Cam-swap/engine won't start
 

So I finally got off my backside and decided to use the intake cams from the dead engine as exhaust cams. Bad start was had when I couldn't get the timing inspection cover to come off because it's welded itself in place. Bent a bar trying to do it, which I was impressed with, as I expected the suzuki-cheese bolt to round before that happened. As a result, I ended up taking the plugs out and turning the engine over using the starter to get the right markings into places I could work with (as I also couldn't find a 17mm socket. Go figure.)

So, decided to go for the rear cylinder first because it's a bit more accessible (although the CCT location made me regret that decision). Managed to get it in, 16 pins between the 2-mark on the intake to the new 3-mark on the new exhaust (marked out as the next valley to the left of the 1F marking as per this image):
http://www.hostile-takeover.com/mack...ntake-rear.jpg.

I didn't take the CCT out because I didn't see much point in putting myself through that much pain, given that I've got a long screwdriver and skinny hands. I regret the decision a bit now, because at one point the cam-chain slipped off both cams while trying to wriggle the new cam into place. I'm about 99% certain that it went back on at the same place it came off...but there's that 1% chance I was wrong.

Being the slightly paranoid guy that I am, I tried very short presses on the starter to turn the engine over (no 17mm socket, remember? Which is a shame). No big clunks, everything turns over lovely and smoothly. Excellent. Decide to try to fire it up with just the rear cyl done to make sure I've not broken anything. Put everything back together, plugs in and caps back on, turn motor over. Front cylinder fires. Rear doesn't. Take off front plug to make sure...still no firing.

Bike now runs on one cyl only, which is peeing me right off. Any ideas on what I've done wrong?

Re: Cam-swap/engine won't start
 

Where to start? Could be anything - re-check everything you've disturbed. Particularly the cam timimg obviously.

Re: Cam-swap/engine won't start
 

See above comment on not being able to get the timing cover off. That's the problem I've got, really

Re: Cam-swap/engine won't start
 

check for a spark on the rear plug, might had cracked the insoluation on the plug, but I would believe you would have allready checked...

Re: Cam-swap/engine won't start
 

Yep, plug sparks fine, swapped front and rear sparks and they're both working (and were both running before, obviously)

Re: Cam-swap/engine won't start
 

ok nothing to add bout the cams as i no nothing about it but on the mt-owners-club forum one of the blokes had the front cylinder not firing on his mt-01 1600cc twin and to force start it he put some fuel in the spark plug hole (not sure how much) then obv replaced the plug back in there and it started up not sure if this is worth a shot ?

Re: Cam-swap/engine won't start
 

You got the cam pointing the right way? Look at cams and go through it in your head, intake compression combustion exhaust

Re: Cam-swap/engine won't start
 

I'd assume there's only one way it can go in if it's lined up correctly with the 2 and 3 pins ;)

Re: Cam-swap/engine won't start
 

Assumption is the mother of all fu*k ups. You can put the cam in 180 degrees out and it'll turn over ok but not fire.

Re: Cam-swap/engine won't start
 

But if it's in 180 degrees out of alignment then the 3 marking on the exhaust cam would then also be 180 degrees out of alignment...which would mean it wouldn't be 16 pins away

Re: Cam-swap/engine won't start
 

I think Northwind has done this.Might be worth a PM and pick his brains?

Re: Cam-swap/engine won't start
 

Managed (after a lot of persuasion) to get the timing cover off. Success. Still lack a 17mm socket. Fail. Will continue this later this week...

Re: Cam-swap/engine won't start
 

Dont know if its any help but i have a digital copy of the curvy haynes manual, assuming you havent already got it.

Re: Cam-swap/engine won't start
 

I've got a hard copy in the garage. It's very helpful...as long as you can get the timing cover off ;) Now that it's off, things should be ok - I just need to get a 17mm socket so I can turn the engine over by hand.

Re: Cam-swap/engine won't start
 

I've not done a swop before but I'd have thought the markings on the new cam would be completely wrong for where you have moved it to. Inlet and exhaust cams are timed differently so why should the markings be interchangeable? An easy way to check would be to pull the cam cover off and position the new cam with the lobes at a particular point, then put the one you took our next to it and compare where the references are with the lobes in the same position. Oh and an easy way to turn the engine reasonably accurately (at least with the plugs out) is to put it in gear and turn the back wheel.

Re: Cam-swap/engine won't start
 

The cam swop is easy enough to do and those diagrams you are using are definately correct - I think they are pretty much what everyone uses.

A couple of things though - it is easy to get the timing 180 degrees out if your distracted by other stuff whilst you are doing this - more than a couple of people have done this so don't definately rule it out.

