Motorcycle General Discussion

[WindyParticipant @windy30762]

Posted by thaiguzzi on 06/07/2019 06:23:50:

Posted by Hopper on 05/07/2019 08:39:57:

Posted by thaiguzzi on 02/07/2019 04:53:08:

Another would be a genuine between centres crank aligner like HD used or a larger J&S bench centres.

I think you can still buy the Rowe crank truing stand with indicators which is in the HD style. Costs about $1,000 though.

I dunno what the genuine Rowe one costs, but the Taiwanese copy , which most people buy and use, is approaching that figure.

Between centres is ok providing they are perfect but a crank aligner chap mentions that the centres can be distorted sometimes after pullers etc. have been used on them.

[WindyParticipant @windy30762]

If you are feeling fit a simple way to align single cylinder cranks.

**LINK**

[JAParticipant @ja]

Only once have I aligned a crankshaft and it was not difficult. I have let others do it.

I have often wondered about crankshaft alignment. Obviously the crankshaft must be aligned for the smooth running of the engine. However I have heard two "stories" that suggest it is not critical.

The old AJS company at Wolverhampton use to put one shaft of the assembled crank into a tightish hole in a big hard wood block. With the shaft vertical the crank would be turned and the eccentricity marked with a piece of chalk. The assembly would be tapped with a mallet until true. This came from either a person who worked there or one of the sons of the owners.

SAAB, as many will remember, made a car powered by a three cylinder two stroke engine. This had a built up crank and the company spent a lot of time trying to find the best way to align it. In the end it was found that the crank aligned itself when the engine first started. The source of this was a very senior Honda engineer, possibly a director of the UK company, who was responsible for introducing the little 600cc sports car in the late 1960s and 750cc four to Britain.

[HopperParticipant @hopper]

Posted by Windy on 06/07/2019 16:24:39:

If you are feeling fit a simple way to align single cylinder cranks.

**LINK**

Looks scary to me. He could at least bolt down the stand with the lead block on top of it. Just begging to crush a finger with it flapping about all over the place like that.

I think with my fitness levels I'll stick with the traditional Thor copper mallet.

[thaiguzziParticipant @thaiguzzi]

Posted by Windy on 06/07/2019 16:24:39:

If you are feeling fit a simple way to align single cylinder cranks.

**LINK**

Bloody Hell! Pardon my French. That's not a tiddly 125 crank either. That's a bit of beef, possibly a Brit 350-500 single.

[Involute CurveParticipant @involutecurve]

That looks like the method used by Velocette as described by Phil Irving in some of his books and Technical papers on such matters.

[old martParticipant @oldmart]

I fitted a new big end and rod to a 125 Yamaha engine at work for one of my workmates. We had everything to hand for the job and I found it to be easier than I had feared. As the big end pin was plain, I had to pay attention to the width of the assembly, so it got measured first, also the con rod side float, just in case. I used a copper faced mallet to get the last bit trued up. I managed 0.001" tir which must have been good enough, as the bike was still going strong three years later.

Villiers engines used pressed in hardened plugs to expand the crankpin after alignment. They had to be drilled out before dismantling the crankshaft to reduce fretting.

When I scrapped an old 350 Royal Enfield model G back in the 60's, I was surprised to find a ground steel liner in the big end of the rod, and the white metal bearing on the crankpin.

Edited By old mart on 08/07/2019 20:29:06

[SamsarandaParticipant @samsaranda]

Back in the early sixties I owned what started out as a rigid framed Matchless G80 that I transferred to a 1956 swinging arm frame, unfortunately soon after the frame swop the big end decided to let go and had to be renewed. Stripped the engine and took the flywheel assembly to our local motorcycle shop to have a new big end fitted and the flywheels re-assembled. Built up the engine with the new big end assembly and everything seemed fine for about 100 miles and then something catastrophic happened with the flywheel assembly and the engine had to be stripped down again. When it was all apart I found that one of the nuts on the crank pin had split in half and the flywheels became independent of each other. Fortunately the engine was only ticking over when it happened so no real damage done. It transpired that standard practice was to renew the crankpin nuts when the assembly was disturbed but this didn’t happen when my big end was replaced so an apologetic mechanic rebuilt the assembly again this time with new nuts. Soon had the engine reassembled and the bike working again, have vivid memories of how viciously that engine could kick back if the manual advance and retard was not set correctly on starting.

Dave W

[old martParticipant @oldmart]

That mention of kicking back reminded me of a R E Connie I had which had Meteor Minor pistons which gave it an 11:1 compression ratio. I could only start it on the centre stand and getting the manual advance retard exactly right was essential or bad things happened.

[thaiguzziParticipant @thaiguzzi]

My bored and stroked 828cc T140. Joe Hunt magneto, no advance retard facility. Set at full advance, 38 degrees, moderate 8.7:1 CR.

