[Hello fellow Montesa owners!]

cleanorbust,

Thanks for the info. I have already ordered a Clymer's manual. I try to only use non-ethanol gas. I have attached a picture or the right side of the bike.

Do you guys use regular unleaded or super to mix? We have 87, 89, and 91 octane here. I think that 87 octane is equivalent to European 91MON. The gas station with non-ethanol gas only has 91 octane. I should be good using that.

[Hello fellow Montesa owners!]

kingscorpion,

Thanks for the informative response.

1. The correct size is 520.

I asked about the chain size because I tried to put on a new 520 chain last night. It wouldn't fit through the chain tensioner. I have a new chain tensioner on order through InMotion.

2. Even at 50:1 every synthetic oil will be enough.

I think that I'll stick with the 40:1 ratio unless I start having problems with fouling.

3. GL-4 is better, but GL-5 probably is an acceptable choice. It will hurt the "yellow metals", but at a high temperature.

I just found a bottle of SAE 90W GL-4 at NAPA Auto Parts during lunch. It is marketed for marine engines, but it should do the trick. 

4. Mineral 10W30 or 10W40 is a better choice. 

On the way back from NAPA, I stopped by Honda and got a bottle of dino juice 10W30.

5. SAE 20 is the original oil.

I'm thinking that I will go with Belray 10W fork oil.

6. Their maintenance is very simple. Just take a look at the points and condenser, and keep the carb clean.

Got it. Thanks. Will do.

7. Jared Bates at Southwest Montesa is a nice guy. We miss a lot John Haberbosch; he passed away a few years ago and had a deep knowledge of these bikes.

I'll check out Southwest. I've heard a lot of good things about them. I also found a site that I hadn't seen before. (clasicaslegendarias.com) They have a huge Montesa section.  Has anyone had any experience with them?

 

I just put a new set of IRC trials tires on. I really liked them on my Yamaha. I know what you mean about the Dunlops. The original Dunlops were on the bike. They were falling in pieces, but I still had a nightmare getting them off. I finally gave up with spoons and visited a friend's shop with a tire changing machine.

I will take your (and cleanorbust) suggestion and go with a 9 tooth front sprocket. I'm going to order a 9/48 combo.

I have attached a picture of the gear oil container.

 

[Hello fellow Montesa owners!]

Hello everyone,

I recently purchased a 1973 Montesa Cota 247 to use in vintage trials. I live just outside of Memphis, Tennessee, USA in Germantown. This bike is replacing my TY250.

I have ordered a fair amount of parts from InMotion Trials. They are great to work with. I have a few questions regarding the bike. I have an owners manual. The information in it is sparse to say the least. I've read extensively on the forums. If anyone knows the answers to the following questions, I would appreciate your advice.

1. What is the stock chain size? I believe it is a 428. Just not sure.

2. I'm using synthetic premix. I've been running 40:1. It seems to run fine with little smoke. Anyone had problems running this lean with synthetic premix?

3. Will GL-5 gear oil hurt the transmission? I've read that you should use only GL-4.

4. What about the clutch? Will synthetic motorcycle 10W30 make it slip?

5. What weight fork oil do you use in the forks? I have several bottles of fresh fork oil.

6. Is there anything that I should look out for in maintenance? Any known issues with these bikes?

7. Any recommendations on parts suppliers? The suppliers in the USA seem to demand a high premium for parts. This is partly due to the small number of trials enthusiasts compared to Europe.

Thanks so much for your opinions. Hopefully, I won't reinvent the wheel here. So far, I love this bike. I just want to keep it running for the next 50 years.

John