mcman56

On Beta's, 200, 250 and 270 all share the same bottom end.

With the forks removed from the bike, does each individual fork tube compress and extend as expected?

Assuming they worked properly before mounting on the bike, something could be out of alignment. General recommendation is to loosen all bolts except lower fork clamps. This includes fender mount and axle clamp. Flex forks up and down. It should be free. Tighten top clamps, repeat flex, then axle clamp, flex, then fender.

Were the forks extended when you put the top caps on?

When I had flooded the crank case, there was one indication. While kicking, it kicked back a bit. I don't remember if this was when it was finally trying to start or not. It was likely trying to compress some fuel. In my case, I probably pumped the excess fuel into the exhaust. Per the posting above, be very careful with any spark. I once had an 80cc 2 stroke engine filled with gas and you could not even kick it over. I was in a hurry and did not think about spark. It spit out a surprisingly large about of gas and caught on fire around the third kick. It was a good size fire but I had an extinguisher in my truck. My daughter was about 8 at the time and this was to be her fist ride on a bike with a clutch. I wish I had a picture of her face when I pointed to the bike covered in black soot and extinguisher powder saying ..you can ride it now.

Is the plug wet? I have a fairly new to me 2001 270 easy starter. I went to Prairie city last weekend and it was a no starter. There was spark but a wet plug and not even a burp from the engine. After a plug change and lots of WFO kicking if finally lit and puked a fair amount of gas on the back wheel. I had forgot and left the petcock open. I wonder if the Mikuni is more sensitive to leaking than others. Is the plug dry? The idle/ pilot circuit in the carb is likely plugged up and requires cleaning. A crude method to try is, with petcock on, lay the bike on its side for 30 seconds or so to flood the carb. Stand it up and kick with throttle off and choke on. I don't know if it makes a difference but I also noticed that a projected tip spark plug is factory recommend the early Rev3 .

I had a some success quieting down an 2001 270. It is not a night and day difference but there is a noticeable decrease in sound. The bike had a megaphone shaped spark arrestor and I swapped it out for a John Deer style. The link shows the type but I'm not sure it is the exact size. There are 2 or 3 sizes. https://www.ebay.com/itm/Lot-of-2-NGP-49024-AM108146-Exhaust-Muffler-Spark-Arrester-Screen-Type-1-3-8-OD/162488243183?hash=item25d50dd3ef:g:2NIAAOSwWWxY~Wzt Second, I put on a rubber 90 degree elbow on the end of the exhaust so it points at the ground.

Those things shear very easily. I wonder what percentage of people shear one the first time servicing Evo dog bones. I bet they sell la lot of them.

I did some investigation and comparison with another TY175. Most, it not all of the stiction was due to the fork boots. They look like OEM but were some no name boot from ebay. Once I cut the boots off, it feels pretty good.

Can you buy that bleeder or do you make it?

I think the "out the side" method is good for 2 strokes but not the 4 stroke.

I install the air box and make sure everything is well connected before trying to tighten clamps. The box creates a little forward force to help keep the boot in place.

Has anyone come up with a way to quiet them down a bit? I have a new to me 2001 Beta 270 Rev 3 that looks brand new with almost no hours on it. I pulled the muffler apart and the packing looks brand new. Still, it is pretty loud. It probably does not help that it has a spark arrester shaped a little like a megaphone. I would really like to quiet it down a bit. The only thing I have heard of is to reduce the flow diameter with a reducer where the mid muffler meets the rear muffler but I have not tried it yet. It does look like one the universal FMF mufflers may fit in place of the original but I don't know if it would be any quieter.

"some upwards force" Could be an understatement if the bash plate is deformed much. If you have a hydraulic press, you can straighten some before installation.

That sounds correct. The few trials bikes I looked at did not retard at high rpm and I took them to full scream. It could be that the porting is so different they become inefficient at high rpms anyway or maybe they just never reach the kind of rpms where it is useful. I even hooked one up on an oscilloscope looking at all of the outputs of the stator. It was hard to view on a running bike but was clear when running the whole ignition on a milling machine.

