How to hot up my Bucket?

[Tyler_94]

Hey guys, now i race against a few of these fxr150s that are coming from mainly welly and auckland that have been tampard with and absolutely fly around the track. What do you do and is there anything that could be done to my Loncin engine?? Thanks Tyler

[richban]

I am not really familiar with these engines, parts you can get etc. Fish here in wellington has been mucking around with them for a while. If you can find a cheap piston that can take the engine size up to the limit of the rules that would help. I like Mikuni TM 28 carbs they can be found for bugger all. And a good exhaust that is tuned to peak torque would freshen it up I am sure.

[koba]

There is heaps you can do BUT if you are racing on Roys hill I would concentrate on making sure the Chassis, suspension and tyres are up to it first. The Loincin is a nice tame motor standard and great for learing to squeeze everything out of the bike.

Fi5y and Bayden both went way faster than everyone else last time we all came up from welly and Fi5y runs an almost standard loncin, I think it has a cheapo chinese 'Race CDI'.

Whats the frame, wheels and suspension off?

[woodyracer]

tyler has a aprillia rs50 frame so he's sorted with that, on the the "4t tuning thread", and look on some of those websites, maybe put a cbr150 high compression piston in your bike, they are only $100nzd......, also racign CDI's for the loncins are easy to get.

good luck.

[SS90]

tyler has a aprillia rs50 frame so he's sorted with that, on the the "4t tuning thread", and look on some of those websites, maybe put a cbr150 high compression piston in your bike, they are only $100nzd......, also racign CDI's for the loncins are easy to get.

good luck.

Great advise Max.

Erm, can you tell us what he would gain from a high compression piston....what are the gains/advantages Vs the losses/disadvantages of fitting a high compression piston to a four stroke single?

If he does fit a high compression piston, is there anything he will have to check/measure, or can he simply "bang it it" and "go racin'".........

[richban]

Yeh don't listen to Max. You have to wonder how he was planning to get around the 2 valve 4 valve issue.

I can't find much spec on the engine but it did say peak toque is at 8000rpm if can get the bore and stroke size you could have a play with some of the calculators on the tuning page Intake / Exhaust etc http://www.wallaceracing.com/Calculators.htm

[ryanf062]

dont worry tyler its obviously a powerfull bike cos it did after all peal your rear sproket off the wheel didnt it.

[F5 Dave]

Yeh don't listen to Max. You have to wonder how he was planning to get around the 2 valve 4 valve issue.


Look old man ew-er behind the 8 ball, youv herd ov Honads ovaal pisstons yea? well just fit an oval valve with a bit of a file mark in the midel. word.

[Tyler_94]

Haha, yes it did but either it has to much power or to many bolts fell out.

And yes i am running an Aprilia rs50 with the standard suspension and wheels, i have BT39ss on it and i could be looking for some cheap slicks...

[Str8 Jacket]

Hey Tyler I wouldnt stress yourself too much about it at the moment mate. I have raced against you and you are a bloody good rider. Once you develop a bit more you are going ot be surprised at how well your bucket goes! ;)

[NOID]

go the loncin !! Mines Bog standard. CSL here in palmy do a cam for them i think Fi5y said when i was last having a yarn to him. Iv been playing with intake lengths a bit but nothing real scientific yet. im running no filter or intake tube at the moment seems to run good. at the end of the day it comes down to the basic principals of engines, Fuel, Air, Spark

[woodyracer]

Great advise Max.

Erm, can you tell us what he would gain from a high compression piston....what are the gains/advantages Vs the losses/disadvantages of fitting a high compression piston to a four stroke single?

If he does fit a high compression piston, is there anything he will have to check/measure, or can he simply "bang it it" and "go racin'".........

well its a 150cc piston it has to be better than a 145cc one....:laugh::laugh:

dont listen to me tyler, i dont know shit :shutup:, i jsut like thinking i do :shifty:

[Kickaha]

And yes i am running an Aprilia rs50 with the standard suspension and wheels, i have BT39ss on it and i could be looking for some cheap slicks...

Dont they have a 16 inch front wheel?, you'll be lucky to find slicks if it does

[woodyracer]

Dont they have a 16 inch front wheel?, you'll be lucky to find slicks if it does

he'll probualy have to put some second hand fxr rims on then run 125gp slicks........i wouldnt imagine they'd make a slick for a 16" rim....

[Kickaha]

he'll probualy have to put some second hand fxr rims on then run 125gp slicks........i wouldnt imagine they'd make a slick for a 16" rim....

FXR rims might work but aren't really wide enough, especially the rear, and with a the single side rear swingarm I doubt you could adapt one on easily, and I would think the stock rear rim would be to narrow unless you run a front slick on the rear

[woodyracer]

FXR rims might work but aren't really wide enough, especially the rear, and with a the single side rear swingarm I doubt you could adapt one on easily, and I would think the stock rear rim would be to narrow unless you run a front slick on the rear

my rims are pretty similar to a fxr {so thats a 110 back and 90 front} they arnt perfect but as long as you run high tire pressures they are good

[koba]

Haha, yes it did but either it has to much power or to many bolts fell out.

And yes i am running an Aprilia rs50 with the standard suspension and wheels, i have BT39ss on it and i could be looking for some cheap slicks...

Na mate, if they are standard rims your are probably about right with the BT39 SS, slicks go a funny shape when you squeeze them on rims that narrow.

My suggestion would be to get a few people who know there shit (not people who just think they do) to take it for a ride around the track and see what they think.
I don't know who would be up to that up your way, Paddy Doohan maybe?

[Tyler_94]

Yea, good idea. I think Paddy might have already been out on it. I might get a few apinions.

[NSR143]

They are 17" rims and they do take 125 GP size slicks and Tyler IS too fast already... he needs a pie belt and a six pack or swappa crate strapped to him so I can get back in touch with the Firn Boys.!! The only time i get points out of these guys is when... parts fall off.

[Kickaha]

They are 17" rims and they do take 125 GP size slicks .

There's a difference between "taking 125GP slicks" and actually having the correct rim widths so those tyres work correctly

The only RS50 I have seen had a 16 inch front

[F5 Dave]

This was teh bike Lodge(?) built with Hamish's old RS50. It is a later model with the double sided swing arm & 17s both ends.

[SS90]

This was teh bike Lodge(?) built with Hamish's old RS50. It is a later model with the double sided swing arm & 17s both ends.

Yea, the later ones (96 I think) and up had 17in front and rear.

[koba]

Yea, good idea. I think Paddy might have already been out on it. I might get a few apinions.
Get as many as you can, but don't follow them blindly.

[Tyler_94]

Yes it is the one that Lodge had, but i think he probably rode it a little better than me.

yea its got the double swing arm and both front and rear have 17"s.

Its 1999

[koba]

One thing that might be worth looking at on the engine is the Cam Timing.
Often manufacturing tolerances mean it's not quite optimal, plus the factory probably don't set them up for best performance.
You will probably gain a fair ammount of grunt advancing the cam a bit, it's somthing you either need to read up heaps on or get someone to help you as it requires slotting the cam gears. If you get it wrong it can destroy your engine too.
It may have been done if someone else built the bike.

[TZ350]

The closing point of the inlet valve has more effect on power than the opening point.

Back in the day when I played with fast 4-strokes the hot set up on dragsters was to have a retarding cam and you could buy a kit for it, or make your own. The object was to retard the inlet closing point as the rev's went up for more top end power and advance the closing point for low end grunt. Now there are modern performance cars with "Variable Cam Timing" controlled by the engine management system and oil pressure.

Interesting pics here:- http://www.2carpros.com/how_does_it_work/variable_cam_timing.htm

The inlet cam is retarded for top end power........the reason for holding the inlet valve open later past bottom dead center is because of the inertia of the gas column in the inlet tract. Air has weight! and the rapidly moving column can stack more air into the cylinder at higher rpm, so they hold the door open for longer past bottom dead center to allow the cylinder to be over filled.

At lower rpm the air column is moving slower and has less inertia to pack the cylinder so the door needs to be shut earlier to stop any extra air that’s entered the cylinder from backflowing out. The inertia of the air column will keep packing air in even as the piston is rising, up to a point, the trick is to find the right time to close the inlet valve.

[koba]

Ok, after this weekend I'm convinced you would benefit from more power.
Those slicks will prob help too.

I suggest you read up as much as you can about how to make things go faster, there are quite a few good books around.

Here is one:
http://www.scribd.com/doc/11433843/4-stroke-Performance-Tuning-in-Theory-Practice
An old version of a good book. I recommend trying to get the current edition, have a look around and see if you can find it cheap, maybe second hand, If not I can get you a copy but it's quite pricey.

[koba]

The closing point of the inlet valve has more effect on power than the opening point.

Back in the day when I played with fast 4-strokes the hot set up on dragsters was to have a retarding cam and you could buy a kit for it, or make your own. The object was to retard the inlet closing point as the rev's went up for more top end power and advance the closing point for low end grunt.

Yep, but top and power at the expense of a punchy midrange isn't really what I would wan't on Roys Hill...

Variable Valve timing on a bucket would be the shizz...

[koba]

I had another thought today, Did you have an air filter on it?
I should have looked. I didn't hear much induction noise.
I have seen lots of loncins with those little air filters on them, the ones that look like V8 rocker cover breathers...
I don't know for sure but I would bet they are restrictive as.

