Exhaust puzzle

[chaza]

Hi guys
I have a ajs regal raptor 125. I went to the bike today to start it as it's been stood for a few weeks. When it started it sounded poor. I noticed that more fumes were coming out of the left pipe . I touched the left pipe and it's hot as you would expect, but the right pipe was warm. I cleaned the right plug incase it was flooded. Once it got warmed up it idled about 1400 but still more fumes out of the left. I did notice a few tiny bubbles around the rocker cover. At first I thought a stuck exhaust valve, but she idles ok. What's going on here.


Thanks boys
Chaza

[Nobby the Bastard]

[chaza]

Well nobble,
It's a twin carb which were balanced last summer, I say it's the rocket cover because it's the part that covers the rockers it's above the spark plug so it can't be anything else. There is defiantly tiny bubbles around the gasket which I didn't attribute the issue to. It does have a very slight valve rattle, but that's on the side that is working best


Chaza

[Nobby the Bastard]

If two carbs the whole blocked jet problem is now in play.....
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[chaza]

Cheers bobby
I'll have a look at that, ,the carbs are a pig to get back in.

Thanks

[Teflon-Mike]

Raptor uses a derivative of the Honda CB/CM/CD engine.
The carbs were balanced last summer? How many miles ago was that? [patient shrug] And how the heck do you 'balence' a single carb?!?!?! What do you balence it to?
Oh-Kay... first up, these motors are wont to fire up on just one pot, then have the other cut in once the motor starts to get warm, especially if they are a bit tired.
Raptor, on carbs.... this is not a very new bike... ISTR that they went efi around a decade ago... s-o-o.. my 'bet' is that the thing is has either done a lot of miles, and/or spent a lot of it's life laid up unused.
Pretty good odds that the cylinder bore/piston rings are knackered, or at least past their best.
These engines have diddy cylinders, OTMH 42mm stroke, 43mm bore, barely big enough to fit a spark-plug over! (In fact, it's the same plug as a Honda 'Cub' moped, and Honda had to get I think it was Champion to develop that specially to be able to make a four-stroke engine that small, to get plug and valves in the cylinder head!). Any-how... they don't like worn bores or weak piston rings. A-n-d, wings go 'weak' on laid up bikes as they gum up in the piston grooves, and the 'wear' on the bore at high miles that sees them start to play up is almost imperceptible...
You mention smoke on the left pipe... is that as you look at the back of the bike? That'll be the side-stand side... and from memory, the raptor has no centre stand.... so... bike sits on side stand, leaning to the left, oil in the rocker cover settles at the lowest points inside, and on start up, is puddled around the left hand side valve guide... Engine sucks-squash-bang-blow, and oil puddled around the valve guide is as want to get sucked into the cylinder as charge through the carb, gets burned, makes more smoke on that side exhaust....
S-O.....
Suggestion is that you have a tired old engine, sucking oil down the valve guides, and the ultimate answer is that it needs reconditioning...
See handy How2's in profile; it costs about £130 for a new cylinder and piston kit for these things; and whilst in there, and you have the head off, get the valves out, lap them to their seats, and replace the stem-seals.... eliminates the piston ring issue and remedies the valve stem seal 'problem'... but it might be worth getting a block of wood to prop the kick-stand to hold the bike more vertically when left over night or longer.
Whilst you are at it, get the proper tappet tools (I think the part no's for them are in one of the How2's, and they are only about £15 the pair) for adjusting valve clearances, which you will have to do on rebuild, and every 15oo miles or so there-after as routine maintenance.. good odds they have never been done or done properly, a) 'cos its a 125 and little is ever done to them until they stop working and b) 'Cos it's a Chinky 125, worse still, an chinky AJS that have about as much service support as a one legged man who's had his crutches stolen!
'Bubbling' around the rocker cover... that suggests excess crank-case pressure, which would be caused by worn rings, and more indication engine really needs a top end rebuild.... but, also suggests that 'maybe' some-one might have tried tackle the routine maintenence of the valve clearance adjustment at some point... only trouble is that the rocker cover 'seal' is rather prone to not sitting properly in the rocker cover rebate, and or getting skewed when cover refitted... it's a bit of a fiddle to get the cover off, over the rocker-bosses, under the frame top tube, making more ham-fisted mechanics a bit more problematic/likely.... but 'should' be remidied by that top end rebuild.... and some patience and diligence when you do them tappet tickles... hint, remove the petrol tank, completely!
OR.. you just live with it as is, on the basis that a top-end rebuild is too expensive and difficult, so until it stops working all together. avoid and tickle bits round the outside, in vein hope it will make up some defacit....
That's your call... and only you can make it B~U~T....
Personally, i would NOT waste my time trying to mugger about with another Raptor.. I do mugger about with genuine Honda's, though. a) because at least the CB varient offers a genuine 70mph for it, and is quite a nice bike to ride, and b) resale value of the bike after stands some chance of being worth the quids sunk into it... but like I said, its your call... but sysmptoms indicate a tired old engine, that is likely in need of a top end overhaul....
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[WD Forte]

Bobby the Bastard
____________________
bikers smell of wee

[jaffa90]

[Sister Sledge]

Fell over when I read Bobby! Makes him sound tame..
____________________
CCM 404 DS

[Nobby the Bastard]

Why don't you bunch of cock munches fuck right off.

