carl ekblom

30205 is 25x52x16,25 The Pyramid bearing for Sherpa is 25x45x12

I think they are non standard dimensions. Pyramid Parts also stock the conical bearing

Plastic tanks from InMotion are not very expensive and should be good for 50 years or so. I have one original 199A plastic tank and one 199B original plastic tank and they are good. Not very glossy but do their job. I have not found any quality marking but I´m quite sure they are made of HDPE To the best of my knowledge painting HDPE don´t work. Painting plastics is difficult (not lasting) or impossible. Colour is added during the manufacturing process and will often be dull or 1/2 dull Tupperware (PP) can be more glossy but not from paint.

British tank Edit resized

Alpina tank: https://www.ebay.de/itm/Bultaco-Sherpa-Model-Gas-Petrol-Fuel-Tank-With-Cap-Aluminium-Made-GEc/153824255290 Sherpa tank https://www.ebay.de/itm/BULTACO-SHERPA-ALU-BENZINTANK-NEU-BENZINTANK-ALU-BULTACO-SHERPA-ALU/182822949409

https://www.ebay.co.uk/itm/BULTACO-SHERPA-ALU-BENZINTANK-NEU-BENZINTANK-ALU-BULTACO-SHERPA-ALU/182822949409 Claimed to be Spanish also J&C Fabrications in the UK https://www.facebook.com/JC-Fabrications-934592909952839/ Sorry, no experience.

My 74 had black frame, 17/20 inch whees and Pirelli tyres(crap!) Suspension was not good. Bigger Montesas were better. As far as I can remember 73´s had grey frame but the same wheel sizes? I think some people replaced the rims for 18/21?and Dunlop tyres

My old manual says 2,5-2,7 for 199A/198A, but it is written in Spanish?. I think 2,5-3,2mm is good. You may have to adjust later due to personal preferences.

From behind looking forwards What I believe is original 199A rear wheel 67mm is outside WM2 rim

Yes, they are nice bikes. Good project?. Little curious about the throttle. To me it looks like the one for Beta 4T and it should be a very quick throttle for a normal round throttle valve trials carb. I think they from the beginning were made for 38mm(?) motocross carbs

You have a good source for silent blocks? Buying 100´s of them to get 2 is not very attractive.

I think the white framed 199B/198B looks nice?. As my 199B will have a number of modifications (longer rear shocks and modified mounting points, swing arm axle moved forwards and downwards, better brakes etc) inspired by this Yrjö-bike I think it should have red frame and red tank. I think the red Yrjö-bike on picture is a modified 198B.

I don´t know about the configuration at SWM but it might has something to do with brake servo effect from wheel rotation? Servo effect in one direction, opposite the other way round (drum brakes only)

Actually, I don´t think the plastic bushings are made of PA(nylon). I guess they are made of POM which often by mistake is called Nylon. POM is a totally different material and should be superior in that application. Other "good" plastics are available, for instance (if protected from sunlight) PE MOS2 (Robalon) and PET PTFE (if not subjected to lot of water). PEEK is also good but it has a very high price tag. High-density PE (HDPE) is used for petrol tanks and withstand almost everything but is not as far as I know used for bearings. In addition to what Woody says and he is correct For proper fitting I think the frame should be about 0.5mm wider then outside the swing arm bushings. It will then be tight when you tighten at swing arm axle. After tightening the axle and rear engine mounting in place there should be some side play in the swing arm bearings. With the axle tightened and everything is OK the swing arm should move freely up and down by hand without any tight spots. My never ending 199B project. Someone long time ago painted the frame blue? Will be red a la Yrjö Vesterinen

I use it on my Bultaco (1.85 rim) since 2 years. Make it possible to use tubeless tyres on tubed rims. Running Dunlop D803GP. No rim locks. No wandering inner tube. Must follow the instructions when installing . Good product I think?.

The air seal is between the small Tubeliss tube and the tyre so I think they accept a lot from the rim. I think much can be done to an old Akront rim to restore it to an acceptable condidtion but new spokes may be needed Beside that, Morad is clamed to be Akront copies but I have no experience.

Yes, 1.85x18 Akront. Can be little difficult to mount the tyre (or remove) but works well. Before had problem with the tube wandering inside the tyre. Now works perfect with Dunlop 120/100x18 tubeless tyre

Measurements just taken Dunlop 803 120/100, used, 0.25 bar on WM2 rim, 108mm at the widest point Dunlop 803 120/100, new, not mounted, 109mm Michelin Comp 400-18, used, not mounted, 110mm (tube type) Mitas Trial 400-18, new, not mounted, 113mm (tube type) IRC TR11 400-18, New, 0,3bar on WM3 rim, 108mm (tube type) Michelin X-lite 120/100, 0,3bar on WM3 rim, 110mm Not much difference. I think Mitas is not ment for serious trials riding. Michelin, IRC and Dunlop are doing well. I think Motovita is correct. Try to modify your bike to accept real trial tyres. Tubeless fits any rim if you use Tubeliss Current tube at my 199A is the first one. No problem at all with Tubeliss

A good idea would be to try 11/40 first and see how it goes. I currently run 11/42

I use all metal lock nuts. After two years no problem at all. I think nylock may deteriorate in transmission oil and heat

I assume shock has an internal bladder and should function either way. Normal practice is to keep unsprung weight low so I would reverse the shock.

Remember to carry with you when riding: X-tra magnet for lanyard switch

I use football socks to prevent sweat dropping from legs into boots. Make feets little dryer.

Found the BSA C15 is at ebay https://www.ebay.co.uk/itm/BSA-C15-ROYAL-ENFIELD-FRAME-TRIALS-BIKE-PRE-65-TRAILS-3995-OFFERS-PX-BANTAM/293627622614?hash=item445d91f4d6:g:5qoAAOSwmqNdc9tv A B25 would fit as nice as a C15 and be much cheaper to build as you are not limited to pre65. For proper trials I guess a crusader frame should be narrowed around the seat area. To do this I think a fixture to hold the swing arm should be made before any cutting and welding/brazing. Had a peek at your blog and agree. It´s easy to find spares at reasonable cost for Royal Enfields and some Indian parts will fit Reddish bikes. For instance, an Indian 350 alloy barrel will fit a 1949 350?

Found this but C15+ Enfield Crusader(?) From Facebook Classic Trial Denmark. Nice bike? Be aware that B25 may not be pre65 approved everywhere. Only important if you want to compete. I have heard of B25 been changed to C15 lookalike but I guess a scrutinizer would found out