it off the front porch and my wife can be happy.

;-)

You need to sync the carbs.

Yep definitely sync the carbs if they aren't working together it will create all kinds of mayhem ? I used to have an old kawasaki that had 4 carbs talk about a pain. Probably better to take it to a shop they have the right tool to sync them with. I got lucky with mine had a friend at dealer that helped me out. I rebuilt that whole engine but needed that tool to sync the carbs and since the tool was so expensive I got someone else to do it. I rode that bike for 7 years after that and never had another carb sync problem so Im glad I didn't purchase the tools to do it myself. GOOD LUCK,AC

Well, thanks for the answers...

I can tell you it wasn't the sync... these carbs only have one external adjustment, and that appears to be the idle mixture. Since the are CV (constant velocity), and the plate-shafts are locked together, they really shouldn't go out of sync at all short of jet changes or something equally drastic.

I ended up taking them off again (pain in the butt with short, stiff boots) and cleaning them some more. I didn't find anything terrible notable, and all the rubber diaphragms looked brand new.

Whatever it was, I got it because it runs great now. I considered dipping the carbs, but frankly... this can mess them up as often as not, if you miss a gasket or o-ring in there somewhere that the dip will attack. And a good, aggressive carb dip WILL eat those rubber bits.

FWIW also, a cheapo but perfectly usable carb-sync tool only costs around $2.

~aaron

Glad you got it right guess the technology for carb sync has changed anyway good for you. Enjoy the ride AC