Not for wimps………

[Michael GilliganParticipant @michaelgilligan61133]

Posted by old mart on 08/07/2019 21:59:40:

That mention of kicking back reminded me of a R E Connie I had which had Meteor Minor pistons which gave it an 11:1 compression ratio. I could only start it on the centre stand and getting the manual advance retard exactly right was essential or bad things happened.

.

The bad thing happened to my Dad … His Achilles Tendon snapped

MichaelG.

[John MCParticipant @johnmc39344]

Posted by Windy on 06/07/2019 16:24:39:

If you are feeling fit a simple way to align single cylinder cranks.

**LINK**

The guy has the right idea but IMO executes the procedure poorly. Even though it looks brutal a surprising amount of "feel" is needed to do the job properly. He wont get that with his lump of lead dancing around. He also seems to be using excessive force to shift the wheels, something wrong there. Or is it that he cannot get a clean "bump"?

Also the DTI is too close to the main bearing location, he needs to make a close fitting sleeve that "extends" the crank shaft (both ends) so the DTI sits over the ends of the shafts. This is the way to get the accuracy required.

John

[WindyParticipant @windy30762]

Something about a 137mph steam bike at Loring LSR.

2ft dia vertical boiler with 250 copper tubes swaged each end…rolled 4140 steel wall and Tig ed up….pressure tank drives kerosine spray with propane igniter…parallel 180 twin with slide valves…no tranny..direct drive….he has pressure vessel and steam tickets…

[WindyParticipant @windy30762]

At the July Top-speed Elvington speed attempts was given a centrifugal clutch for my project by my steam rocket friend.

I may not use it but it has given me ideas for my own design this one has a wide toothed belt drive that I will not use.

Looks like brake pads have been used for the friction plate.

Have been on the web for friction materials to make my own friction plates but most seem to be just offering a lining service.

Anyone know where I can buy just the material I would prefer bonding but will probably rivet the linings.

Could just do cheque book engineering and have a custom one made but that is not my scene.

[David Davies 8Participant @daviddavies8]

Windy

try brake Reline Services, Cardiff. Tel +44 (0) 29 20702900. They have done odd jobs for me in the past, I found them very helpful. They may have a postal service.

Regards

Dave

[thaiguzziParticipant @thaiguzzi]

Thats a weird looking friction plate.

Last time i looked inside a high hp centrifugal clutch i seem to remember multi plates and springs.

Yours has 5 or 6 springs but how many plates?

[WindyParticipant @windy30762]

Posted by thaiguzzi on 25/07/2019 06:05:23:

Thats a weird looking friction plate.

Last time i looked inside a high hp centrifugal clutch i seem to remember multi plates and springs.

Yours has 5 or 6 springs but how many plates?

I was given the clutch to consider for my project I don't think mine will be a high HP machine like the machine the clutch was used on .

The springs do not push the pressure plate onto the linings but hold it clear. A combination of the centrifugal bob weights and the holding springs decide rpm the clutch engages.

As a test I run it on the lathe and it all seemed to work.

Will consider a few more friction discs etc.there are a few friction materials to choose one has an aggressive engagement others more gradual.

I was wanting a centrifugal clutch the one they use on smaller engines don't seem suitable.

A variable speed transmission I would have liked instead but too much transmission loss.

[old martParticipant @oldmart]

Those friction discs look a bit like sintered bronze, but if they are used dry, they are probably based on sintered metal brake pads.

[WindyParticipant @windy30762]

They are not sintered bronze but are based on car brake pads.

An acquaintance who was a brake tester at Mintex and is still involved in the car rally scene said they look like a pad he has fitted to many cars.

Will check with him as I think there rear Escort pads that have been machined to fit

[FalcoParticipant @falco]

.Hi Members,

I'm tidying up a Moto Morini 250 twin at the moment. There is a small indicator/warning light bulb missing and I have been unable to find a supplier. The bulb is one of the wedge or capless ones but is smaller than the usual ones. It is only 5.25mm diam. and overall length is 18.75mm. The actual bulbous part is 11.5mm long.

It is 6Volt.

Does anyone know a supplier?

Would the LED bulbs that are becoming popular work in the 6 Volt system?

[Neil AParticipant @neila]

I don't know if this is any help, but Rapid Electronics sell a T5 wedge-based lamp 6 volt 1 watt (order code 57-6819) and a 6 volt 0.5 watt ( order code 57-6804).

The dimensions are close to what you quote. Have a look and see what you think.

Neil

[FalcoParticipant @falco]

Hi Neil, I have had a look and that is just what I need.

Many thanks for your help and quick reply. Much appreciated!.

John

[JimmieSParticipant @jimmies]

Ulster Grand Prix on catch-up.

**LINK**

[Ian ParkinParticipant @ianparkin39383]

Just seen this bike advertised on a local forum

have a look at the rear brake actuating rod..

wouldn’t want to be relying on that in a panic stop

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ian Parkin on 17/08/2019 11:51:22:

have a look at the rear brake actuating rod..

.

Might be a litlle spongey, Sir !!

MichaelG.

[Author]

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