Power down on RXS.

[smegballs]

MY RXS doesn't seem anywhere near as powerful as it should be. Its very nippy up to about 35 but then starts to stagger, by 50 its hit a brick wall and I can be WOT in 5th at 50 and not accelerate anymore.

With 28k on the clocks I'm thinking it may be new piston time if its on original rings etc. It always starts fine but just hasn't got any top speed!

What process should I follow to try to sort it? Plugs etc first I imagine? Would a coked up zorst make a large impact? Obviously cheapest fixes first is the way to go...

[Kickstart]

Hi

I would start with checking for a coked up exhaust, and cleaning the air filter. Then plug.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[27cows]

Yep, pretty much odds on that the exhaust it full of cack. Bits of black gunk have a habit of blocking the holes in the baffle if left long enough, causing the top speed to drop dramatically.

I never clean or oil my air filter. Replaced the old (torn) one about 70,000 miles ago and haven't even looked at it since then I've had an airbox full of dead flies/filth/other shite in the past and the bike just carried on exactly the same as always.

A duff coil or alternator can cause a drop in power too, but it's unlikely to be either of those to blame with such a low mileage covered.
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The RXS100: vehicle of choice for Chuck Norris

[Robby]

Bearing in mind that it's an air cooled single, if you're going to remove the exhaust it's probably only a couple of hours extra work to change the rings, which you could do while the caustic is doing its thing in the exhaust.

Piston rings and gaskets aren't expensive. The trick is to avoid the temptation of getting a piston kit, gudgeon pin, small end bearing, new circlips and a rebore.

[MaybeGuy]

plus, remember after it was nicked, the carb was set fucking stupidly (mixture screw held in by about 3 threads) and it smoked like fuck. No idea how long it was run by said scrotes like that either.

Good luck getting that baffle out too...
that one in particular anyway
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[27cows]

In my experience it's not a good idea replacing the rings. The bike runs nicely with the rings bedded in. Changing them does more harm than good. My current engine has done a little over 80,000 miles and still has the original piston and rings in there.

Cut the pointless 6 or so inches of hollow tube off the end of the baffle, to avoid the fun and games with removing it.
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The RXS100: vehicle of choice for Chuck Norris

[MaybeGuy]

it was persuaded in with much hammering. There was no need to put the bolt back in, and thats now with 2 years running on top
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[smegballs]

Might have a quick whirl on the comp tester for cheap thrills? I should expect to see the normal 120ish? I know 2t compression ratio is low as the zorst port is open for a fair while.

[27cows]

The RXS should have a comp ratio of 6.7:1 (no idea what that is in new money).
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The RXS100: vehicle of choice for Chuck Norris

[SW Motech Shop UK]

I agree, it defo sounds like it is having trouble breathing. Either lack of air in the front or lack of air escaping from the rear.
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https://www.motorcycle-road-and-race.co.uk and https://www.sw-motech-shop.co.uk/ and https://www.motorcycle-luggage.co.uk/

[smegballs]

[smegballs]

Wrenched out the baffle and it was pretty clean. It still had a good wire brushing tho. The rxs is leaking a bit at the manifold on the barrel. Would this cause noticeable power loss?

[.Chris.]

I'd recommend cleaning out the rest of the exhaust as you'd be surprised how much sludge gets in there.

The method I used was to jam the front end of the exhaust into a large potato and stand it up in an outside drain. Then mix up some caustic soda (make it nice and strong) and pour it into the other end of the exhaust, repeating until the entire pipe is full. Leave it like that for a good 12 hours, then using something like a broom handle or stick, dislodge the potato, sending the caustic soda / oily deposit mixture down the drain.

Be careful when mixing up a strong caustic soda mixture. The reaction produces a lot of heat - I managed to melt a couple of plastic bottles last time I did this and it's not the sort of thing you want going all over your feet.
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Chris
1985 Kawasaki Z550F

[smegballs]

[Serendipity]

This bothers me a bit:

[ms51ves3]

[Serendipity]

Cheers for the offer, but I already have a donor RXS standing by in the wings. I bought a decent spares or repair from Fleabay a few years back and I?ve already transferred everything except the engine and frame to my older bike. The donor bike has a gearbox problem, but the motor ran fine when I last tried so I?ll source bits from that if necessary.
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2016 CBF1000F - Commuter heaven | 1994 CBR600FR - Awaiting defibrillation

[27cows]

[smegballs]

Found some interesting stuff out yesterday.

While waiting at a cafe for mates to arrive I was giving the rxs a little inspection.

I found a number of small rust holes in the downpipe, where the downpipe is welded to the zorst port flange. These holes are definitely leaking gases as visible 2 smoke comes out when engine is revved. I assume this will not be doing the engine any favours and will cause power loss?

Also the bike recently has started picking up better. I've found that if I hunker down on the tank in 5th gear it will quite happily pull up to 60 or so and get into the powerband in 5th. Once in the powerband it will hold the revs high even up inclines which before were a no go.

The bike seems to be ever so slightly overgeared so that when sitting normally it doesn't quite have the torque to pull 5th and get into the powerband. Once in the powerband however I can go to sitting upright and it will still pull.

Is it worth worrying about changing gearing? So far bike is standard ( I think) gearing , that is 50mph at 6k in 5th gear.

[Kickstart]

Hi

It should be more than 60 pretty easily (years since I rode one but an indicated 70 wasn't that much trouble).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[27cows]

Standard gearing is 15/37 but I always use a 36 rear myself. This makes a small difference to fuel economy and allows a top speed of about 70 in neutral conditions, 75+ when things are favourable (indicated).

A leaky downpipe will cause significant power loss.
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The RXS100: vehicle of choice for Chuck Norris

[smegballs]

[smegballs]

Got the pipe off and after cleaning with a wire brush there were lots an lots of holes

Downpipe too far gone to be weldable to breakers furnished me with one for a tenner which is all nice and chromey.