carl ekblom

MC-nytt (MC-news) trials project bike 1964. Ceriani front fork. They were not uncommon on off road bikes in those days. Modified Husqvarna engine ..

Works fine when using a proxy in the US but not from anywhere else.

I support b40rt Concentric Mk1 when old gets worn in throttle and throttle body causing lean mixture and erratic idle. Only replacing the throttle doesn´t help much. Both the throttle and throttle body have to be changed.

All modern bikes use aluminium alloy AA7075-T6. Don´t use AW6082-T6. It may be too soft. /Carl

I think hot starting sometimes (usually after a stall) is difficult but this helps for me: If the bike has been on its side the float chamber might be empty so move the petrol tap to "manual on" for a few seconds. If the bike don´t start within 3-4 kicks, open the hot start valve, open the throttle to about 1/5 and give the bike a strong and steady kick. Now it should start within 3-4 attempts. /Carl

Yes, It´s boring, boring, boring and more boring. Have a look at this clip Trials World Cup USA 1989 :Is progress going backwards?

He doesn´t ride smooth. I don´t understand all those unnessesary jumps. I would have given him 5 at 0:11, 0:20 and perhaps at 0:25

I thik the rev3 125 have the VHST. The ports should be linked together but there must be a breather hole in the tube under the carb. It use an idle mixture screw, not an air screw. More turns out is richer mixture at idle. Normally it would be around 1 1/2 turns out. /carl

Hello Someone know the original jetting for Sherco 4T with VHST carb? I can´t find anything in the manuals. /Carl

I think THK SB12 should fit but I don´t know if they are cheaper. /Carl

I had a similar problem (endless splitting and banging) with my 2009 4T. In the end it turned out to be dirt in carb. I checked everything but it was not until I cleaned the whole carb seveal times the problem disappered. I don´t think that just blowing the jets will be sufficient. All drillings in carb must be cleaned with clean compressed air. Nowadays I put an extra filter just before the airgun when cleaning a carb. So there are two filters in the air line, one just after the compressor and one before the gun.

I don´t think iceing in carb should be a problem when riding in below -5C as the air is dry when cold. Snow is low density so it is probably more harmful (if any) when riding in water. Use 95 octan fuel as it is 5-10% ethanol and it will mix with any content of water in fuel. /Carl

Andy, I think this nice hub is a pre 65 design http://www.ebay.de/i...=item3f21657ae4 This Husqvarna hub came in the late sixties http://www.ebay.com/...58e256a&vxp=mtr Around 1980 it changed to this http://www.ebay.com/...1671539&vxp=mtr Who would tell wich one is of pre 65 design? A good Husqvarna wheel will last forever and its easy to get spares. I even talked to a guy who had NOS (expensive!) brake plates for sale. A lot of old Moto-X parts on e-bay will fit perfectly well on a classic trials bike. This cheap hub shuld be 100% legal anywhere http://www.ebay.co.u...=item20ba35e0ff

The SSDT pre 65 rules say nothing about leading axle http://www.ssdt.org/... Entry Pack.pdf As far as i know the design is externally identical or almost identical to this 1955 design http://www.hitchcock...ssembly_-_contd. and I have seen it on photos of trials bikes in the late fifties.

I guess that Royal Enfield fork legs would be legal. Its a fifties design. They are 35mm and they are cheap. I will use them on my pre 65 bike. http://www.ebay.co.u...=item27cf241276 or http://www.hitchcocksmotorcycles.com

I think it is a design failure. Check the geomety. The pivot for the rear brake level is located well above the footrest. When you push the lever down, the distance between the peg on the brake lever and ther footrest will decrease and there is no way that the peg on the lever would slide closer to the footpeg under the rubber sole. This will lock the brake lever up and prevent proper braking. The only way to deal with this is to lift your foot from the footpeg and brake with your toes. Most bikes have a proper design with the pivot close to the footrest but Beta doesn´t.

Early winter -15C ouside and snow. This is what I have found to keep myself varm: Avoid cotton. it´s cold. Syntethic material like coolmax is a lot better. Wool is very good. For socks I use a combination of 50%wool and 50% synthetic.

Somtimes this helps: Remove the caliper. Take the pads out. Spray around the pistons with WD40 or similar, Carefully avoid to get drops on on the brake disk. Dry and assemble. /Carl

As far as I know not much trials around Lund I am afraid. Plenty of clubs in Gothenburg area. Links to some clubs http://trialsport.se/triallankar/ http://mcmobil.se/page1.php

Pinking might be caused by carbon deposits in the combustion chamber. I found out that the VHST is sensitive to dirt in the idle jet system. Symptoms will be hard starting, poor running att low throttle openings and..... pinking. I would clean the whole carb, not only the jets but also all drilings and passages in the carb body before trying anything else. Carl

Hello 25 should be smaller. In my world the 4T needs richer mixture. Needle clip in 1st or 2nd clip from bottom. Mixture screw 3-4 turns out with std 27.5 idle jet. The mixture screw is a mixture screw not an air screw so more turns means richer mixture at small throttle openings. Good Luck.

Water pump?

Yes, the large tube is the crankcase breather and the small one goes from the hot start valve to the air box. This tube isn´t reallly needed. If you like you can block the hole in the airbox and take the air directly from outside into the hot start valve. The small mystery tubes from the carb are all air vents from the carb. The T-tubes are used to reduce the number of tubes going down behind the enginee where they end. The large air vent from the vaccum chamber at top of carb should be blocked. Hope this helps.

Bosi is selling Tech forks for Beta. I guess they are good http://www.bosioffro...emart&Itemid=58

Needle in 4th or 5th groove and fuel mixture screw 3-4 turns out may help and check for air leaks in intake system.