Engine problems after 95" build part II - help needed

[Adam76]

Did you get the spring and diaphragm correctly installed in the accelerator pump?

Thanks Hoss, that's what I was thinking.
But the weird thing is it was all working fine when I pulled it off what maybe 2 months ago??

Can it be checked without removing the carb altogether?
I guess I'll have to pull it off and strip it down again. Damn, not a single thing has gone smoothly with this build. 

Thanks for the reply

[Hossamania]

No, carb needs to come off to pull the diaphragm cover. Spray some carb cleaner thru the passage to make sure it is clear once disassembled.
Before you pull it, get it running one more time and twist the throttle a little to make sure it's not squirting.

[Hossamania]

One more thing before you do anyrhing, double check your metering rod, make sure it is pushing down properly on the pump.

[Adam76]

Thanks, will do.
It's had a full rebuild kit through it only a few months ago, so hopefully something simple.
Cheers

[Adam76]

I've taken the carb apart again and cleaned everything out.

Put in back on and at least it runs now. Still needs a fair bit of tuning, so I'll go for a short ride tomorrow and post the results.

[Hossamania]

Did you observe the carb while running before the ride? Pump is squirting, slide is rising with throttle? It shouldn't really be running too rough, especially at idle, even if the tune is off. Check for vacuum leaks. Extended choke use may be necessary until warm, mine likes choke even in very warm weather for a while, obviously longer when it is cool or cold.

[Don D]

Get the carb fixed before a shakedown run. Look at the plugs to get an idea what is happening

[Adam76]

Did you observe the carb while running before the ride? Pump is squirting, slide is rising with throttle? It shouldn't really be running too rough, especially at idle, even if the tune is off. Check for vacuum leaks. Extended choke use may be necessary until warm, mine likes choke even in very warm weather for a while, obviously longer when it is cool or cold.

Thanks Hoss, yes I have the pump squirting again now -- but the slide does not rise with opening of the throttle??

What would cause the slide not to rise?

I've checked for vacuum leaks, pretty sure there's none.

Thanks.

[Hossamania]

The diaphragm got pinched when the top cap was put on, or there is a pinhole in it. More than likely it is pinched.
Never done it myself...... 
Wait, yes I have, more than once. Pretty common.

[Scotty]

The diaphragm got pinched when the top cap was put on, or there is a pinhole in it. More than likely it is pinched.
Never done it myself...... 
Wait, yes I have, more than once. Pretty common.

    

Slide will only rise with motor running though don't forget

[Adam76]

The diaphragm got pinched when the top cap was put on, or there is a pinhole in it. More than likely it is pinched.
Never done it myself...... 
Wait, yes I have, more than once. Pretty common.

    

Slide will only rise with motor running though don't forget

Yes, otherwise there's no vacuum

[Adam76]

OK, so I got the bike running and set the idle speed.

CV velocity needle
46 pilot
195 main
2.5 turns out

Carb seems to be working OK,  but I'm getting a bit of coughing and spluttering / back firing when idling and running gently through the gears.

Does that mean I need a larger pilot jet? Maybe a 48 ?

I'm hoping it's an easy fix so I can actually put some miles on this build. 

Thanks

[Scotty]

Is it spitting back out through the carb or the exhaust?
If through the carb a 46 and a 195 it should be close and sounds like it is leaking through the manifold to head seals and running lean. Putting a 48 in will just mask the problem and not fix the issue.

[Adam76]

OK, thanks. I cannot tell if it's backfiring through the carb or the exhaust. I think it's actually the exhaust....

I'll check for manifold to head leaks again, although I'm pretty sure I've got the flange bolts are as tight as they can go without stripping them 

[Scotty]

Backfiring through the exhaust usually indicates a rich condition as raw fuel ignites in the exhaust.

Going back to the carb did you put the manifold and carb on together with the  air filter bracket ?

See if you fit the manifold and it's not straight or even slightly crooked and then you put a carb in and start doing up bolts to the head etc you can push the manifold and roll the seals.
Needs to be put in as a unit or at the very least HD used to sell a plastic bracket that you could use for carbs and efi to line up the carb and manifold without the air cleaner getting in the way.

[Adam76]

Backfiring through the exhaust usually indicates a rich condition as raw fuel ignites in the exhaust.

Going back to the carb did you put the manifold and carb on together with the  air filter bracket ?

See if you fit the manifold and it's not straight or even slightly crooked and then you put a carb in and start doing up bolts to the head etc you can push the manifold and roll the seals.
Needs to be put in as a unit or at the very least HD used to sell a plastic bracket that you could use for carbs and efi to line up the carb and manifold without the air cleaner getting in the way.

OK, I see.

No, I installed and tightened up the manifold with new seals before installing the tank, carb, air cleaner etc because it was easier access to the flange mounting bolts....

So you think I should disassemble everything and put the manifold on with the carb and air cleaner in place?
That's going to be tricky to get to the flange bolts

Cheers

[Scotty]

Yes I have a 6" ball end allan that slips in nicely to do the top ones and the bottom obviously done from the other side.
It's tricky but it's doable and keeps everything lined up.
Put new seals and fit manifold but do no tighten down.
Fit carb with air cleaner bracket and attach breather bolts but do up only finger tight whilst checking manifold is not binding anywhere.
Once they are finger tight then do up manifold bolts and then finish breather bolts and then put tank and then put filter and cover on.
That works 99% of the time unless heads have been milled a lot and then you may need to do some work to the manifold. But you should see if that is required when fitting without flanges and seals as it should not bind up on the ports when in position.

[Hossamania]

Did you get the slide working properly? If that diaphragm got pinched, that will cause your poor running condition.

[Adam76]

Did you get the slide working properly? If that diaphragm got pinched, that will cause your poor running condition.

Yes, the slide is working properly.

It has to be a manifold leak because nothing has been changed on the carb since it was taken off the bike the last time and it was running perfectly fine then?

Thanks.

[billbuilds]

     Is the float height set correctly and is there fuel in the bowl? Can you see the plunger rod going into the rubber boot above the accelerator pump? Are you certain the the needle jet is installed correctly? Those are some of the things I'd be checking. Good luck and let us know.

[hattitude]

Yes I have a 6" ball end allan that slips in nicely to do the top ones and the bottom obviously done from the other side.
It's tricky but it's doable and keeps everything lined up.
Put new seals and fit manifold but do no tighten down.
Fit carb with air cleaner bracket and attach breather bolts but do up only finger tight whilst checking manifold is not binding anywhere.
Once they are finger tight then do up manifold bolts and then finish breather bolts and then put tank and then put filter and cover on.
That works 99% of the time unless heads have been milled a lot and then you may need to do some work to the manifold. But you should see if that is required when fitting without flanges and seals as it should not bind up on the ports when in position.

 


OP.... This is a video I found before mounting my intake manifold awhile back.... at about 2:25.. he talks about what Scotty is telling you to do above...

I have followed this procedure a couple times and never had leaks...

https://www.youtube.com/watch?v=rEVE9n_3BzA

[Don D]

I used tool 40054-01 in the day.

[billbuilds]

     Be sure to use some spray silicon on your manifold seals so that they seat properly.

[Adam76]

Be sure to use some spray silicon on your manifold seals so that they seat properly.

Thanks Bill, what is spray silicone?

Will a bit of red rubber grease do the same thing?

[Scotty]

Be sure to use some spray silicon on your manifold seals so that they seat properly.

Thanks Bill, what is spray silicone?

Will a bit of red rubber grease do the same thing?

You can get it at Bunnings
WD40 Silicon Spray