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Mat Oxley 1986 IOM TT


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Messages - NYSingh

#1
General Chatter / Re: Treatland Sale
October 27, 2022, 11:40:17 AM
They're good for carbs and carb parts (jets, gaskets, etc), spark plugs/wires/boots (they carry BR8ES), uni pods/filters and general purpose stuff for your bike (bar end mirrors, oils, grips, levers).  But you won't find anything specific to your bike that you'd find on Partzilla or Economy.
#2
General Chatter / Thorough RD400 rebuild video
October 26, 2022, 06:23:46 PM
Came across this 1 hr 44 min long video of Stan Lipert re-assembling an RD400 motor with little explanatory prompts throughout, including him designing and fabbing his own chambers!  Super valuable resource!


#3
FYI there's a 'how to' on testing the autolube pump on the forum:  http://www.2strokeworld.net/forum/index.php?topic=1119.0
#4
Good to see Chuck in there!
#5
The last few times I've pulled the oil line hose off the carb, the whole nozzle comes out as well, which worries me it might wiggle itself out while riding (and no oil --> bad day). I can likely mess with the brass press fitting piece on the nozzle to expand it a bit (or get new nozzles), but wondering if a more permanent solution might be to just drill/tap the injector hole and use a threaded brass barb fitting instead.  Can't think of a risk other than it leaking or vibrating out, but if done right with a suitable gasket/crush washer and loctited, seems it'd work just fine.  But if this was a better solution, imagine the wise engineers at Mikuni would've already done this. Any issues I'm not thinking of?
#6
General Chatter / Fiabusa?!
October 27, 2021, 02:14:03 AM
What happens when you throw a Hayabusa engine in a tiny Fiat 500?


#7
General Chatter / Re: Vice TV
October 24, 2021, 06:16:49 PM
Looks like they'll let you watch 30 mins for free without an account
https://www.vicetv.com/en_us/video/blood-and-wire-onitas-fmw
#8
General Chatter / Re: To expansion pipe or not?
October 22, 2021, 02:05:17 PM
Another consideration is what type of riding you do.  I live in the city I do mostly 20-30 mph riding, and to be honest, the chambers make it kind of a pain. I have to get up to 7k RPM to hit the powerband, so I'm constantly revving high to get it moving, then stop 10 seconds later at the next light/stop sign, meanwhile pissing off everyone on the street, scaring dogs, making babies cry, etc. I've never had stock pipes on my bike, but from what I've heard, they would've let me have just as much fun but at lower RPMs better suited for the city riding that I do.  But, if you're going to be riding at higher speeds for extended stretches, the relative lack of low end power might not be a big factor for you.

FYI if you go with the Vape, Chuck (SUPERTUNE) did a great write up that walks through the process in excellent detail. Even with my limited mechanical knowledge and skills,  I was able to use that to install it with no hiccups. http://www.2strokeworld.net/forum/index.php?topic=855.0
#9
If the nearby city you're referring to is NYC, yes, they're definitely around.  I don't know if "terrorizing" is the right term, but they do ride pretty recklessly (ignoring stoplights, weaving around cars, riding in parks) and ride in groups that can seem threatening to non-riders.  They're definitely loud and annoying...but so is my RD.

My biggest issue is that, because of them, the NYPD have declared an overall war on motorcycles. Since the dirt bikers have no problem running from the cops, the law abiding motorcyclists who stop and pull over are the ones that get ticketed/towed for minor infractions (aftermarket parts, not properly signaling, expired inspection stickers, etc) to show the public that they're 'cracking down'.
#10
You can take a look at the jetting poll for ideas:

https://docs.google.com/spreadsheets/d/1T9KaGS9cCZbq9JfwybwA-co3t1NmSuT4D0GfrSjBrJs/edit?usp=sharing

and submit an entry yourself to help others:
https://forms.gle/WWjCHhmdfmozznhWA
#11
Turning Wrenches / Re: Jetting: 2-1 KN v Uni Pods?
June 01, 2021, 04:18:49 PM
Got it.

Related but unrelated question: (within the acceptable range of airscrew turns) is there any benefit to using a larger pilot jet, or is that just wasted gas?

