# T-cat major oil control problem - thoughts?



## JPs300 (Mar 23, 2011)

Kinda dissapointed right now, not sure which way to go. I'll try to make this an abbreviated version. 

back story w/ bike info is a few threads down for those that don't know 


- First ride got cut short by that upper ball-joint letting go. No biggie, crap happens, fixed the suspension travel problem, popped a couple new joints in that side and out the following weekend. 
- Next weekend we do a night ride, quickly notice that it's glowing the rear head pipe torch red, but blowing a nice 8-10" blue flame out the tailpipe every other combustion hit. Take it home, rear A/F is showing 17.7-18;1 @ idle(obviously way lean) front is showing 11.7-12.1:1(way rich). Download the PC5 software, tune is all over the place, so I download a few maps to try and head out the next weekend. 
- Seems to be running OK, but has a notable hesitation and stutter at lower rpm/part throttle. Contribute it to the tuning, figure I'll get my wideband on it and start dialing in a map myself(I tune 1000+hp race &street cars, not a newbie to this stuff). - While running around I notice it blowing oil out my breather filter, seems to be mostly when it's stumbling and/or when I've been wheeling a bunch. 

I set down and created a tune for both cylinders, based off the best 3 maps that I have. I then dialed on it some with my LC1 wideband hooked-up; establish a pretty good running, clean tune-up. - Didn't do any long term running though, just some short runs playing with the map. - I also re-located my "burp bottle" to get it in a more up-right position and back above the upper frame rail so that it can easily drain back. I flushed it w/ brake clean and made sure everything was dry. Changed the oil and put 2.5 quarts in(was told to keep these motors 1/2 quart down due to oil control issues) 

Out again today, after 10-15min of riding it starts pushing oil out the breather filter almost as if it where under pressure. Leave it sit 30ish min and you'll get another 10-15 before it starts again, leave it any less time and it will be pushing out immediatly when re-fired. 




Any other thoughts? 

thanks guys, 
-Jp 



My burp bottle has been drilled in the bottom ports, top is cut off and has a hose hooked directly to a section of 3/4" PVC running up under my snorks and has a parts-store open-element breather filter popped in the top. The burp bottle is above the upper frame rail, and both lines run downward to their ports. 

Im gonna run a compression test tomorrow, thinking worst case scenario the couple rides running way-off on tune could have torched or pinched a piston/rings.


----------



## JPs300 (Mar 23, 2011)

I have had a few post on HL that it could be a broken ring or pinched ring land. 



What really seems odd, as when I pull the breather filter and stick my finger over the vent tube it's not at all what would be construed as excessive pressure. Just a very light pulse of air, just as any other motor. - My burp bottle is standing up, but is turned(think of a square, but having the corners top/bottom and left/right) with the inlets on the bottom and left corner and the outlet on the right corner. Maybe it needs to stand square for it to drain back properly? 

Gonna do a thorough once-over and check for anything obvious. Pull the little cover off between the cylinders(where the one breather hooks-up) and check for anything unusual there, etc. My buddy is a Snap-On dealer and is going to bring home one of their killer scope cameras to take a look first. Going to see if I can get the right spark plug thread adapater for my compression tester to run that & run a leak-down test as well(leak-down should tell me a lot on the rings). 

Just need to make sure it's not something obvious that I'm over-looking before I pull it out and tear it down. The fact that the breather air pulse is as light as any other motor has me questioning it being anything major. 





I'll update this thread as I go, just looking for any thoughts/ideas.


----------



## wyo58 (May 13, 2011)

Your on the right track for sure check compression and leak down, that should tell you alot. If it's only putting out a small amount of back pressure from the tube it does seem like the rings are ok to me too. Unless that small amount is above the oil and a large amount of back pressure. Out of curiousity how much is there out of the oil fill cap?


----------



## JPs300 (Mar 23, 2011)

^ oil level is just below center of the indication marks w/ the stick not screwed in. No leaks anywhere, just the breather blow-by. 



Digging around a bunch on arcticchat - it seems the sideways burp bottle may indeed be my issue, not having both case fittings as low as possible to aid drain-back. 

I'm going to cut a spark plug up and weld an 1/8npt coupler on so thatt I can run compression and leak down, along with running the camera inside for inspection. - If I don't find anything out of normal there, then I'm going to build a custom oil seperating can to not only fit upright/higher, but also out-flow the stock bottle so as to negate all the issues of the factory burp bottle. 


Will be a few days for I get a chance to do everything, I'll report back then.


----------



## greenkitty7 (Jan 26, 2011)

alot of cats have a problem burping up oil with the ccv run up high for some reason. i tried running mine up one time and it would burp oil all over the pod when i was wheelying. once i looped it and reattatched it to the airbox i didnt have a problem. not sure why but it seems like the cats have a problem with that, maybe its where the ccv is on the cases.


