BrianG

I use a Throttlemeister and like it a lot. However, it is simply a throttle lock, NOT a cruise control. It is great for what you have mentioned, and easily overpowered if inadvertently left set, or if an emergency arises. Given a cruiser and a lot more installation room, I would prefer a real, electronic cruise control, which are available for motorcycles. This isn't sportbike material, though.

Speak freakin' English, would ya???

Just thought I'd try on the Ratchet-irritant hat for a sec.... is all....

You could always mount a set of 4 frame mounted, chrome crash bars like they used to have on the Police bikes....

Based on Ratchet's commentary, I'm relocating my "full" mark to 1 cm above the Roper plate.

Ok... so I'm not Italian, but while we all use Guzzisti as the plural form of the noun for our ilk, I am curious about whether this noun, in its singular form would be subject to subjective "genderification" as Guzzista/Guzzisto, or would the word simply reflect one gender form?

Ya, that. Now ratcher, 0l' buddy.... you know that I'm not one to futz about with inappropriate determinations and arbitrary numbers. What I was doing in this instance was actually paying you an uncommon compliment. Rather than re-do all this measurement and determination for myself, I was acknowledging the time and effort you have put into this determination so that I would not have to waste my time in replicating your meticulous work. If you actually knew the "volume" of oil that you have settled on, I could use that information to replicate your determination of "level" and adopt it, as soon as I button up the donk from the Roper-plate installation.

So, at the end of the day...... how much oil are you putting in with a new filter and the Roper plate in place Ratchet ?

If I had my 'druthers the MG cam would be driven by a cog-wheel/toothed belt in an oil-free chest like most new automotive engines, which could also house the oil pump and alternator drives.

My comment wasn't specifically about the MG engine's head, but about aluminum heads in general. The valve seat is typically an alloy called "stellite" which is very very hard. I have measured ingress of these seats in some instances and, as ratchet pointed out, they are known to loosen, due to impact, occasionally.

I don't know whether you realize it or not, but here's one for ya~! Of course valve train parts wear would lead to a loosening of the lash settings which is what happens in ironhead engines.... did ya know that the tightening on our engines is because valve action is actually pounding the valve seats up into the aluminum head casting?

Yikes... upside down would be even worse! Indeed, the winters up here are at least 8 months long, so it's important to find something creative and engaging to do.... just to save the liver!!

I'll throw in a casual observation in answer to your query Pierre.... With some 40 yrs of experience messing with internal combustion engines and hotrodding everything I could find from flatheads to EFI controlled DOHC Porsches, it is my observation that valve lash clearances hover right around 0.006/0.008 int/exh on most all solid lifter, pushrod engines. Tighter clearances is either a noise abatement strategy, or an attempt to get more high RPM performance out of a lesser cam. Looser clearances are noisy but sometimes used to get street-drivability out of an engine that was cammed very hot for the track, but the driver wanted to roll the streets for a bit of show-off. Our donk is a military truck engine..... 0.006/0.008 should be perfect. If the noise bugs you, 0.004/0.006 will be ok. Tighter than that will give you idling trouble and might scorch exhaust valves. Much looser than that and you are going to start losing top end performance.

I don't know how much it saved because it worked... When dirt biking in the Canadian Rockies we used to fall off quite a bit. Falling onto the right side often left the throttle buried in mud or dirt and quite inaccessible until the bike was moved. A partially opened throttle could have been a disaster if there was no kill switch. I must admit that this was in the days before rev-limiters....

Too true, Pete! But thanks for the belated commentary in any case.... you have nicely confirmed some of my suspicions gathered in this, my forst forray into the MG EFi system. I learned at least ONE very revealing point in this thread.... being that the TPS setting is a rough parallel to the main-jet needel position in our old carbs. I knew that what I had going on was a lean mis-fire situation, but I didn't know enough about the EFI basics to have a clue about where to look. As you and others here have pointed out, the adjustment process is an iterative one that require much circling about the parameters to get it all sorted. When I had finished my first pass through the set-up loop, I ended up with a very rich-smelling idle. Now an old hand like me does not much like the smell of an over-rich mixture, and I didn't know enough about this EFI to understand what might have gone amok...... but as many have stated, the diddling around with the idle stops and balance-nut of the throttle linkage had sure-enough messed up my careful initial TPS idle setting. Resetting that parameter last thing has left me balanced, idling right, and smelling sweet! These forums are almost the best part of the internet!! Here's grist for your grinder, Ratchethack! Why on earth did MG place the TPS on the remote throttle body? Life would be so much easier if it lived on the active TB unit, leaving balancing as the only significant adjustment for the right side and no need for going round and round this silly circle where one adjustment messes up things on the other side..... Maybe this is a good winter project.......

That was a great ride. Everything seems nominal and drivability is excellent! I'm fixed, and the process was really quite easy!

OK Zebra fans........ Intake spigot boots checked and no leaks found. Compression checked and 110/105 psi rt/lt found valve lash rechecked.... 0.006/0.008 retained since adjustment last week-end I chose the "TPS from the closed throttle" parameter as the sensible baseline parameter.... mostly because it's pretty much a useless number for anything else.... and that in itself is enough to make an engineer pick it. Given this assumption I manipulated the mechanical issues to get the throttle place on the bore wall (closed). Initial reading was 106 mv......... final adjusted reading was 156..... (crap that thing is position sensitive!) Then I set Idle to somewhere between 1000 - 1100 Vague-alia RPM...... so it sounded right, ticking over nicely but not quite doing the Harley "potato - potato - potato" thing. Then I balanced the TB's at 2200 RPM and then at idle I adjusted balance with the air-bleed screws that started at 1/2 turn out (we are at 3500' MSL) Then I checked idle TPS output and I see 485 at that nice slow tick-over with no apparent desire to change directions. ROAD TEST No real change in power. VERY real change in drivability...... NO hickups at idle..... NO chuffing at part throttle.... Positively Honda-like throttle response, and immediate starting when hot (which was a minor concern before this event) So... A cigar is really a cigar......... and resolving the problem is, for some, simply a matter of normal procedure. I'll count myself lucky in that regard...... Back in school one of the clinic supervisors said "If you hear hoofbeats.... think "horse", first..... not "zebra"!

Ok... as far as I'm concerned, a baseline or datum point is the design reference point from which everything else flows and from which individual variation and error grows. SO... I chose the "TPS from the closed throttle" parameter as the sensible baseline parameter.... mostly because it's pretty much a useless number for anything else.... and that in itself is enough to make an engineer pick it. Given this assumption I manipulated the mechanical issues to get the throttle place on the bore wall (closed). Initial reading was 106 mv......... final adjusted reading was 156..... (crap that thing is position sensitive!) Then I set Idle to somewhere between 1000 - 1100 Vague-alia RPM...... so it sounded right, ticking over nicely but not quite doing the Harley "potato - potato - potato" thing. Then I balanced the TB's at 2200 RPM and then at idle I adjusted balance with the air-bleed screws that started at 1/2 turn out (we are at 3500' MSL) Then I checked idle TPS output and I see 485 at that nice slow tick-over with no apparent desire to change directions. ROAD TEST No real change in power. VERY real change in drivability...... NO hickups at idle..... NO chuffing at part throttle.... Positively Honda-like throttle response, and immediate starting when hot (which was a minor concern before this event) So... A cigar is really a cigar......... and resolving the problem is, for some, simply a matter of normal procedure. I'll count myself lucky in that regard...... Thanks guys...... I'm off riding!! (Just for yucks I checked cranking compression and show 110/105 rt/lt -- is this close?)

OK.. this is my first shot at setting the MG TPS but still.... the instructions I have found posted on this forum don't make sense to me. Mostly what I've found is a recommendation to set the baseline "with the throttle closed - to 150 mv". THEN there is a reference to the idle speed value of any where from 485 - 515 mv (depending on whose numbers you like. Well, this doesn't make sense to me. If you set the baseline a 150 with the throttle closed, the idle value is going to be what it is...... dependent upon your individual choice of idle speed, amongst all of the other things that affect throttle opening. SO... Which is the critical value?? closed throttle at 150 mv OR idle(at whatever RPM) at 485-515 mv?

Yes indeed........ For me it's check the PC III and if that's not it.... It's back to the basics/ intake boot integrity/leak check valve clearance check TPS check/set TB balance and idle set ign timing check... if I can find timing marks in there somewhere..... ... then maybe on to the esoteric Now I hate to hijack my own thread but.......... someone mentioned that a minor exhaust leak could be the culprit here.... I don't get that one.... could someone expound on that theory?

Thanks for that. I'll pull the sensor and have a look. I've never seen a post here where someone actually found crap on the sensor, though. I wonder if my PCIII is dying,...... again. I had one crap out catastrophically. I'll unplug it and have a go on the road. One thing that's different in my situation is that after the valve adjustment, the idle is rock steady. No hiccupping or attempting to reverse direction as was present before the adjustment. Just the light throttle hiccup at around 3000RPM. I'll also try a number of other power settings just in case I've oversimplified the issue by too much forum reading!! I read that thread thoroughly now, and what I think you have not taken into account in terms of chain stretch is the "crawling up the sprocket" and then crashing back down that occurs in a worn chain. This is what will eventually cause a "step" on the driven side of a chain sprocket. This would contribute to the ign scatter that has been observed. My point was that chain replacement as a WYAAI issue should be contemplated once you have cracked that chest.. I always replaced a chain twice before replacing chain and sprockets back before I was too sophisticated for drive chains!

OK... so how did you do this? I would venture that if Pete Roper is correct about the mechanics of chain wear (and I believe that he is correct) it would be my suggestion that a better tensioner will not resolve a worn chain. This along the lines of hoping that more rear wheel adjustment would help a worn drive chain issue. It might seem to reslove the "slack" but it won't help the sprocket tracking. If mis-engagement of the rollers in the teeth is a significant part of the issue of the instability causing the scatter, the right resolution is chain replacement.

You, my friend, are on waivers!

OK, that seems doable...... In this particular ign system, how "stable" ought the spark signal to appear? How would one determine the acceptable threshold for scatter? Frankly, I have not bothered to time many pointless ign systems since I see little reasson for variation from initial settings.

No carbon canister is present. I have Mistral slip-ons and a drilled air box. I have installed a PCIII that was tuned on a Dyno-jet dyno. It ran well after this. This issue began late last season...... 2 years after the mods. New irridium BPR6EIX plugs were installed along with the valve adjustment las week-end, and that smoothed the idle right out and elevated the idle speed about 300RPM