73 ts400 engine rebuild

[jcetto]

hi guys im new to the cite and just recently bought a blown up 73ts400 apache i have all the seals and everything to get the job done was just wandering if anybody had any advice on piston to cylinder clearance i have a second over 83mm wiseco piston the book i have was published in oct of 76 and says .075-.085mm is that good any advice on anything would be great thanks alot

[H2RICK]

You SHOULD have a piston clearance spec from Wiseco marked on the box and/or on the paperwork IN the box with the piston. Otherwise, you'll have to contact Wiseco. I do know, however, that forged pistons like the stuff Wiseco makes need MORE clearance than the OEM cast pistons.

[jcetto]

Thanks buddy appreciate it I haven't got the piston yet in the mail but will deffinately check it out are you familiar with the oil pumps in those motors were all the year motors use the same pump

[H2RICK]

were all the year motors use the same pump

Nope....and don't ask me what the exact differences might be.....but it might have something to do with the output amount of oil......or maybe the arrangement for the arm that the cable operates.......or maybe Mikuni made some small internal or external changes to the pump for durability reasons. I wouldn't guarantee any of the above guesses without having an example of each of the various pumps (listed below) on a bench to compare them.

Your TS400K original pump part number was 16100-32810 which also fitted the TS400L (1974), TM400K and TM400L (the motocrossers of the same vintages).
However, that number was changed up to 16100-33001 sometime before 1977 but the model application list remained the same.
The TS400M (1975) used part number 16100-32011 which still current in 1977.
The TS400A (1976) and B (1977) both used a different part number again, which was 16100-32210 which was still current in 1977.
This info is what is shown in my big Suzuki crossover book of 1977, so the part numbers are "official"....at least of that date. It's the best I can do for you, pal. Bike Bandit and CMS are no help whatsoever.

Is your pump not working at all ?? Other problems with it ??

[jcetto]

I really appreciate the info buddy I don't know if the pump works or not I haven't reassembled the motor yet I'm still waiting on some things do you have any advice to test it out of the motor if such thing can be done or what to look for once everything is back together or than white smoke I was gonna run a lite premix during break in just to be safe any opinions would be great thanks a bunch

[H2RICK]

The "light premix" is an excellent idea for startup after a rebuild.....but you should ALSO make sure that the piston/rings/wrist pin bearing are all totally saturated/coated with undiluted injector oil as you assemble the engine. Then, try to start the engine as soon as possible after getting it back together so that the injector oil on the parts mentioned above has as little time as possible to drip/run off the various parts. This will help with keeping everything nice and slippery. The neighbours might not care for this method, though......
As well, you need to bleed the tank-to-pump line BEFORE startup to get rid of any air in that part of the system as well as any air in the pump itself.
Lastly, you will need some method of temporarily holding the pump arm in the wide-open position during startup. A human helper is a good idea since your pump is down low on the left side of the engine.
With the arm held wide open and the engine running, you can then watch the 2 injector lines from the pump to the engine and see the air bubbles as they advance down the lines and into the engine.
When all the air is out of the system with the pump held wide open you will suddenly get a huge increase in smoke from the exhaust when the last of the air gets bled out of the system. Let the pump arm return to its normal position, put fresh undiluted gas in the tank and you should be good to go.

[jcetto]

Thanks for the info appreciate it