Fucking tame....
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[chaza]

Hi guys
Teflon.....you asked about balancing a single carb,...... (BIG GRIN) it has two carbs = balancing... It hasn't done many miles. Maybe your not a fan. I don't think all you doom a gloom is acurate, you bleary like the Honda. But thanks for your input



Chaza

[WD Forte]

Chavs Raptor MKII is a twin cylinder twin carb 125
After 2011 ish they started using EFI ( i think)
Bubbling from the rocker cover suggests excess crankcase pressure
worn rings, valve guides or a blocked breather mebbe?

A quick look at the AJS site doesn't show that model anymore, only
the latest models which suggest little interest in support
but they do list a few spares
How many and availability is open to question

Be interested in Bobbies input on this
( cover your ears children)
____________________
bikers smell of wee

[chaza]

I'll do a compression test tomorrow and see, the bike has only done about 9000, but I'll take a look.

Thanks
Chaza

[trevor saxe-coburg-gotha]

noddy the holder
____________________
"Life is a sexually transmitted disease and the mortality rate is one hundred percent."

Mobylette Type 50 ---> Raleigh Grifter ---> Neval Minsk 125

[Nobby the Bastard]

Knackered rings would explain all the symptoms.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[chaza]

Hi guys
I started the bike today, all seems as it should be. I wanted to do a compression test but I don't have the correct part, I'll have wait till it arrives. But the problem seems to have gone. Maybe some crud in the jets maybe.

Thanks for all your input.

Chaza

[Nobby the Bastard]

[chaza]

I agree si ill monitor that for now

[Skudd]

[chaza]

Hi guy
I was intending to Chec the crankcase breather but I don't seem to have one. Where it is supposed to be in the manual mine is not there. I have a pipe from the top of the rocker cover, but no crankcase breather I can see. If I have one where is it......
Ajs tell me it's to the rear into the air box but when I check there is a pipe, but it's blanked off as is the one on ajs website. So I'm a bit puzzled now how it breathes. I was wrong the symptoms haven't gone away, today I started her to warm her up, as before one pipe gets hotter much guile then the other. My compression tester has not come yet.

Chaza

[chaza]

Hi guys
I have just been talking to ajs, they tell me the parts book doesn't show the breather or where it is routed, could if be if has no breather, and it breathes some other way.

Chaza

[Teflon-Mike]

The crank-vase vents from a hole om the top of the crank-casee half castings, from memory, just behind the carb(s). The actual vent, has a labrathyth seal, a maze of bafles basicaly, cast into each crank-case half to catch xs oil before it leaves, then theres a short 1/2" pipe on the top of the cranki-case for the vent pipe top attach.

The AJS engine is made on sub-contract, and AJS have over the years mixed and matched bits from the Honda parts catalogue and their own revisions, B~U~T as it's in the die of the crank-cases, I very much dount that they have changed the labaryth arrangement. And there would be little reason for them to blank off the vent, which would need to be plugged.

On the Honda's the vent pipe from the cranbk-case, either vents via a rubber hose, over the back of the gearbox, to between the rear engine mount plates, with the carb-over-flow pipes, or its closed looped back into the air-box so that any spent vapour gets burned in the cylinders.

Have a poke and a prod round that area see what you can find, look for hoses that are there, and more carefully for places ones may be missing.

On the CB's, common for the vent hose to be pinched between engine and frame, if the engine's ever been out, or to fall off of any-one has tried to feed old pipe into the gap between engine and frame, and given up, 'cos it don't fit!

I suspect on the Raptor the breather would be routed into the botom of the air-box; if so and if you have XS crank-case pressure, common if the engine oil has been over filled.. especially easy as bike has no centre stand so oil level checked on the side stand canted over top the left... XS oil blown out, into the air-box... and wow, check the presses.. you see smoke on start up when it gets sucked into the engine! (after clogging the air-filter!) And wow check them presses... bike leans to the left on the side stand, guess which side the XS oil settles in the air-box, and which side carb then sucks most oil and vapour into the pot to burn.......


____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[chaza]

Thanks Teflon, but I have looked, the manual shows the crank breather on the top of the crank, I do not have that fitting I have zero fitting on the top of the crank. In fact ajs tell me the book doesn't show the routing of the breather. I have just one pipe which goes to the air box which ajs says it it the crank breather, but that one goes straight to the top of the rocker cover. So until I can find the dam breather I can't check it.
I asked, if the book doesn't show the breather or its route, is it possible it breathes somewhere else.
Maybe I'll fit a breather attached to the filler port.


Chaza

[Nobby the Bastard]

[chaza]

I've just had an email from ajs depending on the age of the bike, yes your right, it's confirmed my bike breathes from the rocker cover.
So now I'm left with the pressure build up causeing my bubbles issue and pipes issues as before.
I'm waiting for my compression tester to come so I can see what it says.


Chaza