Fly wheel issue.

Hi all,

A simple question I'm hoping someone can answer, I have test fitted the fly wheel to my DCC.
When I refitted the rear wheel the clearance between fly wheel & wheel is zero.
With the key to the flywheel/crankshaft removed, to rotate the fly wheel.
There's enough contact to turn the rear wheel when rotating the fly wheel by hand.
20220603_143917 by Trev Read, on Flickr
The key is in the picture just to test fit it.

Could someone give me an idea of the sort of clearance should be between the two.
I believe it is close but not this close.

I'm going to measure the center line of the cylinder block, and compare it to the center of the crank shaft.
To see how they match up horizontally, in case the crank bearings are too low.

Thanks in advance.
Trev.

Hi Trev,

there is definitely something wrong here. On Pied Piper there is about  5 to 10 mm clearance between flywheel boss and wheel. It is tight but definitely not as small or non existent as on your engine. Will measure tomorrow to give you the exact dimension if you need it.

What surprises me is that the distance between axle and crankshaft bearing is set and fixed by the horn plate resp the mounting faces thereof. The only idea I have is that the rubber coating on the rim is thicker than it should be.

Might be good to check with STW.

Cheers

Elwood

Hi Elwood,

Thanks for your info, I'll give STW a call today.

There was an issue with this horn plate being warped/curved, this was straightened and corrected by STW.
Not sure if something else is going on with it.

Regards

Trev.

Hi Trev

Thanks for calling to support. I will do my very best to assist you in finding the issue and getting you back on track so to speak.

As a note for readers. I have supplied Trev with some "landmark" measurements and design sizes so hopefully we can find the "oopsie" quickly.

Hi,

Big thanks to Lynn & STW for the help and assistance with my fly wheel issue.

I have reset the position of the L/H crank bearing and now have about 5mm clearance.
20220611_151941 by Trev Read, on Flickr
It looks closer in the picture, but there is just 5mm there.

Thanks again for the help & assistance.

Trev.

Hi

Can we have the measurements please, would like to check mine before I get too far, main dimension would be the distance between the centre of crank and axle.

Hi Nigel,

I'll measure it tonight & post.

Trev

Hi,

As requested I have measured the distance from the rear axle center to the crank shaft center.

It's 400.5mm on my DCC.
This measurement comes from:
Rear wheel dia; 736mm half of which is 368mm
Plus from the rear tyre (outside face) to the center of the crank shaft 32.5mm

I would say 1 or 2mm each way and all should be OK.

As I said previously, the clearance on my engine is just under 5mm.
Hope this all makes sense and helps other builders.

Trev

Hi Trev

Thanks for this, checked mine all ok, thanks for your help.

That gap is about right, on a muddy Rally field the flywheel picks up mud! Don't bother painting the centre hub, it'll only get scratched to pieces. A light rub with an oily rag keeps it rust free.

Thanks for the reply Steve.

Unfortunately It's already had 2 coats of etching primer, 2 coats of primer and first coat of crimson.

We'll see how we go once it's running.

20220701_141611 by Trev Read, on Flickr

Haven't got a pic of it in crimson.

Trev