tuning and break-in problems on 48mm bbk on 85 spree

[atp]

So I bought one of Taz's 48mm kits on ebay and installed it. Granted, I never ran the bike previous to the installation since the old cylinder was * up when I bought it. I have followed the break in instructions provided and it starts and idles great, but my main problems are twofold, which is making it hard for me ride it enough to break it in. excessive smoking @ idle and even worse off idle. And, very bad bogging @ half throttle, so much so that it feels like it's gonna die and forget about hills, gotta turn around. Also on a side note, it is difficult to start when cold (and by cold I don't mean cold, I live in Austin, most days are 100+,and I have tested the bystarter and it is within spec.)

So here's my baseline.
removed airbox (had previously drilled 8 1/2 holes in airbox cover with stock airbox filter and it dogged out.)
covered intake with doubled over pair of nylons (I didn't have a free flow filter at my disposal.)
oil injector pump operational
32:1 mix in gas tank per instructions
stock keihin carb, freshly cleaned.
idle: 2500rpm (can't get it to stay running @ anything lower, I know stock idle is 1800rpm +/- 100rpm)
idle mixture screw: 2 turns out
Spark plug: NGK BP5HS
Spark plug gap: .025.
spark plug condition on chop: brown (comparable to "real good" on spark plug chart)
piston top condition: black carbon build up with perfect clean circle directly underneath spark plug
main jet: 87
needle: 76P
needle position: 4 (second from bottom)
my compression is still reading 50psi after about 6 miles and 4 heat cycles
Dead spot @ half throttle up until about 3/4 throttle
have pulled it higher into throttle band to see if it disappears and real power develops after 3/4 throttle very quick pick up.
I may have left out some info germane to this problem, if so ask and I can get it.

So from what I've gleaned from this forum is; due to location of bog, it's most likely my main feed circuit is too rich, either the main jet is too big or needle setting is too rich. I will adjust needle down and see what happens
The other variables that may be affecting this setup
too high oil ratio
too hot spark plug
wrong main jet

I'd like to get some guidance on what direction I should go in next. Thanks in advance.

[TexasHills]

If i remember correctly. My taz kit came with a new jet. I had 2 go through 3 tanks of gas like he recommended. Now i only put a cap full of 2 stroke oil in the tank. Plus i add fuel stabilizer. For the ethanol in all of my bikes. I also have the carb. tuned to factory specs. I only have 4 holes on my air box cover.

Hope this helps let me know.

[atp]

Great, thanks for the info. I replaced the main jet that came in the kit. it is an 87, I don't recall what the original was. Did you happen to do a compression test after break-in? and if so what were you're results?

[dakotabs]

Are you sure the compression is 50 PSI. That is too low and should not run

[atp]

I thought so too, I'm using my automotive compression tester that I use at least once a month. I used it last week to confirm a dead mis on a 4.0L jeep, it gave consistent readings then, and I've used it before and after that. I thought maybe it wasn't seating properly, so I tightened it down with my curved long jaw needle nose, same reading. Runs relatively well except for bog and excessive smoke. Insert emoticon scratching it's head. Will post more findings soon.

[atp]

I began to suspect my inductive tach was off, so I used my older tach and hooked it directly up to the switching wire of the coil. I probably wasn't idling at 2500 rpm after all since it was closer to 1800 rpm on the second tach. After realizing my gaff, I started back from scratch and used twilight's post from this thread (http://www.hondaspree.net/phpBB3/viewto ... g&start=15) as a guide. I set the idle to 2300 rpm and went round and round with the idle mixture screw (pilot circuit) and found 2 1/2 turns out yielded the highest steady idle, I then reset base idle to 1800 and it ran better than it ever had from 0 - 1/2 throttle. And since it was acting rich in the midrange, I moved the needle down from the 4th position to the 3rd position; took it on a test run, best it had run since i've owned it, I actually got up a hill. Did a plug chop and it was between "good" and "real good" (http://hondaspree.net/wiki/images/2/23/ ... amples.jpg) I then opened up the plug to .028" and cleaned it. Everything seems moderately good, but I didn't want to wring it out since it's not fully broken in. I'm still dealing with tons of smoke and low compression, everytime I do a plug chop I throw in the compression tester and it's always 50 psi. I then decided to try my hand at tuning it with the air box on. I drilled 4 more 1/2" holes in the airbox cover making the open area equivalent to (3) 1" holes. installed everything and tuned it using the previous method, ended up with 1 1/2 turns out. got it running great from 0-1/2, but no matter what needle position I put it in it bogs terribly under load, same problem as before. 1st and 2nd position were really bad. Upon 1/2 throttle application immediate bog 3rd, 4th and 5th were slightly better, none yielding incredible insight. I would say the 3rd or 4th position worked best. What I can't figure out is if the airbox (even with perforated cover) acts as a restriction (less air = richer), why does enriching the main jet circuit make it run better. Also with relatively free flow of the nylons my airbleed (pilot circuit) was 2 1/2 turns out and with the airbox it was 1 1/2 turns out, that is counter intuitive to me since I'm assuming the airbox acts as an enriching agent. Still would like some help withe smoke issue, to high oil ratio, wrong heat plug. I definitely need some help on this one. thanks.

[patthesoundguy]

0.025" has been found to be the best plug gap on a spree. Just sayin if you have problems try putting the gap back to that gap and see how it goes. Maybe your exhaust is clogged. That will cause rich condition that would be really hard to diagnose. Are you holding the throttle wide open when you doing the compression tests? And are you squirting some oil in the cylinder first, And cranking till the needle stops? Taz did his homework with those kits, it shouldn't be as hard as its been for you. I hope we can get you rippin' around like that thing should. Something else to keep in mind is that the 84 and 85 sprees have reed blocks that are much smaller than the 86 or 87. That could be coming into play here as well. I'd check out the compression issue, if its truly only 50 psi as you are finding that would likely be the major issue. You could have a gasket issue causing it or bad crank seals. I'd try the compression tester on something else to verify its reading correctly, rule that out first.

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[atp]

I will move it back to .025" I detected no improvement anyway. I was beginning to lean (no pun intended) towards a fundamental mechanical failure as opposed to a tuning issue. I've never heard this scoot run since it was in failure when I bought it. The two that I considered were clogged exhaust pipe and leaking crankcase Is there a procedure for diagnosing a clogged pipe and a leaking crankcase? I know it shouldn't be this hard, and I can see the light at the end of the tunnel, sometimes it produces real power, although a little zingy, but nothing consistent. regarding compression tests, yes I'm holding throttle open, and no not squirting oil since I assumed there was enough residual oil from mix, but I will try that. I will also confirm correct operation of comp. tester. I'm also wondering if the supplied main jet is not rich enough for whatever reason. Is there a reasonably priced jet set?

[patthesoundguy]

Jets can be hard to get above a certain size from the dealer, treatland may have the jets to fit the carb. I'd call Benji there and maybe you can measure your jet and get him to confirm the size of the jet. The easy way to check a clogged pipe is to start out with a stiff pics of wire jammed in the tail end to make sure no insects have made a home there , next bake the pipe in a BBQ campfire or wood stove

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[atp]

I tried poking the exhaust with a welding rod and got about ~6" in before I hit a baffle? seems grimy but not clogged, wouldn't I get a persistent rich condition on plug chops if it were? because most look good, but are more towards lean. I've tried most every permutation thus far: open carb, carb with doubled over piece of nylon, single piece of nylon, air intake hose solo, air intake hose connected to box without filter, and airbox with filter. and within those variables I've moved the needle in practically every position. I can post my results later. some yield decent 1/2 throttle acceleration on flat land but bog under load, others bog as soon as I get 1/2 throttle regardless of load, and others I can actually get up a hill past 1/2 throttle, but have poor acceleration in the pilot circuit. I'm beyond frustrated, but I know there is a solution, just don't know what it is yet, I'm going to double check my float level try swapping in my original 70 main jet just to see what happens. I did check my compression tester against my regulated compressed air (100 psi) and it read 90 psi so it was off by maybe 10 psi (I didn't have a car handy to test on) so I have to assume it's close to being correct.

[patthesoundguy]

Ok... if its not fouling plugs out then the exhaust may be ok, hard to say. It really sounds like a lean condition, the way a spree works when you pull the airbox off with a stock jet. It just bogs when you give it throttle. Id put the needle back int the middle position. You could try plastic pop bottle caps that fit in the air hose and see if you can get some success with different size holes in them that may get the lean rich figured out just to see where which way it needs to go. Will it rev up with no load? Is it only bogging under load? I know one thing if the compression is correct at 50 or 60 psi its not gonna run right untill you fix it. Crank seals may be in your imediate future.

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[bfowler]

I really think you should address the 50 compression issue before moving forward. I'm hoping that it's just a faulty compression tester but if not then a bottom end rebuild could be in store for you. Get the compression issue squared away before you move forward

[atp]

OK, that will be my next step, I found this video for pressure testing the case of a 2 stroke http://youtu.be/ySu2NC1X7s4 anybody have an opinion on it? could I go higher than 6 psi? seems kinda low to me, considering. If I could regulate my compressed air down to 10-20 psi and use soap water it would save me the grief of making a contraption.

[paulpauly7]

any more than 6 or 7psi and you will blow the oil seal out