02' cr250r to lean?

[BJAWES]

I have an 02 cr250 that has 15 hrs. on it. It ran great until I put on a SST pipe, FMF shorty silencer, and V-force reeds. When I first put on the pipe & silencer I could tell I lost alot of top end, but had a huge hit on the bottom and mid range. I just put the reeds in 3 days ago, and now I have to kick at least 4 time holding the throttle 1/2 way open to get it to start (warm). Now I have even less top end, it sounds like air is just running through the motor (at 1/2 to wide open throttle) with no power. I plan on taking out the stock 380 main jet and putting in a 400, I also plan on switching the #74 needle to a #73 (also richer), and keeping the clip in the stock #2 position. I live 1/4 mile from the ocean (humid) and only ride in sand. My bike doesn't pop or bog down at full throttle and the spark plug doesn't show any signs of a rich or lean condition. Am I doing the right move or should I go buy a lawn mower engine? Thanks for any help you can provide!

 

[TravisP]

lets see how long did you run the bike after pipe and reeds? after about 20 hours the top end should be rebuilt and if you ride in the sand and dont maintain your air filter i would say every hour or so. did you install the reeds correctly did you use a new gasket are the reeds sealing when reeds lose there tension that is one of the first signs is the bike gets hard to start

 

[BJAWES]

The bike was ran for about 15 minutes after the reeds were put on, the pipe has about 5 hrs on it. The reeds are new and can't possibly be wore out, they only go in one way ( you cant put them in wrong ). The gaskets are new and have a light coating of GMS on them so I know they aren't leaking. The reeds come from the factory at the highest tension setting available, that is where there at now. The air filter was cleaned and dried and sprayed at the time I did the reeds. I just moved over here to the sand and only have 5 hrs. on the bike in the sand.

 

[elf]

Sounds like its rich if you have to hold the throttle open to get it started. After market reeds usaly make your bike run richer.

 

[BJAWES]

Elf, thanks for the help. It would make sense due to the stiffness of the new reeds and the fact that they are set at the tightest that the bike would be rich at start up by not letting as much air by. Thanks again. bjawes

 

[Radiator Ron]

Bjawes, i just read an article you said you've been a technician for 13 yrs, surface heads on wood, dont worry about too much compression kick it over make sure it feels good, and now you cant jet a 2-stroke. In the high tension setting the reeds shouldnt affect jetting, I cant say what the pipe will do. There are 3 different jetting specs i use with my bike @2500ft 75+f/ 6bey31-74 2nd gr, 360m, 32.5p 35-75f/6bey30-74 2nd gr, 370mn, 32.5 p 35-f 6bey30-74 3rd gr, 380 mn, 30 pilot. I use a slightly leaner needle(bigger diameter) than what honda calls for. Reason is in following hondas spec in manual if you run the needle listed the bike will have a blurber when you chop throttle in turn and reapply, going leaner gets rid of it, but it causes bike to surge slightly at idle after wot clutch in. I prefer leaner bottom bike runs incredibly well. 32.5 pilot should be fine for all temps, I drop down in winter cause i ride in snow and sometimes you cant keep enough speed in woods to not coast. It helps clean it up. You need to read your plug for the main mine is always tan, if its dark and low on power lean it down. This bike is very sensitive to jetting. On the track i can usually tell when its rich, it will lose top end power in a hurry. So if i havent confused ya yet here it goes: get some mains and needles, run the bike hard with a large (380) main jet for a few minutes and check the plug lean it out till you have a nice tan color to a light brown you should have good top end power. then set your throttle response with a needle, if the bike blurbers go leaner, but keep your needles in the 2nd groove. Dont forget to increase main as it gets colder wot with lean main will ruin pistons. I also run 32:1 Pennzoil 100% synthetic marine.

 

[BJAWES]

Rad. ron, yes I have and do take warp out of heads on a wood board it is actually a thick "cutting" board which is very true to a flat surface. As for the compression I believe I said to "watch for high compression and DO NOT start the motor if it is excessive or hard to kick". Now for my jetting, I just moved from Idaho (2800 ft. very dry) to the oregon coast (sea level, very high humidity), Yes I do know how to check a spark plug for proper jetting, jets are as follows: SJ: 32.5; NC: 2nd; JN: 6bey30-74; MJ: 380. This is stock and that is the way it is now. Like I said earlier my plug shows no sign of a rich or lean condition. I wanted anyones advice who has put in a larger main jet due to the change in altitude and humidity, I am new to the sand and the sea level humid coast. I do appreciate your help- thank you. One thing I will not do is run penzoil any thing and MARINE? I'm not trying to be smart but WHY?

 

[Sandy Whoops]

On my stock '02 CR250 at sea level / 75 F., I've found going 1 size smaller on both the pilot and the needle (clip 2nd from top) works very well. I will be trying larger main jets next. Originally, I tried a smaller main. Though it ran better than stock, it was only masking the real problem.

Really don't know where you should go with those mods, though. You should order up a collection of brass from Service Honda, or order the complete jet kit, and start experimenting.

Will be interested to hear your findings.

 

[Radiator Ron]

I'd try a 6bey31-74 if i were you, see where it gets you. I was just busting your balls a little. Why pennzoil? Because its one of the best lubricating, cleanest burning oils i've seen in a 2-stroke. Oils are a touchy subject everyone has theres, but i have rebuilt hundreds of engines and can tell some oils used by looking at the remains. I used to use pennzoil premium outboard for my bikes and still do in engines in area that dont have pv's. The synthectic seems to burn as clean in the cylinder but has less pipe residue. I also feel that the oil has better anti-rust inhibitors which a bike is subjected to. That has been a problem with syn oil (no rust prevention) pennzoil seems to be on the ball. The big thing I don't like these days is the push on castor oils, there terrible. Castor oil was used in high performance engines where there tuning was on the edge. Where a standard oil will repell from excessive temp castor oil will not. So very excessive heat that needs lubricated would benefit from castor. A standard bike does not. I feel castors stick rings and can cause premature rod bearing wear. Not something I'd use. I was'nt telling you to use pennzoil just that thats what i use@ 32:1.

 

[BJAWES]

Rad. ron & sandy whoops, thanks for your time and advice it is much appreciated. I have ordered a couple of main jets and two different needles, hopefully this weekend I can try a couple different combinations out. I will post what I come up with. I use RED LINE synthetic oils, not because I know thier background it is just word of mouth from a couple of in depth oil freaks, and I wanted to try something new. It seems that any company reps that come around are trying to push a product on you will put others down. I don't believe in putting others down to pick yourself up, so instead of reading thier pamphlets and listening to thier BS, I decided to go by what others think and what works for them. The penzoil slam was just something I added to see how well you would back them up. I need my balls busted once in a while, it lowers my cockiness a peg or two. Thanks again- bjawes

 

[BJAWES]

It's 62F, a fine sunny day. I just got back from a 10 minute ride, my bike pulled hard through all the gears, I even rolled on a wheelie in 4th from mid throttle. Not impressed? I did it in sand. With stock gearing. My changes were exactly as I put in the first thread, 400 MJ, #73 JN (2nd pos.) air screw is 1 1/4 from the seated pos. Only thing is I don't quite have the high RPM/WOT that I want. I will be trying a 410 & 420 MJ today. The bike is running "tits"! Anyone want to meet at competition hill? bjawes