NEW WISECO #871m0****

[100hp honda]

glen posted pics of the new one on page 5. shouldnt need more info than that if your familar with wisecos of the past . supposedly theres new rings but that has no affect on cutting windows.

[M.F.D.B.]

it hot seized above the exhaust bridge,
it was my own fault, the bore was 90 mm with .003 " piston to wall clearance. I rebuilt it to .004 clearance and new piston and ran it like a raped ape.

Fixed

I would have shut it down but the cops weren't far behind... in town.

Not a good practice on a questionable motor...

[Roostius_Maximus]

...it needed a 192.

[Roostius_Maximus]

its more likely that the motor needed more octane or had too much advance and adding mainjet fattened the burn into not detonating

[dubious01]

yes, I didn't expect to get chased , normally they never used to bother... I lived on the edge of town and the cops never cared until this day....

I dumped a 198 in it, and c-12 to start safe
then pulled timing, and dropped the main gradually, but still ended up at 192.

I was in total disbelif too, cause I have modded a few 500's in my day, and never needed more than 178 main in the past on mod motors,

I still have a collection of needles, but it would still ping momentarily at 1/2 -wfo, and about 3500 rpm, pulling out of corners etc...otherwise I would have kept dropping the main. I think the head design was / is a big issue still. The squish actually trapps some of the charge out at the edge of the piston, causing a second flame front when it finally ignites... just a theory of mine, but the clay I checked clearances with indicated this. I tried cutting the squish as Eric gores does, but then so much was cut out of the bowl, the compresion was too low for my liking.

This was back in 2004-05, not much was known or shared about CR500 mods on the other cr500 board compared to now, in fact the other board only a few guys on the boards, even knew who Glen howell was, or how to reach him

In the end i realized I needed a differnet ignition curve for my motor set up, too much advance in low rpm, and when I retarded it enough, not enough timing to pull up top like it should.

In any event, that bike is still the fastest I have ever ridden, and the people I consigned it through still bring up how incredibly fast it was, when I talk to them, the same guy still has it and still spanks any dirt bike its been up against.
My area of the woods might be small, but that bike is still king around here from what I have been told.

was it tuned to perfection? no
It needed a powerjet, and a different ignition curve.
No needle, main, stamped pipe, or stock cdi box was going to bring that motor to its potential,

[dubious01]

next time I have a variety of cdi boxes, flywheels, carbs, powerjet, and egt on hand... and thanks to this place more knowledge.

egt will really help take the guess out of things I think....

Its pretty hard to read plugs accurately with some fuels, and also when there is a very specific rpm, and throttle position to tune, without effecting the other TP, and RPM ... egts are really handy to have then.

[M.F.D.B.]

If cutting the improper squish (most likely cause of the detonation issue) caused too low a compression then you didnt mill the head enough in the beginning.

[dubious01]

If cutting the improper squish (most likely cause of the detonation issue) caused too low a compression then you didnt mill the head enough in the beginning.

well, you need to tell eric gore and Honda that.... I followed erics book , using honda's head...

the squish angles on the stock head and piston do not have a taper that opens the gap from outer edge to center, when modifying it to do so as eric gore recommends, then the compression is far to low for my desire.

the head was milled .040" , then the squish modified

My solder wire had .060 clearance at the edge of the piston, and approx .035 " part way in, so the squish band was still not following the contour of the piston, in fact, it closed in on it...


anyway, that motor is gone, and I have 2 new ones to work on, and learned allot along the way, and have much more $ resources to work ou the bugs than i diod back then.

I am still wondering what the weights, and intake skirt cutout is on the new 871 MO piston though if anyone knows...

[M.F.D.B.]

Squish band and comp ratio are independent. You have to mill the head enough to compensate for the material being removed when cutting the squish band. Its a commonly overlooked issue...

[AlisoBob]

..... it would still ping momentarily at 1/2 -wfo, and about 3500 rpm, pulling out of corners etc...otherwise I would have kept dropping the main.

Pinging at 1/2 throttle pulling out of a corner at low revs has nothing to do with main jet selection.

[100hp honda]

Its a commonly overlooked issue...

not if your a professional. seen jerry and petes way of doing it. i prefer jerrys method. only so much you can do with honda head though. best way is install coolhead and call it a day . been saying it for a long time... guess roostious finally ran the numbers through his magic program and joined the coolhead bandwagon also

[M.F.D.B.]

The blank dome option is cool too...

[100hp honda]

yes indeed. can do cool shit with a blank. seems like i seen one with dual plugs

[dubious01]

..... it would still ping momentarily at 1/2 -wfo, and about 3500 rpm, pulling out of corners etc...otherwise I would have kept dropping the main.

Pinging at 1/2 throttle pulling out of a corner at low revs has nothing to do with main jet selection.

yes thanks Bob, thats why I had a pile of needles and jets, because 1/2-wfo was the problem.

[2strokeforever]

seems like i seen one with dual plugs

where who and how much?

[dubious01]

Thanks for the heads up on the cool head btw, good info.

how close do their squish bands follow the angle, or radius on top of the piston?


I was just hoping I could do this with a stock head, as i want a decompressor in the head, I have seen a few cracked cases at the kickstarter , and don't want to chance it.

who here has cut the squish band to try and acheive an angle that resembles the piston dome + 2 degree's, without pinching off the outer part of the squishband from the bowl?,

how many cc does your head turn out to be?
how much did you mill off the head deck?
how deep was the initial cut on the squish band?
what angle did you determine ?
was it multi angle, or hemispherical squish band?
what piston to head clearance?




ps still looking for the wiseco 871MO piston weight, and intake cutout radius/ size.
I guess I will call Wiseco.

[100hp honda]

seems like i seen one with dual plugs

where who and how much?

not somethin you buy at the corner store. prodesign could do it but im not sure how involved they get with stuff like that. its worth asking but they may tell you to have local machinist do it.

[M.F.D.B.]

I was just hoping I could do this with a stock head, as i want a decompressor in the head, I have seen a few cracked cases at the kickstarter , and don't want to chance it.

The ONLY thing that breaks cases is people mis-clocking the kick starter shaft. The foot peg is what stops the kicker, if clocked correctly...

[100hp honda]

if you had massive compresion i could see how it might take its toll after a while especially if your big gorilla like bob. then again the kicker bangin the footpeg cant be good either . might try some heater hose to lessen the impact

[M.F.D.B.]

When the kick arm hits the foot peg, the energy travels in a straight line, from you knee/hip, etc. to the foot peg, into the frame...

The one exception to this is a back fire pushing back against your foot. Unless the bones in your feet are stronger that the case, your foot breaks first, simple physics...

[Roostius_Maximus]

you can make a blank for a coolhead like nothing, shaft of aluminum and a lathe. I have a 55 a 63 and 66 and a empty head, also have one with a 63cc dome on my af

[M.F.D.B.]

Sounds great, can I borrow your lathe?

[AlisoBob]

The foot peg is what stops the kicker, if clocked correctly...

When I clocked my motor in my CRF250xA/F chassis.... I made for god damm sure that the cast in "colision pad" on the CR500 kickstarter hit the footpeg squarly.

Oh yea, I forgot ..... I'm an idiot because I didnt roll the motor over enough to satisfy Clyde....

[Roostius_Maximus]

Sounds great, can I borrow your lathe?

come on down

[M.F.D.B.]

Down? You mean WAAAY UP?