gap between cooling fan and cowl

[smithy]

I have a huge gap between flywheel fan and cowl.....over 10mm...is there anything suitable I can shape and stick to the inside of the cowling to take up the gap and aid cooling....it is electrex ignition on a Spaniard......my gp with varitronic has very little gap at all
thanks for any help

[pacemaker]

Smithy I reckon you have an Indian cowl as the Indian cowls are narrower.

[Digger]

Or a series 1....(Note to self read the post properly)

[Storkfoot]

I suspect the issue is the Electrex flywheel. Anyway, if you search back through your Jetsets, there was an article covering this about a year ago.

[drivera]

I have just measured the width of the two types and the Italian Cowlings are 50mm wide and the Indian ones 60mm wide , so if you have an Italian cowling fitted and still have a 10mm gap I would say there is a problem with the fins on the flywheel !!

[coaster]

Use a needle file or a dermal to elongate the holes so that the cowl sits closer to the cowl. This won't be visible when fitted

[HxPaul]

The Indian fan cowls are deeper to accommodate the fans with the longer fins.

[rossclark]

You can also add some packing inside the cowl to narrow the gap.

[Scooter Paul]

You can also add some packing inside the cowl to narrow the gap.

That could work. 10mm thick polystyrene tile cut into a 'polo mint' like shape to fill the gap between the blades and the shroud but still allowing air to come in through the grill.

Paul

[Knowledge]

10mm thick polystyrene tile cut into a 'polo mint' like shape to fill the gap between the blades and the shroud but still allowing air to come in through the grill.

Paul

I don't think that polystyrene will do the trick, but polythene would be OK. In my first oily rag article, I wrote about minimising the gap between the fins and the cowl in order to stop the air cavitating off the end of the fins.

After I wrote the article, someone wrote to me and suggested that the polo could be made from a polythene chopping board, such as those sold by Ikea. Thanks whoever suggest that.

[smithy]

many thanks for all the ideas

[mickyb]

Just robbed a nylon chopping board from the kitchen, cut to same shape as cowling and now gap is around 3mm. Good idea that

[Wack]

It may have been me but I used an Aldi one I'd like to know how you ended up with a small gap with a Varitronic as they're like the light AF fins , miles from the cowl?

[smithy]

It may have been me but I used an Aldi one I'd like to know how you ended up with a small gap with a Varitronic as they're like the light AF fins , miles from the cowl?

its a stainless cowl ..bought off mb dev a number of years ago..(now powder coated ) ...couldn't be any closer to the flywheel to be honest
cheers!

[rossclark]

Just robbed a nylon chopping board from the kitchen, cut to same shape as cowling and now gap is around 3mm. Good idea that

You're welcome

[Nelly]

I know this is an old post, but I'd be interested to see any pics of the bodgery involved to 'convert' a chopping board into a flywheel cowl packer.
How were they fixed and did it aid the cooling of the engine?
I've just noticed I have quite a gap between the fan fins and the cowl too.

[rossclark]

I screwed one through from the inside with nylock nuts on the outside.

I have to admit I'm a little nervous of it coming loose and wondered if cork tile might not be a better choice as the flywheel would just chew that up if it come loose.

[Wack]

It'll be fine with nylocks.

[Dazts1]

If it was me I'd trim the flycowl to push it closer to the flywheel. I know this means probably welding up the fixing holes and redrilling. Doing this would be the job done once. No chance of your chopping board coming loose and smashing around with your flywheel.

[Adam_Winstone]

For use with small light AF flywheels I buy the Indian long fin cowl, which allows me to cut a strip (incl. all of the existing holes) off and then drill new holes at the position that allows the face of the cowl to sit close to the fins. I then carefully bend/shape the front section so that it flares out to the union with the head cowl.