Theres not much to disturb when you do the rear (assuming you did it with the tank still on) so as Sid Squid said I'd just go back and double check everything you've done for correctness.

Finally - I find the tensioners a nightmare too - especially the rear for some reason, but I've always taken them out so the chain is nice and slack. I would definately recommend marking up the cam chain somehow before you start moving things though just as some sort of insurance policy incase it does slip.

Re: Cam-swap/engine won't start
 

unhitch your horse and go buy a socket for a start....;), don't cut corners, basic logic will show it's timed right or not.

It's not a complex job, and I'll admit I haven't done it for a number of years now, but can't remember any problems.

Cheers Mark.

Re: Cam-swap/engine won't start
 

put it in gear - take the spark plugs out and turn it over using the back wheel..

Good luck with it all

Re: Cam-swap/engine won't start
 

Neeja,
To try and clarify the point Sudoxe and Spoon have made. The cams (as I'm sure you know) move half the rotational rate of the crank. This means it's possible to have the front cylinder at TDC, (F mark visible in the timing cover), and all the points line up correctly but have the crank one full rotation / the cams 1/2 a rotation out of sync with the other cylinder. Everything will turn over fine, but instead of the cylinders now trying to fire 270 degrees apart, they will try to fire 90 degrees apart, this doesn't work out well.

I would also suggest that using the starter motor to turn the engine once the cams have been out isn't a great call. Simple reason being the starter motor's very strong and can bend a valve if you've got the timing wrong. Turning by hand you should be able to feel the resistance and stop if you're concerned.

Jambo

Edit: My understanding of the process is that K3+ intake cams should replace curvy intake cams, and the curvy intakes should be moved to the exhaust. If this is not precisely what you're doing (I can't remember what year of bike you have) then it's worth clarifying.

Re: Cam-swap/engine won't start
 

Just to clarify, I've not got a set of K3 intake cams, but I do have 2 sets of curvey intake cams after taking my lunched engine apart. Instead of replacing intake with intake from K3, I'm just swapping out my exhaust cams for intake ones. Should make a difference, although nobody's sure how much.

I always thought that if the cylinders were trying to fire at 90 degrees that the engine would still fire, just badly. When the first attempt was made to start it, only the rear cylinder had a plug in it, so it should've been running on just the rear cylinder, with the front doing nothing but spitting out fuel-smelling air from the spark-plug hole :) Unfortunately it didn't fire at all.

And the only reason I turned it over with the starter was that I rolled it forward in gear first and didn't hear any clunking or feel any resistance - I was pretty confident that it all went back in in the same place as I left it, but apparently not. Picked up at 17mm socket on the way to work this morning, so should have this sorted tonight or tomorrow, depending on what time I get back home after a trip out to see a friend.

Re: above comment on removing the CCT - I was planning on taking the front one off because it's reasonably accessible. The rear one I had difficulty taking the cover bolt off...didn't fancy trying to remove it completely because I had a premonition of the nightmare I'd have trying to get it back in. Oh the irony. Hindsight, people...it's a wonderful thing :D

Re: Cam-swap/engine won't start
 

I find rear one loads easier to get to than front! Just take right rearset off and is easy.

Before you even think about marks just look at cams. Find roughly TDC on back with a rod down the plughole and look at cams, rotate engine and go through in your head the 4 stroke cycle. I reckon you've put something in wrong and it's got 2 exhaust strokes instead of 1 intake 1 exhaust.

Re: Cam-swap/engine won't start
 

Thinking about it, I'm reckoning the same. I clearly just got (un)lucky when putting the cams in that I managed this amazing feat of engineering.

As mentioned earlier, I've got the timing cover off now (with the help of an old honda CG exhaust), so I can check the timing properly. 17mm socket+timing cover = piece of cake. I did take the RHS rearset off...getting at the CCT itself wasn't too bad, it was the winding it out without it flicking back in that made me swear lots :D

Re: Cam-swap/engine won't start
 

The only hassle I had doing the cam swap was getting the coil connections crossed so that the front signal went to the rear coil and visa versa, result hellish missfires, easy fix though. I reckon when you dropped the chain it all went out of whack, thw whole process was fairly easy, apart from taking out the cam chain tensioner, if you are using the web info where the pic came from read all the comments right to the end.Theres an important part missing in the first bit, after setting one cylinder you need to rotate the crank a full 360 degrees before doing the next one. Other wise you get big bang timing which is amusing but not productive.
Cheers
Pod

Re: Cam-swap/engine won't start
 

As much fun as it sounds to run the engine like this, I'm trying to avoid it ;) I was aware of this, however - I've got a Haynes manual that I was using to check on the cam-timing marks, and it makes sure to mention rotating the engine to make it all line up. I just wish I'd used a pen that didn't rub off so easily when marking the cams/camchains, as this whole thing could've been avoided :P

