Kiss my Keyster (carb kit needles)

[clarenceada]

I agree with LM. Back when Hotshoe started this thread it was because the Non-Stock Keyster needles didn't work right but the Stock Honda needles did.


Clarence

I think I'll throw in on this.
In my opinion if ya have the valves set correctly (assume the adjuster screws have a good contact surface and the stems are not grooved) and the timing is set correctly (clean contacts on the points) and ya have a good set of plugs and wires ya can most times set the carbs as the tuning idea says and Forget About All the Special Tools, Test Equipment and go ride the bike!.
For some reason this generation of 250/305 owners are looking past the fact that HONDA designed/made a engine that Any Fool Can TUNE.
Change This/Change That!!!!!!!!!!!!??????????????
When ya change all the Running Parts Ya will more than likely have a engine which has more tuning problems than stock for sure.
When Ya build a Big Bore Engine (bigger Cams and Stronger Valve Springs) ya may find that it is More Difficult to Keep Running than stock or at Worst "Have A Grenade Blow Between Your Legs as I witnessed both many times in the 60's.
Those who race Know Ya have to Take That Engine Apart Often to BE SURE THINGS ARE NOT COMING APART!
And Some of Ya Think Ya can "Just ride the street" like a Stock Engine???????????
KISS! "KEEP IT STOCK STUPID!. .....lm

The old post I found some time ago was about a do-it-yourself version consisting of just an oxygen sensor and voltmeter which could be done for way less than $100.00.

Will keep digging!

[brewsky]

I agree with LM. Back when Hotshoe started this thread it was because the Non-Stock Keyster needles didn't work right but the Stock Honda needles did.


Clarence

I think I'll throw in on this.
In my opinion if ya have the valves set correctly (assume the adjuster screws have a good contact surface and the stems are not grooved) and the timing is set correctly (clean contacts on the points) and ya have a good set of plugs and wires ya can most times set the carbs as the tuning idea says and Forget About All the Special Tools, Test Equipment and go ride the bike!.
For some reason this generation of 250/305 owners are looking past the fact that HONDA designed/made a engine that Any Fool Can TUNE.
Change This/Change That!!!!!!!!!!!!??????????????
When ya change all the Running Parts Ya will more than likely have a engine which has more tuning problems than stock for sure.
When Ya build a Big Bore Engine (bigger Cams and Stronger Valve Springs) ya may find that it is More Difficult to Keep Running than stock or at Worst "Have A Grenade Blow Between Your Legs as I witnessed both many times in the 60's.
Those who race Know Ya have to Take That Engine Apart Often to BE SURE THINGS ARE NOT COMING APART!
And Some of Ya Think Ya can "Just ride the street" like a Stock Engine???????????
KISS! "KEEP IT STOCK STUPID!. .....lm

The old post I found some time ago was about a do-it-yourself version consisting of just an oxygen sensor and voltmeter which could be done for way less than $100.00.

Will keep digging!

I agree with keeping it simple, and do not advocate adding a fancy expensive A/F monitoring, data logging system to the 305.

However, some here, including myself, do not have the luxury of having a stock exhaust and intake system, nor the means to purchase one at current prices....and that means fiddling with the carb(s) to get it "right".

Plug reading is somewhat of an art as shown in this thread.

The PO of my dream had actually filed off the bottom angle of the carb slide in an attempt to get it right.

A dyno and sniffer is a good, but expensive tool to achieve the elusive perfect carburation, but even that is just a "simulation" of the bike's actual operating conditions.

Being able to directly read A/F ratios on the road under actual operating conditions would be even better.

A simple portable oxygen sensor stuck in the end of the exhaust wired to a voltmeter doesn't seem that complicated to me, and is just another tool.

[Snakeoil]

I don't think anyone here has done anything but suggest various ways to determine if the engine is running properly and what some of the finer details of those ways might be. Brewski hit the nail on the head. If you get a bike with some modified bits, and original bits are not available, then you need to go down the trial and error path to get the bike back to, or at least as close to perfect as you can.

