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Mat Oxley 1986 IOM TT


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Messages - jmendoza

#1
Turning Wrenches / Re: Colder left cylinder
September 13, 2020, 08:14:46 PM
First off, be sue both of your carbs are exactly the same when it comes to
1. Float height
2. Pilot air screw setting
3. Slides open the same amount at full throttle
4. Needle clip positions
5. Idle speed screws are with 1/4 turn of each other.
#2
Hello everyone,
sorry for not being on the forum more, been busy with work which keeps me away from home.

The  1st annual Bike-toberfest will be at Cooks Corners in Trabuco Canyon, Orange county, on the 2nd Saturday, the 10th of October.
https://cookscorners.com/  Cooks has food, beverages (adult and kids) plenty of motorcycle and vehicle parking and a large shaded patio as well.

  We will get going around 9PM, but you are welcome to show up at any time. Awards will be at noon, AFTER the Smoke-Out. 
There will be some awards presented for the bikes, so be sure to have yours all polished up!
'
Camping is available  3 miles away at O'neill Regional park,  https://www.ocparks.com/parks/oneill/

Looking forward to seeing all of you again at Cooks and re-newing old and new friendships.

Jay

#3
Turning Wrenches / Re: Bore and hone
May 07, 2020, 12:30:53 PM
Very nice work Chuck!

We had a local guy here who like Chuck, had been  doing 2-stroke boring for 50 years. He has a row of 3 Rottlers and 4 Kwickways, several Sunnen rod/keyway pedistal hones and a large derrick type Sunnen hone (looks like a grasshopper oil well). Best of all, like Chuck, he used torque plates for all the 2-stroke Air cooled Yamaha cylinders and other makes as well. His two sons now run the shop as Bill sadly passed away early this year.   

Chuck so correctly points out that experience is crucial when boring a 2-stroke, as they are very tricky to do correctly given the ports and relatively weak liners when compared to a 4 stroke engine block.   I gladly pay $90 a hole, or more, for someone like Chuck who has the right tooling and experience.  If we did not have the Qualls here locally, I would be shipping my cylinders to Chuck.
#4
Turning Wrenches / Re: RD250/400 Transmission
May 07, 2020, 12:15:49 PM
RD250 has a different primary gear on the crank, different ring gear on the Clutch basket, and hub and  a different input shaft. The splines may be the same but the length of them is different due to the depth of the clutch assembly.

I know you can swap tranny parts between the DS-7, R5, RD250 and RD350, but not the RD400. 
#5
Turning Wrenches / Re: R5 tachometer indicators
May 07, 2020, 12:02:45 PM
Note how Mark's R5 tach needle has an aluminum round medallion on the center of the needle, just like the speedo needle, and the small white increments on the RPM scale.   Your Tach is probably off an Enduro model.  It looks just like the one on my 1971 CT1-C
As long as it works it should be just fine.
#6
Turning Wrenches / Re: RD 400 Rear Master
May 06, 2020, 07:33:50 PM
That widget is for filling the lower unit/gearcase of an outboard motor with oil.

The Mighty-vac is a better tool, and works great but requires a little patience, so here is the easy way to success:

Clear the brake line using compressed air, failing that, replace it. Make sure the rear caliper
piston is free. or rebuild the caliper. 

Fill the brake reservoir, pump the pedal a few times, attach the mighty-vac hose to the the caliper bleeder, open it and suck some fluid using the mighty-vac. Close the bleeder, top off the reservoir, and go have lunch or a beer. It takes about an hour for the fluid to slowly percolate through the system, and the air bubbles to rise, so the longer the better. Tap the caliper and line with a screwdriver handle to break the air bubbles free. Then you will find you get pressure really quickly and have good pedal with minimum bleeding.  I learned this the hard way, and have used this trick for years now.

HTH,
Jay 
#7
Check the plugs to see if they fouled.  Then while they are out, do a compression test with throttle wide open.

HTH,
Jay
#8
Turning Wrenches / Re: RZ Oil Pump Stroke/Shims
May 06, 2020, 07:19:00 PM
Too much minimum pump stroke will usually just foul plugs, especially at low speeds and city driving. A minor nuisance, but no harm other than excessive carbon build up if run that way  for a long time. Easily corrected using brass shim stock if you don't have any of the Yamaha pump washers.

HTH,
Jay
#9
Turning Wrenches / Re: R5 tachometer indicators
May 06, 2020, 07:04:08 PM
You are not going to like this but guess what?

That Tach is off an AT-1, or CT-1, or another Yamaha because it is smaller than the speedo.

Looks just like the one on my 1971 CT1-C

Jay
#10
He did not break it in enough.
I have used .0016" clearance on my air cooled RDs with OEM pistons and never had an issue, but I follow the break-in procedure and do not flog the engine.

Typically, seizures that occur where the piston clearances are tightest (below rings on the skirt) are due to lack of lube.
Seizures in the ring land areas are typically from overheating.

But in a new engine that has not been broken-in and has tight clearances, the piston wrist pin bosses are the thickest areas of aluminum and therefore expand the most, causing the typical 4-corner seizure mid-skirt as pictured above.

