Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Robs engine rebuild help thread

Right. Clutch time.

I fit my clutch this evening but it looks like my rod has worn short so I had to order a new one.

I also think that my clutch inner cable is too short .

Should the clutch mechanism (later type) be completely relaxed with the cable attached?

I think the cable length has been made shorter to compensate for the worn rod.

And how tight should the springs be? I think I read somewhere that one coil should be visible.
Does that sound right? It's lifting crooked on one spring should that one be backed off a little, or the others tightened?

Proberbly basic stuff for you guys.

The three ball ramp should be fully relaxed with the cable slack ( the 3 mounting screw heads should be visible through the three holes in the moving part), it will "click " loudly if it isnt. Screw the cable adjusters in at each end of the cable,theres about an inch on each one. Use the clutch pressure plate centre adjuster to set the push rod clearance about a 1/4 to 1/2 turn from touching. this beds in fast and closes as the plates settle in , recheck after a few hundred miles. or sooner.

Try setting the clutch springs with the centre stud just flush with the screw slot bottom, fix a pointer up using whatever comes to hand use the casing flange tapped holes to mount a screw with a bit of stiff wire. Spin the clutch withdrawn and tune out wobble by tightening the high spring, or slackening the low side.

A couple of finer points on tweaking the springs, the adjuster screws have a dimple /pip which engages with the end of the spring, when fine tuning bear this in mind, you can feel the pip ride over the spring end as you tighten, 1/2 turn adjustments that dont meet pip to spring end will change in use as it settles in, its better to err on the light side, your left hand and the clutch cable will last longer, you can always tighten up later if you get slip, this will show up in 3rd when tackling hills.
Aim for somewhere like 6 - 10 lbs pull at the hand lever with a spring balance to check .



This works for me with 750 springs. I dont know about the 7 plate set up , but it would be a good starting point, if it slips in use you can tighten them up later.

Shortening the cable to suit a worn rod is a bad idea,

have you got the ball bearing that goes between the end of the pushrod and the 3 ball ramp cup, if it was missing it might account for the pushrod discrepancy?

While you are in there slather the three ball mech with bearing grease , the black stuff with moly in it, then you will know where the black drool is coming from later, wink, it helps keep the clutch light.

Thanks Gavin.

The little ball is there and so is the clicking noise, even with the adjusters fully backed off.

My manual only shows the early type clutch but that has a springy thing between mechanism and cable. Should the late type also have that?

My rod is about half a cm too short and looks cut. Almost looks like some numpty has cut it to compensate for too short inner .

With some of the clutch conversion kits like the SRM pressure plate you had to shorten the rod about that much

I have the SRM pressure plate kit and its still too short.

My cylinder kit is sorted now and will be sent today along with a new clutch rod.

The early type clutch has the springy thing, not yours the cable inner goes straight to the op arm., you need a new cable from the sound of it, either for a 70 or 71, or make your own. its not unusual to cut the push rod in half and add an extra ball bearing, you may get away with that. When cutting push rods, clean up cut on grinder , then heat to cherry red and quench in oil to harden the end.

I make my own cables. I`m trying to find somewhere local that has cable elbows, so I can add one for better pipe clearence at the same time.

Yup, cherry red and quench in oil. will do, cheers.

something to think about , to get the correct push rod length, remember that as the clutch pack wears down, the centre adjuster screw will be backed out, cut pushrod to length so that the centre adjuster is screwed almost flush with the lock nut for the new plate stack. As it wears in this leaves max adjustment.

The female threads into the outer ally case for the cable adjuster boss are 1/2" UNC, ( 13 tpi),, maybe get a small dia tube bend and weld to a drilled 1/2" UNC threaded rod about an inch long with lock nut to fit the casing , the adjuster could go mid cable. When I need stuff like this I go to the dump with a hack saw and an adjustable spanner, rake about in the metal skip for inspiration.

Cables, wires and electrics all sorted.

According to tracking, the rest of the parts should be here by Friday... Not long now.



Hard to see on the pic but I found some flexy heat protective stuff (in metal) I fit to the clutch outer and when you bend it, it stays put. No Idea what its realy for but found it at my local hardware shop.

Could someone post a photo of the correct route for a tbolt rocker feed pipe please?

Ok. Ive got a strange one here...

I`m finnished builing the top end and added oil and currently priming the motor.

When turning the motor over I get a click from the right hand inlet cam follower or cam. the others are silent.

What have I done wrong now?? Its not the tappet because I have taken the rod off the rocker arm to see if I could localise the sound.

A tight cam follower might do this, strip , examine, maybe a burr, dirt ? Remove idler pinion and spin cam with no push rods before pulling the barrels, that should help isolate it.

Ohh jezus..... thats 3 nights work.

Its a real real pain to fit and remove the head becaus there isn`t enough room to lift it without removing the studs.

Join the club , i got the lump in , then found the crank wouldnt turn last rebuild, cocked up the TS bearing spacing, now I just whistle at it and it jumps out ,I wish.

Before I went to bed I span the engine a couple of times on the kick start and it clicks just before the both inlet valves are activated. The cam and shims and bushes are brand new.
The only parts that are re-used are the followers but I inspected them and they didn't look worn and moved fine in the seats.

I also span the motor without the head on and it was silent.

Why would the cam gear click on the 2 outer lobes?

Could it be that the followers dont quite follow the cam?

I used some sticky start up grease to keep the followers in the barrel but maybe that shouldn`t affect it while they are under spring pressure.



Didn`t get any sleep last night.

I`m loading up the video on youtube... comming soon

Here!

As NickL has already mentioned, take a closer look at timing gear backlash as the source of the clicking noise.

I had a similar issue recently on a Triumph engine I built - http://www.britbike.com/forums/ubbthreads.php/topics/728934/re-does-this-sound-right#Post728934. The dry timing gears made a considerable clicking noise, even although the backlash was not excessive. When I applied some oil to the gears, the noise reduced considerably and sounded normal, although I've not actually run the engine yet!

Ahhhh....

I wasn`t ignoring Nick, I just wasn`t sure what he was saying.

The central timing gear went in dry and the sound could come from that area.

What did you oil yours with Bry?

I just squired some 20W/50 engine oil on the idler gear teeth with an oil can to test with the timing cover off.

Ok. Not a big job. I`ll try that tonight.

cheers.

Wow fellas.... I will sleep very well tonight.

Thank you so much!

[video:youtube]https://youtu.be/7QU4n6GictE[/video]

If I told you that the motor was completely quiet after oiling the timing cogs I'm pretty sure you wouldn't belive me!

If I have to remove the inner timing cover again I'm pretty sure I'll remember to empty the gear box next ...

Hahaha

Me too. I was worried that I had done something terribly wrong.

Mocking up exhaust brackets...

So I have booked myself in to a motorcycle show on Saturday, in the riden to the show catogory and I havn`t even fired her up yet!

Made some fittings for the right hand pipe, hopefully do the other side tomorow. Unfortunatly the hole in the frame is in another possition on the left hand side to make room for the rear light switch so I cant just measure the stuff I made tonignt.







I think it will be pretty sturdy when the tie bar is fitted to the headers, Made the bracket out of 3.5mm stainless.

I kicked them up slightly which is how they are fit on a picture I found in the Metisse book. Loads of room for the clutch cable and exhaust is off my leg for when standing on the pegs.