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Discussion Starter #1
Can turning the screws out too far cause any damage to the motor?
Also, if a bike pops on decel and has no vacuum leaks and has been coastered could turning the screws in stop the deceleration popping or do you always turn them counterclockwise (out) to stop it??
My bike has no leaks, its been coastered, new plugs, runs like a raped ape, has V&H Cruzers on it and with the idle screws backed out 3.5-4 turns each it still pops like a mother on the front cylinder (Brake side exhaust)
 

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Can turning the screws out too far cause any damage to the motor?
Also, if a bike pops on decel and has no vacuum leaks and has been coastered could turning the screws in stop the deceleration popping or do you always turn them counterclockwise (out) to stop it??
My bike has no leaks, its been coastered, new plugs, runs like a raped ape, has V&H Cruzers on it and with the idle screws backed out 3.5-4 turns each it still pops like a mother on the front cylinder (Brake side exhaust)
Betcha a beer you have a leak somewhere...:beerchug:

Do you have washers under the exhaust bolt acorn nuts? With V&H Cruzers, you need them.
 

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Discussion Starter #3
Betcha a beer you have a leak somewhere...:beerchug:

Do you have washers under the exhaust bolt acorn nuts? With V&H Cruzers, you need them.
Yes, I put washers under the acorn nuts. I have new crush gaskets too. There are no leaks anywhere that I could find. I used an incense stick that smoke steady. I had the bike running and I moved the smoke all over the motor. No leaks anywhere.
Can you answer the question about the idle screws? My Clymers manual doesn't say anything about adjusting them. Can backing them out too far cause deceleration pop or hurt the motor??
 

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Yes, I put washers under the acorn nuts. I have new crush gaskets too. There are no leaks anywhere that I could find. I used an incense stick that smoke steady. I had the bike running and I moved the smoke all over the motor. No leaks anywhere.
Can you answer the question about the idle screws? My Clymers manual doesn't say anything about adjusting them. Can backing them out too far cause deceleration pop or hurt the motor??
Hmmm. To my knowledge you can't hurt anything backing them out. Others will chime in and verify/challenge. 4 1/2 turns is really the limit. You didn't take the baffles or packing out of the V&Hs did you?
What's odd.... it's the right side! The rear cylinder (short exhaust) is usually the side folk have issues. ''Bout all I can offer. Good luck
 

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Check your mixture enrichener (air cutoff) valve on the front cylinder carb to see that the diaphram is in good shape and moving freely. Watch for the spring and a small o-ring on disassembly. Also make sure the VERY small vac passage in the cover is clear.

If you have no vacuum leaks, you might still be lean even with the screw out 4 turns. Check plug color in the front after you get a couple hundred miles on those new plugs. If whitish, your lean. Could be a jet or main jet valve issue.

Try running seafoam in a few tanks of more stable higher octane fuel. Might pop less.

I would probably check carb sync for good measure.

Good hunting ...
 

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Contrary to what has been said on this forum, V+H does suggest going up to a 135 main jet with the Cruzers regardless of ear shave or not.
 

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Contrary to what has been said on this forum, V+H does suggest going up to a 135 main jet with the Cruzers regardless of ear shave or not.
Good point JM and accurate, however, we have hundreds of V&H users who have not had to make the change. I believe they suggest re-jetting not specifying jet size. BTW: 135 is stock (at least on mine)
 

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The stock main is 132 but my bike had a 125 in it to compensate for elevation....this is why some are different. If you're getting a lot of popping on decel and your screws are out that far then the Pilot jet is probably to small. As far as rejetting for the new pipes a lot say changing the exhaust you wouldn't need to rejet, but every mech I know suggests going up a step on the mains. Changing exhaust means changing back-pressure
 

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Discussion Starter #10
I should be able to figure this out. I took the bike to work today. Its a 40 mile ride. Bike ran flawlessly except for the popping on the clutch side exhaust pipe during deceleration. The right side doesn't pop at all.
The clutch side pops constantly during deceleration unless I pull the clutch lever in. If I give the bike a quick blip on the throttle during downshifting or decelerattion it barely pops at all.

