So, my White Wonder is experiencing an odd clutch issue following an engine rebuild (done by someone very experienced, it had new seals and mains, the clutch and gearbox looked fine so just went back in as-is).
When cold everything works as expected, but when it's thoroughly warmed up there's a clunk or two as you pull away. It happens in any gear, and you can hear it as well as feel it through the frame - it's like something isn't quite engaging until the wheels are in motion, or as if the chain had excessive slack. Once moving it feels fine both on and off the throttle.
Does anyone have any ideas? I hope we don't have to split the engine again
Turbofurball, when you had your engine rebuilt, was it done by a friend or by a professional you didn't know?
The reason I ask is I have a 348 that could do with an engine rebuild and I don't know anyone in the south who will work on a Montesa.
Thank you, I found the number in the end and it is a b40 frame. It is under some thick paint and only just visible. I probably wouldn't have found it if I didn't know where to look.
Thanks, thats really helpful.I will definitely have a read through this page when I get a chance.
There is something else different about my bike. It has an alloy barrel and it was said that it could be a works barrel/engine. I can find aftermarket alloy barrels, but they all have 10 fins. My bike has a 9 fin alloy barrel. Strange...
I guess it doesn't really matter what it is, as I couldn't be happier with the bike.
That's nice. Try the BSA Otter site, Charlie the site owner is very helpful and has a wealth of knowledge and archives he refers to
It's funny you should mention that. I have spent a lot of time on that site this week, it's a great read.
16 hours ago, b40rt said:
My B40 has the frame no on the left (as your sitting on it) front engine mount.
I did check here and can't locate it. i wonder if the paint on the frame is so think it has covered it up.
12 hours ago, trialsrfun said:
I think you may have a modified WD BSA B40 frame.
The two tubes from the rear of the tank to swing arm pivot have been reshaped attaching much lower so as not to rub the ridrrs legs also I think the head angle has been altered, look at the down tube above the engine mount.
You have a good looking bike which ought to work rather well.
Thanks, I did look into the b40 frame, but they have a removable rear subframe and my bike doesn't.
I haven't had the chance to ride it in anger yet as it still needs running in. I'm looking forward to getting out on it.
I was wondering if anyone could help me identify a bsa frame.
The engine is a b40 and I was told the frame is a b25.
There are a couple of things that seem strange. The log book has it down as a March 65 bike, but I am pretty sure the earliest b25’s were 68. I have the frame number in the log book, but I can’t find it on the frame, does anyone know where it should be.
Also it seems like the frame has been modified. There should be 2 center posts, from the foot pegs up to the front of the seat. It seems like these have been modified to one center post. After having a look on google I can see a couple of b40 trials bikes that look the same.
Does this look like a modified b25 frame, or maybe a c15 frame?
It's funny you should mention the brake rod, as it's one of the things I want to change. The previous owner had routed it like that, because if it takes the original path (inside the shock) then it get's pinched by the spring. This is mainly due to the way the falcon shocks have been put in. If they were upside down then it wouldn't be an issue.
This is the best tutorial I could find, it shows the whole process sped up, with captions telling you what grade of wet and dry to use. It's well worth a watch, especially as the results are so good.
I haven't done this myself yet, one day I'll get around to it.
That's a nice looking bike Sam. I see you've got rid of that rather pointless toolbox. I'm tempted, just to make cleaning a little bit easier. I'm never likely to put anything in it. Do you have a protector for the swing arm pivot? The chain is being a little bit unkind to the paint on mine.
Thank you, however the bike pictured isn't actually mine. It was just a photo I found on google. Mine (pictured) isn't quite as clean as that. I've never got round to doing the clutch arm mod, mainly because I fitted a set of domino levers and the clutch now feels light enough.
Mine has the toolbox, although I've never used it. I've kept it for originality and the fact that complete air filter/toolboxes are hard to find. I don't have anything protecting my swing arm either, just the tensioner underneath the arm.
They are great bikes though, I should really get mine out more.
What is the "chain link clutch lightener" mod? There's no bit of chain anywhere in the system so I assume I haven't got it. Actually I find the clutch effort to be pretty good. One finger is a bit hard-going but two fingers is fine, and I don't think that reduces my control on the handlebars significantly.
You essentially extend the clutch arm by using a 428 chain link, giving it more leverage and making it slightly easier to pull.
You should be able to make it out in this picture.
Hendrik, that is a great looking bike. I too use a Mikuni on my cub and it's amazing, it starts first kick and so far has never let me down. It also helps that the club I ride in doesn't mind. I know some clubs will not allow pre 65 bikes to run Japanese carbs.
Anyway,with the shocks I faced the same dilemma as you. I ended up going for NJB Experts for a few reasons. I heard great things, the price was good and they didn't look too modern. They have been great so far, no complaints. I also use steel falcon shocks on my Fantic and they too are great, and rebuildable. I hear great things about Rockshocks, but for me they just looked too modern.
I can't help you with the forks as my bike came with Metal profile. I'd love to get my hands on some heavyweight triumph forks one day though.
That is one gorgeous looking cub, I wish mine looked that nice.
My wiring is a bit of a mess, so when I get time I will be doing the same as you and fitting the STK200. Let us know how you get on and if you have any issues.
Send me your email address and I will send you a pdf version of the hand book. It's not a workshop manual but it has exploded diagrams of everything and about 8 pages at the back with specs and service info.
I also had a miller sump guard fitted when i bought the bike. I can only echo what everyone else is saying, it works well protecting the bike, but you can't use it on a bike stand.
So I ended up getting one from Chris at Meriden Off Road. So far it's been great, it slots right on, it's stable on a bike stand and seems to do a good job protecting the cases. What more can you ask for for under 40 quid.
yes, thanks for that, i have looked at their site its very good. I have not stripped things yet but the forks are solid! won't move a mm let alone an inch.
The bike seems to unmolested with the exception of the handle bars, what's the pet/oil mix ratio? its broken the gear select spring but i have a new one.
the first job is just to get it running then it is my intention to give it a sympathetic restoration.
Inside your forks there will be aluminium pistons. These fit inside the stanchions and the tolerance is small. They tend to develop small hairline cracks on the surface, then they swell and jam inside the stanchions. I managed to source some NOS parts from Spain, but even though they were in a sealed bag, they too were cracked. Long story short I managed to reduce the diameter of these aluminium pistons slightly and they now work perfectly
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Cota 349 weird clutch (gearbox?) issue
in Montesa
Posted
Turbofurball, when you had your engine rebuilt, was it done by a friend or by a professional you didn't know?
The reason I ask is I have a 348 that could do with an engine rebuild and I don't know anyone in the south who will work on a Montesa.
Thanks,
Sam