mcman56

I did do some parts chasing Some TL parts are shared with the XLs. I was able to get intake valves here. https://www.xlintperformance.com/ IMD was selling piston kits on ebay. They were very nicely made. The machinist who bored the cylinder thought they had the original Honda molds. Gaskets came from ebay. A China copy petcock from ebay worked after installing Honda OEM seals. A China copy 22mm carb worked well after increasing the slide cut away. It was well made and accepted OEM Keihin jets but needed the bowl seal replaced. It seems like China o-rings do not like US gas or maybe just California gas. I think All Balls sold a steering bearing kit and fork seals. These guys had the transmission output shaft that the seal runs on. https://www.davidsilverspares.com/ These guys have some general Honda stuff. https://4into1.com/?srsltid=AfmBOoqk_OxNHRz3n01ZkipB_bpjTyDPO1CO1xnau5oSRcIMlS0ChZAQ The main bearings are or were no longer available. They use some kind of custom bearing with a larger OD than anything available. Be sure they need to be replaced before pulling them off. I didn't. All Balls listed a kit but they were just a standard bearing. There are solutions but none are easy or cheap. I replaced the ignition advance mechanism with used parts from ebay. IIRC, they were from an XL125 but looked the same. As mentioned, CMSL has some things too. I could not find an intake manifold so ended up having to machine one.

At 69, I agree that tall bars make things easier on old backs. The TL250 is a heavy beast. I had one and it weighed 250 lbs without gas. It was also a bit short of ground clearance compared to other bikes. It did have a very nice fork. I find that the TY175 is the easiest bike to ride by far. It is maybe 60 or 70 pounds lighter than a TL250, not a whole lot more than a 4rt. It kicks easy, starts easy and turns very tight. Power is slow and very easy to control yet it easily lifts the front wheel to go over things. For a mid 70s 175, It is quite surprising what kind of hills it will go up in 3rd gear. It is not as capable as a modern bike but easier to ride because you are not constantly working the clutch and brakes. Even with modern shocks, its primarly weakness is suspension. When going up a rocky creek bed like they seem to do all of the time in the UK, you feel like a ball in a pin ball machine. But, that may be true of most twin shocks. If you don't do a lot of that, you may really like one. If you are set on a 4 stroke, a Honda Reflex is also much easier to ride than a TL250.

When I bought a con rod kit for a Beta 125, it came with the big end pin. Don't they all? It is basically the inner bearing race. (unless I'm confusing termonology) Beta USA told me people were just buying complete cranks. IIRC, the price was about double but you did not to pay someone for the crank building work. The 125 crank was a little tiny thing with lots of plastic for filling volume. It looked like you needed some specilized fixturing to support it in the press. It was not mine so I took it to a specilized shop. The guy who did the work did not want to tell me or show me how he supported of held it.

Have you tried contacting the Sherco factory direct? A few years ago, I purchsed a 2001 Beta Rev3 and could not find documetation. I emailed the factory. They sent me photocoppies of the owners manual and parts list.

I keep hearing about tarrifs but have yet to see any personal impact. What do people in other countries see? When ordering from the UK, prices are less VAT with no import duties. The last time I ordered something was about a month ago. However, last year I sent a swingarm to the UK for repair. It got stuck in UK customs for several weeks. It ended up costing a total of $100 with import duties and fees to get in the country. This really surprised me. Is that normal? There were no US customs cost when it came back.

I'm in the US. Are those top hat pieces aluminium or steel? I assume the ones from the original bike were made for the smaller head pipe so would not fit but I could make new ones. If it reduced the 26 mm pipe to 18, maybe 22 mmm would be appriate for the 30 mm 300 exhaust? That would equal the same 50% reduction in area which seems quite large. I don't see the pipe avilable but it sounds like a pricy experiment. I did spend some time looking for the software and dongle to tune the engine. It was unclear if what I found would work work for this bike. If you are interested in selling the used unit, PM me. I also found this link but it looks like they just sell maps and just for max power. It does not mention hardware. https://oldskulltuning.com/montesa-cota-4rt-keihin-tuning-maps/

This is a 2018 300RR. I don't see anything like that on the parts diagram. (The power bomb pipe with O2 sensor is for the street version) I would like a softer off idle response.

Where can you find these restrictors? I have found nothing.

Has anyone tried a 260 head pipe on a 300. It looks a good bit smaller and I wonder if it would soften the response. I would like my 300 4RT to run more like a Beta 300.

It seems like you could use lighter springs with more preload to attain the same pressure when clutch is engaged. Initial force to move would be the same but would increase less with lever travel. Does the 260 use the same springs as the 300? I see the springs but not the plate. Are they still available? https://japan.webike.net/products/24020409.html?srsltid=AfmBOoqgYESkjfxhn34zme3dmDSwGPvYs9Hpdu39pFhoKpODKapkK5Nt Could this be the same. https://jbanyeres.com/product/special-clutch-springs-for-montesa-cota-4rt-and-4-ride-measuring-281mm/

Does it have the same transmission ratios as the trials engine?

I did get one and install. It does feel more lively and seems to absorb more for a more cushioned ride.

Maybe here https://ricksmotorsportelectrics.com/l/aftermarket-stators?srsltid=AfmBOooPHVWzz3Ug93MZ2_SBhLpL4CSpiGre4s0rPjAvfj3MdIMHyP4V

Why do they rub? Do the springs have a smaller inside diameter? Is the plate just slightly thicker with the groove to center the springs.

Are HP and torque numbers available for the standard Beta 300 4t, maybe with rpm numbers? I have one of those too. In a tight section, the Montesa feels much more powerful so I need to use very little throttle. I thought it was overall more powerful. However, the other day I took it to some open trails with good size hills. There it feels similar to the Beta. I wonder if there is a real power difference or if the fuel injection just makes it more responsive.

Thanks for the clarification. I was installing some spacers to reduce spring preload. I planned to pop the plates out to see if it had dimpled plates but was surprised that the plates could not just slip out. It is sort of the reverse of every other bike clutch I have ever had apart. I learned something new.

I had the clutch cover off and am struggling to understand how the clutch actuator works. Every bike I remember controls the bike from the opposite side of the engine. A rod goes through and pushes the pressure plate out to create clearance and release the clutch. On this bike, the slave cylinder pushes in the opposite direction. So, is the movable pressure plate on the back side of the clutch pack when compared to other bikes? The parts list looks like that.

How much do these links raise the bike? Does it provide a softer ride? The H&D description is hard to interpret. I'm not a trick rider but would like something more compliant so easier on an old body. The Montesa rear suspension also feels quite dead compared to my Beta 4T. "uprates the soft rear end and aids the ability to 'trick' ride and hop around the rear end by providing an even more progressive shock."

The parts list shows one but I don't remember if mine has one. https://www.tytrials.com/trailandtrialsuk/cat_57217-Clutch.html

In addition to the diaphragm for the slide, the carb has a diaphragm with spring on the side. On a CV carb diagram for a different bike, I see something similar identified as a coasting enricher. I think I have also seen something called an anti backfire valve on other carb diagrams. Could that be the culprit? Is the purpose of such valves to prevent a pop? The bike runs well so I'm reluctant to change jetting. MK-BSR33-79-Detail-Sheet-copy.pdf

This is their rule book. https://www.ahrma.org/ahrma-handbook/ I'm no expert but the few AHRMA events I have seen even have a class that allows modern bikes so you should be able to find a class for anything. IIRC, otter frames are not legal for their pre 65 class. I have seen TY175s with extended swing-arms and lay down shocks competing but I don't think they meet the letter of the rules. Based on absolutely nothing, I wonder if no one is too picky about the rules unless you are going for a championship.

Plug color is a bit uneven but doesn't look too bad. It doesn't smoke. I am running much leaner than stock jetting. When I got it in 2018, it had the factory jetting of 27.5 pilot and 120 main but ran poorly. The advice was to go richer but when I went that way it was worse so I went the other way. It kept running better the leaner it got so I ended up with 17.5 and 115 which is much leaner than all recommendations. The engine is getting up near 300 run hours so I wonder if it has slightly less vacuum and is less tolerant of lean jetting.

I have a 2016 300 4T standard model. It has started to produce a little pop in the exhaust when closing the throttle from small to moderate openings. The pop is not loud but sort of echos in the exhaust. It starts, idles and runs well but has become cold blooded so needs to run for several minutes before it will take any throttle when cold started. I checked valve clearances and cleaned the carb with no affect. This is with California pump gas. Has anyone experienced this? I'm not sure if I should go up on the pilot size or raise the needle. Carb access is not great on this bike.

I was curious so looked at the manual. It looks like the minimum piston clearance for the 250 is 0.050 and the maximum is 0.080. What is the 0.100 "Assembly" number?

It definitely should do much better than that. Could someone have geared it way up?