Since I'm a total scatter brain with my threads, pics I upload and other non sense I figured I'll just start a blog of my motorcycle learning curve and two wheeled adventures.

Just so everyone is up to speed my junk is a 12' KLX250S. I love cars and four wheeling, I'm a mechanic full time but recently got into bikes and I love it.

Anyway, my most recent purchase was the IMS tank off another inmate. Having recently re jetted my bike and added a slip on the fuel range took a crap.

I got the tank from FedEx yesterday and unboxed it...it was literally bran new and untouched! Even the parts kit was never opened.











The installation wasn't bad but man putting the plastics back on sucked. I wouldn't say the tank fits like crap but it sure as hell doesn't fit like a metal tank does. It took a lot of loosening of hardware, brackets and trial and error to get it dialed in. At the end it was totally worth it and I'm happy. It's funny because the tank came with a note stating the fuel capacity might be with in 7 percent of the advertised 3 gallons because the manufacturing of plastic tanks is difficult to do. I guess that might explain the fitment too!

 

good golly I need a new tank, filling up every 80 miles(2 days) is a PIA

 

my ims tank installation and fit was actually perfect....my only head scratching moment was the rubber bumper on the lower bolt of the fuel tank (near the airbox)....i realize i had to flip it over to make it fit and have everything align perfectly for the side plastics...if i install it without doing this, nothing aligned

 

What's your range with the tank now? I'm hoping for 125 minimum.

 

have gone 150 miles without having to switch to reserve...get roughly 55 to 60 mpg from gas pump fill up calculations...

 

No doubt, if the tank is roto-molded, melted plastic injected into a hot rotating mold, that is then progressively cooled as the plastic is rotated around in a fashion to coat to a consistent thickness through out the mold, which is very likely. Maintaining any consistency of size in molding of these parts can be difficult and is affected by a variety of manufacturing conditions, including -hard as it is to believe - the humidity and temperature on the day it is molded. Then there is also the humidity and temperature of the day when the part is installed. The company I dealt with brought me up to speed on the variations in this kind of plastics molding. It's almost like a black art when trying to hold tolerances.

When working as a quality control engineer for an excavator company I had to deal with several roto-molded components and the variation in sizes, among a plethora of other issues. As said the temperature at installation can and was a major issue. We had fitment problems with interior parts because the engineers designed for steel with a thermal expansion of around .007 inch over a 90 degree range. Parts that dropped right in place during the winter took extreme wedging to fit in during the summer and they didn't understand why.

I realized plastic expanded at a higher rate, but the plastic part which was about 36 inches long would expand about .375 (3/8) inches over the 90 degree range, versus .007 inch designing and keeping things tight as one would with steel. Try to stuff a panel that is 3/8" wider than the opening was a bit challenging in July and August. At that point I paid attention to some other stuff that was similar. When I looked at a dash boards in a Ford trucks I saw those kinds of gaps and the use of soft (neoprene?) gaskets adhered to one of the panels to fill the expansion joint when at the max, then compress as the joints closed up when temps went up. Plastics... who knew?

You likely experienced that kind of fit issue. Almost too much variation due to the characteristics of the plastics as molded when fitted to the bike. Tolerances have to fit within a range and they darn near didn't.

FWIW - In a side note, there was a post from another rider using one of those tanks. It was about being careful when threading bolts in and tightening with the inserts on those tanks. He had one of the inserts spin in the plastic. Don't know much about it, but you could drill the bolt heads for safety wire, then put anti seize on the bolt threads and tighten them down snug, but not as tight as you would with the steel tank, then safety wire them in place relying on the safety wire to keep the bolts from rotating out. Not a high stress situation. But better to do something like that than to fight with stripped out fastener mounts. His tank was still in warranty or the like and was replaced after he sent pictures of the tank drilled full of holes as the company required - make it useless. Then they sent another tank.

 

The problem you describe is problematic in a lot of plastic tanks not just the klx/IMS. To ensure the problem would never happen on my te450, I used a 3/4" 6x1.0 stud trimmed to size, washer & nut. Seems like you read about this problem in more muddy/rainy times of year

 

Really? My bike gets about 45, I don't think I ride it terribly hard but I do let it idle while I suit up almost every time. I corrected the speedo so it's dead on.

Thanks for the info on the plastics. Makes me feel like I'm less crazy. I didn't over do it on the fasteners so hopefully I won't have issues later. I guess making a metal tank would be to expensive or heavy for most guys. I love fit and finish and great quality but I know anytime you stray from stock or oem, being "bolt on" goes out the window.

 

How did you correct the speedo? IIRC, using some type(can't remember the name) of speedo healer makes the odo off.
I idle for quite a while in winter and never lose that much MPG to that longer idle time, my MPG is different but not by much.
I still get high 50's/low 60's, even running 13/47 on the street at speed.

 

I used speedodrd or what ever...I think it's from 12 o'clock labs. I'm pretty sure the odo and speedo should be good. I used an app on my phone and used my Garmin GPS to verify. I never checked the odo though only mph. I guess I'll have to do another test and see.