Honda XRV Forum banner

1 - 20 of 31 Posts

·
Registered
Joined
·
164 Posts
Discussion Starter · #1 ·
I've now had my first short ride on the SLR and enjoyed it very much. It's so much lighter, narrower and more chuckable than the Strom.

However, having EFI on my last 2 bikes has spoiled me a little. The SLR has a stumble just coming off idle which is a bit annoying. It feels as though it's a momentary eakness in the mixture. If this was an Amal carb I'd be looking at the slide cutaway but my CV experience is a bit limited. I've seen reference to shimming the carb needle which presumably enriches it slightly - anybody here care to enlighten me?

Thanks in advance
 

·
Ridden for years
Joined
·
2,806 Posts
I'm going from memory, does it have evap? Remove.
Have you checked the position of the mixture screw? Check.
Have you checked air filter condition?
I assume you've checked and set valves.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #3 ·
No, no evap.

I've only just got the bike so have a number of checks to make yet. It's done only a thousand miles in the last 8 years so I wouldn't be surprised to find all sorts gumming it up. My plan is to ride it as it is for a month or so then give it a good going over, and will of course check all the things you mention - I just wanted to be familiar with the mod from anyone who's done it.
 

·
Registered
Joined
·
695 Posts
SLRs don't have the smog pump fitted - it arrived with the FX.
My money is on the slide lifter mechanism. I've seen two carbs now where this has been seized.
If you look at the pulley that the throttle cables wrap round you'll see that there is a cam profile running around the periphery. This acts on a little lever with a nylon bearing that runs on the cam.
When the throttle is opened the action of the cam lifts the lever and this in turn rotates a shaft set into the carb body. The shaft acts on a fork inside the carb body which lifts the whole slide assembly of it's boss. If the lifter shaft is seized, it will be seized in the "up" position which means that the carb slide will not be seated on its boss when the throttle butterfly starts to open. This can cause the misfire.
Obviously you'll also need to check for blocked jets and drill ways, but I've had one bike which had the same annoying problem, which I couldn't solve and it turned out to be this. Also one of my spare carburetors came with the lifter shaft seized.
 

·
Registered
Joined
·
742 Posts
Is this the VE40 carb the same as fitted to the NX650?
If it is there should be a small felt bearing in the carb body that the butterfly shaft rides on, I assume that this should be lubed.
I only discovered this when I was stripping mine down for ultrasound cleaning.
I do think that these benefit from a small shim under the needle, I found some washers the correct size in an old scrap computer 0.5mm is what I used.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #6 ·
Many thanks to both - I'll investigate when I take the carb off, although will probably live with it as it is for the time being.
 

·
Registered
Joined
·
209 Posts
SLRs don't have the smog pump fitted - it arrived with the FX.
My money is on the slide lifter mechanism. I've seen two carbs now where this has been seized.
If you look at the pulley that the throttle cables wrap round you'll see that there is a cam profile running around the periphery. This acts on a little lever with a nylon bearing that runs on the cam.
When the throttle is opened the action of the cam lifts the lever and this in turn rotates a shaft set into the carb body. The shaft acts on a fork inside the carb body which lifts the whole slide assembly of it's boss. If the lifter shaft is seized, it will be seized in the "up" position which means that the carb slide will not be seated on its boss when the throttle butterfly starts to open. This can cause the misfire.
Obviously you'll also need to check for blocked jets and drill ways, but I've had one bike which had the same annoying problem, which I couldn't solve and it turned out to be this. Also one of my spare carburetors came with the lifter shaft seized.
Cheers Bud.

Mine has suffered from a misfire at low revs and your diagnosis was spot on for me. Just looked and the lever that opens on the cam was stuck open, a squirt of silicon spray and its moving nicely now.

Cheers, Ian
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #8 ·
Well spotted!

SLRs don't have the smog pump fitted - it arrived with the FX.
My money is on the slide lifter mechanism. I've seen two carbs now where this has been seized.
If you look at the pulley that the throttle cables wrap round you'll see that there is a cam profile running around the periphery. This acts on a little lever with a nylon bearing that runs on the cam.
A prize for that man.

Mine wasn't seized as such - was able to move - but it seems the spring has either broken or lost its "springiness". The roller wasn't dropping back to the lower portion of the cam at all.

I've made a temporary fix by adding an extra spring but will add sorting it out properly to the list of jobs.....

IMG_2235_zpsdbhjldtq.jpg
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #9 ·
Re: Well spotted!

