Curvy has flat spots.

[ricky_t]

Hi all

I have a 99 curvy that does not offer the instant acceleration it used to have. It still gets to the same high speeds. The carbs were balanced in December by a local garage.

Can you help?

Thanks

[Sid Squid]

Not with a sparse description like that, no.

Could you give us slightly more to go on?

[ricky_t]

After re-reading my first post it is a bit vague!

Idle is fine and the choke seems to work so I think the choke plungers are ok. As you ride along and open the throttle there is hesitation around the 3-7k rpm. After 7K the bike is normal once again.

It feels like there is turbo lag as it you have to wait a second before greater acceleration occurs.

I am going to check if there is an air leak around the air box.

[Biker Biggles]

Does it have aftermarket exhaust or air filter?Does it need a service and plugs/air filter renewing?I would get the plugs out and inspect them anyway,and I would get the choke plungers out and make sure they are not sticking as a routine check as well.

[ricky_t]

The bike was completely serviced in December by the dealer, new plugs, coolant etc.

I have been out to the bike now and think it is the carb balance so I have bought a carbtune and see how that goes.

[Alpinestarhero]

See how the balancing goes; if it dosn't help too much, just check the spark plugs for any sooty deposits. You may have a slightly rich-running engine; this could be down to wear and tear on the carb jets / needles (how many miles on the bike?) so they could need some adjustment (I cant advise at all for that!) or it couuuulld be the choke, more specifically some corrosion on one or both of the choke plungers meaning they dont shut fully...it only needs to be open a fraction of a gnats bollock to richen the mixture, which could be giving rise to the problems you are encountering.

Keep us posted :)

[ricky_t]

I have balanced the carbs today and got them sort on with my new carbtune device.

Unfortunately the problem is still there I noticed my last tank only got 100miles whereas normally i would get about 130.

The bike still needs the choke to get it started but when I turn it off it goes back to normal revs as it should be. Could the plungers still be stuck?

The bike has done 25000 miles and the plugs are brand new about 150miles ago. I am going to search the forums on how to adjust the choke plungers now.

[gettin2dizzy]

What did the plugs look like when you changed them?

[ricky_t]

No idea it was done at service time last year. I am going to remove them now and see.

[custard]

sounds like my other halfs hornet.

give it a handful below 5k and it hesitates then goes like a scalded cat. This has been caused by enrichening the mixture (hamfistedly), so as previous posters have said check your jets. running rich would also explain shorter fuel range and sooty deposits.

[Alpinestarhero]

could the plungers still be stuck?




Unfortunatly, yes :( only takes a small opening to cause a problem

[ricky_t]

Bike is fixed:D:D:D:D:D:D:D:D

It was a crankcase breather pipe that was disconnected at the crankcase side! Oh silly me for not checking the obvious first.

At least I have now lubed my throttle cables and my carbs are balanced.

I don't think the plungers are stuck now because the performance is back on track. They may still be sticking but I'll get it sorted when/if they cause a problem as I don't really want to do the choke plunger job!

[Alpinestarhero]

Bike is fixed:D:D:D:D:D:D:D:D

It was a crankcase breather pipe that was disconnected at the crankcase side! Oh silly me for not checking the obvious first.

At least I have now lubed my throttle cables and my carbs are balanced.

I don't think the plungers are stuck now because the performance is back on track. They may still be sticking but I'll get it sorted when/if they cause a problem as I don't really want to do the choke plunger job!

Hurrah!

Save the plunger job then for another day, even if its just a preventative measure so you dont come a cropper

Ah, the good ol' breather hose

Carry on!

[ricky_t]

Problem is back again.:mad::mad::mad:

I have also noticed a lack of engine braking so I think it is the choke plungers as previously mentioned. I have taken the carbs off and the screws to the plungers are made of cheese!

I also need a new choke cable!

I am really unhappy.

[ricky_t]

If the bike still idled at 1300rpm and still has flat spots could it be the choke plunger?

[ricky_t]

Just taken carbs to local garage and they are stuck!

I couldn't get my screws off with my impact driver so I have given them to people who can do the job!

Bit annoyed as this year the bike cost me £500

rear tyres -£120
Mot and retest - £44
Battery - £42
EBC HH pads - £50
Labour to strip and clean) front brakes - £70
Tax -£70
Carbtune -£62
Labour to strip and clean carbs -£35

Hopefully it will be worth it considering I have spent 33% of the bike's value!