Looking to purchase a 1970 US90 - Need advice from the experts

[IronBear]

Thanks for sharing Sled. I'm wondering where in NH it came from.

Anyway, I thank everyone for their comments for this thread. I'm going to be picking this beauty up on Monday. I'll post more pictures early next week.

[IronBear]

Hi guys,

I just picked up the US90 yesterday and made the following observations with the bad first:

• Bike has no spark - which is understandable after sitting for 34 years
• Tank has some rust inside - It will need to be cleaned out
• The pump is missing on the right side of the frame. The owner is going to try and locate it for me
• It seems like it has low compression, but I don't know what the numbers should be. I'm going to rebuild the engine anyway (at some point)

The good:

• Tires are in great shape
• Original toolkit is in tact
• Seat is in great shape with no tears or foam missing
• From what I can tell, the muffler is in good shape

I'd like to get my hands on a service manual if someone could point me in the right direction, then that would be great.

Thanks again,
IronBear

[sledcrazyinCT]

Cool that you bought it! If I remember the US 90 service book is only 36 pages. I would like to make a print out for my resources if you come across a PDF.

[IronBear]

Cool that you bought it! If I remember the US 90 service book is only 36 pages. I would like to make a print out for my resources if you come across a PDF.

Sure I'd be happy to do that.

[DohcBikes]

Adjust the valves, the engines are notorius for tight valves causing loss of compression. Have fun.

[IronBear]

Adjust the valves, the engines are notorius for tight valves causing loss of compression. Have fun.

Thanks for the tip. Once I get my hands on a service manual, I'll be sure to adjust the valves.

[coolpool]

Nice purchase!

No spark: Check the obvious first.
1. Replace the plug and gap correctly.
2. Trim 1/4" off the end of the coil wire going into the sparkplug boot. They have a tendency to get corroded inside there at times.
3. It has a two position kill switch; make sure it's on and/or disconnect the black and green wires from it to rule it out.
4. The points could just need a cleaning. Open up the round silver cover which will expose them. Slowly pull the engine over and watch for them to open. Once they are open, insert a dollar bill in between the points and hold it there. Pull the engine over letting the points close on the money. Once the money is in there good and tight, pull it out. Repeat this until the points are clean. Might as well check the adjustment while you're there, .012-.014 is what I recall as being correct.

Do not inflate the tires until you know what you're doing! Sounds silly but It's easy to overinflate and stretch them which by then they never go back.

[sledcrazyinCT]

Do not inflate the tires until you know what you're doing! Sounds silly but It's easy to overinflate and stretch them which by then they never go back.

Exactly......

[IronBear]

Nice purchase!

No spark: Check the obvious first.
1. Replace the plug and gap correctly.
2. Trim 1/4" off the end of the coil wire going into the sparkplug boot. They have a tendency to get corroded inside there at times.
3. It has a two position kill switch; make sure it's on and/or disconnect the black and green wires from it to rule it out.
4. The points could just need a cleaning. Open up the round silver cover which will expose them. Slowly pull the engine over and watch for them to open. Once they are open, insert a dollar bill in between the points and hold it there. Pull the engine over letting the points close on the money. Once the money is in there good and tight, pull it out. Repeat this until the points are clean. Might as well check the adjustment while you're there, .012-.014 is what I recall as being correct.

Do not inflate the tires until you know what you're doing! Sounds silly but It's easy to overinflate and stretch them which by then they never go back.

Thank you for the thorough explanation Coolpool! I'll be sure to follow your instructions.

Couple of questions, what should the tire pressure be set at and second, where can I obtain a service manual, preferably free if at all possible?

Thanks again

[IronBear]

Here are some more pictures of it

[coolpool]

The tires should be set to a maximum of 2.0 PSI. If you send me your email I think I have an electronic version of the manual I can send you.

[IronBear]

I cleaned the points and was able to get spark from the coil wire after trimming it. This was when I placed just the coil wire to ground, but when I added the spark plug boot to the spark plug to ground, no spark was present but this was with the plug that was originally in the bike.

I'm waiting on a new plug to show up. If that doesn't help then I'm going to replace the spark plug boot as well.

Another question, is there any carburetor rebuild kits for these bikes? I'm also going to need an air filter as well. The carburetor needs a complete overhaul.

Thanks again

[coolpool]

Yes there are carb kits available and the foam is still offered at the dealer; although it's not cheap. At least not in Canada. To be honest, I have 4 US90's and all the carbs have ever needed was a good cleaning(s). Of all my trikes(10) I've only had to do one carb with a new kit. Maybe I just got lucky?

[83ATC185]

Cant wait to see this thing cleaned up!