Cleaning up the carbs/rejetting

Following, yet again from my problems here, and having found it's going to cost me a bit at any garage, I've decided to just go ahead and drain my carbs and clean them out.

First things first: Tools: Socket/spanner set, pliers, screwdrivers, etc.. anything else?

Secondly: Am I taking the carb off, then I can do all the fiddly stuff indoors? or must it all be done on the bike?

I've fitted a CCC can, and removed the baffle. Since doing that, I've lost the poewr surge at around 6k, and it doesn't pull as well above about 6k.

Hence, I may as well rejet while I'm at it. I've got Catpoopman's instructions off the net but have a couple of questions:

Shiming the carbs: will it help, does it affect the mixture?

Where can I get the jets for rejetting. Is the procedure he states the same for UK bikes?

I basically decided, that if I didn't try, I'd always be scared of doing detailed work, so here goes. But I may need some help on the way.

[northwind]

OK spec bikes have slotted needles so we don't need shims. In your case, I reckon bigger main jets would be better- just one size up, whatever that may be (stock jets are Mikuni; I can only think in Dynojet- plus, DJ jets are easier to buy. Really not sure what size is the equaivalent of the stock jets though)

You'll want to own either good mole grips or an impact driver (the sort you whack with a hammer, not the sort you run with an air compressor)- the bolts that hold the float bowl cover and the carb cables on are a great combination of soft and stuck. If I was doing someone else's carbs for the first time I'd also want to have some of that screw-grip stuff that they sell in Maplins, or some valve lapping paste to put in the screw head to improve grip. Probably the hardest part of the entire job is getting them out!

You can get the carbs right off the bike once the choke's disconnected- if you disconnect the cables at the control end rather thanthe carb, it's much easier. (I'd still say to remove the cables at the carb end once the carbs are off anyway- it's worth doing, they're not going to get any less stuck if you leave them alone.

Find 8x M5x10mm bolts before you do it, you're going to chew up at least one of those bolts...

It's not immesnely difficult to do- but you need patience and some competence with tools to do it right. The question is, are you sure it'll fix it? Do you have any more specific diagnosis than "bad fuel"?

Dynojet kits are expensive and I fancied just buying one or two sizes of jet, rather than a full kit. There must be a distributor in the UK.

Is it not possible to use a wrench with a flat head screwdriver piece instead of an impact driver?

What will need to be disconnected from the carbs before removing it? In photos I've seen there're a lot of pipes/cables. If it's too much I might just do it in-situ.

Will get some of those screws as a back up.

I don't know how else to diagnose. This is a quick lo-down:

1. Bike been running a little lean (I think?) since putting on the CCC can and removing baffle. Lost the power surge at about 6k.
2. Filled up with Tesco 99RON, and the bike was even worse. Noticable power loss from standing start. Ran for 2 days like this.
3. Next morning, started OK, but seemd to be idling lower. When i took the choke off it stalled. After that wouldn't start; starter motor's fine, battery strong.
4. Changed sparks to the NGK Iridiums, still not starting.

What I can think of to do now:
1. Test HT leads with a spare plug.
2. Try starting with the air filter intake covered.
3. Drain tank and check the fuel pump/filter.
4. The carbs.

Does that seem about right?

[northwind]

I read your other posts, couldn't really figure out what'd cause it...

PDQ sell individual DJ jets. They might do needles individually, not sure.

Apart from the *&$!^& choke cables, the carbs are fairly simple to remove. Fuel hose (between the pump on teh RHS and the carbs. Various electrical connectors. 2 hose-clip deals attaching the carbs to the engine. (front one is awkward to get to)

The screws are all phillips headed. The impact driver works well because it's force in as well as round, means it's less likely to jump out or round off. The heads are big enough to work well with mole grips. It's not a question of torque applied, more how you apply it without damaging the heads. Some people manage to get them off just fine, mine were all difficult.

Originally Posted by northwind

Find 8x M5x10mm bolts before you do it, you're going to chew up at least one of those bolts...

CLICK HERE free post....£1.65...can't go wrong, TBH i get most of my stainless bolts from this guy, the only ones he doesn't do is M4x10 counter sunk (rear brake res) and flanged buttons which i get from chewy22 here http://www.chewys-stuff.co.uk/

They're off!

Ok it wasn't bad really. The two rubber hoses connected to the airbox were quite bad, beginning to split, so might need replacing, though nothing too major.

Then everything was fine, until it got to that choke cable! Talk about screws made of cheese! That head is completely gone. Eventually, I just disconnected the cable from the control end, though a bit of the plastic surround snapped.

I drained the carbs. Each took around 20 seconds to drain! Sounds to me like it was a bit flooded?

Anyway, next step is to take it apart and see whether there's any problems I can notice. I didn't encounter anything that seemd like it could be the problem while taking the carbs out, so I'm hoping I'll find it in the carbs.

I'm getting those replacement screws, but a few questions:

1. What do I use to clean the carbs?
2. What am I expecting to see that could cause the problem? Note that the valve things seem to move freely along the needles.
3. What size jet do I order from PDQ?

Thanks for all the help, especially northwind!

A couple more questions:

1. Will adjusting the air-fuel mixture using the mixture screws be enough, or ar the jets essential?
2. Isn't 2.5 turns the factory standard anyway?

I just want the bike to run well with my CCC and a standard filter.

Cheers.

[northwind]

The mix scres aren't master screws, they adjust the idle circuit. They do have a bit of an effect on other parts, but no more than everything else does. So no adjustoing them to try to adjust the top end!

Jets shouldn't be essential for your bike. While I had it open I'd want to go up one size anyway, but it's not going to be vital.

Couple more questions:

The Haynes manual says to renew the sealing rings and o-rings. Where do I get these from?

What size main jet do I order? It's just a CCC (debaffled) and stock filter.

And what am I looking for that might be messing things up? Is 20 seconds to drain the floats a long time?

Thanks again.

[northwind]

Don't bother with the rings, unless they seem damaged or worn.

Draining the floats... Not sure. It can take a long time or a short time depending on the angle of the carbs etc. I wouldn't worry about that.