There must be some kind of vacuum leak or something I am overlooking. This can't be normal.
I can try backing out the idle/air screw on the brake side of the bike (rear cylinder) a little more but I really think its just about ready to fall out.
I put a dab of silicone on it to keep it in just in case.
Where else should I look for leaks?
I tried smoke and I couldn't find any leaks anywhere.
Bike runs perfect except for the popping. It only has 5200 miles on it and was garage kept from day one so its practically a new bike.
I can live with the popping if I have to but I would prefer not to. I set off a few car alarms going through a neighborhood because of the popping.
 

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I have the same issue right now and its because my pilot jets are to small, go up a step and your problem should be solved, If youre good with a wrench you can pop the float bowls off after draining them and use a small peice of 1/8 in. tubing to hold the jet with to get thread started then tighten close up the bowls and you'll need to reset air screws. If the cut off valve isnt your issue then the pilot jets are. (99 percent positive) Also keep in mind the rear mixture is always a bit leaner then the front. I usually turn my rear carbs air screw out around a 1/4 to half turn more then the front.
 

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Discussion Starter #12
I have the same issue right now and its because my pilot jets are to small, go up a step and your problem should be solved, If youre good with a wrench you can pop the float bowls off after draining them and use a small peice of 1/8 in. tubing to hold the jet with to get thread started then tighten close up the bowls and you'll need to reset air screws. If the cut off valve isnt your issue then the pilot jets are. (99 percent positive) Also keep in mind the rear mixture is always a bit leaner then the front. I usually turn my rear carbs air screw out around a 1/4 to half turn more then the front.

So what you are saying is I can pop the bowls off and replace the pilot jet while the carbs are still on the bike?? Wow.
On many of the Harley CV carbs I have worked on I also had to remove the float which meant the carb needed to come off.
I can look in my Clymers manual when I get home but until then... where exactly is the cut off valve?
One last thing... when I am turning the carb screws out aren't I richening up the fuel?? Should I try opening up my rear carb air screw as much as it can go without falling out before I go for a rejet?

Would I only rejet the rear carb since the front one doesn't pop at all??
That almost makes me think that its not a jet issue but rather a vacuum leak issue.
 

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I know what you mean thats why I just did my ear shave hopeing to eliminate any vac issues. From a dealer mechs opinion once the screws are past three turns its an indication that the pilot jet is to small. You can go as far out as 4 turns I believe and its worth a try. I am going to swap my pilot out here soon but after all the carb stuff Ive done in the past week or so Im waiting a little. The cut off valves are the little circle part on the side of the carb two screws hold it on. If you google image search vn750 carb the third row has a couple photos of the caps for them.
 

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I havent had to touch my float yet fingers crossed lol and yes turning the screws out richens the mix. I really didnt want to swap the pilots but after playing around with them a lot Ive noticed I can only make it pop more or a little less.
 

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Discussion Starter #15
So, I saw the pics of the cut off valves. I guess the only way to check them is to disassemble the carbs. I know on the Harley CV carbs I had to buy gasket rebuild kits because once you started taking the carb apart you needed to replace the gaskets.
I am wondering if I should live with the popping this season and during the off season I can do an ear shave and a rejet. I just registered and got metal plates for the bike today.. I would hate to take if off the road for a while.
 

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Good point JM and accurate, however, we have hundreds of V&H users who have not had to make the change. I believe they suggest re-jetting not specifying jet size. BTW: 135 is stock (at least on mine)
I believe that 132 is regarded as stock. I looked up the 135 in Kaw parts and it specifically says for " racing use only ". Don't know what to make of that. 132 was listed as stock. V+H suggests 135 based on the stock 132.
 

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Yes the 132 is stock and 135 is the recommended jetting for sea level when going to a good aftermarket exhaust. For ex. Cobra V&H ETC. If straight pipes then 138 is recommended. It says for racing use because changing the jetting effects emissions. Theres a whole write up about high elevation jetting and old warning labels etc if you had to use the different jets in the manual I have lol. As far as leaving it for the summer you should be ok as long as youre not running so hot it cooks a valve. I've run mine lean for about 3 years untill I learned more....Anywho after all my ear shave stuff I still have some popping and will try the new pilots this weekend. I'll try and let ya know if I got em in with the carbs on still. Oh and you can pop the air cut off valve covers off with the carbs still in the bike they are on the side of each carb just two screws..Check for tears etc and make sure to replace the little o ring the right way one sides flat and one rounded...sorry for being so long winded lol hope it helps.
 

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