racin69z

I wound up buying a motor city spark orange box. It's running great. They answered my questions quickly, and I like the simplicity of the wiring. I decided to go that direction.

It was in fact the CDI. Runs great with a new one.

I need a new CDI for my bike. Searching old posts it looks like the consensus used to be only get OEM. Is that still the case, or is the dynatek a good reliable unit? I can get their coil and CDI cheaper than a new OEM. But if it's junk then no point.

I need a new CDI for my bike. Searching old posts it looks like the consensus used to be only get OEM. Is that still the case, or is the dynatek a good reliable unit? I can get their coil and CDI cheaper than a new OEM. But if it's junk then no point.

I finally got around to working on this thing again. Changed to fresh gas, no change. Changed back to the stock carbs no change. Changed the stator and pickup coil, no change. It just will not run under power over 6k rpm. Anyone near southeast Missouri that has a CDI that I can borrow? I tried 2 different Chinese CDIs and neither would even start the bike. I hate to buy an expensive name brand or OEM CDI and that not be the issue.

I am running pump 91-93 depending on what I can get. I'm not sure where that gas came from Missouri or Michigan. That's actually a great idea. I will buy a some fuel and try that.

Chokes are off. Haven't had a chance to fool with it lately but I'm starting to think it's ignition related and just showing up as rich in the plugs. My experience has always been ignition make plugs appear lean, but I just don't understand how it is rich all of a sudden. Up a silver lake I even turned the gas off and as it ran out of fuel, it still wouldn't rev, so I am going to dig into that if the stock carbs do the same thing these are

I don't have any other filters, but I ran it without filters on the blacktop for a small stretch and it didn't change anything

Air filters mint. 32:1 super techoplate ever since it's built. Thanks for the ideas.

I have a mild built banshee. Build consists of dune ported cylinders, FMF fattys, cool head 135 psi v force 4 reeds 30mm oko carbs with fuel inlet enlarged, uni filters. Ran great all spring and summer. Drove 600 miles to silver lake and ran it for and hour running normally and all of a sudden it's popping and acting stupid rich. Altitude was within a few hundred feet, temp was the same as when I jetted back home. I did plug chops until the plug looked what I thought was good in the spring. Now it won't run clean enough to do a chop. Fouls borh plugs rich in seconds. I am very hesitant to jet down, because if whatever phenomenon caused it to go rich goes away, then it will probably burn up. I've replaced the coils and wires thinking they may have gotten weak with no change. I am going to try the stock carbs if I don't get any other suggestions.

They are greyish with color change at the 90 degree bend.

Right plug pics

I have a mild 358 build with stock carbs that I am tuning on. I think I'm fairly close on jetting but wanted some more experienced opinions. I feel like my jets are smaller than most with similar builds. I am at 270 right now, and it still feels a little fat up top by seat of the pants. Started at 290 and it wouldn't rev out good at all. I got it warm, ran it up the road, changed to new plugs, run 1-6 held 6 for a few seconds pulled the clutch and shut it off pulled plugs and drove back on old plugs. Each ring has a light and dark side. Moreso in the left plug. Left plug is the first two pics

I'll be damn thanks a lot

Well that was it. Tapped those holes cleaned out the trash and put bolts in there. Idles like a champ with a 32.5. I couldn't find any 30a or I would have tried those. I have no idea what that was supposed to be hooked up to. Partszilla shows a hose that looks to be 340mm long going somewhere. Going to look in my service manual. The entire last year I fought this idle. I never could get it to idle stable at low rpm. Now it will.

I've got the carbs off and I'm checking them out. All the fuel and air passages are open and flow carb cleaner. I found a hole that goes straight in to the vacuum side of the carb. I'm sure that would be a large air leak and would explain the stupid large jet. I'm a bit new to banshees and this bike was a box of parts when I got it. Going to do a web search on it. Here is a pic of the hole with my finger touching it.

I am having trouble on my pilot jetting. I seem to be running way larger than people with similar builds, and I can't figure out why. It's a stock stroke, 64.5 bore, diy aggressive play/trail/dune port (192-127 timing, slightly wider transfers and exhaust, opened intake windows a bit), v force 4 reeds, fmf fattys power core silencers, cool head with .020 domes, .038 squish(tighter than I hoped but that's where it landed) stock carbs, k&n pod filters. Float level is 21mm from gasket surface to the bottom of float with the carb upside down. Right now I'm at 320 main 45 pilot it idles best with this 45 pilot with the air screw all the way closed which seems to me it's too small which makes no sense. The air jet is a 1.6 which i assume is stock. Going to go up on the main as it's a little lean. Thinking I either need to go down on air jet or up more on pilot which seems crazy. Any thoughts?