We used to coat our pistons with blue Dykem, assemble and fire up the engine, then take it apart and polish the piston skirts with 600 where the Dykem was scuffed off and then re-assemble go racing. This was a quick-break-in technique for racing only.   
#11
Thanks guys, we will look forward to seeing old friends once again.
We have just gotten confirmation and commitment of a sponsor for the event so there will be some modest prizes and awards.
The awards will be the high quality hand made solid hardwood plaques with 10 coats of hand rubbed finish, topped with genuine blown up 2-stroke engine parts. This is a 2-stroke Hooligan tradition we are going to re-instate.  I am also looking for someone who would like to do the event t-shirts, please contact me if you are interested. 

This event is open not only to 2-stroke bikes, but any 2-stroke powered machine, and all Vintage motorcycles are also welcome.  If you want to volunteer to assist with the event, I have many small tasks that don't take much time, just a little effort, so feel free to contact me.  Most of all, we hope you all will come out and attend. It has been 5 long years since we had an event here in Orange County and look forward to doing it again as it is long overdue.
Remember, this is all about, and for, you guys; it would be nothing without you.

Jay
#12

Autolube is your friend,
if you run pre-mix, carry a set of spare plugs!
The stock airbox  is actually quite good and makes jetting really easy, just use stock jets.:)
Yamaha knew what they were doing when they engineered the airbox: it is part of the tune of the bike and the jet needle taper and the carb design is for a stock airbox.  The restriction in the DS7 and R5 is not the airbox, or the filter, it is the intake port area, so bigger carbs don't help very much at all unless you do a bunch of porting, and then you have a bike that is more suited for the track than the street.

For jetting, simple rule, go way too rich and then work back down one jet size at a time.  This is the safest way because there are too many variables like milled heads (compression) porting, type of air filter, type of exhaust, ignition timing...they all have an effect so it is impossible to give you exact jet sizes for your custom set-up. Sounds like you are close however, so see what size jet makes it go rich and start working backwards from there.

BTW, more oil does not equal less power, but it does equal more cooling and lubrication.  I run 16:1 in my Yamaha KT-100,  as it turns over 15K, any less oil and it seizes!  All too much oil will do is foul plugs, but that is better than seizing due to too little oil.   
#13
Turning Wrenches / Re: RD200B back on the road
April 08, 2020, 06:20:28 PM
Rodney,
the RD200 got a full rebuild. It had 2360 on it when I got it, and at 3200 I did a total overhaul. I bought a second RD200 to get the parts that were missing because back then, they were much harder to find. Engine is on 2nd over (.50mm) new Yamaha pistons, has new seals, rods, bearings, gaskets, sprockets, chain, rebuilt carbs home made epoxy-glass reeds, new tires, new filters, brakes and cables, rebuilt forks overhauled autolube pump, all new oil and fuel lines.  Replaced the tank,rear fender, bars, headlight, taillight lens, couple blinkers, rebuilt dynamo, points and condenser, tach, and new seat pan with a Pit Perspective cover (correct stock reproduction), original tool kit, and now it has just turned 4000 miles.

It would be easier to list what is original as opposed to what all has been rebuilt/replaced, but the engine and frame number match!
Th RD200 was the first bike I purchased that was over 5 years old, and I will never  buy a "project" bike again.  It took far more money and time  to get it correct than if I had just bought one in good running and cosmetic condition.  Age and sitting introduces a whole new set of problems that were never issues back in the day when  they were still new. It used to be crash damage, abuse, and wear related issues that you had to deal with and repair, plus the normal service as outlined in the manual. But the RD200 proved to me that once a bike has sat for years, just walk away....they will need a lot more than you could ever believe!
#14
It is interesting how my 100cc Go Kart engines use pipes that are bigger in diameter and volume than the tuned pipes for my RZ350. .
#15
We have had so many request to do a show again that the 2-Stroke Hooligans are going to host the 1st annual  Bike-toberfest on the 2nd Saturday of October at Cooks Corners.
We hope this Corona virus thing has passed by then, and if not, we will reschedule.   All of us are looking forward to re-visiting the old days and a relaxed lo-key home spun vintage motorcycle meet. You can park where you like, come whenever you want and leave whenever too.  Covered/shaded areas for displaying your bike/s, Cooks has great food, cold beer and live music after 1:00pm. A great family outing, and O'Neill Regional park is 3 miles away for people wanting to camp. No entry fees, just come and re-live the old days like we used to with Doug Johnson, and /or take a nice drive through Live Oak Canyon, it's all right there and we are looking forward to seeing everyone once again as it has been a long time since the Hooligans hosted an event in the OC.   Yes, in honor of Doug, we will fire up the strokers at noon and do a "smoke-out"   If I get motor-vated,  I'll make up a few hand made con-rod trophies with the hand rubbed lacquer finish that the 2-Stroke Hooligans are famous for. As always, I'm looking for volunteers to do simple tasks like help us with set-up, moving tables, and putting up banners, and most importantly; Having Fun!

Jay