I'll share everything I know. Got a second? We threw around some ideas a while ago in some thread I remember. Thinking of that I wish I would have got some pictures of the inside of my cylinder. The triple exhaust ports were pretty neat. However if I was to build another one I would try a bridged port for even more area.
As for the DS, I plan on leaving it alone. Yea right, I know. I've got my buddys Banshee with the V-Max cylinders on it to tune with yet. I'll be mixing gas for a while yet. The only idea I had left for my LT was to put two cylinders on it. Thats when I decided to quit drinking in the shop or get rid of the quad.

 

LMAO!!!
I'm thinking there are many a good idea generated from the induction of alcoholic beverages.... I've had a few myself! A twin cylinder??? That'd be cool!
The last time I had alchoheimers, I was thinking about grafting a jug from an 800 polaris engine onto a 250R bottom end. Those motors are downright salty, and I'd be very happy with 1/2 that much power in a quad!!

I'm always out to learn all I can about these dinosaurs. I'm building a 250/500 hybrid this winter provided I can find another basket case motor. (seen any laying around anywhere??) I will go all out on this one with peak HP being the goal, and not so much on the reliability aspect. Probably on the bottle too.
Great minds think alike... I was thinking a new sleeve with a bridged exhaust port so ring support is no longer an issue.

Not to cloud your mind or anything... but a turbo would be fun to play with on that DS!!

 

Ohhhhh yeaaaaa a turbo. That WOULD be cool. Great, now you got me thinking. I was only going to put on a slip on. As long as I'm taking off the silencer, I might as well put a turbo in between. I'm going to try and control myself but Haydays is next weekend and I know I'm going to see a hundred turbos now. Probably $10 a piece!
As for your next project. I think go with an aluminum sleeve for heat transfer. And I have an idea for a bridged exhaust. The biggest problem of them is it creates a hot spot. How about if you made it about 15mm - 20mm wide or so and ran coolant through it. The coolant normally runs up the front right corner of the cylinder. When I put in the triples, they blocked that off so I drilled a cross hole under the bottom of the exhaust port to feed the left side of the cylinder. You can see the hose I used to re-feed the right side. Anyway, if you drill that cross hole, then you can drill a hole down through the bridge port to get coolant through it. The bridge would have to be pretty wide but who cares? You can then run the two exhaust ports to the wrist pin bores. I think the biggest problem is finding a piston without the sides cut by the wrist pin area. I used a KX 500 piston for that reason. The problem with that is they only come 86mm and you probably want to big bore.
Actually, that might not get much more area than triple ports because once you get that wide the front transfers will get in the way. Maybe a 8mm wide bridge with a small coolant hole?

 

Duneaddict, out feeding the addiction? Nothing wrong with that one.

After reading your reply I'd like to change my questions. First, what is your rpm range and would you consider it low, mid or top end, or a combo. I am thinking about getting a tach/egt so I can keep track of mine. Does your pipe work in the rpm range you designed it for and is that low/mid/top? I understand the time involved in building the pipe. If you combined the shape of the paul turner pipe(the head pipe) with the rest of the shape of the lrd pipe do you think you could get your pipe design to fit in the frame? With the type of silencer you have how loud is it, where you ride is there any noise restictions?

When I had mine ported in around 93' all I had to go by was magazine articles so I went with a trinity stage 2 job(I know from doing an lt500 search here that you have had bad experiences with them) and I was happy with that. Now that I have been on the computer a couple years I see that there is more to it than just sending your parts out for stage what ever work. Macdizzy has a series of articles on port mapping and there is a go kart site as well that has some info so now I am trying to understand why the port shapes/sizes etc. are being changed and what effect it will have.

Do you think a large single such as a 500 will realize as much gain as a 250?

Halfliter, I have no doubts with your fabriction skills that if you wanted to put a turbo on a ds650 you could do it. Didn't there used to be a street bike that had a turbo? Maybe a turbo seca? Not sure but I bet the size of the turbo would be close. Good Luck if you do try it!

Thanks Guys.

 

I wish all threads were this intelligent and informative.

Sorry to crash your conversation but could you guys tell me which year is the best Zilla to buy. I know they added another stud to hold down the jug on one of the later year models but that's about all I know.

Thanks in advance, -RT

 

TRX440, the 87' has 6 head bolts vs. 7 for all the others. It also has a bigger intake area and reed valve. The carb is also different on the 87. I think the later carb is better. Also I think some of the gear ratios are different in the trans. The 87 is also the one with the rectangular tube upper a-arm. As far as better I guess that would depend on how you are going to use it.