I agree with LM's comments in that I constantly see folks trying to improve on the OEM design. I've always thought that a bit foolish for a run of the mill street bike. If you are hot rodding it, that's one thing. But those that try to improve on the standard design is perhaps fun, but personally, I'd rather ride it.

There is a discussion going on on another forum right now where a rider wants to increase the amount of oil in the bike's oil tank (Oil in Frame) now that he's just finished an engine rebuild. The known experts on the site have confirmed that the original factory tests never developed any overheating problems and the test were done in AZ. So overheating is not an issue. Modern oils are superior to what was available back then so if you do regular changes, oil life is not an issue. I still have not figured out what he's trying to accomplish, but he's hellbent on doing it.

What I liked about this thread was all the info that surfaced. The article by GJ was a great find. I view these discussions as electronic versions of the old BS sessions folks would have in the general store, sitting around a pot belly stove, passing around the jug and talking about ways to make their farm equipment or Model T work better. It's all good stuff to me. And even if I think to improve on the OEM design can at times be of little value, talking about it makes everyone that much smarter on the subject. LM's comments actually give me a lot of comfort that the engine is pretty forgiving to tuning variations. That cannot be said for a lot of engines. My bike as a gutted stock exhaust and somebody put 130 jets in it. Seems to run pretty good and plugs are not appearing to be overheating. But she burns a bit of oil to so that could be masking a lean condition. I just put 135 mains in it (got the last pair the dealer had) because that was the stock jet and I'm expecting it might be a little more responsive with those jets, not to mention less prone to holing a piston. Won't know until spring comes, though.

Getting back to the AFR measurement, I'm going to ask my cousin if he has any charts for O2 sensor voltage readings. I would think that it's simply a matter of which O2 sensor you have and the AFR mixture for any engine can be determined with that sensor if you know it's voltage/AFR calibration.

regards,
Rob

[Hotshoe]

I was digging around on-line looking for jets this evening (thanks for the 145 Fred, 1 down 1 to go) and ran across this site with a link to a Keihin carb tuning guide;

http://www.motorcyclecarbs.com/Keihin_C ... 46C560.cfm

The graph showing the effect of the various jets vs the throttle setting was particularly helpful to me so I thought I'd share it.
Pass the jug Rob, Chuck Wineinger

[LOUD MOUSE]

That's a great explanation of "what happens when" for sure.
Notice how the air and main jets work and when.
This info should help those who want to get a perfect burn for the plug color.
I did notice how the main jets were determined. ...........lm

I was digging around on-line looking for jets this evening (thanks for the 145 Fred, 1 down 1 to go) and ran across this site with a link to a Keihin carb tuning guide;

http://www.motorcyclecarbs.com/Keihin_C ... 46C560.cfm

The graph showing the effect of the various jets vs the throttle setting was particularly helpful to me so I thought I'd share it.
Pass the jug Rob, Chuck Wineinger

[e3steve]

Interesting article, Chuck; I'm glad you posted that.

As for the tuning? I'll stick to pulling my plugs, thanks. That said, my motor is stock.

[teazer]

LM is right on the money. We have two possible approaches to the issue.

The easy way is to assume that Honda engineers way back in those dark days knew more about setting up the jets than the rest of us ever will , so just jet it and forget it.

Or we can pretend we have some idea about the subject and buy a wise band O2 sensor with AFR and data loggers and add a TPS and analyze the data. If we don't actually know what AFR we are looking for we'll soon get lost. Even if we think we know what AFR we are looking for, we still have to fine tune it on the road.

That's an interesting way to go about the job and a great "learning opportunity".

We use exhaust gas analysis on the dyno with highly modified motors with oversized carbs because it's way easier in Spring than running around a race track and coming in once a lap to swap jets.

What we usually do is to get the idle more or less right and then set the main jet by feel backed up with flat out plug chop. Then we fine tune the needle and jet and cutaway for best feel at different throttle positions.

Even after a dyno session, we fine tune at the track because what works on the dyno at WOT rarely is what I need on the street or the track. It just lets us know what the heck is going on and sometimes helps us to understand what the bike is doing.