Friday, May 26, 2006

Running in - Dialling in, teething issues and general fiddling.

Did about 150miles today, with a windscreen frame and gearbox tunnel, so tuning begins....It runs WELL don't me wrong, however- Kind of frustrating .... cause I had some issues I couldn't dial out over the longer term driving... The engine runs nicely and works but a bit rough and inconsistant, midly overadvanced for first 10miles by about 1-2degrees, quickly fixed on 11 deg for now...33 total, safe for running in!

I have awesome compression, low blow by and increased compression ratio, this roughness is down to number of issues I think. I tested various jets to be sure it wasn't a fuel issue and what should work didnt and anything else was rich- found the roughness persisted on all jets tested. I ended up back on a 50idle and 112 mains - which are the the "ones". I think, maybe 115main would be best but the 3 point change wouldn't be enough to give this roughness in certain areas and times..

I tried to cure it with a 52idle but this is too rich and a touch lumpy and plugs midly fouled, there was bog from 1250rpm-2000 on 52 idle so its not that!! as it tells me its too rich! 50 is good sometimes but not always there's something odd going on, related to heat, traffic and how the engine has been used before.

I went back to 50 and its improved but there's a bizarre inconsistancy issue, which gets worse on open road the more load you put the engine under -and the engine runs well just after some town work when cylinder temps are low...As I cannot use a 52 idle without lumpyness 50 must be right as before, and I am fighting an issue unrelated to the carbs!! Having been round the houses on the jets I have concluded that the last engine was on the cusp of the BPR6ES and BPR7Es, winter the 6 was best and summer the 7...

Seems now it needs a 7 always, but it was 10.30pm when I concluded this and my neighbours might get annoyed with further testing! The 50idle is right I think yet the engine doesnt run 100% all the time only some of the time. I see from the plugs they are a bit white on the tips yet the metal outside is blackened a bit, which tells me that the mix is about where I want it with regards to what worked in the last engine, bit black on the metal bit, brown on the middle, tuned engine always wants a little more than stoimetric fuel ratio...

The plug tip won't colour up on the correct jet and richer jets just go rich and the engine goes rich rough!!.. So I switched to 7's after coming to the conclusion that the 6 is overheating and ending up white being no1 was whiter than 2-3-4 and 2-3-4 were gradually graded in colour, I think they are too hot and causing a roughness -through effecting the fuel mixture when they overheat= hot =burning off some fuel mixture, misfire, fluff and effecting the "ideal" jets character...I felt before the 7 was better at higher end, but maybe now its better all over....Might even push an 8 at trackdays?!

Sometimes the engine feels right after town work and gradually goes bad -there's definate issues with the plugs!

If you boot it after low rpm and low load town work it runs nicely for about 45seconds then goes a touch mute and lumpy (this is a small in effect but it pissed me off) - suggesting the need for a cooler plug....the plugs only working in a very small operating window and rapidly gets overheats or something.

Its not as smooth as it was before, it was like silk.

Also the rad shroud is so effective the engine can't get over 65C on open road even in 21C heat this afternoon! , which compounds the plug issue surely? As when I blank the rad off and increase the temp the plugs are only gonna get hotter with the extra heat introduced in the engine?

I can only ramble atm till I can run the engine on the 7's tomorrow...Often you find the plug temp rating can make a huge difference to the smoothness of the motor...1 grade can make a motor -give a motor an utterly different character.

As I went round the houses and failed to find a fix I am lead to only 1 conclusion, the engine creating more cylinder heat now at all times and has moved into a solid BPR7ES heat range....

Its too early to drawn any great conclusions but this one seems obvious weighting up the facts.

I idled the engine in the garage with the 7's and seemed good...Also on the 6's and 50 idles it used to pop and bang a touch when rev'ed statically but drove superbly, on the 6 and 50 now -it seems too smooth to me, smooth at static seemed to equal crap under load before... As the 7 gave a bit of pop and bang rev'ed in the garage thinks should improve...Static revving on a tuned engine shouldn't be dead smooth from my previous experience, as this leads to a lean under-load driving condition, as static and loaded are two completely different things, and static reving character should be completely ignored and running underload is paramount.

As it fluffs on the 52idle, overlap is not as good to mains and plugs were a bit black. 120main is too rich, rough and lumpy - there is only 1 conclusion, proof of that conclusion will be tested tomorrow... I think when you get to 10:1 comp ratio that 7 plug is essential.

Bar this rough running it shows moments of clarity and I did give it 1 boot to 5K in 2nd and seemed pretty healthy!

So hard resisting the urge to see whats it got, i'll leave that for now! This roughness must be remedied first.

No comments: