New guy from Vancouver...

[mouellic]

I've been lurking for a while but this is my first post... I'm hoping that over the coming months, you can all give me a hand getting my bike ready for summer!

Picked up this bike off CL a couple weeks ago. Rode it for a week or so and everything is working, but it's smoking pretty bad. I'm going to make it my winter project. The goal is to give it a bit of the Café treatment, without any permanent mods. I'm sure that one day I'd like to return it back to stock and throw some collector plates on it...

First step will be diving into the engine and taking a look at the jugs, I suspect it's not too pretty in there.

I also have a set of Mikuni VM28 roundslides off an RD400 that I would like to use on the bike, but I'm not exactly sure if they'll work as they were set up for a 2-stoke... Would they be much of an upgrade over the stock Keihin carbs?

Aside from rebuilding the engine, upgrades over the winter will include Hagon rear shocks, Tarozzi rearsets and clip-ons, new tires, led's all around, and a new lower profile seat that will work without griding away anything.

 

[1976cb356]

That bike is super clean, and I am no expert but smoke means its running to rich right? And from what I heard (great advice) mikunis shouldnt be used unless you do engine work and I have a huge feeling vm28s arent going to work. Not trying to be a debby downer, just advice I got. VM32s I think is what you can use if you have a stock motor, but isnt much of an upgrade if any at all. Nice looking 360, looking forward to what you will do. I bet crazy pj or sonreir (cb360 gods) will post any second.

 

[Big R]

You have that backwards: vm28's are good, vm32's would be too big.

Mouellic- have you done a compression test yet? And where is it smoking from? Check your oil level if you haven't already.

 

[1976cb356]

You have that backwards: vm28's are good, vm32's would be too big.

Mouellic- have you done a compression test yet? And where is it smoking from? Check your oil level if you haven't already.

oh alright, now I know.

 

[Big R]

No biggy.

But if you got those 28's off of an RD, there probably would need some changes. I think it's the emulsion tube and the needle? Better wait for somebody else to come in on that one though.

 

[mouellic]

The PO who restored it without touching the motor said he measured the compression at 115 psi, which leads me to believe that I need to crack the top end and take a look. It's definitely burning oil. I'll be moving it to my work where I'll have a better shop set up and start tearing into things within the next couple weeks.

Regarding the VM28's... converting a 2-stroke set up to 4-stroke; pretty straightforward? And again, better throttle response?

 

[Big R]

115 could be pretty decent if the test was done on a cold motor or if the throttle wasnt open, etc. Best way is to do the test yourself.

And I really can't help with the carbs- I've never converted them personally.

 

[mouellic]

Ok, so I finally got around to testing the compression. It looks like I was getting about 90psi in eat cylinder with the engine cold. I added a bit of oil through the spark plug hole and saw the pressure go up to 120 psi on each side. I then ran the bike for about 10 minutes to burn off the oil and heat up the engine and then tested the engine while it was still hot and got a reading of 150 psi on each side.

I also noticed that the left cylinder is smoking a lot compared to the the right cylinder when you rev it, yet both have the same compression.

So, what's the scoop? I know I should be getting around 170 psi. I don't mind taking the head apart and giving it a fresh bore, with new pistons, but I have no clue on where to get pistons for this engine other than on Ebay.

 

[teazer]

Do a leakdown test and listen for where the air pressure is hissing out. Most likely past the rings which may be stuck. Time to pull the top end and get it right.

RD carbs are set up like 4 stroke carbs and use a 4 stroke type needle jet/emulsion tube which is perfect for a 4 stroke. They will have to be re-jetted though. performance gain over stock carbs probably not enough to warrant the work unless you throw out the air filter and mufflers and can't get stock crabs to carburate properly.

 

[ProSimex]

The VMs will look nicer and perhaps give a bit of performance. If you wanted to do pod filters then they're the way to go. Nice looking bike.

 

[mouellic]

Do a leakdown test and listen for where the air pressure is hissing out. Most likely past the rings which may be stuck. Time to pull the top end and get it right.

RD carbs are set up like 4 stroke carbs and use a 4 stroke type needle jet/emulsion tube which is perfect for a 4 stroke. They will have to be re-jetted though. performance gain over stock carbs probably not enough to warrant the work unless you throw out the air filter and mufflers and can't get stock crabs to carburate properly.

I'm going to need to swap exhausts anyways to run rearsets and I'm going to be running pods aswell, so I'm sure I'll have to re-jet the stock Keihins anyways. How hard is it to get the jetting right on the Mikunis Vs The stock CV carbs?