timing advance mods

I have an XJ650J and am in need of a few degrees of timing. Iwas thinking of enlarging the stator mounting holes via die grinder. Does anyone have any thoughts?

 

That will work.
You'll get more advance.
Order a dozen Head Gaskets; too.
If you run the Advance outside the Timing Box on the Rotor ... you'll be needing Head Gaskets.
You'll get good at removing the Cylinder Head and installing new Head Gaskets.

 

lol I love the way you say things rickomatic kinda take the sting out of the cold hard truth .

 

why would you need to advance the timing ?

 

Nitrous?

 

cheap HP?

 

LMAO

 

This engine is being modified for hillcliming,it will use nitro for fuel.

 

HOLY CRAP! 8O

Nitromathane is NASTY stuff. :evil:

Mean even! :twisted:

 

Might wanta get TWO DOZEN head gaskets then.

 

OK, hill climbing, why didn't you get a 750 ?? or a 900?
How are you going to extend the driveshaft?

From what I know of Nitromethane, it will double your power, giving you about 150 HP, which will totally shred the tranny.

You also can't conveniently gear the bike lower.
But it sounds like fun !!

 

Headgaskets I fear will be the least of problems, but it wil provide awholelotta fun.I ran across a couple of junkers ,So why not have some fun...as for the drive shaft,a welder and some scrap steel should do the trick.

 

headgaskets????? most single cylinder mc engines can handle up to 14:1 before they need to be o-ringed, and timing advance should not harm the headgaskets unless you are pinging!

are you running straight nitro, or are you going to be mixing with gas? 1-4 ratio of nitro-gas should be within the safe realm for the tranny.

 

As far as the fuel mix.there are several factors to consider,ambient air temp,barimetric presure and humidity.Nitromethane is normally mixed at the last possible moment before use.As far as mixing it with gasoline,Idon't think so.At least not this particular application.This project of mine is more of an experiment.My plan is to mix it with alcohol,not sure at what ratio.Any thoughts???

 

i have very little experience with nitro, mainly because we race under fuel restrictions. i would start light on the nitro at first though, i think it yields very good results on bike engines and overdoing it will just waste a clutch (or worse!)

how much timing were you looking to get?

can you use a degree key on the flywheel? i havent had my xj apart to see how it is designed, but we use the offset keys on all our single cylinder machines and it works great.

 

Hey, Zookie400. I don't have much experience myself. That's why I'm here! I've been luyrking for a time,and I thought once Igot past the SMART-ALEC remarks that all newcomers get,Somebody with real interest,and honesty would have the guts... to try and help a fellow XJ fan!!!!!!!!

 

Well, ... you just take old Zookie's advice and Advance that Timing ... then, hook-up the NO2 and take it out for a spin.

See what happens.

 

Let me just say. That the project I'm talking about is not my daily rider. The XJ650J that I ride as often as I can is totaly stock. It is a loyal, reliable trusted dream of a bike. Screw around with it, and it will leave me by the road sooner or later. To me a daily rider's reliability is paramont. The project bike is just that. a project, an experiment in limitation.How much can an air cooled beauty such as an XJ can take. Any thoughts ?

 

so much for giving experianced advice

When rickomatic gives advise its not to be a smartalec as you say.
so go ahead and play with your project and keep us up to date

 

i bet it would surprise the snot out of a lot of people how much power could be squeezed out of these. there are single cylinder honda air cooled 450cc engines at the track that are coming close in hp to a stock xj750.....they are reliable from a racing standpoint...wich means the engine lasts a season.

an extra 4 degrees of timing is almost nothing. as long as the engine still starts without trying to turn over backwards, and can run idle-redline without pinging, you are golden! it may require 93 vs. 87 at the pump. when it comes to damaging the engine, i would be more concerned with a lean mixture than an extra few degrees of timing.

RICK - do you have any real world experience with advancing the timing on your xj? do you know for fact that it is going to ping with 4* adv.? all other bikes/sleds/atvs i have played with respond very well to some timing, and so far it hasnt caused any pinging or a grenaded engine.

the more i think about it i almost want to try it on my bike to see how the MPGs respond.

 

And if no one tried anything new, we would all be riding around on the same exact bike, making no progress on anything useful.

 

Nitrous is useful, for SPEED nothing more.

my bike already goes nearly 100 mph why do I need to go any faster?

as for everyone having the same bikes well not really see there are exhaust mods, chrome mods, carb mods, sproket mods, wheel mods. and then you have paint oh and lighting as well.

so instead of getting into a pi*&ing contest about this just do your project and please keep us informed on the progress.

anyone hear anymore on the fuel injected XJ?

 

Not true. Nitro-methane as a race fuel is extremely efficient and allows some interesting final-power setups. Such as 15:1 and up compressions, nitrous spray, blowers, and more.

Nitrous oxide is a wonderful thing that, when used PROPERLY (which, sadly, it rarely is), is a quick, cheap, easy power adder. In car drag racing a lot of people that run nitrous have it set up so the juice only sprays at WoT. Some people have it on a push-button for activation. It can be used to add to peak power within a certain rpm range, or you can spray it from just off-idle to redline and make more power through the whole range.

The point of going to nitrous, normally, is because if you tried to attain some of the power levels that a lot of race-only vehicles produce on pump gas, it either just flat out isn't possible, or the cost is so astronomical that it is nowhere near feasible for a normal race team.

Sorry to rant off on a tangent here, but I get very, very sick of people immediately dismissing nitro as a "go fast button" when the people using it as such are usually the minority.

Edit: And my SECA 750 will do well over 100 already. I still want it to go faster.

 

Back in the '60's, we used to street race and die on Friday Night and hit the Drag Strips on Saturday and Sunday. Putting Nitro-methane in the Tank to "Juice-up" the horsepower was S-O-P. How much was always the question?

The left-over Nitro eventually found it way into our Bikes.
I remember one guy who ran "The Juice" almost straight ... in his Norton Commando ... fiddling with the Carbs to find as much power as he could get and wound-up breaking a few windows in the Grade School as he passed-by, cranking it open on a back street.

Back then, 2-Stroke Bikes out-numbered four strokers. And, the 4-Strokers available were just coming of age ... so, if you had a 4-Stroke Bike ... it was probably pretty small (under 400cc's) and Juicing it meant wrecking-it.

But, the need for speed has always included using The Juice. Just remember: If you Juice (or Gas) an XJ Bike ... you are going to get a response that will send the needle on the Tach over to the right-hand end ... REAL FAST!

Fast enough as to where it might be a real good idea to have a Rev Limiter to save you from scrapping the Engine by over-revving it!

 

This man speaks truth. I've already over-revved my seca WITHOUT any juice. That needle goes past 8500 and it pops redline in a HURRY after that. I got lucky enough that it didnt burn anything, (even though I split the cases so I could measure my mains to be sure).

Man, I say go nuts on this. I'd love to see what one of these bikes can really do as a base for a serious performance project, rather than minor tweaking that most of us do. Make it yours, make it fast, make it loud! :twisted: