Most likely culprit? Valve clearances or carbs?

[Steve]

Two questions in this first statement:

I fully understand the bike would run like crap as is but was hoping someone could confirm or not if the motor is so sensitive that tight clearances would stop it firing on three cylinders? Assuming the carb rebuild was ok.

1. Yes, tight valves WILL keep it from starting.
2. Wild assumption, as we have not yet heard whether you followed the "strip and dip" method of cleaning.

Thou didst not follow exactly the procedure as one had not seen that excellent "how to" at the time. Thou shall start again, good practice!

OK, this apparently answers the "did you dip them?" question, but in a negative manner.

It also says in the how to that the bike may not even run without the air box.

Not quite true. It will start OK, but will likely have problems responding to ANY throttle input.

You can easily get 'em to tickover without the airbox fitted. Just don't bother twisting the right grip.

See?

What do spark plugs (#!, #2, #3) look like after #4 carries on for a while- wet ,dry?

Number 4 looks normal but the others were dry. There was fuel in the float bowls and the float level is correct. Pilots/fuel ways blocked?

To me, this is rather conclusive evidence to show that your carbs are not clean enough to allow gas to flow through them.

I did check the pilot jets were clear with a piece of wire but I couldn't get them out.

There are holes on the sides of the pilot fuel jets that you can't poke with a wire unless you remove the jets from the carbs.
Besides that, there are small passages from the pilot jets to the mixture screw that you can't poke with a wire, either.
You HAVE to dip the carbs.

I will get to the valve clearances but I'm now thinking the carbs are probably where I should start.

Actually, you do them both at the same time. On the first day, start by stripping the carbs down to itty-bitty pieces, put the pieces for the first carb in the dip. Remove the valve cover, start measuring your clearances. Some guy named "Steve" has a spreadsheet that he offers that will help you record these. Look in his signature. Remove your shims (one at a time, please) and record their sizes in the spreadsheet. When you find out what sizes you need, order them from the "shim club" on GSR or from Z1 Enterprises. (Z1 also has the best price on valve cover gaskets.) This is also a good time to order new o-rings for the carbs from cycleorings.com.

On the second day, remove the first carb's parts from the dip and rinse them in HOT water, then spray carb cleaner through the passages and follow with a blast of compressed air (wear safety glasses ). Put the second carb's parts in the dip.

On the third and fourth days, you can repeat the activities of the second day, but by the fourth day, you should have received your shims and o-rings. Finsh assembling your carbs, put your new shims in, re-check your clearances with the 'new' shims, start the bike.

The bike won't run for crap without the airbox. Period. You can tape over the carb openings, leaving only about 20% exposed if you just have to listen to it run before committing funds, but it will still run like crap.

Again, it will start and idle just fine without the airbox. If you really want to hear it rev, and maybe even go for a ride around the block, fold a shop rag in half and clamp it to the outer carbs, while keeping it taut over the inner carbs. This will work well enough for a quick ride, but is not accurate enough to do any jetting checks.

.

[GelandeStrasse]

Thanks loads for all hints and tips guys! What a great forum. I now have a plan of action to follow, yay! All that shooting in the dark business is frustrating. Now I have some benchmarks to aim for. This kind of info is not in any manual!

Thanks again, watch this space

[GelandeStrasse]

Just wanted to share my excitement now I've been set on the right path by GSResourcers!
Update: all pilots on cyls 1, 2 + 3 totally blocked and number 4 clear matching the symptoms exactly. Brilliant!

[hampshirehog]

Just wanted to share my excitement now I've been set on the right path by GSResourcers!
Update: all pilots on cyls 1, 2 + 3 totally blocked and number 4 clear matching the symptoms exactly. Brilliant!

Don't just clean those carbs. CLEAN them.....! Take your time and do a really, really thorough job; it'll save you time and heartache in the long run.

[GelandeStrasse]

Don't just clean those carbs. CLEAN them.....! Take your time and do a really, really thorough job; it'll save you time and heartache in the long run.

10-4 that, just waiting a couple days now while the release spray to works its magic on the pilot jets

[BassCliff]

Hi,

Refer back to your "mega-welcome" for the necessary maintenance lists then check my website for the "how to" guides. You have a 30 year old motorcycle that needs 20 years worth of maintenance. All of the systems, components, and sub-assemblies must be checked, cleaned, repaired, replaced, adjusted, etc, in order to have a good running machine. Take absolutely no shortcuts in order to save a lot of frustration.


Thank you for your indulgence,

BassCliff

[tkent02]

Just wanted to share my excitement now I've been set on the right path by GSResourcers!
Update: all pilots on cyls 1, 2 + 3 totally blocked and number 4 clear matching the symptoms exactly. Brilliant!

Damn, we're good!

[Steve]

Damn, we're good!

You got THAT right.

(We're humble, too.)

.

[GelandeStrasse]

Hi,

Refer back to your "mega-welcome" for the necessary maintenance lists then check my website for the "how to" guides. You have a 30 year old motorcycle that needs 20 years worth of maintenance. All of the systems, components, and sub-assemblies must be checked, cleaned, repaired, replaced, adjusted, etc, in order to have a good running machine. Take absolutely no shortcuts in order to save a lot of frustration.


Thank you for your indulgence,

BassCliff

Thanks, links saved, advice gratefully absorbed, bet you guys love ignorant newbies

[Nessism]

Thanks, links saved, advice gratefully absorbed, bet you guys love ignorant newbies

We love helping newbies...mostly those that do a little homework, search out answers here and on basscliff's website, then come and ask intelligent questions that show they are actually trying! Guys like that are golden and don't stay newbies for long.

[GelandeStrasse]

just sharing a little shim removal tip to contribute after all the help I got recently

I found using a small piece of aluminium foil folded over a few times as a ramp to slide the shims up and out made the job quite a bit easier than fiddling around trying to grab the shims with needle nose pliers. Less likely to scratch anything too or damage the cover gasket face.

'pop' the shim with your screw driver, insert foil ramp and then push the shim out from the other side out with another zip tie, it'll come far enough so you can grab it with your fingers.

[btbarb]

Good one, I like the idea of the zip tie as an extra hand.

[BassCliff]

Hi,

It looks like necessity is the mother of invention. Good work.

It looks like somebody used some goopy stuff to glue down the old valve cover gasket. That's going to be fun to remove. Be very careful not to scratch or gouge the surfaces. Use only grease on the new gasket. It will make removal much easier next time.

You can also use hemostats to help in the shim removal. I found an inexpensive pair at the Army/Navy surplus store.


Thank you for your indulgence,

BassCliff

[cowboyup3371]

That or tweezers

[tkent02]

Levitation is the quickest.