Running on three

Message

bogey · #1 Post by **bogey** » Tue Jul 20, 2010 6:44 pm

Hi,

Got an RD 500 recetly for a project. Eventuall going to strip and rebuild but I started to mess around with it and started it up. It hadnt run for 4 years and i was suprised it started after a few kicks. Anyway it is only running on three cyclinders, the bottom left aint running. Its sparking Ok so it isnt that.

Smokin a bit so certainly some oil or fuel getting in there. Any ideas on the most likely problem and the fix???

I now like the idea of getting it running and having a spin before i strip it so I be grtefull for any icomments or tips.

Thanks

Brian

rdryder · #2 Post by **rdryder** » Tue Jul 20, 2010 7:13 pm

How,ya Brian.

If you,ve got spark, most likely carb related.
Could be just a clogged pilot jet. Easy fix.
The float bowls might be gummed up with the bike sitting so long.

Could strip carbs blindfolded at this stage

, so lets know if you need a hand.
Great bikes when they run

Paul

bogey · #3 Post by **bogey** » Tue Jul 20, 2010 7:36 pm

Hi Paul,

Thanks for the reply. I have stripped off the plastics and the intake manifold on the left side. Can you tell me how I get the carbs off. i know there are clamps holding them on and I need to loosen these with the screw, but can I get at these without taking off the rad or removing the fuel tank???

Any tips on taking off, stripping & sleaning the carbs would be greatly appreciated.

Regards

Brian

rdryder · #4 Post by **rdryder** » Tue Jul 20, 2010 8:09 pm

bogey wrote:Hi Paul,

Thanks for the reply. I have stripped off the plastics and the intake manifold on the left side. Can you tell me how I get the carbs off. i know there are clamps holding them on and I need to loosen these with the screw, but can I get at these without taking off the rad or removing the fuel tank???

Any tips on taking off, stripping & sleaning the carbs would be greatly appreciated.

Regards

Brian

Brian, the rad is,nt touched. Pull the tank up and secure it, you will be able to unscrew upper clamp then.
Leave fuel pipes attached to petcock. Undo throttle cables, pull off carbs
, remove choke cables and fuel pipe that runs to carb.
Thats it.
Do you have a manual?
I,d start by unscrewing float bowls and jets . Clean out jets with compressed air.Clean bowl, Reassemble and see if problem is fixed.
No harm to drain tank, Use fresh fuel.
To thoroughly clean carbs, I would have them ultrasonically cleaned.
It removes all the crud inside and outside.
Hope this helps.
Lets know how ya get on.
Paul

Andrew · #5 Post by **Andrew** » Wed Jul 21, 2010 11:39 am

Hi Brian

A good starting point is a service manual

I'm sure there are a few guys on this forum who might have it in pdf format, they might even send you a copy to get you started.

If not, go onto ebay and buy one on CD.

How long has your bike been standing without being started???

Good Luck

bogey · #6 Post by **bogey** » Wed Jul 21, 2010 2:33 pm

Thanks guys for the help.

Yep I downloaded the sercice manual in pdf format. However it is in an image format so it is not searchable which would be usefull so if anyone has a copy in a txt format that would be great.

In the manual I have, in describing carb removal it shows removal of the radiator prior to removal of the left side carbs and does not clarify if this can be done without removing the Rad, It shows removing right side units after the engine is removed from the frame.

Paul you mention the top clamp, what about the bottom one, is this accesssed from the top as well or is there some other way of getting at it??

Andy, the bike has been standing for probably 41/2 or years or so. I know the crank seals might be an issue but I am keeping the fingers crossed. I would love to get it running right before I do the complete strip down. Everything seems to be working fine except for the back brake so it seems to have been stored reasonably well. I was amazed it started at all as I thought as a minimum I would have to strip the carbs, clean and rebuild but there you go.

Anyway I am going to strip and clean them now, put it back together and hopefully bring it for a good spin or two before I start the project proper.

I will get on to ebay for one of them CD's because I am certain it will be needed before long.

