Help with a JTR 160, please

[(F5)]

There is a large brass bolt in the radiator with wires to it. When it gets hot the cct completes and your fan should start.

That looks very similar to my 00 but few frame changes.

In road racing people run lots of oil, like 20:1 of synthetic which is way more than the bottles usually recomend, but better protection and more power from better sealing.

You can't hurt it putting lots of oil in. You own a 20yr old Spanish bike and all the bearings are old. I'll let you decide how much you want to push the envelope of good lubrication.

The big thing is getting the jetting right. On my 200, using NZ gas at close to sea level and 60:1 for Trials use - so many differences, it was pretty stumbly. I found 1 size smaller pilot and 1 smaller main worked wonders. Maybe the previous owner/s has already changed, but surprisingly few do.

I found my Honda dealer stocked dellorto jets as they owned montessa but that was years ago.
The mixture screw is really for how it reacts from closed to just open. In is richer, out leans it but if you are to 3 screws out go size smaller pilot jet.

Oh yeah mine was difficult to operate the choke lever as it was close to frame. Had to poke it fully on, and drilled and fitted a cable tie to make it easy to pull to close.

Always run carb out of gas. Mine would stick the float jet so would start and run for a min then die and need a tap to get it running again. Ahh, dellortos.

[Chesterspal]

Originally Posted by cbutler

First off that's one sweet bike. Trials bikes are hard to find of any size you'll find that parts are expensive for them.

Thanks for the kind words. Plenty of similar trials bikes in my area. All the 250cc and higher bikes you could want in Beta, GasGas but nothing lower, until last Sunday, as I said. Also, the vintage twin shocks. Tons of them in great looking shape around here. I own a mint 1986 Honda TLR200 200cc trials bike but it has been a bear to learn on. I find the 4-strokes harder because if the engine braking causing the bike to chug in low gear. You easily lose your balance. It throws me off.

Was suggested I buy a "newer" modern trials bike, less than 200cc, to learn to ride in. So, that was how I came to own this one.

If that rear fender is bolted on you need to unbolt it and replace the bolts with zip ties that way when you flip it and you will it just breaks off if it's bolted the fender will break the one for my 01 cost a$150.

Thanks for the suggestion. I will do so. I'm sure I'll be falling off often enough

90% of trials riders mix 80:1 or 100:1 like F5 said if you plan on riding it on trails you might want to go 60:1 I don't. If you do ride that on trails they do tend to get hammered it is not a dirt bike.

This one also has that choke lever way up under the frame with a cable tie attached. Where I live (and can practice a bit in the yard) is around 100' above sea level but where I can legally ride is more like 500 feet higher.

Well, I also own a Honda XR-80R dirt bike so will not be wasting this GasGas for that kind of rough riding. Still a bit confused about this oil mixing. Only owned one two stroke and it was a small scooter.

What is the advantage of altering the ratio? Is it that you have better engine/bearing protection with a lower ratio but the trade off is more smoke out the exhaust, more fouling of the spark plug... what exactly?

Also, are you running E10 gas? I have a simple method to remove the ethanol to obtain pure gas. I do it for my 1965 Triumph. Adding 1 quart of distilled water to a gallon of premium 91-93 octane gas, shaking the crap out if it, then, letting it sit for 12 hours. You can then drain off the ethanol and water leaving just gas. The octane drops 2.5 points so the reason for using premium gas going in. This lets you leave the gas in there all the time with no issues of eating the rubber, the seals, etc. will not gum up over time.



This is Shell 90.5 octane puregas I made three years ago. Look at the clarity and golden color. This is the way gas used to look. It smells sweet. No harsh alcohol odor to it. This gas will last forever this way.

[Chesterspal]

Originally Posted by nhgas

Where do you live? Rascal's Cycles used to be the gasgas trails dealer in Massachusetts. I think he is still has a repair shop in the Brimfiled MA area....

I'm in Connecticut. Yes, the bike originated from Rascalls back in 1996 according to the paper work I have.