----------



## JPs300 (Mar 23, 2011)

The t-cats have a factory oil seperating "burp bottle" between the two 1/2" crank case vents and the 3/4" air box inlet. - The burp bottle is a notorious bottle neck, causing performance loss and creating excessive back-pressure which tends to lessen seal and gasket life. The problem is, you can't just remove the bottle as they do push some oil out and you need something to catch it and let it drain back, so as not to just dump oil in the air box. 

There's several methods to modify the bottle to open up the flow, but the stock design leaves a lot to be desired for proper seperation, even more so when modified to flow enough. Since its fitment is already an issue for me I'll just go outside the box and build a better seperating catch can and go from there. The pressure at the breather is less than that of many fresh single cylinder engines I have been around, so I'm 99.9% certain it is not a major engine issue.


----------



## J2! (May 8, 2010)

Couldn't you just do a yfz catch can mod to it like alot of people have done with these brute motors ?? On mine, I have no catch can, just two hoses to the crankcase with a "T" and one hose up to the snorkles with a filter on it. Never had any problems with it, even with the 840 kit in it.


----------



## JPs300 (Mar 23, 2011)

From what I've found digging on-line, it would seem the issue is much more dominant with the t-cat 950 than it is with the smaller versions. Mine being even more CC could make that worse yet. 

The factory put the "burp bottle" on them because they do spit some oil out of the case vents. The point of the bottle was to catch the oil and allow it to drain back, instead of having it spit into the air-box. Problem is the stock bottle constricts the vent flow, plus it only has a single baffle system to seperate the oil from the air. - Guys with stock bikes are modifying the bottle to increase flow and gaining some performance and extending the life of their seals and gaskets. 

I figure w/ all the issues I'm having w/ it spitting oil plus trying to fit the bottle around my snorks and get it vented reasonably, I'd be better off building a better bottle entirely from scratch.


----------



## JPs300 (Mar 23, 2011)

Well, my luck strikes again. 

Rear cylinder has 145pis and around 11% leak-down, front has a whopping 35psi and is hissing out the breather. - I'll get it out of the bike and torn down in the next few days, hopefully is just a broken or pinched ring and it hasn't hurt the sleeve.

I guess the "good" news is that this thing has a boat-load of power for only being a 1 & 1/4 cylinder.......


----------



## speedman (Nov 3, 2010)

wow jp cznt believe you are having problems with the new bike already, hope you get everything worked out. are you going to ryc for tgw?


----------



## JPs300 (Mar 23, 2011)

Pending anything more than just rings/gaskets, I should still be there. 

Freaking SpeedWerx gets $46 for the ring set and $56 for the head gasket! That's plenty for a single set of rings and completely ludicrous for a head gasket. They're MLS though so as long as they're not damaged I'll just spray coat them and put them back, thus hopefully just the ring set and a good hone.

Either the overly rich front cylinder pinched a ring land and is causing this, or for some reason(likely improper end-gap during assembly) it broke a ring. That 35psi is w/ the cam decompressor active(doesn't kick-out till 3k rpm), thus explaing why I couldn't get enough fuel out if it @ idle/below 3k but why it runs ok above that.


----------



## speedman (Nov 3, 2010)

JPs300 said:


> Pending anything more than just rings/gaskets, I should still be there.
> 
> Freaking SpeedWerx gets $46 for the ring set and $56 for the head gasket! That's plenty for a single set of rings and completely ludicrous for a head gasket. They're MLS though so as long as they're not damaged I'll just spray coat them and put them back, thus hopefully just the ring set and a good hone.
> 
> Either the overly rich front cylinder pinched a ring land and is causing this, or for some reason(likely improper end-gap during assembly) it broke a ring. That 35psi is w/ the cam decompressor active(doesn't kick-out till 3k rpm), thus explaing why I couldn't get enough fuel out if it @ idle/below 3k but why it runs ok above that.


 
idk what it could be but hopefully nothing bad !!


----------



## JPs300 (Mar 23, 2011)

Timing of other things going on may make or break whether I can get to TGW next month. - We've got a race coming up on the 22/23 @ BMP and have to get the car ready for that, plus the wifey's bimmer just crapped out a water pump thus mandating the full service I've been putting off on it.


----------



## JPs300 (Mar 23, 2011)

update -

I'll leave all the engine problems in the "other" thread on here, but they were not contributing to this issue. I built a custom oil separating can using a 5" section of 2" exhaust tubing. I has a tapered "sump" in the bottom to direct any catch oil back towards the crank case lines(dual 1/2") and 3 baffles between them and the 1" outlet at the top. 

As soon as I get a chance to upload some pics I will. Didn't take any while building it, but I can whip something up in MS paint to show how it's baffled. - Fit under the plastics well up high beside the air box and cured the breather/oil issue.


----------



## JPs300 (Mar 23, 2011)

This is officially fixed. We rode for 7-8hrs this past Friday, no oil coming up the breather snork.


----------



## bump530 (Jan 5, 2009)

glad to hear it. i wish i could of fixed the oil problem on my brute. that was one of the reasons it got sold...


----------

