Hucklecatt

I still have the originals if someone is into fuggly saddle bags... PM sent.

Great stuff Erik - thank you!

Just as followup I used Sirius Consolidated to find these parts. Diaphragms only at ~$27.00.

Just as followup I used Sirius Consolidated to find these parts. Diaphragms only at ~$27.00.

Hi all: Very sorry for posting off-topic here, but hoping someone has experience with this... Need rebuild parts for an early 1996 Royal Star standard with the 28mm Mikuni carb set. Specifically need diaphragms and O-rings for pilot screws. Cannot find ANY kits for this carb. model - all help appreciated! John

Hi all: For an early 1996 Royal Star standard with the 28mm Mikuni carb set. Specifically need diaphragms and O-rings for pilot screws. Cannot find ANY kits for this carb. model - all help appreciated! John

Just confirming that you know your carbs are in good shape - that the diaphragms are not pinholed, that the jets are clear as are all channels within the carb body. If you are over-gassing your mixture no amount of spark will overcome that.

As mentioned, you are referring to a carb size that was superceded by the 32mm. This is complicated by the fact that later models also used differing jet sizes for front and backside carbs in later models. A WAG is that you are running 117.5 Mains and 22.5 Pilots with (possibly) adjustable needles. That is the typical DynaJet or Baron's Stage 1 kit setup. If you are not mechanically inclined I would enlist a brother VentureRider to help pull, clean, and verify your jets and needles, and clear the idle adjustment hole of its protective brass insert. At that time, I would highly recommend you replace the rubber diaphragms X4 since they get pinholes and become unusable over time.

It's funny, but sometimes simply having the bike on a sidestand will influence the floats and the side to side performance at cold idle warmup. You might try holding the bike upright and shaking it just a bit to see if there is a noticeable change.. - BUT - As carefully as possible, check header temp at warmup time. A cold header pipe will reveal a lot. I would guess that your idle circuit would benefit from adjustment. Do this before you perform a carb synch. - AND - ABSOUTELY get a carb synch. Not hard - a long (12") standard screwdriver and a synch device to do so.

Worked in the bicycle industry and worked with everything from Campagnolo to Chris King headsets. Remember that after adjustment on any headset, tightening the top nut will provide your final preload. Perform the adjustment, but keep in mind that when you cinch that acorn nut down, additional load is placed on the bearings and will provide the final swing test feel for your bike. If you have repacked the bearings, it is almost certain the viscosity and amount of grease will give you a false sense of tightness. 100 - 300 miles will set things into place at which time it is a very good idea to recheck this adjustment. Fork judder was the scary part. With carbon fiber forks, and even steerer tubes through the headstock, you could not allow oscillation and front-to-back forces to occur or your fork would simply break at the crown/bottom race/steerer tube junction. Not so much with our big bikes, but what a difference a proper adjustment can make!

Okay, so to be absolutely obnoxious about this, at http://www.yamahapartshouse.com/oemparts/a/yam/50043abdf8700209bc78d0c4/drive-shaft, item number 32 is removed and greased at both ends? Huge thanks!

Would someone expand on the shaft greasing task? Are we talking about removing the four acorn nuts and pulling that part for greasing?

I still have a set of the mercury-based synch tools - even these move as you have described, though not quite as much. So yes, you are tuning the pair, the other pair, then the two pairs. A long screwdriver is very useful for this task. You will notice immediate results in riding, and will want to revisit this procedure if you readjust the idle screws or if your machine is working out built-up carb residue from sitting.

Great thread here! I would only add that our early bikes now suffer from pinholes in the rubber carb diaphragm, and the inlet boots as well. I will again be stripping the carbs to replace both (x4) items over the winter myself as a preventative task.

Ah-ha! The hunt is on! The shop that did this removed the airbox, then removed the carb covers, ditched the old needles, original springs, and should have removed the brass blocking items that cover your idle screws. They have installed the DynoJet kit's adjustable needles and longer springs and put in a K&N. Your Jardines flow a LOT of air, so it is not surprising you would set that needle at position #3. (Instructions at http://www.dynojet.com/pdf/4148.pdf). From the description, your plugs sound very good. I do a lot of plug reading via plug chops and if you are not seeing "white hot" (all white; small dots showing heat damage from lean condtion) and not all sooty from a rich mixture, you are in the sweet spot. Most important is not to stray too far into a lean condition - a rich mixture may soot up everything, but a lean condition causes seizures in the worst case scenario. Stray/expermiment into a lean condition with your eyes wide open! So I would go/stay with position #3. However, you should closely follow advice on http://www.mrlarsson.com/pdf/files/dynojet-troubleshoot.pdf, especially the section on Acceleration Problems with an eye to how the bike responds at steady cruising (my ref. above to the "twist grip" evaluation). Really sounds like you are in good shape all around. At this point, proper idle adjustment and a spot-on synch should be job 1, after which you can safely run the bike and evaluate its performance. TIP: Get a VERY long screwdriver to perform your synch adjustments - trust me! I bought one of about 8" in length to reach in to the screws.