Maybe experimenting with bellmouths and/or an open carb is worthwhile.
Make sure shit isn't going to get flicked off the back wheel and into the carb tho.
If you wan't to run a filter (prob a good idea as I imagine it gets dusty up there in summer) maybe try making somthing with heaps more area, maybe somthing like an RG150 airbox and filter...
Some bike shops sell the foam stuff that is petrol resistant and you can cut it to shape.

You can even gain power in different rev ranges by mucking about with the volume and inlet lengths and sizes on the inlet. Its a nice cheap and easy aspect to play with, you could build a fibreglass airbox or just find some old plastic bxes or somthing and get creative with the hot glue gun to start with.

There is heaps of info on the net about airbox tuning, also have a look in the ESE thread as they are paying with it on their GP125s at the moment, there are some great links.

[Kendog]

I have seen lots of loncins with those little air filters on them, the ones that look like V8 rocker cover breathers...
I don't know for sure but I would bet they are restrictive as.
I had one of those filters on mine at the start, but got rid of it as it was too restrictive.
Ran open from then on with a full cover just in front of the rear wheel to stop road shit being flicked up into it.

[NOID]

yea i ditched the air filter after i was informed that my bike mite go better without it. im in your boat kendog not running anything. i just tape it up when im not racing. not the best thing for the carb probably. iv started work on and air box,going to be a trial and error thing made from icecream containers and hot glue. maybe i could put a air dam/scoop out the side of the bike !

[woodyracer]

yea i ditched the air filter after i was informed that my bike mite go better without it. im in your boat kendog not running anything. i just tape it up when im not racing. not the best thing for the carb probably. iv started work on and air box,going to be a trial and error thing made from icecream containers and hot glue. maybe i could put a air dam/scoop out the side of the bike !

ive got an air-dam already made up if oyu want it, never got aorund to fitting it to my fxr.......and my cbr wouldnt like it.

[froggyfrenchman]

Hey Tyler, Best advise i can give you is dont take too much notice of what you read on the internet. (no offence everyone!)
On the net it is way too easy for any joe bloggs to jump on and post almost anything. 100 hours of internet research will produce 10,000 different and conflicting theorys about what you can/cant do. Every one of them will be backed up by "it worked great for me / my mate / a guy at the pub / old time racers / my sisters bosses hairdressers husbands old mate.
Pick one or two guys that you know personally (prefrabuly local) that know their onions when it comes to working on engines. Talk to them and follow what they say. They can give you the theorys - along with both the up and down sides of any changes you make. It dosnt even really matter if they have never heard of a loncin, a single cyclinder 4 stroke as about as simple as engines get.
Hmmm, starting to look a little preachy here. Didnt mean to come across that way. Can i just say... this is not a dig at anyone who has posted their ideas! just my opinion.
BTW - im no genius engine builder, i rely on advice from others then do the work myself.
Good luck little Firn. But not too much luck, I will be out there soon and would like to be in front of you...... hmmm Retard your ignition timing and use a much smaller carb :sweatdrop

[fi5hy]

Like I said to you at the track the other day there is more corners than straights at Roys Hill and more horse power at this stage is not what you need. For sure you are on the right track in trying to find some good rubber for your bike, once you have good rubber and have your corner speed at the max of the tyre grip and or handling thats when you need to start looking for more power. As for my bike the little Loncin was standard for the first three years and the only reason I started to find more horse's was I couldn't ride the thing any harder around the corners to compensate for the faster guys with more horsepower. In short (bike skill before horses)

[Tyler_94]

Thanks guys, i dont think much will be happening with the engine but i might have found some rubber that might suit.

[woodyracer]

Thanks guys, i dont think much will be happening with the engine but i might have found some rubber that might suit.

rubber is the key to a fast bike!!....

[NOID]

thats cool dude im looking for some good rubber too. maybe look at creating an air box / intake runner, simple and cheap and yet you will gain smalll amounts from them and cost next to nothing. dont try and run your exhaust in the same configuration as me, yes it gets it out of the way and looks trick but it ends up being right beside your intake that isnt an ideal. . revisit gearing of your bike maybe, if your like me i was only just hitting forth the other day, F1shy was punching though the gears, using his tourque to full advantage and it showed !!!

[NOID]

thats cool dude im looking for some good rubber too. maybe look at creating an air box / intake runner, simple and cheap and yet you will gain smalll amounts from them and cost next to nothing. dont try and run your exhaust in the same configuration as me, yes it gets it out of the way and looks trick but it ends up being right beside your intake that isnt an ideal. . revisit gearing of your bike maybe, if your like me i was only just hitting forth the other day, Fishy was punching though the gears, using his tourque to full advantage and it showed !!!