Airbox elbows won’t line up

[Mad Hatter]

I’ve been fitting the Airbox gubbins to my project bike (new year, new project bike) and was having a real problem getting the carb elbows to line up with the tube coming out of the Airbox. The elbows were about 4 mm out of alignment toward the rear of the bike. I could just about force them to line up with the Airbox spigots but something obviously isn’t right. Then I remembered I’d had similar problems on my Basic but just put it down to being one of those airhead idiosyncrasies at the time.

I put the kettle on and did some checking of the parts catalog to confirm I’d got the right part number elbows and rubbers etc, all of which looked correct, then I had a eureka moment when I spotted that there should be a pair of 3mm thick special washers (8.4X16X3) (13721337205) fitted between the front face of the Airbox and the motor. I definitely didn’t have these fitted to the project bike and on checking they weren’t fitted to the basic either.

I’m hoping that if I fit the washers it will move the Airbox back enough to properly line up with the elbows.

Anyone else come across this one before?

 

[Mad Hatter]

I need some help here gents….

I got hold of some 3mm thick special washers and tried fitting them between the airbox and the motor as shown in the parts catalog. As expected this moved the airbox back by 3mm but then hole for the bottom bolt that attached the airbox to the top of the gearbox doesn’t line up….

 

[Mad Hatter]

I removed the special washers and refitted everything as it was before and this is what I’ve got. I’ve tried loosening all of the hose clamps to get the best alignment possible but this is as close as it gets.

I can just about force them to line up with a lot of hand pressure but when I push the rubber connecting tube up onto the airbox spigot it all slips back out of line. Something is clearly not right but I’m struggling to work out what it is.

All of the rubber connecting hoses are new and so are the elbows.

Any suggestions appreciated because I’m stumped by this

 

[Mad Hatter]

Meantime though I’ve fitted the rear brake and the indicators, so at least there’s been a bit of progress

 

[peepingtom]

im sure you will have checked but are the carbs properly in the front rubbers ? if you remove the front rubbers and the line up the rear first do they fit in the space ok?

 

[Mad Hatter]

The carbs are definitely fully inserted into the rubbers and the rubbers are pushed onto the spigots in the heads as far as they’ll go, but I’ve just done as you suggested and this is how it looks.

 

[Mad Hatter]

When I measure the gap between the faces and compare it to the depth of the rubber, the rubber looks 3mm oversize, but if I trim the rubber down, the gap between the carb and the engine is only going to be about 1.5mm which seems too little for comfort

 

[Mad Hatter]

I’m now wondering if the spigots in the head are sticking out too far. Does anyone know how many mm they are meant to stick out from the head?

 

[SteveHop]

None of mine line up properly .
The airbox cmes right up to the back of the starter motor cover so don't think it can move back any more .
All i do is to spray the pipe and the rubber tube with WD40 so that it can slide easily and i rotate it as i push it over the aitbox outlet .
Seems ok once you have tightened up the clip

 

[SteveHop]

Just remembered , the pipe to carb clip needs to be loose as well .
This allows the pipe to rotate a bit so that it finds its best position.

 

[F8GS]

Hi not sure this is the case but the basic had a secondary air system fitted as standard and it looks like your has an non secondary air system airbox on it as I cannot see the blanking points in the side of the box.

Could it be that the air box is different? I think you may need to investigate this perhaps.


Sent from my iPhone using Tapatalk

 

[mikeyboy]

I think you’re letting your OCD get the better of you

 

[Mad Hatter]

Don’t tell me, they all do that