I was casting round for ideas to make an extension 'can' that would attach to the end of the CRF 230 silencer and replace the rather battered K&N air filter I have been using to reduce the 'pop' effect of this disappointingly noisy little Honda engine.
Based on the premis that the solution lies somewhere in the workshop, I suddenly found myself looking at a heap of oil filters for various engines I no longer own.
Hmmmm
ticks a few boxes doesnt it -
right shape hole in middle at one end only screws on , with a nice rubber seal to keep it in place internal perforated structure locating sound deadening filter material between it and outer skin. Not particularly heavy Lots of different length and dia options at the motor factors.
So, having chosen a suitable looking filter, how was I going to attach it ? The thread looked like half inch BSP but the thread pitch turned out to be metric.
Anything in the plumbing fittings boxes ?
Yes, a few options but all requiring a fair bit of work as some kind of support was required that could be secured by the three bolts that hold the existing silencer internals in place.
Suddenly , there it was, the piece I needed hiding in a drain stopper (-; with a nice bit of half inch bsp thread sticking out.
I even found a big thread cutter to rearrange the threads in the filter
so cut cut cut, drill drill drill, bish bosh and here it is -
glad I photod it before I painted the can cos Ive got a reference number to get a replacement.
Dunno how effective it is yet, cos I need a fuel tap for the XR4 .....
I luv sheds, especially when they are not freezin cold and damp
Ok, more today -
thought a bit of expanded metal and some roof insulation would be nice, so in it went before final assembly and admire.
Total weight of the modification is about the same as the lump being left out
Unable to wait for the replacement fuel tap now fleabaying its way to me, I opted for a funnel stuffed into the fuel line to the carb and gave it a whizz.
Bike hasnt been run since it was abused in North Wales in early Nov '09 but it lit up ok and I have to say the exhaust note is a lot quieter.
The real test will be if I have strangled it and it needs a bit more air flow.
Waiting for the front brake master cylinder to come back from the local bike repair man, so watch this space -
whisp
ps. I didnt realise you could play the pics as a slideshow but now I do, Ive put them in a more logical order
-- Edited by whisp on Tuesday 30th of March 2010 11:20:05 PM
Love it! I would go down the route of fitting Beetle end pipes as I did that on a B40 to shut it up and it worked well. Not sure my bike qualifies at the moment as the engine is still awaiting it's new piston and therefore very quiet!
Finally got round to assembling all wheels and brakes and after a charge up the bike was ready for a test run.
After a bit of a warm up, I took it up a longish hill. It wasnt very happy to be honest, reluctant to rev out and when I got to the top and stopped, the filter tip was smoking a bit
Took it home and next day I noticed that the exit holes were blocked by bits of filter paper ( now who would have thought of that ) so I removed it from the bike and gave it a good blast through with the air nozzle until no more bits of paper came out.
The next test was much better and while there might be a bit of a flat spot at 3/4 throttle, whilst under load, it feels like it will be ok. So thats the downside.
The upside is that it really is a stealthy machine now !
I am seriously impressed with the way it can be ridden with so little noise that the chain and tyre noise is more apparent than the exhaust.
Hopefully this rather subjective view can be confirmed by others in the near future.
