Hi guys.

Well I finally managed to get the float bowls loose. Who ever removed them before me must have been a ham fisted idiot using a chisel instead of a screw driver. All the screws need replacing.



I've done 2 lots of jets so far and they have all been pretty clean, although the pilot jet on the affected cylinder looked a little suspect until I blew through it. Think they have been apart recently. On that cylinder I found that float isn't spring loaded any more. Is this a problem?

The main jet sizes have been 120 rear, 117.5 front.

The gaskets are knackered and will all need replacing.

I think the screws are M4 x 15mm. Can I just buy some from ebay or are these a Honda only item?
Where is the best place to buy the float bowl gaskets?

Thanks again,

Mitch.

You can get everything you need, plus some awesome friendly advice and a good chat, from Rick Oliver.

His parts/price list is at the top of the V4 General section, he'll sort you out

I had a similar problem. Cleaned carbs, checked and checked again. Still dropping a cylinder. Checked coils and plugs and they seemed fine. In the end I changed the plugs, and the HT leads. The plugs probably needed changed, but I'm convinced it was a corroded HT lead that was the issue. For the all the cost of the cable, and an hour to fit, its well worth changing it over. I think the cable was 2 pounds a meter, and 2 is more than enough.

Sam-NI wrote:I had a similar problem. Cleaned carbs, checked and checked again. Still dropping a cylinder. Checked coils and plugs and they seemed fine. In the end I changed the plugs, and the HT leads. The plugs probably needed changed, but I'm convinced it was a corroded HT lead that was the issue. For the all the cost of the cable, and an hour to fit, its well worth changing it over. I think the cable was 2 pounds a meter, and 2 is more than enough.

Hi thanks! Have you got a link to the cable I'll need to buy? I did a resistance test on the leads and coils and all came back ok. Wouldn't this rule out leads?

Would I be right in saying if the float spring is missing (if the seat is still there) the seat could be getting stuck shut when the float fills up?

Icemaestro wrote:Would I be right in saying if the float spring is missing (if the seat is still there) the seat could be getting stuck shut when the float fills up?

I really don't know tbh. I'd like it if someone could chime in before I get the carb back on the bike. How do you replace the float springs and where do I get them from? I''d prefer not to have to remove the carbs again in he near future!

If the spring loaded pin is stuck down, then the float height [and fuel level] will be high which may give poor low rev performance [not so noticable at higher revs]
Can you free the pin with brake cleaner and tapping/poking the centre pin, I have freed them in the past.
New springs are not sold on their own, it will be hard to re seal the needle even if you get it apart.
Old carb needles never used springs, I think they dampen the action to reduce seat wear.

The weight of the float will pull the needle off its seating when the fuel level drops.

Carb blockage isthe most common problem.

The carb screws will have been knackered by somone using a normal screwdriver and not a JIS screwdriver at some point in the bikes history.

I got a set of JIS screwdrivers from Blair (http://litetek.co/Tools_Koken.html) - same guy who sorted out the viton carb seal sets and they are very nice indeed. Alternativly Rick Oliver does a SS set of allan screws to replace them all for about a tenner

Not sure what you mean about the float no longer being spring loaded? As far as I can remember and as far as I can see on the schematics (http://www.cmsnl.com/honda-vfr400r3-199 ... ml#results) there is no spring. When you are working on the Carbs you will be, I assume, working with them upside down. So picture them the corect way up with the float bowl fitted and (if my memory serves me right) the floats drop down unseating the seat valve (http://www.cmsnl.com/products/seat-set- ... ygWA6ywWy8) allowing fuel to flow into the float bowl. once the upper level is reached the float rises seating the valve and stopping the fuel flow into the bowl.....no springs.
I would just check all the components are clean and free to move.

The float needle valve has a spring loaded pin that sits on the float level adjuster.

Hi guys, in reply to the float 'spring' issue, if the carbs are upside down and I push on the floats, they all spring back to their original position. On the misfiring cylinder this doesn't happen, although the valve does still open and close fine and is not stuck.

Is there a guide on here for setting float heights? This is all new to me and I'm desperate to get it done in time for my trackday.

Also, Is it worth me getting a new set of HT leads from RO? Mine look like the originals. Secondary coil resistance was 24k ohms I think which was with the multimeter in the plug caps. Is this proof that they are functioning correctly?

Thanks again,

Mitch.