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Hello friends,

I am looking for the timing specification for a 1971 Yamaha At1.

I'm installed a new vape system and set the piston to 1.8 btdc.

I installed the base plate and made sure that the bolts were in the middle of the slots, then I installed the flywheel and matched the timing mark on it with the base plate timing mark.

Now my question is once everything is installed and aligned, how do you verify that the timing is not too advanced or retarded seeing as there is no external timing marks/pointer to reference with a timing light, besides the one on the flywheel and the base plate? Thoughts?

Thanks for your help y'all. Seems like this carb is completely wrong for this bike. Time to find a spare one or go aftermarket. Thanks for the prompt replies.

Hello fellow 2t nerds. I need a little bit of help identifying the carb that is on this motorcycle. I ordered a carb kit for it based off the year/model bike and it does not at all fit the carb that is currently on the bike. Attached are the pictures of the carb. If anyone can help I would greatly appreciate it. Thank you!

Anyone's ever used these?

https://youtu.be/JO56Lxh09_M

If you check out the Mikuni Pocket Calculator it has elevation correction.  For example, a change of +5000 ft means the main jet (4/042 type) should be downsized from a 220 to about a 200 (actual calculated value of 197.5). Temp and humidity changes will also vary the output.

That is a great resource. I will look at the carbs in a couple of days and see what jets are in there and go from there.

Properly maintained, you could daily ride an RD400 for 10 years without "needing" a rebuild.

Not at this level of tune. Every 7500 miles I have to put in new pistons. It makes double the whp from what it made stock.

Hi fellow 2 stroke friends. I am moving from Savannah, Ga to Denver CO and I am a little worried about how the bike is going to run at that elevation. I would assume that the oxygen density is lower in Denver than in Savannah due to the elevation. Therefore the bike would be a little fat/rich for its new environment. The doubt that I have is will I have to change the jetting? We already run the carbs on the leanest clip setting on the tm34's. So all I can really change is the pilot and the main. Curious how you guys go about adjusting carbs when running them at a higher elevation.

Any tips or tricks would be greatly appreciated.

Also since I am moving to the other side of the country, Chuck will no longer be able to assist me on maintaining the bike. Besides logging miles, and top end noise is there any other way to know/measure when new pistons are required? Might be a dumb question, but I was curious if there was a was a way to measure wear or any tips/tricks.
Because If I have to visually inspect the pistons, then ill just send the jugs off to be bored, and order up a new set of pistons. Not that the bike needs a top end rebuild currently but I want to prepare myself for when that time comes.

Any solid engine builders near CO? Only 2 that I know of that are still doing work is Garret, and SCR? I'm open to other recommendations.

Thank you.

Man that thing is ugly lol

Sorry but I don't think my build is lazy at all. Fully rebuilt the motor and transmission, took the bike all the way down the frame, replaced all the wear items brakes, bearings, hardware etc. Yeah I chopped some unnecessary tabs off here and there. But overall the bike is much nicer, faster, and stronger with all of the upgrades/modifications I did to it. Personally a bone stock rd400 is cool, but it's boring to ride compared to a hopped up one. Just my 2 cents. 

Street bike, pump all day. Track bike pre mix.

So I have a supercub 125. I did the dhm high compression piston setup, intake exhaust and cam, and it really woke the bike up. A lot of the trail guys on adv rider suggest dropping the front tooth by 1 and it really wakes the bike up. Just an fyi nice pickup!

Anyone on here going this year?

Congratulations, not sure what part of florida you're in, but you should try to make it up to the annual 2 stroke meetup.

Location would be helpful for those interested.

What chemicals do you guys suggest to clean the read of these bikes off? My swingarm and rear wheel is covered in oil/dirt. Any recommendations to make cleaning a little easier? Because car was soap ain't doing it lol