Tired 206??

D

Don Westlie

New member
Looking for some conversation on this...

We have a 206 that has 2.5 sprint race seasons on it and this year it seems to be down on power. Will be good at lower RPM in corners but on straights it is a dog. We can make up 2-3 karts in the corners but lose all of it on the straight.

Last week we switched out to a loaner motor and no longer lost the straight like we did. We moved our carb and clutch so only change was long block.

Have done leak down on ours and all is good. Carb and valves are set correctly by Jimbo. Checked valve lift and cam lobes are good. For all testing it seems to be a "good" engine.

Anything you guys can think of that we may be missing? Any thoughts are appreciated.
 
Sometimes, 'tired" valve springs are the culprit, noticed more at higher rpms. I'd recommend changing springs at least a couple times a year. The reality of a slightly out-of-round cylinder (normal wear) comes to mind, a loss of compression through the rpm range.
 
With that amount of run time, I doubt the valves are sealing very well. Could be time for a valve job, or maybe you can just lap them back in. While your head is torn down, throw in a new pair of valve springs as wise maint. Chances are a nice hone in the block & new rings would help too assuming the bore is still round.
Best wishes,
K~
 
If it is a LO206 you cant hone the cylinder or change the rings, and the spings are kinda a non-issue with the rev limiter. I would say try a leak down and maybe lap the valves.
 
I know when I had the heads off mine last winter the bore didnt look so good...I doubt they would pass any leak down. Take the head off and see if the bores are all scratched up...might be time for a short block.
 
“We can catch them in the corners, but they pull us on the straights.”

You do know that’s how it works with equal power?
 
JimEli said:
“We can catch them in the corners, but they pull us on the straights.”

You do know that’s how it works with equal power?
Click to expand...

Yes I do and I am pretty frustrated so don't take this wrong, but if you can't help or have no real suggestion don't give me a smart remark and move on.

Read what was written. We can make up karts in the corners (by corners I mean all of them in all situations, see we race with more than 4 corners. See above SPRINT.) and I lose it all on the straights. That is not equal power. When the motor is not stretching its legs we are good. As soon as it starts getting up in the RPM's it is falling off. Again not equal power. I also wrote that I switched out the motor to a loaner and problem on the straight went away.

Now I know why I never ask any questions on here...
 
mopdog said:
I know when I had the heads off mine last winter the bore didnt look so good...I doubt they would pass any leak down. Take the head off and see if the bores are all scratched up...might be time for a short block.
Click to expand...

Thanks mopdog, I'll take a look. I'm going to try a set of springs too. For a couple bucks and a little time it's worth it before buying a new engine or short block.
 
We are in the same situation, with kart, setup, and driver we are better than most in the corners(sprint) but we are just not as crisp or pulling as hard in the straights. We are on our 4th season, with this engine.

The post above about equal power makes no sense, I would not want to follow an explanation it would be a waste of time.
 
Keep it simple. Check your head. If the valves and springs test good then it has to be in the short block (which could be in the bore or a worn cam). You know by now the 206 motor are so close that when your off a little, your off ALOT.

It seems like you've got a pretty good handle on your stuff so keep it simple. If you know the carb is set right, and the ignition is good, and the head is OK, the problem is in the short block.
If you needs a short block you can trade you old one in and since its still in working order, I'm sure Brian or Jumbo would give you fair credit towards the new one.

Bruce J.
 
A guy I race with had this problem too. Apparently something with the compression release messed up the lifter/cam lobe. Check the lift height on your exhaust valve, that was the only sign of issue with his motor. Briggs replaced everything since it was a compression release issue.
 
Jimbo found the issue. Had a little metal flash hanging in the intake. Not sure were it came from but glad it didn't cause catastrophe. Ran the 206 Cup this weekend at RA and ran good. No issues on the straights. In tech Steve Vermeer and the guys checked it over really well. I guess it's good to get teched once in a while! No major issues were found.
 
Don,it was nice meet you and I really appreciate the effort on getting stickers for the weekend!Hope everyone had a good day of racing!I'm looking forward to the next 206 race at Eau Claire.Hope you can make it!
 
Steve, it was a great time. Wish we could make the others. Not in the cards this year. Definitely looking forward to next year. Great job!
 
That's well-timed good ifo guy's! I hv a WF Mini-Spirnt engine on the bench right now in a quick-fix (pls Help) situation where it lost 0.3/sec last weekend and they need the motor 'good' for this wkend. I wanted 2do a leak-down, 1st off, but I don't have a 10mm adaptor (dang-it). So, started the tear-down and looking for the/a reason. The ONLY thing I 'see' is that the cylinder bore has NO x-hatch remaining, but the top-ring gap supports a .005 feeler gauge. That leads me too believe the 'Builder' (Big name out here) utilizes a 'mild' hone in his builds(?) This builder also recommends 'refreshments' after (6)races...ie: 3-4hrs where-by this motor has (10) races or, 5-6 hrs. Bryan Carlson suggest that better Air Filtration might 'could be' better as well. I figure on Re-hone, new Top/Compression Ring, Re-Lap/Lap the Valves and new head gasket and should be good-2go! Additional input welcomed!! (Thx Bryan!!!)
 
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