Regards

Brian

rdryder · #7 Post by **rdryder** » Wed Jul 21, 2010 4:26 pm

Hi Brian, I have a manual you can borrow and copy. It does come
in handy

Where in Dublin are you?

The lower clamp is reached from just above lower head, you should
see the long retaining screw running at 45 degree angle from lower
reed block.
The radiator stays put, it does not interfere with carb removal.
Have fun

Paul

oldguy · #8 Post by **oldguy** » Wed Jul 21, 2010 4:54 pm

Brian,

When I had my bike

I could almost take off the carbs with my eyes closed.

The lower clamps can be accesed from below the radiator and inbetween the frame. I used a 1/4" drive socket wrench with a flex extension and proper size socket.

Good luck with the bike!

Dave M.

bogey · #9 Post by **bogey** » Sat Jul 24, 2010 5:00 am

Hi guys,

Thanks for all the tips. I'm going to have a go at cleaning the carbs today.

Where in Dublin are you?

I'm in Skerries Paul so not that far from you. I am often out Maynooth way so I could meet you re the manual. A copy would be really handy and I'm sure I am going to need it.

I'm hoping I have dirty carbs, because if that's all it is I'll be happy.

Brian

bogey · #10 Post by **bogey** » Sat Jul 24, 2010 3:48 pm

Thanks for the tips lads, using them I got the carbs off. So far I just took the bowl off one( the cylinder taht wasn't running. When I took it off there was some fine black dsut or grit in the top half of the chamber. Obviously settled there cause I turned it the carbs upside down when taking the bottm part of the chamber off. Going to strip and clean both tomorow and then reassemble and put back on.

Anyway was just wiondering do you thing this type of dirt/sediment in there would stop a cylinder from running???

Any comments would be appreciated.

rdryder · #11 Post by **rdryder** » Sun Jul 25, 2010 1:39 pm

bogey wrote:
Anyway was just wiondering do you thing this type of dirt/sediment in there would stop a cylinder from running???
.

Hey Brian, was there any fuel in that carb?

There are some threads on the site re:the rubber diaphram in the
petcock perishing and finding its way into the carbs, that might be
worth investigating.

Paul

bogey · #12 Post by **bogey** » Mon Jul 26, 2010 1:37 pm

Hi paul,

Yea there was fuel in the carb ok. petcock seems to be working fine as well. The dirt seems more like a fine grit than perished rubber.

But I think I have bigger problems. After cleaning the carbs I noticed the fuel lines where they connected to the tank were almost coming off and leaking after moving the tank around because they had no clamps fitted. I put a clamp on each and sorted that no problem.

Whilst i had the tank up I changed the plugs and whilst doing that decided to do a rough check to compare compression on each cyclinder. Low and behold the non running cylinder did not seem to have any.

I decided to take the head off and take a look. Looked okay initially but when i looked closely there was series of little indents around the bottom edge of the piston with corresponding items on the head. Also there was more movement of the piston in the cylinder compared to the other one.

I am thinking it might be a broken ring!

What do you think??

Regards

Brian

rdryder · #13 Post by **rdryder** » Mon Jul 26, 2010 2:43 pm

Brian, if it was my bike I would pull the barrels off and have a closer
inspection. Post pictures and members here will give you an informed opinion. Option B, would be to bring it to a mechcnic who knows
these engines. The only guy I know is Niall in Lucan Motorcycles.
It would be wise to do a proper compression test too , on all cylinders.

Paul

aaronmvrider · #14 Post by **aaronmvrider** » Mon Jul 26, 2010 7:58 pm

you mean like this...upper right throttle side..... pinched oil line from previous owner

bogey · #15 Post by **bogey** » Tue Jul 27, 2010 9:23 am

Wow.

Nothing as bad as that. Similar indents but only to a limited are at the edge of the piston. No damage to the piston edge and not to the same degree as in this case. However could be the arly stages of the same thing.

Must check my oil lines just in case.

Brian