I have a 2001 Rev3 that is a little sharp off idle so I would like to try a weight. I have one for a 2008 but it is a different size. I can make one. Does anyone have any details like diameter, thickness weight or even a picture. I find nothing on line.

Are you saying that when running well, idle is 20 degrees BTDC and reved up is near TDC? That seems backwards. The last picture suggests it is stuck in retard mode and does not advance with rpm. The CDI should handle advance but you have tried a few so that is odd. Are the CDIs from the same year? The ignition mapping switches are supposed to affect advance but supposedly at higher rpms. Does yours have a map switch? They supposedly work by seeing if the switch is to ground or not when started. Have you checked all grounds and connections? That is a frustrating problem.

Does the stator have multiple trigger sensors? I understand some have a low speed trigger and a high speed trigger. When it runs poorly, is it everywhere or just idle or just higher speeds?

Not the same bike but a 2008 Rev 3 was 8 degrees BTDC at idle and 12 BTDC at high rpm From my understanding, a system designed without any kind of advance will give you around 5 degrees just due to increased voltage making things happen quicker. By contrast, a 1997 Techno had 21 degrees of advance. I can't find the numbers but it went from something like 5 degrees at idle to 26 at full scream. I suspect that porting is different to take advantage of the additional advance. One failure mode is that an ignition with advance can get stuck in full retard or full advance. You may have that failure mode. If you can catch it running good and bad with a timing light, it should tell you something.

Maybe my memory was incorrect. I may have swapped out two thick for two thin. It did help some.

If you want to soften off idle power, wouldn't lifting the cylinder be a good thing. I think that is where most people struggle with trials bike power hence the use of flywheel weights. I once heard a vintage trial rider describe modern bikes as abrupt. My 2008 had open bearings with no seals. At some point, Beta went to sealed bearings that look just like wheel bearings. I recently rebuilt an evo and it had sealed beings and that is what I put back in. Splat shop sells them. I have never seen main bearings with metal seals but have not had that many bikes apart so am no expert. However, i would think you want them open to get lubed by premix or well sealed with a lifetime worth of lubricant. https://www.splatshop.co.uk/sherco-crankshaft-bearings.html

I had to change my clutch style when going to the 4t in tight full lock type turns. Instead of a coordinated opening of the throttle with operating the clutch, I had to hold steady throttle up above idle and just use the clutch. This took out one variable and was much easier to modulate.

1.0 is probably more standard. 1.5 would drop compression a little.. maybe making it easier to kick, more detonation resistant and possibly a little softer in power. People add extra base gaskets exactly for those reasons but I have never done it so don't know how much of a difference it makes. I have a friend that recently went from a standard compression head on a 250 evo to a lower compression head and can not tell a difference so maybe you have to be sensitive to small changes to tell. Rotating counter clockwise should make it trigger earlier and advance the timing. I don't have a spec for a 2008 270 but most everything I see shows it about in the middle so it would be the safe place to set it. Certainly not the same bike but I recently had a 2008 200 and changed from mid position to full advance. Pick up off of idle was slightly quicker but barely noticeable. It did not detonate but another bike might.

I have a few responses. 1 - Probably not essential but desirable. 2 - The evo and rev motors are almost exactly the same so the manual is good. 3 - Generally set in the middle. Full advance can sharpen the response a little. Full retard can dull the response. 4 - 0.5 mm is on the tight side. 1.0 is the usual recommendation. It is best to replace the head gasket but I have reused them with some copper spray-on head gasket sealant. 5 - You can use a round piece of aluminium a little smaller than the outside diameter of the inner race of the bearing. Sit this on the inner race, heat the aluminium and let it transfer heat to the inner race. I used a black anodized piece of aluminium and it was heated enough that it turned kind of a gold color. 6 - It depends on the type of response you want.

Mine is a 2016 standard 4t. The tube is the same as the replacement KTM part. I just needed a replacement tube for the standard 2016 and did not want to buy the whole assembly. This likely does not apply to 2019 style.