I am building a banshee using a new set of Wossner pistons. The pistons both have a bit of a raised spot at the very outer edge of the crown. It doesn't look like a mistake, because both pistons have it. It's about .010" tall. I am wanting to set the squish to around .040-.045". With that raised spot it will tight it that one spot. The spot reflects light differently and can be seen in the picture. I am thinking of putting them in the lathe and removing it. Any thoughts as to the purpose of it and if removing it will be a good idea?

I got to thinking about it. I think when I bolt the clutch hub on it will pull that shaft into the larger bearing. And the same for the sprocket. Making no endplay.

Is there a specification for end play on the transmission shafts? I have around .030" on each shaft. Seems a little excessive. Can't find anything in the Yamaha service manual.

I have been reading up on pistons. Almost every post I read says stock or mild builds, run Pro X or stock pistons. High HP builds run forged Wisecos. What I don't know is what is considered mild and what is considered high hp? I am running stock cylinders at 64.25 mm bore with 189 degrees exhaust and 127 degree transfer duration. Cool head with 20cc domes. IIRC 155-160 cranking compression. .045" squish. FMF fattys, stock carbs/pod filters for right now. Planning to try some 30mm next year. Last year I ran Pro X pistons that were correctly sized to the bore. At the end of the year, I had a spark plug that kept coming loose on the left side. It was a cheap china dome for the pro design cool head. Not sure what was the chicken or the egg, but either way left side piston was damaged. Did the damaged piston cause the spark plug to come loose, or spark plug come loose and suck air and damage piston? Not really sure. The piston had some of the skirt broke off, wrist pin was loose, and it was contacting the head. I would think my build is considered pretty mild. I like the idea of the closer wall clearances/ more forgiving warm up/hopefully longer life of cast pistons, but I only got 1 year out of the last build. I can't really blame the piston type, because it very well could have been the cheap dome that caused the whole deal. For similar builds, what are most folks using? Thanks Lynn

I did the porting myself. I had notes on it, but cannot seem to find them. Pretty basic. Maintained the same angles in the transfer, raised and widened the transfers, widened and raised the exhaust. Only number I can remember is 195 or so on the exhaust which I think is a pretty aggressive dune/mx port. It makes poor low end good mid range but seems to peter out at high rpm. I am going to pull the head and measure the durations and then re-evaluate it. Probably get some larger quality made domes.

Skeeter, is that sarcasm lol?

Thanks for the reply. I built the motor, so no builder to contact lol. I did forget to mention the squish is .045 measured with a piece of solder in a few places.

I have an issue with mainly if not always the left spark plug loosening on my banshee. I have a set of cheap Chinese 19cc cool head domes on it. The spark plug threads seemed a little loose to me right out of the box. I probably should have sent them back, or not ordered cheap crap at all, but I don't seem to learn. Here is some info about the build just to make sure its not detonation or lean. Pro X stock replacement pistons 1st oversize. FMF fattys. MX/dune port, I cannot find my notes on port specs, but I think the exhaust was at 195, cannot remember the transfer. 19cc domes. With throttle open kicking until it stops, I have 170 psi of cranking compression. Timing is advance 4 degrees. Stock carbs with 340 mains(largest in my kit.). I cannot remember the pilot jetting. K&N style pod filters. 32:1 gas to oil ratio. Currently running 93 octane fuel with 1 quart of VP madditive per 10 gallons of fuel, but I have tried vp113 with no change in symptoms with the plug. The piston top seems to have the right coloration, plug ground strap timing mark doesn't show too high of timing. Could the cheap domes with poor thread engagement be causing this? I can convince myself either way when I think of it. They tighten up without stripping, so I would say even though the thread engagement is poor, it probably should stay tight unless stripped. But if the thread engagement is bad, then as it heats up, it gets looser and then shakes out from vibration. I will say these banshees shake like a dog shitting fish hooks. Its hard to keep things tight. The vibration is nuts. Any suggestions are appreciated. Thanks Lyn