Symphony of destruction

[Guest]

Right now I'm going with a stock 83 1100 motor until I get the funds to put together a 1230 motor. I need to have another head built and purchase an 1150 crank + gaskets ect....
Probably in the spring I'll put it together. I won't count out another 1166 cause I do have two good pistons.

 

[salty_monk]

Get it in there Bill... Fancy riding the Crest before the cold weather sets in??

Dan

 

[49er]

One of Bill's neighbors snapped this.....those damn L's it always somethin.............

Bill, with friends like this, who needs enemies?

Was this the first blow up or the second?

 

[Guest]

Bill, with friends like this, who needs enemies?

Was this the first blow up or the second?

The last...............

 

[Guest]

Get it in there Bill... Fancy riding the Crest before the cold weather sets in??

Dan

I'm in.

 

[salty_monk]

A Sunday prob as I know that suits you. Never know it might be my shakedown run for the 750 too... seeing as the last time was the shakedown for the skunk might as well follow form!

It's open all the way through now!

Dan

 

[Steveb64]

Snip'd

Steveb64, my brother did the same on his RD350 a few years back. I ported and tuned it for road racing and he went and fitted the wrong heat range plugs and destroyed the plugs and pistons in short time.
His attention to detail improved immensely after that experience.

Yeah, that's the problem with two strokes. The RD350's were quite notorious for it... Too lean will do the same thing too. Blown base gaskets can also cause nasty things to happen... DAMHIK.

Snip'd

I've put aside a set of near new CR31 Specials for the 1100G project. With these, I won't need to open the ports up and they will flow way better than the stock BS 34's. Just some pocket, valve guide and transition work to the pockets. I'll push the CR up to 11-1 on that one, sticking with 2 mm OS JE pistons. As with the 850, I'll bring the custom piston weights down to the stock weights.
I'm still toying with fitting pods as I can't find any stock airbox rubbers around 50mm dia. It's not that I can't tune to the pods, but I'm not keen on wearing the effects of weather conditions influencing my performance from week to week. The needles on the CR Specials have 7 clip positions to choose from, and I have 3 sets to play with. Luxury or confusion??

A couple of hints - My 33's started off as 31's, with 31mm inserts fitted (the CR's have a replaceable screw in end - the bit that fits into the manifold rubbers), and I had a hell of a time getting the jetting right - until I noticed that the carbs were stamped '33', but when I measured the venturi size - they were only 31's. I got a local machinist to make up a new set, with a 33mm ID, and tried them. YAHOO! Made ALL the difference.

So if you have any trouble getting your jetting right (particularly the needles) - try upgrading to 33's.

I ran with pods the whole time - K&N's worked best, and didn't cause too many problems in the wet. And it can get REALLY wet here... At one stage, I tried refitting the original airbox, with a K&N filter in it - but found it messed up the jetting too much - the outer cylinders ran really rich!

And I hate to pop your bubble - but there's more than just needles to play with on the CR's. You've gotta get the main jet and the main air jet (and the air jet can make a BIG difference) set right first, then get the right shaped (taper) needles, and also get the low speed air jets sorted too...

IIRC - I used to run #240 air jets with the pods, and #220's with the velocity stacks fitted.

BUT - there's some help! Check this site out: http://www.factorypro.com/tech/carbkei.html - it's for the FCR's, but the CR specials are close enough for it to be useful!

 

[49er]

Yeah, that's the problem with two strokes. The RD350's were quite notorious for it... Too lean will do the same thing too. Blown base gaskets can also cause nasty things to happen... DAMHIK.

And I hate to pop your bubble - but there's more than just needles to play with on the CR's. You've gotta get the main jet and the main air jet (and the air jet can make a BIG difference) set right first, then get the right shaped (taper) needles, and also get the low speed air jets sorted too...

IIRC - I used to run #240 air jets with the pods, and #220's with the velocity stacks fitted.

BUT - there's some help! Check this site out: http://www.factorypro.com/tech/carbkei.html - it's for the FCR's, but the CR specials are close enough for it to be useful!