 

I would get a '88 or newer. They had all the little updates as mentioned above. The '87's were not bad machines however. In fact, I would buy an '87 if it looks better than another year. The only real problem with the 87's is the one less head stud. My friend has one and never gave him a problem. I heard it is though. The only problem with the newer ones is they have a small reed cage. I had a V-Force in mine and was able to make some good power. I'm pretty sure they all use the same Mikuni TM 38 carb. I think it is an awsome carb. I would say, just like any quad, buy any one that don't look rough. I've seen alot of rough looking LT's for sale and alot sold. Then all I hear is how unreliable they are. I wonder if it's the same quads? Hope this helps.

 

Hi RT,

Jump right in here... Tom and Half are both right on the $$ with the differences... The '87 has one fewer head stud than the 88+. Suzuki did that to remedy head gasket failures. If you look a little deeper, the stud diameter is larger also (10mm) which allows the stud to hold torque better also (The 8mm studs have a tendancy to pull under torque)
The '87 has a larger reed cage area and they do flow better than the newer models under extreme modifications... if you leave it stock, you won't notice any difference.
The 88+ does have a closer ratio on 4th and 5th gear (Hope I remember right here) hence the stock sprocket differences b/w years.
The '87 TM mikuni has different internal circuitry than the 88+
Gosh, what else..... Round upper A-arms on the '90 model, different front bumper on the '90, and the biggest mod (Insert your favorite banshee update here) Graphics....

Are there any years better than others? I'd say probably not... Unless you're looking for an all out drag monster, I'd look for an 88+...
All the shortfalls can be corrected on the '87 model without too much hassle.

Hope this helps!

 

HalfLiter: Oh yeah!!!!! Turbo and just a little bit-O Methanol!!!! Hang on to your shortz!!

Now all this is making me think that a thumper might be kinda fun to tinker with... Think I'd choose the new Yammie 450 since it's so light. I rode one last weekend, and for a stock thumper... it ran pretty good (Gosh I hate to admit that...)

Hmmm... you think an alum sleeve with some of that high tech Nicasil? The heat transfer would be much better.... And I hear you on the bridge issue... I've played quite a bit with the Honda version, and spent alot of time relieving the bridge, and also drilling the piston with lube holes... I haven't had much trouble... The thought of cooling the bridge is pretty wild. I suppose a guy could figure the coolant flow rate needed to dissipate the heat based upon metals used, etc. (I'd have to go back and find my fluids and thermo books from school)
I was going to ask you about that extra hose.... Now I understand what it's purpose is... Very trick!

I definitely want it to be a big bore, so I'll look at that KX piston... I'm just now starting my homework for the next build (My last build Wen't ka-boom this past weekend)
Jeez... More horsepower here I come!!!

 

Hi Tom,

Yes.... I finally have enough sand down my shorts to last me a few days anyhow. Feel much better except I hurt my baby on the last ride...
My first recommendation: PUT A TEMP GAUGE ON THERE!!!!! I had one, broke it, and didn't get it fixed for the last ride.... OUCH! Back to the drawing board.

Lets see, my RPM range would be considered a Mid to Top End motor. Per my calcs, critical piston speed is ~7,200RPM so I didn't want to exceed 7K just in case I had a little over-rev.
These motors have gobs of low end, and the type of riding I do doesn't require much anyhow. What little bit of port work I did had virtually no effect on low end power, just made is much stronger upper mid to top end.
My pipe is set-up to sign off at approx 6,800 RPM, so it compliments the porting very well. I have no doubt I'll spend the time to fit my next pipe in frame... HalfLiter musta spent months getting his to fit... Cut/weld Cut/weld Cut/weld Cut/weld Cut/weld Cut/weld Cut/weld Cut/weld Cut/weld Cut/weld
Gosh I'm lazy...
At first I didn't run a silencer, but that thing was an ear drum breaker! We have no noise restrictions, but I hate loud toys anyhow... The silencer is also homemade, and is no louder than any other aftermarket pipe out there..
Yes, I really frown on the "puppy" shops (e.g. Trinity, etc.) Thier stage II port job is nothing more than removing the casting flash from the ports... But that's another story all together.
There is a TON of info out there on 2cycle engines, and I have soooo much to learn. MacDizzy is a fairly decent source for info. I've learned quite a bit from Rick, and the members of that forum.

I don't think a 500 has as much to gain as a 250... here's why. My stock 250R was somewhere around 32 HP (Don't shoot me, but that should be pretty close) I haven't dyno'd it, but the software estimates (Not including pipe) my setup to be in the 63HP range, which is around double the stock #...Sure wish I could find 96 HP out of my 500 without the little blue bottle...
The 500 can be vastly improved as it's really chocked down.... just not as much IMHO.

Regards,