Honda TRX250R Forums banner
1 - 10 of 10 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter · #1 ·
So the 250r,400ex swap project is pretty much complete and finished I went to test it out. Appears to have a "rev limit" which would indicate to me its rich so I went down the list starting from 165, 162 now I'm at a 160 and appears to still be doing it I had this problem before when I originally acquired it, and went down to a 148 main. I have changed all electrical new stator, new harness, new coil, and plug cap, I did get a new cdi but it didn't work so I just stuck with OEM one. I have also replaced reeds and a new 38mm air stryker. It's odd because it idles great and starts first kick every time.

Here's a pic of the plug from the most recent test run. (Has Only Had 3 Test Runs)

Hand Photograph Eye Automotive tire Asphalt


Also here are the engine mods.

Head: Cool Head with 22cc dome
Reeds: Boyesen Rad Valve (had esr but removed it due to clearance issues on the 400ex frame)
Pipe: FMF Don Elmor Pipe with CT silencer and Head Pipe
Cylinder: The cylinder is a bored 265 with basic smoothing on the ports.
Carb: 38mm air stryker, 160 Main Current. Idle 48 or 50 cant remember but bottom end runs fine.
Current Altitude: 250-300ft Above Sea Level.
The plug is a br7es and I run 40:1 Dominator.

-Thanks
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #3 ·
Plug too HOT
Need to have a 8 or I run 9 plug
So instead br7es use br9es
Thanks! I had br8es originally and it still did it but that was when I had an electrical issue but never tried the 9's. So I will pick up a pair of those and give them a try.
 

·
Registered
Joined
·
433 Posts
My guess is you still have an electrical issue & by running a 7 series plug along with the 160 main I'd be concerned about burning a hole in the piston. I'm at the same elevation as you unless I go to the coast & my wife's R with an unported 88 cylinder at 66.75, oem 86 head with an oem atc head gasket & 200psi cranking compression, b8es plug, the same pipe, rad valve & AS carb as yours & I have a 178 main & 48 pilot in her's & it run's very well.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #5 ·
My guess is you still have an electrical issue & by running a 7 series plug along with the 160 main I'd be concerned about burning a hole in the piston. I'm at the same elevation as you unless I go to the coast & my wife's R with an unported 88 cylinder at 66.75, oem 86 head with an oem atc head gasket & 200psi cranking compression, b8es plug, the same pipe, rad valve & AS carb as yours & I have a 178 main & 48 pilot in her's & it run's very well.
I would only assume its probably the CDI as that's the only thing I can think of that's OEM. My main concern is getting a CDI that's not complete trash. From the rick one, I had it just straight up didn't produce any spark out of the box. I also noticed for the short moment I ran it, it had a decent amount of spooge built up under the exhaust flange. I will give the ricks one another try as I do still have it I could have just not been kicking it fast enough when testing to see if it produced a spark.
 

·
Registered
Joined
·
686 Posts
The spark is generally very weak with the OEM ignitions. You definitely have to kick it like you mean it to even see a spark. It’s best to have two people when you’re testing for spark - one to kick, one to watch the plug. Also, make sure you gap your plugs to .018-.020”.
 

·
Registered
Joined
·
3 Posts
I have a similar setup, except [email protected], 66.5mm bore unported cylinder, stock head, use br8es plug, 32:1 castor oil and have 175psi compression (stock TRX head gasket). I run a 178 main and a 48 pilot (this seems to be pretty standard for many with similar setups). I also have a bone stock R and run a 162 main in the PJ, foam uni filter w/ no air box lid. Both run pretty good. Your plug does look much blacker than mine do. Is the PWK brand new? Have you done a leak down test to check for air leaks?

I had a used PWK38 non airstriker that would run good during and immediately after warmup, but would sometimes spooge heavy well into a ride and leak gas if I left the petcock open when parked. It turned out there was a "hidden" corrosion pit on the needle seat that was barely visible even after lapping the seat. I took a pick and scratched at a slightly discollored area of the seat and a chunk of corrosion popped off and it was dark green underneath, like corroded copper or brass would/should be. The bowl would slowly and intermittently overfill and run rich, spooge, and overflow. A new genuine PWK38 A/S fixed it.
 

·
Registered
Joined
·
79 Posts
Is the stator OEM or some aftermarket brand? When I bought my 85 it started and idled fine but anything past half throttle it would break up so I started reading on here and most of the time when people had this problem it's electrical. Mine had a junk non-oem cdi and stator and when I swapped both with used oem and it cleared the issue up. Mine is a 66.5mm bore, CR head gasket(from what I was told from previous owner), FMF exhaust, PJ carb, 36:1 927 mixed w/93 pump, UNI filter w/no lid and I run 48/155 in NJ and it runs pretty damn good
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #9 ·
Is the stator OEM or some aftermarket brand? When I bought my 85 it started and idled fine but anything past half throttle it would break up so I started reading on here and most of the time when people had this problem it's electrical. Mine had a junk non-oem cdi and stator and when I swapped both with used oem and it cleared the issue up. Mine is a 66.5mm bore, CR head gasket(from what I was told from previous owner), FMF exhaust, PJ carb, 36:1 927 mixed w/93 pump, UNI filter w/no lid and I run 48/155 in NJ and it runs pretty damn good
Sorry for the late reply. The Stator was OEM. Very old had a lot of wear. Replaced it with a ricks stator then ended up having a flywheel key shear and rubbed the flywheel on the stator got that sorted out fast. Then replaced the stator again along with everything electrical. Even with both stators. It did the same issue. That is why I think its the CDI as its the only OEM part in it that hasn't been replaced. Worse comes to worst I can just search for a used OEM working CDI.
 

·
Registered
Joined
·
79 Posts
I’d bet it’s the stator. If you search “stator” you’ll find a lot of posts that complain of problems with aftermarket stators and cdi’s so it’s always best to use oem. The problem is they don’t make them new anymore so you’re stuck with used.
 
1 - 10 of 10 Posts
Top