Thanks for the heads up on the CR31's and your link. I did come across this info perviously when Googling for the suggested needles. No bubbles burst here, just a tired old tuner hoping not to have to re-invent the wheel too much, with this set up.

The PO bought these carbs from Sudco, pre-jetted for fitting to his GS850. He spent around 2 hours trying to get the needles right but wasn't happy with his results and went back to his Mikunis. I bought them sight unseen at a good price and have stored them until I'm ready to tackle the complete 1100G rebuild. They are genuine 31's, not sized down at the inlet sleeve.
The PO was running very rich pilots and needles, so I'm not surprised it didn't turn on as he would have liked.

I won't be tuning these things for a couple of years or so. I won't be too proud to pick your brains at that time, should problems arise. I'm expecting to have to chase the main/needle/pilot combo a bit. A real positive though, the PO's main jet size is in the ball park.

 

[TheCafeKid]

I dont see a 1200 kit of any size being a good idea for daily rider/street use, ESPECIALLY in your neck of the woods


What kinda smoke you blowin there kid??? I run a 1230 with turbo AND nitrous every day to work and thats 100 mile round trip:-s I used to do do it with a 1327 same trip in the dead of summer with temps around 110 to 120. NEVER A PROBLEM.

Well, Im assuming you built it from the ground up no? Not just slapping a bore kit on the otherwise stock mill and going with it?? I can see building it from the ground up and having no problems, overseeing every little detail, but that, im sure, cost $$$$$$$$$$$$$$$$$$$$$$$$$$ out the wazzuuu. For those of us just trying to get the punch out of the motor with a moderate bore kit, and unchoking the head and whatnot, its quite a bit cheaper. And with a turbo, Id assume the motor stayed abit cooler no?

I didnt say it couldnt be done, and like I said, im no guru. But for ME to do it, on a budget, its not a feasible option. I'll stick with a moderate kit, building the motor for it as I go, so im SURE I have no....well, the pic down there says it all... I cant afford to build it twice. Heck, Its a long project being able to afford to build it once. Im not a drag racer. For that kind of money, I can go buy a Busa, slap some Heli bars on it and flatter 'sets and a GS logo, and call it good

 

[Steveb64]

Thanks for the heads up on the CR31's and your link. I did come across this info perviously when Googling for the suggested needles. No bubbles burst here, just a tired old tuner hoping not to have to re-invent the wheel too much, with this set up.

The PO bought these carbs from Sudco, pre-jetted for fitting to his GS850. He spent around 2 hours trying to get the needles right but wasn't happy with his results and went back to his Mikunis. I bought them sight unseen at a good price and have stored them until I'm ready to tackle the complete 1100G rebuild. They are genuine 31's, not sized down at the inlet sleeve.
The PO was running very rich pilots and needles, so I'm not surprised it didn't turn on as he would have liked.

I won't be tuning these things for a couple of years or so. I won't be too proud to pick your brains at that time, should problems arise. I'm expecting to have to chase the main/needle/pilot combo a bit. A real positive though, the PO's main jet size is in the ball park.

One thing you could check - unscrew the front (spigot? tube? - Keihin call it a 'mount adaptor' in the FCR book), and measure the inside (venturi) diameter of the carb. If it measures up to 33mm, then you can upgrade your carbs to 33's for a relatively small cost - and 33's will work better on an 1100 than 31's!

The jetting problems I was having (IIRC - it was 20+ years ago!) were that I could get the top end spot on, but then it was way too lean below half throttle, or I could get the bottom end right, but then above half throttle went way too rich - until full throttle, which jetted OK! Changed the carbs to 33's, and the problems all went away!

I may end up raiding the air jets off the CR's for the Duc, so if I do, I'll try and remember to check what needles are in them...

Sudco do a pretty good job of their jetting. The FCR's I bought (from ca-cycleworks) were damn near spot on out of the box. Even had the idle speed set right! :lol: ...But because I've got new headers as well, I need to faff around a little...

