dan williams

Gotta be a throttle cable pulled out as noted above. The only other possibility is a split open intake manifold or debris in the carb to hold the slide open. If it was a relatively short term event the bike may be fine. The damage to the owner is severe. If the bike runs OK there is most likely no damage to the top end as the chrome bores are pretty resistant until the piston actually starts fusion welding itself to the bore. If you still have normal compression your rings are not stuck (first clue of a seizure) and you probably dodged the bullet. Best to get into the habit of twisting the throttle before you start the bike and making sure there is a good solid thwock sound from the carb when you let go. Not only is it reassuring but it seats the cable.

As many as possible. I’ll work the first one and may work one of the Vermont days because they are always looking for checkers. The July event will be pulled from the schedule as the club has cancelled.

Not sure I’d call that clean. Also that’s one of the 3mm thick plates. I take those out and replace with the 2.7mm thick plates on the 2T. What’s that groove in the pads? I’m out of the 3mm spacers I had made so I can’t send any to you.

Well yes and no. The CDI has a microcontroller in it that looks for a trigger signal. If it see a pulse in the wrong place or just one when its expecting two it's entirely possible for the CDI to get confused and fire at the wrong time. Unless your stator plate is rotated far from where it should be I think you have a bad trigger coil and the CDI is just doing the best with what its got for a trigger pulse. You're correct that there is no real help from Beta for determining how good the stator/CDI is working other than the thing runs.

Either a floating ground, scrambled wiring or stator as it's the trigger coil that goes when the stator gives up the ghost.

It's winter here (single digits F) and I don't have a heated garage so the short answer is no. Plus I screwed up the jig I had for drilling the extra holes when the chuck on my cheapo drill slipped. The drill bit bound in the hole and bent the drill bit ever so slightly which I didn't notice until after I drilled all the holes, reaming out the locating jig I made and pooching the spare indexing cam I bought. Made me step back and reassess the plan. Then real work intruded and I haven't got back to it yet. I do have a second jig but I've been considering taking a different tack. I've got most of a cam drawn up in eMachineshop and the cost to have custom cams made isn't too bad so I might just forgo the drilling and design my own cam with a custom profile. I'm leaning towards a steeper cam angle with a flat top. Like the older Japanese bikes where there is more resistance to the initial rotation but no resistance once up on top of the flat between gears. This would take a bit more effort to shift between gears but make it more positive once a gear is engaged. I think this is what gives them their "snicky" feel. I'd also go much shallower on the neutral notch. Unfortunately with the cam sitting in a case well and having to fit under the clutch basket there's not a lot of room to play with dimensions. This is just the initial drawing so no modified profile or neutral notch. Or indexing holes.

Here's what I have from the annual New England Trials Association meeting yesterday. I'll correct as I get more info. April 14th RITC Trials School Exeter RI. May 5th King Philip Trail Riders, Trials Wrentham MA. Wayne Galvin May 19th Meriden Motorcycle Club, Meriden CT. June 9th Springfield Motorcycle Club, Brimfield MA. Leo O’Shea June 23rd Stateline Riders, Hoosick NY. Max Parkes August 11th RITC, Exeter RI. Sept 7th & 8th Green Mountain Plonkers, Richmond VT. Denver Wilson, Tom Butland Sept 22nd RITC, Exeter RI. Joe Antonelli Sept 29th Meriden Motorcycle Club, Meriden CT. Oct 12th & 13th CATRA, Northville NY

Eeeek! No, that won’t work. I’m sorry I didn’t realize you had one of the Jitsie accessory screws. I thought you had the original screw that came with the carb. I tried one of those on my 2013 EVO and ran into the same problem. http://www.carbparts.com/keihin/pwk28parts.htm parts 17 and 18

There is a certain sense of satisfaction hearing the placebo switch click and feeling like you've done something. Actually I think it only affects the mapping at high RPM and since I spend so little time there it makes no difference to me.

Ryan Young used to have an excellent video on changing fork seals on a Sherco with the Paioli forks. It's worth a watch if you can find it.

Just wanted to add something that happened with a Keihin on a GasGas. Bouncing the front gagged and sputtered the engine and was very like the issues mentioned above. Turned out the choke was partially on. So while trying to diagnose the bounce sputter issue I had never considered a leaky choke circuit. So if your bike gags on downhills or while bouncing the front end have a look at your choke valve.

What happens when you turn the idle up is you are not running on the pilot circuit anymore so the mixture screw does practically nothing. I have used the extended cable air screw as well as the regular flat blade type air screw. I'm pretty much convinced it's better to just use the regular screw without the cable and make a couple of long thin flat blade screwdrivers for adjusting the mixture screw. The cable screws are just kind of a pain. If the carb is clean and jetted properly I'll adjust the screw at the start of the day for temperature and the bike will run fine all day. If the pilot circuit (not just the jet) is blocked I'm chasing the mixture all day and it never feels right until I clean the carb.

I remember seeing them years ago on the web but not for a while. When I do the disassemble and clean on my carbs I'm real careful. They may be impossible to source now.

The Keihin on your bike is notorious for plugging the pilot circuit because the passages are really small. As lineaway said, pull the carb, disassemble and blow it out with compressed air being careful to not force too much pressure through the body. There’s a couple of sealing rings in the Keihin that are damn near impossible to source if you damage them. I find I have to do this routine about twice a year.

If you don’t ding the stanchions you should get years out of a set of seals. You need to do a careful visual of the tubes. If you have a nick in the tube no seal will last very long.

I’ve used PVC pipe cut to length with great success (no bunged seals). You have to be careful of the protruding lip on the wipers. I usually take a dremel to the inside edge to chamfer the inner edge of the PVC pipe to clear the wiper lip.

Don’t mix coolant. Use one of the premixed coolants based on propylene glycol like Engine Ice or Silcolene Pro-Cool. Non-toxic and easier on your cases than tap water.

The market for used 200s is really good.

Certainly looks like a tooth to me and I agree that looks like a gear dog to me too.

Does look like the CDI moved so you can get to the choke and gas tap. Unlike the 2018.

You guys are just awful.

Carbon fiber reeds will make a world of difference. I like the Moto Tassani reeds. They stopped selling ones specifically for Beta but you can use the housing for a ktm65 and get the medium reeds and the bike will lose no top yet grunt like a freight locomotive. When I get home I’ll look up part numbers.

If the octane is sufficient there’s really no difference other than residues. I used to run 93 pump gas all the time and the bike ran fine except once in a while I’d get a bad batch and the bike would run awful. After one particularly nasty crash from bad fuel I just said the hell with it and switched to VP C-12. The main advantage is consistancy. The engine always runs the same. No aging issues with fuel and no funky residues in the carb. Worth the money to me.

Mine hasn’t swelled but I’m running VP with no ethanol. Then again I wouldn’t pass up free bling if they throw it my way.

When you say revved out under load are you talking about a short burst or high speed road/fireroad/trail riding? The Keihin fitted to Betas is unable to supply sufficient fuel to keep the 300s float bowl supplied at full blat. Since most trials bikes aren’t ridden that way, prolonged full throttle, it usually doesn’t show up but put in a full throttle blast down the road and a 300 will start burbling and coughing from fuel starvation. Shocked the hell out of me the first time it happened. Thought I blew it up! All my large Betas with Keihins have done this. If it’s just short bursts then a disassemble and clean of the carb is a good idea. There is another possibility and that is you’re just not used to the power delivery of a trials bike which has instant power off the bottom, a healthy mid range and an early sign off.