crapping out at 5500

[mason79]

Hello Gents,
I bought a new mac 4 into 1; beautiful, and the foam Unifilters from JC Whitney 45 bucks for 4,

I went to 147.5 mains and 45 pilots as per the suggestion on the forum, stock was 137.5 and 42.5 pilots

mixture screw out 1.5 turns.

my engine is stock,

I lost alot of torque from idle to 3k then I feel a burst, but thats not the problem,... for now

my plugs are black and sooty when i rode it for 30 miles or so, and i did not rev past 5500 without craping out,

on my way home it would not rev past 4500 without crapping.

the petcocks are feeding fine

my bike ran fine with the stock pipes and air box , even though i did not sync the carbs, mercury is ban in California now, so that is for later ,I just did a visual, but the idle climbs to 2000k



i got home and clean the plugs and took off the filters cause i thought maybe there was too much oil on them making a rich condition.

and rode around the block, pull a plug and it had turned black, still won't rev past 5500. even with the filters off.

my float were the same as when i had the stock arrangment.

so my problem is black plugs, won't idle at 1000, won't rev past 5500

i really like the way everything looks now it just has to run.

thanks for the help!

[Goin Commando]

Sounds to me like your jetted too fat. Try changing the mains back to 142.5 and see what happens. If it gets better then you're goin the right direction.

[mason79]

Originally posted by Goin Commando
Sounds to me like your jetted too fat. Try changing the mains back to 142.5 and see what happens. If it gets better then you're goin the right direction.

how about the pilot back down? and thanks man.

[Hired_Goon]

Mason, I also have a four into 1 exhaust and pod filters. I haven't rejetted yet apart from my pilot jet. Running 45 as well replcing the 42.5.

I'm still running the 137.5 Mains and it runs perfectly.

I would suggest going back to 137.5 mains and trying from there. Get it to idle first and run nice at idle. Then go up 1 size in the mains rather than the 2.

Give it a run using standard mains and see if it falters at any revs.

Mine pulls like a schoolboy right up to nine grand but runs far to lean for my liking. Got to be careful not to do any fast constant speeds till I get the jets replaced. I am going to go up 1 size only to start with when I get my hands on some jets. (damn postal service seems to have lost them)

I also used a colourtune to set my mixture screws and found 1 and a quarter to 1 and a half was spot on for colour. Maybe try a quarter turn in.


Other causes can be a faulty diaphragm not lifting one slide. Had that once wher it showed the same symptoms as yours. Eg died at a certain rev range.

[Ken Talbot]

Mason, turning the pilot back down will only change what's happening at idle, it won't do anything for your plugs being black at operating speed. Start back at the stock jets and see what the plugs look like there. If they're a bit lean, start with adjusting the floats a couple of milimetres. If they're still lean, then go up a jey size.

BTW - all of this is just shooting in the dark if the carbs are not properly synchronized, either with a set of mercury sticks or with a set of vacuum gauges.

[mason79]

Yes Guys,

I never synced the carbs and i will eventually, no one sells mercury anymore, i may have to buy gauges.

that said the bike kicked butt with the stock setup, to redline and started right up every time and idled even better.

i am going to do as you all are saying, but i just can't understand why almost everything i read here says, pods effect jetting more tha exhausts and with the combination, you must go up, up, and up.


now in practice, keep the stock jetting, and play with the floats which is fine by me cause heck it's free, but why in the heck didn't they say that before?

okay your'e saying it now, i'll go change to stock, which i thought was kinda lean to begin with, the engine pinged climing a hill on a hot day,

i guess i should buy a timing light as well

while i'm at it i think i'll spring for a torque wrench and shims...

[John]

Remember to check to see if the inner diameter of the filter boots where they attach to the carbs is not blocking the different orifices in the inlet of the carb. That has been known to cause major problems.

[TopCatGr58]

Mason,

Wait, before you put the stock jets back in! You put on Indy filters. WHAT did you do with the vent tubes for the carbs? IF you just connected them together, or plugged them up, then that's the problem. The bowls need to vent and will run very rich and poorly until you do.

However, after reviewing your post, 147.5 does seem a bit too rich. The guide says 4 sizes - 1 for combined changes, so 145's at max. You might also have too much oil in the filters?

Like Goon said, I too, ran the 4-1's first, and then put on the Indy filters when I did my big bore, and I didn't rejet at that time, and it seemed to run okay, but the plugs did seem quite lean, so I went up 3 sizes from my stock 110 to 117.5, have nice color and plenty of power to redline. Good luck!
T.C.

[mason79]

lip service

Originally posted by John
Remember to check to see if the inner diameter of the filter boots where they attach to the carbs is not blocking the different orifices in the inlet of the carb. That has been known to cause major problems.

i took them off and they are foam unifilter, they are not notorious for that lip...

[mason79]

Originally posted by TopCatGr58
Mason,

Wait, before you put the stock jets back in! You put on Indy filters. WHAT did you do with the vent tubes for the carbs? IF you just connected them together, or plugged them up, then that's the problem. The bowls need to vent and will run very rich and poorly until you do.

However, after reviewing your post, 147.5 does seem a bit too rich. The guide says 4 sizes - 1 for combined changes, so 145's at max. You might also have too much oil in the filters?

Like Goon said, I too, ran the 4-1's first, and then put on the Indy filters when I did my big bore, and I didn't rejet at that time, and it seemed to run okay, but the plugs did seem quite lean, so I went up 3 sizes from my stock 110 to 117.5, have nice color and plenty of power to redline. Good luck!
T.C.

hey t.c.,

i did not plug the vent hoses, they are longer and they are up and outa the way, sort of if you can call that little space a space.

yeah 3 for the pods and 2 for the pipe minus one equals, 4 up from 137.5 stock to 147.5 and one on the pilot for every 3 on the mains,

runs like crap, the "jetting hints" if it has not stood the test of time and is inaccurrate, may i suggest a revision or deletion?

anyhow thanks for the help man.

-mason

[Hired_Goon]

I think the jet tips section is still on the money but maybe needs a bit added to show the correct procedure for getting it right.

Pipes usually are not a problem and can be run happily with standard jets.

The pods, however, changes the airflow dramatically.

IMO, the changes should be made gradually. EG, go up ONE jet size at a time, tune and test till performance starts going downhill. Then go back to the previous size jets or whichever set YOU felt worked the best for YOUR bike.

NEVER replace two sets of jets at once. EG up 1 pilot and 1 main.

Always test after a single change. Means a little more work but can save a LOT of time trying to work out which bit caused the performance loss.

These bikes are all the same but are also very different when different mods are done.

Cheers
HG

[mason79]

back to stock 137.5 and 42.5 pilots runs better than stock,

1 to 2 % loss below 2750 rpm, negligeble, and clean all the way to 8500, and powerful!!

idle smooth at 1k.

start quick when hot, nice not for the darn leaky new" petcock proble, don't you just love it?

glad i did it! thanks guys again!