Popping sound

[toadwillie]

I have a 1985 project vmax. While riding it has started making an odd popping sound from I believe under/inside the air cleaner box. Mainly at cruising speed, about 4000-5000 rpm. Under acceleration it does not usually happen. I have synced the carbs to the best of my ability, and changed the air filter. I am running 87 octane fuel. Every thing I believe is stock. I have also noticed on the #2 intake where the tin intake cover screws on there is a small crack just to the right and down from where the screw would go in. Can't tell how deep it is but it does look a little wet around it.

It hasn't always done this. It did when I first purchased it last year, it stopped for a while when I had some issues with my CDI box getting water inside. After drying out the CDI I put the bike back together and it ran like a champ for a couple weeks until I found water in it again. I dried it out again the same way but has not run the same since.

Could this crack be my issue? Or should I plan on replacing the CDI box?

 

[naughtyG]

If there's a crack in the intake and air is getting in then that could be your popping explained. You could try JBWeld on the crack, if it doesn't work it'll prolly be best to replace the part. Many maxes are being parted out here so you should have no prob getting it.

If your TCI keeps getting wet you need to find a way to keep it dry - maybe wrap it or get silicon sealer in the right place. Again if you choose to replace you should be able to find one decently priced here - just ask.

And welcome to the club!

 

[toadwillie]

Thank you. I was hoping someone would suggest JB weld. I'll give it a go and post the results back here.

 

[jfeagins]

It might just be time to do a pea-shooter routine, or a full shotgun proceedure to clear all the little ports & jets in your carbs too.

 

[toadwillie]

How to I go about doing those? I'll be honest. Carbs make me nervous. At the same time though I do want to understand how to do maintenance on them.

 

[tugla]

you can go to the tech section and under carbs will find lots of threads on how to do the shotgun and peashooter. its well explained and dont think you will have any issues doing it. im sure someone will post a quick link to it if you cant find it.

how did you sync the carbs, do you have a carbtune or weber?

 

[toadwillie]

I made my own tool. (I'm cheep, always try the less expensive way to fix things) 4 vac gauges and 1/8" hose. One to each vac port. Synced #1 to #2, then #4 to #2, then #3 to #4. Then adjusted the idle and repeated until my idle was 950-1000 rpm and each carb was at -22 to -23 psi.
I hope this is right? There was a noticeable improvement the way the engine idled.

 

[jfeagins]

I made my own tool. (I'm cheep, always try the less expensive way to fix things) 4 vac gauges and 1/8" hose. One to each vac port. Synced #1 to #2, then #4 to #2, then #3 to #4. Then adjusted the idle and repeated until my idle was 950-1000 rpm and each carb was at -22 to -23 psi.
I hope this is right? There was a noticeable improvement the way the engine idled.

That should work for synch'ing.

Here's the link to the tech section for carb cleaning.

http://www.vmaxforum.net/showthread.php?t=111

It'll lead you to this VERY USEFUL website:
http://vmax.lvlhead.com/tips/shotgun.htm

 

[WVxNitemare]

I made my own tool. (I'm cheep, always try the less expensive way to fix things) 4 vac gauges and 1/8" hose. One to each vac port. Synced #1 to #2, then #4 to #2, then #3 to #4. Then adjusted the idle and repeated until my idle was 950-1000 rpm and each carb was at -22 to -23 psi.
I hope this is right? There was a noticeable improvement the way the engine idled.

I thought you had to.sync 1-2 then 3-4 and then sync 4-2.... You sync each side first then sync the sides together.

Sent from my GT-I9000M using Tapatalk 2

 

[toadwillie]

I thought you had to.sync 1-2 then 3-4 and then sync 4-2.... You sync each side first then sync the sides together.

Sent from my GT-I9000M using Tapatalk 2

Ya, that is what my repair book said. I thought it was a misprint. But I read the thread here on how to sync carbs. It is explained very well. I understand now why it is to be done that way.
Thank you for calling me on it.