Re: Cam-swap/engine won't start
 

Personally I've found pens / tipex to be of help when doing the ZX6R as the cams don't sit quite flat until you've clamped them down, so it can be a little tricky lining them up. On the SV this isn't a method I'd rely on for 2 reasons:
1) It isn't needed as at the position you're lining the cams up, the lobes are facing away from the buckets and adjustments can easily be made by hand because there's no load on them.
2) There is no sight of the chain touching the crank. Because of this your marks at the top can all line up while the chain has moved a tooth at the bottom, leading to a wrecked motor.

Just do it the way it's laid out in the manual, it works much better than using pens & tipex for this configuration of engine.
HTH

Jambo

Re: Cam-swap/engine won't start
 

The pen isn't to line the cams up as such, it's so I knew which tooth went to which pin on the intake side (which I wasn't changing), in case the cam-chain slipped. Unfortunately it rubbed off.

Quick update: Problem found. My intake cam is on exhaust timing and the exhaust cam is on intake timing. Guess who was tired when doing this yesterday and forgot which was front and which was back? :D

Re: Cam-swap/engine won't start
 

lol so now the problems solved would you mind telling my what this does :) ?

Re: Cam-swap/engine won't start
 

For a pointy? Not much, unless you just want to do what I'm doing moving curvey intakes into the exhaust. Normally the full swap is putting K3+ intake cams into the intake side of a curvey engine, and moving the intake cams to the exhaust side. Gains somewhere between 3-9bhp (depending on who you believe etc.). Putting curvey intakes into the exhaust side while still keeping the curvey intakes? Nobody's quite sure, but given the difference in lift between the stock exhaust cams and the intake cams being used as exhaust cams, it should be noticeable.

Re: Cam-swap/engine won't start
 

well i have a pointy but i think i get the drift, so how come you did it if there is not much efect ?

Re: Cam-swap/engine won't start
 

Dude...I'd sell my grandmother for an extra 1.5bhp. ;)

Re: Cam-swap/engine won't start
 

Update: Rear cyl now fires happily. Moving onto the front.

Re: Cam-swap/engine won't start
 

Must be the same reason people pick the sv as a race bike lol, craziness. Its a shame we cant put a proper engine in the sv, 180bhp naked pointy :D lol

Re: Cam-swap/engine won't start
 

haha lmao :P

Re: Cam-swap/engine won't start
 

Now finished, back together and running. Will test tomorrow on the way to work, and hope nothing goes bang :D

Re: Cam-swap/engine won't start
 

Well, nothing went bang.

Gained nothing top-end, really (expected), but it feels quite a bit more lively lower down. Seems to pull harder from 4-7krpm, so there's much less of a jump as it hits 7k.

The bad, though: Bike doesn't seem to want to idle nicely - idling very high and erratically, and even putting the choke on full left it at under 3k (when it normally jumps to 3k with full choke from cold). Also got into work to discover my left boot had a spraying of oil on it. I'm assuming that one of the breather hoses wasn't on the airbox properly and it's come from that...but can't get out to check till later this afternoon. Bugger.

On the upside, it didn't go bang.

Re: Cam-swap/engine won't start
 

You've got an air leak by the sounds of it. Check you put carbs back on right. Sounds to me like you didn't put airbox back right especially since one of breathers popped off too.

Re: Cam-swap/engine won't start
 

I had a look at lunch-time and it's not the breathers. I'm actually wondering if it's just oil on the radiator - it got fairly covered last night (had it hanging down under the front cyl while working on it, and there was a bit of spray when starting the engine the first time due to me leaving the cover off). There's a few small drops of oil under it at the moment, but nothing major. I'm thinking that oil got into the rad and as it's warmed up this morning it's dribbled out, as there was nothing leaking last night when I had it running for 2-3 mins.

The air-leak sounds likely...it was about 1:30am when I was putting the air-box back on, although the carbs never came off the bike. Thinking i might not have put them back onto the front carb properly in my haste for bed :D

Re: Cam-swap/engine won't start
 

Slightly worse than I thought.

Rear cylinder is down on compression because it's leaking through the top cover at the rear. Spraying a fine mist of oil and can feel it blowing.

Think the rear screw thread has stripped.

Re: Cam-swap/engine won't start
 

Top cover won't lose you compression. Just a little oil.

Re: Cam-swap/engine won't start
 

*ignore*

Bike has now started working on both cyls again. Rear one only fires intermittantly at idle, and idles low, so probably carbs need balancing given that they've not been done in 12k miles...