Hypothetical ex:
(1) Airscrew: 1 turn, pilot 37.5
(2) Airscrew: 2 turns, pilot 40

Assuming that 1 and 2 both have the same optimal fuel/air ratio, would having more fuel+air from setup #2 have better performance/torque at low speeds over #1? Common sense seems to imply that more gas = bigger bang, but not sure it's that simple.
#12
Turning Wrenches / Jetting: 2-1 KN v Uni Pods?
June 01, 2021, 02:37:34 PM
Do 2x Uni Pods flow more air than a 2-into-1 K&N? Enough to require up-jetting the pilots/mains?
#13
Turning Wrenches / Re: Tuning//Syncing issues
May 22, 2021, 05:46:02 PM
Well!!! Looks like the culprit has been caught!  That *!3f&ing little pin in the carb emulsion tube has been the source of my frustration for years and had no clue!  Took the carb off, and even after just 20 mins of riding the needle jet was already twisted a bit (see photo).  Pushed the pin in, staked it gently with a center punch, put her back together and BAM, all the carb sync/idle issues disappeared. Now both sides are crackling nicely and the cylinder temps are steadily within 5 degrees of each other. Just went on a 2 hr ride and this is the best the bike has felt since I got her :whoop:

Probably still have to find the perfect pilot+needle position+main combo, but a big step forward today! Thanks for all the help!
#14
Turning Wrenches / Re: Tuning//Syncing issues
May 20, 2021, 12:15:35 AM
Sorry, one last thought:  as I was reassembling the carbs I noticed that on the left carb, the little pip in the body inside the emulsion tube that's supposed to align the needle jet so it only fits in one way was missing or broken off.  Could this be causing fuel to get sucked through? I wouldn't think so because the washer below the main jet should seal the tube but just trying to think through the possibilities.

I took a video of me reassembling the carb for reference - you can see what I'm talking about around 4:18-26 (if you happen to watch more than just that part, I apologize for my swearing particularly when trying to assemble the choke lever - didn't intend to share this out when I filmed it!):
https://photos.app.goo.gl/umNakcXde91qVeCfA

#15
Turning Wrenches / Re: Tuning//Syncing issues
May 19, 2021, 11:40:13 PM
A few questions:

  • Is the process I went through to sync the carbs accurate or did I do anything wrong there? And did each side sound right individually?
  • Should I be tweaking the airscrews along with the idle screw?
  • If so, should I do them one cyl at a time like I did for the sync?

Quote from: m in sc on May 18, 2021, 03:56:31 PM
double check the float levels.   
I did that right before I took that video when I cleaned out both carbs and reassembled - almost spot on 23mm from gasket surface to top of float (gasket removed).

Quote from: Alain2 on May 18, 2021, 04:11:48 PM
What is the problem with the bike? How does it ride? The engine sounds very good to me.
I think my biggest issue is that it seems unresponsive in terms of power.  It revs easily enough and will get to 9k no problem, but it doesn't have much oomph below 7k.  I know that's to be expected with chambers meant for racing, but even still, seems on the weak side.  When it does hit the powerband, power comes on but still seems subdued.  There's a bit of hesitation around 8k-9k but still accelerates through.  Even in 1st/2nd at 8-9k, the bike doesn't feel like it wants to lift the wheel at all. I've read that improperly synced carbs can cause poor acceleration so wanted to verify my sync process to eliminate that as the cause before I move on to jetting changes.

Quote from: 1976RD400C on May 19, 2021, 06:46:39 AM
Does it sound ok as it accelerates?
It sounds pretty good on the pipe at > 50mph.  Below that it sounds, i know how how to describe it, but just 'not quite right'.  At some point in the coming days I'll try to record a video operating the bike to give a better picture of how it sounds through the gears.

I went for a ~20 min ride today (half highway, half city streets) and below is what the plugs looked like after.  I know it doesn't tell much since I've been on 2-3 rides with these plugs, but to give a general sense of the state of tune.  Left still seems richer based on lower cyl temp, the less regular 'pop pop sound of the exhaust, and spooge coming out the header (even after filling the flange up with ATV), but plug doesn't really look rich to me. It actually died at a stop light, but noticed that the choke flipped on during the ride, so need to fix the choke lever spring so that doesn't happen.  Funny how if the bike is warm at all the choke almost acts like a kill switch.