end of restauration

[rammstein86]

Hi guys,

My RD 500 is almost finish after a complete rebuild (engine, fairing, frame, etc). I run with the bike 40 km and i have 2 small problems.

The first is : I cannot find the neutral when the bike is on the floor, engine start. Gear pass good, no crack etc, just the clutch a little directly. But is the rear wheel is on the floor, or me in the bike, i cannot find the neutral. But if the bike is in the work stand, engine start, or engine off, i find the neutral at the first try.

It seem to be the clutch plate not take off enough. I know my push lever assy (in the front sprocket cover) is very used, one ball is missing, etc. I wait a new one to see if the problem is that

Oil : Motul transmission oil 10W30 (1,6L)

Do you have another idea ?

The second is : After 1 week no start, the bike have problem to start with 4 cylinders. 2 rear cylinders doesn't start immediatly. One start after few seconds, the other start after 15 - 20 seconds. I think it's a fuel problem for upper carb. If i restart the bike later in the day, no problem, 4 cylinders immediatly

I know the bike have many oil rebuild inside and maybe the spark plug are too much messy. Maybe it's the problem for starting rear cylinders.

Carbs are rebuild with all keyster kit
Spark plug BR9HS

For the carbs, main jet is #165 (Keyster kit), Jet needle et needle jet are the keyster kit. But in this photo, the manual say "Main air jet" are different for upper or lower cylinders.



I dissassemble all the carbs for cleaning and i'm not sure to put the good main air jet in the good carb (up or low).

Can you tell me what part number is the "main air jet" in the exploded view ? The main air jet can be dissassemble or it's fix in the carb body ?

And i have a question : Do you know someone to make this modification on a YPVS controller ?

[Linx]

Hi,
You definitely have clutch drag. Probably your lifting mechanism but could be a warped clutch plate.
Starting problem almost certainly a carb issue. You'll have to take them off clean and check them again. Maybe choke not working on those cylinders.

[TwoStrokeNut]

Pay close attention to your fuel hose routing to your four carbs. Make sure it is downhill all the way, without bumps that could trap air.

[steveho]

Re. YPVS modification, see https://www.ebay.co.uk/itm/275346366915 ... media=COPY

(Same guy/company as shown on your paperwork——2-Stroke Labs)

[rammstein86]

Thanks for your answer.

Someone can say me witch is the main air jet in the photo (#1.8 for upper cylinder ans #1.6 for lower cylinders) ? In red or in black ? or nothing ?
The small jet at the right of the black circle is the pilot air jet

[rz500guytexas]

Need both balls in the clutch I believe. I would hope you installed all ne clutch if you rebuilt it. You need to check float height with a hose as manual shows. Be sure chokes are working and cables routed correctly. Need to get it running and take it out and clear the engine out. That does not mean rev it up in the shop. Needs broke in before you try all the tuning stuff. The manual has all the carb info I would think. Also agree on the fuel line routing, Be sure lines are large enough and going down all the way to carbs. You will get no where with the crankcase and pipes full of fuel and oil

[rammstein86]

In the clutch you have only one ball (the other is in the clutch mecanism in the sprocket cover)
Normally all parts are in the clutch. Maybe a curvy plate

I try to make the fuel level with a hose like explain in the manual but i don't have the jauge. I find a level but not change if i play with the float.

Hose are large enought. I need to the Line fuel routing

And for oil and fuel in crankcase, no problem. i have a tap oil and a tap fuel without depression

[Linx]

Thanks for your answer.

Someone can say me witch is the main air jet in the photo (#1.8 for upper cylinder ans #1.6 for lower cylinders) ? In red or in black ? or nothing ?
The small jet at the right of the black circle is the pilot air jet

Main air jet is in red.

[Luther]

Reds air in for the choke, main air jet is fixed size behind the brass ball, black circle.

[TwoStrokeNut]

Maybe this image will help...

[rammstein86]

Thanks a lot.

Maybe my problem is the choke.

With your help, i know where Can i need to search

[Luther]

All I want to add until you come back and tell us how it runs is try to get all 4 carbs the same. Throttle cables no kinks, slides all same gap when shut, all open the same time, oil pump lever moves when slides move, you don't want oil pump lagging behind. If everythings the same and you get different color plugs then fuel levels in the float bowels may be different. Look that the fuel valve tab on all 4 floats is the same not kinked up. Reread the manual, float level check with a hose. Fuel level needs to be just right or everything goes rich or lean making you think jetting is way off. There was a service bulletin but don't start too low or lean.

[rammstein86]

The fuel level with hose Can be make with the motor ON ?

[Luther]

Yes I've done that and ride around town

[MK]

I used Bel Ray MC 4 for ages in all of my two-strokes.
As a couple of people recommend Motul Transoil, I gave it a try with exactly your results. Neutral was hard to find and overall it felt like clutch drag.
Drained the oil, filled with the usual Bel Ray - problem solved.

Unfortunately MC4 was discontinued, current product is Bel Ray Gear Saver Transmission Oil 80W.