88 max and need tech help

[bmwtech]

hey everyone im new here and also new to my first bike and first vmax. i bought an 88 about 2 months ago and every week something else breaks on it, no concerned with that really i dont mind getting my hands dirty and learning about bikes. but when i bought the bike i didnt know what to expect out of it heard it was fast but i didnt really know what fast was. started changing all fluids, syncronized the carbs and fixed some wiring problems( corrosion in connector for ignition switch and rectifier was melted at the connector). anyway to my problem, i changed the fuel filter which was almost completely clogged and it woke the bike up, i mean it really moves. well just the other day it started acting the same as it did before i changed the fuel filter, boggin and backfireing on acceleration and struggles to reqach redline. i checked to see if all my wires are getting a signal with a timming gun and they are, changed spark plugs and still runs the same, if anyone has any ideas please help. sorry you had to read this short story.

 

[maleko89]

Check your fuel filter again. If it's dirty, may have to drain and clean your tank. It might be time to rebuild the carbs too.

Welcome to the VMF!

 

[maxcruiser]

I would start with the gas tank - there's a drain plug at the bottom of the tank - remove it and drain in it out - check to see if fuel is dirty, rust, etc... Also flash a light in tank the see if there's rust in it - recheck fuel filter and if ok, than pull fuel line off carb bank and aim it in an empty can turn on ignition to see if and how fast fuel is pouring into can, if ok, than loosen drain screws on carbs and pour fuel into container to see how much comes out of each carb and how clean it is.

Maybe also be time to do a carb overhaul (cleaning).

The sparkplug condition will also give you a good idea on how each cylinder is running - while plugs are off, also a good time to check for spark on each one.

Good luck

Mike

 

[bmwtech]

removed fuel filter and it is clean with no debris in it. the bike has 31000miles on it removed the hose from the fuel pump and pumped it into a glass jar and had nothing in the fuel that came out. the problem is almost intermitent. i took it out yesterday and it worked great for a few miles and then would go back and forth between bogging down and runnin like a bat outta hell, now it just runs bad all the time today.

 

[maxcruiser]

Maybe a float needle that is sticking - do you know when the last time the carbs were overhauled? If not, would be a good time to do it.

Mike

 

[bmwtech]

alright thanx guys for the quick responses, ill probably pull the carbs sometime this week and go through them and will update with more info.

 

[lankeeyankee]

As stated drain your tank again with the drain bolt at the bottom of the tank. Use a coffee filter to see how much your catching. If the inside of the tank is rusty you may want to think about Gel coating "TankGel" its a kit .
Good luck keep us posted.

 

[bmwtech]

alright today after i got off work did some work on the bike. started by draining the float bowls to see what came out and one wouldnt even drain barely any fuel the others seemed mostly clean but then i looked in the bottom of the glass and there it was, rust. i drained the tank and looked inside and there was alot of rust inside. removed tank(not as easy as i thought) and shook it and you could hear all the rust rattling around. you think this is treatable or should i get a new tank? also i removed the carbs and will be rebuilding them in the comming week. and where can i get this "tankgel"?

 

[shawn kloker]

I think Creme is easy to find.

 

[shawn kloker]

I think Creme is easy to find.

The filter should be catching the rust?

 

[m-cman]

I would not recommend Creme for tanks. If not PERFECTLY prepared and applied, it often delaminates and lets moisture accumulate between the lining and the tank. The will destroy a tank in short order. I have used several different tank treatments over the years and now use one from KBS Coatings. It is a 3-step process but the final coating is an epoxy type coating and it seems a lot better. Also used Eastwoods product but it is about a 12-step process and a real PIA! Requires muriatic acid, acetone, etc. Real easy to mess up your paint. I used it on a 68 Triumph 650 tank BEFORE I had it painted. Have tried the phosphoric acid treatment (many brands - I used Sudco) and it works if the rust is not too bad and doesn't have any pinholes.

Right now I recommend the KBS Coatings product. It seals small pinholes also. The large motorcycle tank size is enough to do two tanks. Did my Max and my CB550F tanks. Have to follow the instructions to the letter though.

 

[one2dmax]

I haven't tried it but you can have the tank "boiled" at your local radiator shop. Supposed to work quite well.

Sean

 

[shawn kloker]

I have heard of putting some gravel in and shaking the shit out of it to get the loose rust out.

 

[one2dmax]

Yes, i have done that before. Works pretty well. I have used a gallon or two of water with nuts and bolts. Shake it all over and it will remove the bulk of the heavy rust anyway.

Sean

 

[ecarri100]

I have used the creme, but if not prepped right willscrew up the tank in a short time. also it is best to use one of the methods mentioned to knock loose the big rust. i have used nuts and ball bearings.