Cracked Airbox

[penno350]

Any top tips on repairing a cracked 198 Airbox or is it dig deep for a replacement? Any views on best source for replacement?

[big john]

Any top tips on repairing a cracked 198 Airbox or is it dig deep for a replacement? Any views on best source for replacement?

Dig deep for a replacement, they were crap when they were brand new, they were prone to crack after a bit of use. Repairing them is not an option, they just split somewhere else, believe me its not worth sorting them!

Big John

[pschrauber]

Any top tips on repairing a cracked 198 Airbox or is it dig deep for a replacement?

Any views on best source for replacement?

Dig deep for a replacement, they were crap when they were brand new, they were prone to crack after a bit of use.

Repairing them is not an option, they just split somewhere else, believe me its not worth sorting them!

Big John

Had the same problem too, you may ask www.bultacouk.com in your home country if they have any replacement,

(I think they might have). If not you can get replicas out of fiber from Orlando Calonder in Switzerland.

(www.orlandocalondersa.com)

My airbox have cracks too, here both of them the original on the left side, the replica on the right:

You have to drill the holes for the fasteners and the sidepanel by your own, even the hole for the airbox cover

has to be recutted, but then you can be sure it will fit. The airbox cover is from a 199b model but he has

replikas of the other models too.

I know it might sound silly, but I will give a repair of the original airbox a try, after reading this book:

Motorrad restaurieren von A bis Z sadly in German)

The autor has found a plastic repair set from Henkel here in Germany that can repair all sort of plastic cracks.

The repair set is no bargain but workes perfect. It's based on a two Compound mastix that you can use as a glue and filler,

then you need a special primer. You can even remount broken plastic brackets that suppose to hold side panels or likewise,

He states and shows that this stuff is very strong,(stronger than most plastic materials that where used originally).

Glue and Filler: Terokal 9225

Primer: Terokal 150

mix pistol: Teromix 6700

I haven't used it until know, because there are some other pieces for other restaurations/rebuilds going on where

I want to repair plastics too, cause of the cost of this stuff I will repair all of them at once.

I have already used Henkel products like Loctite 3463, (steel filled metal knead that is as strong as normal steel),

that showed very good results.

May be there are some other british brands that work too ?

Edited May 22, 2011 by PSchrauber

[vfrneil]

Hi there,

I had similar trouble with my airbox. Specifically splits originated at all 3 front holes. These are stress cracks and whilst it is possible to fix them with plastic repairs they will return.

What I did was have an aluminium donut made to the right dimensions which sits around the hose aperture and pullss all the cracks back together. You can then use a plastic repair which will last as the stress is now all being taken up by the ally donut.

I hope this is of some use.

This is the "before" pic.

And following the repair

[penno350]

Hi there,

I had similar trouble with my airbox. Specifically splits originated at all 3 front holes. These are stress cracks and whilst it is possible to fix them with plastic repairs they will return.

What I did was have an aluminium donut made to the right dimensions which sits around the hose aperture and pullss all the cracks back together. You can then use a plastic repair which will last as the stress is now all being taken up by the ally donut.

I hope this is of some use.

This is the "before" pic.

And following the repair

Thanks for the replies chaps, much appreciated.

Edited May 23, 2011 by penno350

[ps1000]

I Agree - you can repair them using a combination of glue and aluminium collars..but the bottom line is sadly they are cr4p and will most likely split again

[pschrauber]

Update airbox crack repair:

I tried this Henkel Terokal stuff out, used it on a it on s smaller crack at the rear top of my airbox.

It worked very good, very important is grinding the surfaces of th plastic with wet amd dry sandpaper

(150 or lower) and to clean the surface very well using aceton or thinner. The primer that have to be

applied too has to dry on the surface, which does take half an hour.

Here is the first glued an filled crack after align with sandpaper:

After this good result I know went further to the cracks that are around the upper front mounting of the airbox, again drilled a hole at the end of the crack and widened them, afterwards the where grinded and cleaned with aceton and thinner, here after applieing the primer and waiting for getting dry:

This PU stuff looks like poop, luckily it does not smell likewise, (it does not smell at all, very disturbing), here after application:

At least I'am very impressed, I will therefor try out this stuff at my helpless cracked chainguard too:

Probably someone is intrested in the result.

[hightown]

My airbox broke away at the 3 front holes of the airbox,I brought the airbox hose round fixing plate from bultaco [uk],I fitted it too the inside of the airbox hose aperture and glued the broken parts into the 3 holes, I then screwed the two plates together which made a very strong joint,I also fitted two rubber washers under the bolts to separate the airbox from the frame to stop any vibration which i think may have caused it to split

Hightown