 

[Kris V]

Hey Kris...so is there any truth in needing a timing curve to this whole "Turbo Thing"?


Yes there is. I use a Dyna two stage retard box for the turbo. Along with a pressure switch in the intake manifold that actuates the two stages of retard. I retard the first stage 18 degrees and second stage at 22 degrees and the results are!! It also keeps the detonation down to a dull roar.

 

[Kris V]

I'm in.

I`m in also now that the fire is pretty much done. No scenery but a nice road.

 

[49er]

One thing you could check - unscrew the front (spigot? tube? - Keihin call it a 'mount adaptor' in the FCR book), and measure the inside (venturi) diameter of the carb. If it measures up to 33mm, then you can upgrade your carbs to 33's for a relatively small cost - and 33's will work better on an 1100 than 31's!

The jetting problems I was having (IIRC - it was 20+ years ago!) were that I could get the top end spot on, but then it was way too lean below half throttle, or I could get the bottom end right, but then above half throttle went way too rich - until full throttle, which jetted OK! Changed the carbs to 33's, and the problems all went away!

I may end up raiding the air jets off the CR's for the Duc, so if I do, I'll try and remember to check what needles are in them...

Sudco do a pretty good job of their jetting. The FCR's I bought (from ca-cycleworks) were damn near spot on out of the box. Even had the idle speed set right! :lol: ...But because I've got new headers as well, I need to faff around a little...

Yeah, It would be handy to know what you've got working, but it really does depend on the state of tune of each engine you're comparing against to be of value. The needles I got with the carbs are YY6, YY7 & YY8. The PO had the 6's fitted, which are the richer set, only 2 down on the richest available in the 7 clip range. And this needle range is suitable for up to 33's.

I will measure the bores. It would be easy to go 33's as well!

 

[Steveb64]

Yeah, It would be handy to know what you've got working, but it really does depend on the state of tune of each engine you're comparing against to be of value. The needles I got with the carbs are YY6, YY7 & YY8. The PO had the 6's fitted, which are the richer set, only 2 down on the richest available in the 7 clip range. And this needle range is suitable for up to 33's.

I will measure the bores. I'm sure it would be more cost effective to do batch machining throughout the range, but I doubt that serious tuners would expect to find that on this type of carb. My transitions were smooth where the spigots met the bores. I would have a step on my carbs if I went to 33 spigots, unless I did some radical machining, like increasing the spigot depth into the body. Not really interested in going there!!

The join/transition on mine was smooth with the 31mm inserts fitted - they had an internal taper from the join to the end. You should (if your ID=33mm) just be able to buy some new 33mm inserts - I guess from Sudco. ...Just checked, and it looks like it. They call them mount adaptors, but when you go to the parts list, they don't give much info - just to 'call'.

My thought is that the different venturi sizes are achieved by changing the 'mount adaptor', and relying on the large range of jetting available to tune around any odd flow dynamics. ...and looking at the parts list, it looks like there's two sizes of throttle bodies - small (26-33mm) and large (35-39mm), so that would follow my thoughts.

When I was doing mine, I lived in rural NZ - and it was a long time ago - and there wasn't a lot of Keihin parts available, so I got a local jeweller (who happened to be a master craftsman watchmaker) who was also a mates dad, and liked doing stuff on a lathe, to make me some, as the thread is really fine where they screw into the carb body, and I didn't trust the local engineering shops to do a decent job. He did a damn fine job too!

 

[Dave8338]

Hey Kris...so is there any truth in needing a timing curve to this whole "Turbo Thing"?


Yes there is. I use a Dyna two stage retard box for the turbo. Along with a pressure switch in the intake manifold that actuates the two stages of retard. I retard the first stage 18 degrees and second stage at 22 degrees and the results are!! It also keeps the detonation down to a dull roar.