[Chesterspal]

Originally Posted by (F5)

There is a large brass bolt in the radiator with wires to it. When it gets hot the cct completes and your fan should start.

On this bike it appears the thermal switch is inline with the return hose from the cylinder head. See picture.

In road racing people run lots of oil, like 20:1 of synthetic which is way more than the bottles usually recomend, but better protection and more power from better sealing...You can't hurt it putting lots of oil in.

This is something I need to find out. Do not want to damage anything.

Can someone tell me what these adjustments are used for. I assume they affect the front shocks but I do not feel any real difference compressing them at one extreme setting to the other.



I'd like to add handgrip guards to this bike. Have them on my dirt bike and they have saved me more times than I can count. However, those guards will not work on this bike as the shift/brake mechanisms are in the way.



Can someone take a picture of what they use on their bike so I can see just how they fit up?

[cbutler]

Yes that is your thermostat housing. You can test your fan by unplugging it jumping the two terminals on the wires and starting the bike the fan should run.

Those are your compression and rebound settings. One fork is compression one fork is rebound. Unless you're a high-level Rider you'll feel no difference I was told to just set mine in the middle.

Back to your oil premix you can mix more oil and it does lubricate better and seal the Rings better but there's a point to where you're just throwing money out the window. If it makes you feel more secure makes it 50 to 1 it won't hurt it it would create a mess with this excess oil not being burnt. I have been running mine at 80 to 1 with Amsoil Sabre at 80 to1 for two years with no problems and I do ride mine in the woods at my clubs property

Are you talking about Bark Busters if so I would suggest not putting them on. On a trials bike the likelihood of you breaking your wrist would be real good

[(F5)]

That's right it was an inline arrangement, it's been a while. We have gas without ethanol available.
If the jetting is close most of the fuel mixture will be burnt. If it is rich combustion won't be complete, extra mixture will be expelled. That mixture contains fuel and oil.

Additionally trials bikes spend a lot of time, I'm going to use the term slightly erroneously 'Off-pipe', so more mixture is wasted than an engine run at speeds closer to optimum, and thus more being short circuited out without being burnt.
Don't lose sleep over it, people get worked up over oil discussions.

[gasser]

My friend Chris is spot on - Amsoil Sabre at 80:1 or even 100:1 is an excellent oil and would be my first choice. If you decide to go with a more oil rich mixture like 50:1 or 60:1 Amsoil Dominator or Interceptor might be a better since they have a lower flashpoint. More oil makes an engine run cooler - not a bad thing in and of itself but the engine needs to get hot enough to burn off the excess oil and the temp at which that happens is called flashpoint.

[(F5)]

So is 'burning off' the oil the most important thing? I have other requirements but ya know.

[Chesterspal]

When I drained the gear oil out, it looked a but suspicious. It appeared to be Royal Purple, which is fully synthetic and not to be used in these bikes. So, I compared it to some 5w30 RP I use in my cars.



As you can see, the RP from my container (on the left) is identical to what came out of this bike.

Honda makes a 5w30 conventional oil without friction modifiers for wet clutches and I plan to pick some up, today.

The fill port on this older bike is on the side above the sight glass. I read where I need to lay the bike in its side to pour in the 650cc (ml) of oil.



The sight glass is odd in that it is indicating the proper amount of oil is there even though I drained out exactly 650cc. Not sure if this is just a window or if it fills with oil from the bottom and maybe it got turned up and is staying filled?

Anyone ever have these out and know how they work?

The prior owner gave me a small container of Belray two stroke oil. Nothing on there states a mixture. Will look for that Amsoil Sabre when I'm out today.

What do you folks run for tire pressure?

[(F5)]

The glass is likely dirty. You might get a bit of brake cleaner with long spout for a short directed squirt and drain/evaporate to clean it.

Try 4psi in the back and 5 in the front and experiments from there. Low pressure gauge will give you a better reading than one expected to be accurate at normal pressures.