Actually, thinking about it and looking at the picture, it probably hasn't fixed it at all as the pivot is probably attached to that forked part just above the lever and that doesn't move so probably the spindle is seized after all.
 

·
Registered
Joined
·
695 Posts
The shaft runs in bronze bushes in the carb body, there are no seals and corrosion gets into the bushes and seizes the shaft.
It's an easy enough job, pop the carb top off, remove the diaphragm and slide and access to the lifter shaft is easy. I just cleaned it up and applied RG2 grease on reassembly.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #11 ·
Yes I will do that but will try a bit of plus-gas first as I'd rather not start stripping it at the moment.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #13 ·
Done that job - nice and easy. But to do it I took the carb off as the idle screw has been bodged in the past (still is - I'll need to drill it out when I get a replacement).

But how on earth do you get that rubber boot from the air cleaner back on? I've tried every way I can think of and the bit on the inside of the carb just refuses to go back over the carb inlet despite fashioning all sorts of weird & wonderful tools, smearing it with GT85 etc. Everything is touching something else so there's no room, and the section next to the frame tube just won't go. I can't put the air cleaner end on last as it has an internal trumpet to funnel the air in (although I've considered in desperation chopping that off).

Any hints and tips gratefully received before I set fire to the thing.......
 

·
Registered
Joined
·
695 Posts
Heat the rubber boot up so it becomes pliable, like it was when it was new.
I have a fan heater in my garage and I sit it on top of that for a couple of minutes.
Alternatively you could dunk it in just boiled water from the kettle, but then you need to dry it before fitting.
With it made pliable you'll find it much easier. I usually slip the end over the carb first, then push the other end into the airbox. I've found it easier to completely remove the hose clamps, then thread them around the tube when everything's in place.
 

·
Registered
Joined
·
211 Posts
Even cold it goes on easy if you loosen the air box mounting bolts (3 if I remember correctly) to get some play in that.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #16 ·
Tried heating it up and apart from burning my hand no joy... I will try DrD's suggestion. The other thing that's struck me is that when I took it off I didn't take the cable abutment off the carb but disconnected the cables. I'm wondering whether the abutment is stopping the carb from going into position properly.

Clutching at straws now.....

Still my extended idle screw adjuster has arrived from Taiwan so at least once the carb is back in place I won't have to take it off again.

David Silver has the boot in stock for less than £10 so may try a new one if all else fails.
 

·
Registered
Joined
·
742 Posts
Practical sportsbikes had a feature on restoring rubber boots to make them flexible again.
Oil of wintergreen is the stuff to use and an old pot and a chipbasket.
25ml of the oil in a litre or so of water and bring to the boil, place the old boot in the chip basket and turn it down to simmer for 30min or so.
Take it out and let it cool and refit.
The oil is available from Aromatherapy shops or the like.
Supposed to work very well on old hard rubber airboots and the like.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #18 ·
Sounds interesting and would be relaxing I suppose....

I've got the remains of the idle screw out with the help of a drill guide. Isn't a lathe a useful thing! I had exactly the same problem with my Dominator - screw seized in place and various previous attempts to adjust it had destroyed the slot.

However the replacement extended item I got from Taiwan doesn't fit as the plain portion and taper are different so I've ordered one from Lings. They're on back order so will take a few days.

This was supposed to be my riding around bike while I rebuild the Sunbeam........
 

·
Registered
Joined
·
695 Posts
Just use a standard idle screw, apply Coppaslip to the threads and it'll never seize in place. Not sure why you think you'll need to be adjusting it all the time?
If the bike's standard set it 2.5 turns, if you've pulled the baffles then it's 3 turns. I adjusted mine when I took the baffles out and I've not had to touch any of them since.
 

·
Registered
Joined
·
164 Posts
Discussion Starter · #20 ·
Not sure why you think you'll need to be adjusting it all the time?
I don't. But once would be nice......

Given the awkward position I did think the extended one would be helpful but it's a different length above the thread.

I suspect someone has had a go at the screw to sort out the problem you identified with the slide lifter. But it was very firmly seized in place. I will as you suggest use copaslip when I refit it.

I'm gainfully using the time while I wait to reposition the reg/rectifier and reroute the cables as there was a connector colliding with the back of theair outlet from the airbox. Also removed the 3 bolts (well actually 2 as one was missing) allowing the airbox to slide about 8mm further back. Every mickle maks a muckle as my grandmother never said.
 
1 - 20 of 31 Posts
Top