I'm thinking of going the same route with the 'Bird. Say 11-12< TDC at
0-8-psi and back to 9-10 at 9-18psi. The car has a knock sensor and a PIP on it but that just puts the brakes on a little too quickly for me. When temps are 60+- degrees and about 80+% humidity the thing will pull like a frieght train all the way to redline. There is a 3-stage boost controler that can be set for various driving and that with some real control on the timing and things could be a blast.

Winter project? :-k

 

[posplayr]

RustyBronco Posted this link; something to consider. These plugs are kind of like a "pre-ignition fuse"

http://www.strappe.com/plugs.html

Platinum and gold-palladium alloys can survive the combustion chamber environment as very small wires, and in that rests their great advantage. Electrons leap away from the tip of a small-diameter, sharp-edged wire far more willingly than from one that's fatter and rounded. So the fine-wire plug requires less voltage to form a spark than one with conventional electrodes, and the difference becomes increasingly biased in the former's favor as hours in service accumulate and erosion blunts the iron-alloy electrodes. There are, of course, drawbacks with precious-metal plugs: they are more expensive, and they are very sensitive to excessive ignition advance. The overheating you get with too much spark lead effects plugs' center electrodes before it can be detected elsewhere in an engine, and when subjected to this kind of mistreatment fine-wire electrodes simply melt. In one sense this is a disadvantage, as it means the ruination of expensive spark plugs. Seen in another way it's a bonus feature: it is better to melt a plug electrode than an engine

 

[49er]

RustyBronco Posted this link; something to consider. These plugs are kind of like a "pre-ignition fuse"

http://www.strappe.com/plugs.html

Platinum and gold-palladium alloys can survive the combustion chamber environment as very small wires, and in that rests their great advantage. Electrons leap away from the tip of a small-diameter, sharp-edged wire far more willingly than from one that's fatter and rounded. So the fine-wire plug requires less voltage to form a spark than one with conventional electrodes, and the difference becomes increasingly biased in the former's favor as hours in service accumulate and erosion blunts the iron-alloy electrodes. There are, of course, drawbacks with precious-metal plugs: they are more expensive, and they are very sensitive to excessive ignition advance. The overheating you get with too much spark lead effects plugs' center electrodes before it can be detected elsewhere in an engine, and when subjected to this kind of mistreatment fine-wire electrodes simply melt. In one sense this is a disadvantage, as it means the ruination of expensive spark plugs. Seen in another way it's a bonus feature: it is better to melt a plug electrode than an engine

We used to use gold palladium plugs on the RD Yamis because they were prone to meltdowns. Cheaper to replace 2 plugs than have to do a complete engine rebuild.

 

[posplayr]

Ray is right. What he is saying is that Bill was running too much timing for the elevated CR with that modded head. The lower octane fuel you used, just lit the fuse.

You've really got serious timing issues when an engine starts pinging at low rpms and low loads. The safe option is to park it up until you address the problem.

http://www.strappe.com/plugs.html

I was reading and rereading this link that RustyBronco posted. It corroborates what Ray and Ian were saying but provides more details. Sounds like we need to figure out where the timing needs to be set and then work mixture and heat range from there.

We cannot stress too strongly the need to give spark advance your closest attention, because excessive spark lead is the most frequent cause of detonation, which is a real engine killer. You can't stop advance-produced detonation with a cold spark plug, nor with anything but a wildly over-rich mixture. Also, excessive ignition advance has a bad effect on performance. We ran a 250cc road racer at the drags a few months ago, and found that retarding the spark about five degrees from the manufacturer's setting raised the trap speed from 106 to 110 mph. Similarly, there's a 125cc motocross machine residing in our shop which runs a lot stronger and cleaner since it has been retimed for less advance, jetted leaner, and been given a hotter spark plug.

 

[posplayr]

So this is what my plugs looked like after getting back from the trip. There are 4000 miles on those plugs and two different top ends.

There is some soot there although there is some variation across the plugs.

 

[posplayr]

Closeups of those plugs if it helps

Closeups of those plugs if it helps

#1 plug ....................