Author Topic: Carbtune issues (Read 10907 times)

IAmCitizenMe · « **on:** April 05, 2010, 03:24:03 PM »

So I got my Carbtune in the mail today. I set it up all proper and started my engine. It backfires like hell and idles like crap and I am getting no reading on the Carbtune. I checked and double checked and everything is set up properly. Am I missing something completely obvious?

Nikkisixx · « **Reply #1 on:** April 05, 2010, 03:27:07 PM »

How did it run before you hooked up the carbtune? Is it poping through the carb or exhaust?

IAmCitizenMe · « **Reply #2 on:** April 05, 2010, 03:50:09 PM »

It popped a little bit out of the #1 carb and exhaust but now it won't even stay idling. It has to have something to do with the adapters. I'm using the plastic ones and I screwed them in nice and tight with my fingers. But now I have to pull the choke all the way out for it to run at all. Quite frustrating.

IAmCitizenMe · « **Reply #3 on:** April 05, 2010, 04:07:43 PM »

So I unhooked the Carbtune and put the screws back in and now it won't even start. What the heck did I do wrong?!

scottly · « **Reply #4 on:** April 05, 2010, 04:19:50 PM »

Got gas?

IAmCitizenMe · « **Reply #5 on:** April 05, 2010, 04:21:57 PM »

Quote from: scottly on April 05, 2010, 04:19:50 PM

Got gas?

Yup. Plenty of gas.

Johnie · « **Reply #6 on:** April 05, 2010, 04:21:57 PM »

Just double checking, you did put the restrictors in each tube correct?

IAmCitizenMe · « **Reply #7 on:** April 05, 2010, 04:23:22 PM »

Yea. The restrictors are all connected correctly.

domer · « **Reply #8 on:** April 05, 2010, 04:32:44 PM »

sounds llike you might have a fuel delivery issue... clean petcock screen? in-line filter? clean carbs? pulling the choke out to keep it running means its starving for gas... yet backfire through the carbs means lean. either way i think a little more info is needed about your set up...

Johnie · « **Reply #9 on:** April 05, 2010, 04:37:00 PM »

Forgive me but we are grasping here. Are you sure you installed the adapters to the correct spot on the carb. Again, no offense just grasping here at how it could have gone from running to not running at all? I saw a guy attach the adapters to the air screw holes once rather than the sync ports.

IAmCitizenMe · « **Reply #10 on:** April 05, 2010, 04:45:03 PM »

The carbs are clean, petcock screen is clean. Gaps, timing, spark, all checks out fine. Before I hooked up the Carbtune the only problem I had was some backfiring through #1 due to some old rubber couplers which have since been replaced. So I hooked up the Carbtune and it all went south and now it won't start.

I had put the tank up on a shelf and ran a longer fuel hose. Other than that and attaching the Carbtune, I didn't adjust or change anything.

Quote from: Johnie on April 05, 2010, 04:37:00 PM

Forgive me but we are grasping here. Are you sure you installed the adapters to the correct spot on the carb. Again, no offense just grasping here at how it could have gone from running to not running at all? I saw a guy attach the adapters to the air screw holes once rather than the sync ports.

Man, I hope you're right, even if it does make it glaringly obvious the degree of my newbie-ous-ness.
This appears to be the only place to attach the adapters. And they fit perfectly.

Johnie · « **Reply #11 on:** April 05, 2010, 04:47:35 PM »

Yup, that looks like the sync port alright. Are your plugs wet?

Brian G · « **Reply #12 on:** April 05, 2010, 04:59:32 PM »

I'm thinking that something else has happened between the time you connected the carbtune and replaced the screws for a test run. There's no way that simply removing and replacing the sync port screws can affect your engine to that extent.

I see in the photo that the tops are off of the carbs. Were they off when you tried to start the engine? Perhaps worn slides are allowing air from the top to lean out your mixture. With the tops on the carbs, perhaps manifold vacuum pulls the slides tight and reduces the air leakage?

Johnie's right - we're grasping here....

Good Luck,
Brian

IAmCitizenMe · « **Reply #13 on:** April 05, 2010, 05:25:21 PM »

Okay. I, thought maybe having the fuel tank to high might cause too much pressure. So I cut the extended fuel line I was using short and set the tank closer to the engine. It seems to be running better, but I am still getting zero readings on the Carbtune unless I rev it up around 4,000.

