Total Re-build..what are all the bits for?

[Hairy_Mark]

Hello folks,
Some of you may remember the long saga of my wobbly Raptor. For some reason it didn't like being thrown down the road at sixty (ish) mph. Ever since it has got an unsettling wobble on some rough surfaces, especially in bends....nice.
Anyway, I got a new frame, following up a good tip from a member. I'm ready to drop the engine out now, but couldn't help noticing a whole bundle of weird gubbins on the way.
Most of this concerns what look like vacuum lines linking the air box and the cylinders, next to the exhaust pipes. there's some sort of vacuum operated valve in the middle, next to the rear throttle body. What is this crap and do I really need it? I think I've read something about it on raptor Chapter, but I can't quite remember.....demensia sets in early these days.
Then there's what looks like a breather pipe coming from the rear cylinder only and going to a couple of linked plastic pots. I assume that's necessary, but wondered why only the rear pot needed it.
Finally, there's a T-shaped duct under the airbox that used to go to the restricted air inlets. Since I've already ditched the small rubber air inlets, does anyone se a reason why I don't get rid of this T-piece and just draw air straight in from under the airbox?

Well, I'm off for a nice cup of cocoa....can't understand why cocoa comes in cans marked 'lager', but it still has the effect of making you sleepy before bed time.

[shedmonkey]

Hi Mark the pair system consists of pipes coming from beside both the exhaust ports up to that valve on the rh side then to the front of the airbox and a small vacuum pipe from a small solenoid valve ,all this can be done away with providing the airbox,exh port holes and vac pipes are blocked off. Dont know about duct

[Hairy_Mark]

Thanks, shedmonkey,
Good news if I can get rid of it...less weight and less fiddly bits to put back together, but it begs the question, 'What's it all for?' I noticed after I'd penned the first post that the crankcase has a breather attached to a bit I didn't have to remove to get the engine out. That seems weird too. The crankcase has to breath, so does the rear cylinder head, but the front cylinder manages to hold its breath?

[shedmonkey]

The pair system is sort of exhaust gas recirculation (exhaust is allowed back into airbox but can allow air into exhaust and this causes popping on over run) the breather on the engine goes into a canister on lh front of engine and connects into airbox

[Hairy_Mark]

Thanks again Shed,
It's as good as in the bin. I like ripping off useless junk. By the way, I'm convinced about the bend in my frame, It's even clearer when you strip everything out. The lower gearbox mount is hard up against the frame on one side, with a huge gap on the other side. The top pair of gearbox mounts look bent and the tubes we measured at the swinging arm can be clearly seen to be at two different angles...not so on the replacement frame I got.
I can't figure out why the lads in Dewsbury didn't pick up on it when they measured the frame on a laser device...despite the fact that it showed the tail out of spec, wheel misalignment and wheel offset. Who cares if the frame's straight as a die from the engine mounts to the headstock, if the rest's like a banana? When I've swapped everything and road tested, I think I'll get back on to them. A 250 mile round trip on a wobbly bike and a bill close to £400 doesn't seem right when you've got to fix it yourself when you get home!

[dizzyblonde]

You went all the way to Dewsbury for that,

Shoulda popped a bit further for tea and cake
Don't trust anyone there, eyes too close together for my liking

[Miz]

The pair system is sort of exhaust gas recirculation (exhaust is allowed back into airbox but can allow air into exhaust and this causes popping on over run) the breather on the engine goes into a canister on lh front of engine and connects into airbox

My understanding of "PAIRS" is that it allows fresh air into the exhaust on the over-run (once the vacuum increases and opens the valve), this helps out with the exhaust emissions readings.

[Hairy_Mark]

Miz,
That makes sense. So what you're saying is that I can take these off, but it may run into trouble on an MOT. That all depends how close the engine is to the limits. Has anyone out there taken this system off and had no trouble with the MOT?

[Hairy_Mark]

Just an afterthought. Like me, heaps of people dump the restricted air inlets. With these off, there will be less vacuum pulled in the exhaust and so the pair system won't open as fully or not at all. Also, there will be more air pulled into the engine on the over-run, which may offset the emissions readings anyway, as it will allow for a more complete burn.

comes back to my last question. Has anyone fallen foul of emissions in an MOT, having removed this system and the inlet restrictions?

[shedmonkey]

Ive had mine off for ages with no mot probs

[Hairy_Mark]

Basically, Shedmonkey,
all I have to do is ask you for the answers! Cheers!

[Miz]

Miz,
That makes sense. So what you're saying is that I can take these off, but it may run into trouble on an MOT. That all depends how close the engine is to the limits. Has anyone out there taken this system off and had no trouble with the MOT?

No trouble at the MOT as far as I know, I don't think they test them unless the vehicle is smoking!! I have just stripped mine off and have put 600g of bits in the stores..

[Hairy_Mark]

Miz,
Thanks for the reply. I haven't weighed the bits, but 600g is 600g. I'll get to sixty that little bit faster and in the complete confidence that PC plod can't object to my emissions!

[AZ]

MOT is no problem as bikes are not tested for emissions,just visual smoke .