Johnie · « **Reply #14 on:** April 05, 2010, 05:41:46 PM »

That is strange. I get a reading on my Morgan when I am barely able to get an idle? I have to admit I am stumped...

IAmCitizenMe · « **Reply #15 on:** April 05, 2010, 05:43:18 PM »

Does it matter what tube you attach to which carb? I am completely floored.

scottly · « **Reply #16 on:** April 05, 2010, 05:46:45 PM »

Quote from: Brian G on April 05, 2010, 04:59:32 PM

I see in the photo that the tops are off of the carbs. Were they off when you tried to start the engine? Perhaps worn slides are allowing air from the top to lean out your mixture. With the tops on the carbs, perhaps manifold vacuum pulls the slides tight and reduces the air leakage?

Johnie's right - we're grasping here....

Good Luck,
Brian

IAmCitizenMe · « **Reply #17 on:** April 05, 2010, 05:54:23 PM »

Quote from: scottly on April 05, 2010, 05:46:45 PM

Quote from: Brian G on April 05, 2010, 04:59:32 PM

I see in the photo that the tops are off of the carbs. Were they off when you tried to start the engine? Perhaps worn slides are allowing air from the top to lean out your mixture. With the tops on the carbs, perhaps manifold vacuum pulls the slides tight and reduces the air leakage?

Johnie's right - we're grasping here....

Good Luck,
Brian

Right, sorry. No, I put the tops back on and it made no difference. I've been out in the garage tinkering with it. I'm wondering if there is something wrong with the Carbtune, but I highly doubt it. I'm going back out to sit down and stare at the machine all night and see if I have an epiphany.

mlinder · « **Reply #18 on:** April 05, 2010, 05:57:55 PM »

I had this happen once to kits 650.

Was so weird. I mean, bike ran, but carbtune was unresponsive.

I dorked around with something else for a while, came back, and the morgan carb tune worked fine...

scottly · « **Reply #19 on:** April 05, 2010, 05:58:17 PM »

Hey, have you, uh, tried sucking on the "Carbtune" to see if you can get any kind of reading?

IAmCitizenMe · « **Reply #20 on:** April 05, 2010, 06:01:00 PM »

Quote from: scottly on April 05, 2010, 05:58:17 PM

Hey, have you, uh, tried sucking on the "Carbtune" to see if you can get any kind of reading?

No. I haven't sucked on my Carbtune... Hell, I'll try anything once...

Brian G · « **Reply #21 on:** April 05, 2010, 06:09:02 PM »

Quote

So I cut the extended fuel line I was using short and set the tank closer to the engine. It seems to be running better,

I think that's a coincidence. Within reason, when the float bowls are full the needle valve should be closed and the fuel flow isolated regardless of the tank height.

I'm fixated on the fact that the carbtune is not reading (you mentioned that it did give a reading at 4000 rpm so I'm assuming it works); if it is not reading then there is no vacuum. And the only reason I can think of for no vacuum is an air leak - and one that is common to all four carbs! (This is more-or-less supported by the fact that you needed large amounts of choke just to keep it running.) Having said that I would have no idea where to look for a leak of that magnitude and look forward to reading any suggestions that the forum heavyweights might care to make should they stumble across this thread.

Regards
Brian

IAmCitizenMe · « **Reply #22 on:** April 05, 2010, 06:10:24 PM »

Sucked. All four tubes responded. I'm going to go eat some leftover ham and let my blood pressure get back down to normal before I hurt someone.

domer · « **Reply #23 on:** April 05, 2010, 06:17:45 PM »

dont quote me on this... but i thought i might have read some where on here that the plastic adapters are complete #$%* and should be replaced

its out there, but all 4 could be leaking... sucking enough at 4k to get the needles to twitch? just a thought...

IAmCitizenMe · « **Reply #24 on:** April 05, 2010, 06:25:09 PM »

Quote from: domer on April 05, 2010, 06:17:45 PM

dont quote me on this... but i thought i might have read some where on here that the plastic adapters are complete #$%* and should be replaced its out there, but all 4 could be leaking... sucking enough at 4k to get the needles to twitch? just a thought...

Yea, I read that people have bought metal adapters, but 4,000 rpms is a lot. I can't imagine that the plastic onces are that useless since everyone swears by the product.

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Author Topic: Carbtune issues (Read 10907 times)