Author Topic: Friend gave me a project (Read 3669 times)

5dracing · « **on:** July 07, 2005, 03:44:31 AM »

A friend of mine gave me a project bike to work on for him. It's an 87 TT 350 Yamaha. Anybody ever worked on one of these? I believe it will need total top end rebuild. When I started it it smoke a blue trail.

alan · « **Reply #1 on:** July 07, 2005, 04:04:24 AM »

I would do a compression check before you deside to open up the top end! I would also drain any and all old fuel out and put in some fresh with proper mix!

Alan

Ps Keep us posted!

JDRooster · « **Reply #2 on:** July 07, 2005, 05:47:43 AM »

TT350 is 4 stroke, no mixing required. I'd check the valve adjustment before I rebuilt the top end. It could be that the valve seals are rotted out and it's getting oil from there, especially if the compression is good. Check the seals and adjust the valves. The TT's were great playbikes. The forks are weak but otherwise alot of fun. My best buddy had an 86 TT600 and that thing was a monster back in the day!

alan · « **Reply #3 on:** July 07, 2005, 06:17:56 AM »

Quote from: JDRooster

TT350 is 4 stroke, no mixing required. I'd check the valve adjustment before I rebuilt the top end. It could be that the valve seals are rotted out and it's getting oil from there, especially if the compression is good. Check the seals and adjust the valves. The TT's were great playbikes. The forks are weak but otherwise alot of fun. My best buddy had an 86 TT600 and that thing was a monster back in the day!

OOOPPSS! I forgot they had 4 strokes back then!

John · « **Reply #4 on:** July 07, 2005, 08:05:41 AM »

Smoke from low rews = valve seals, smoke from high rews = piston rings. Open the oil refil plug and check for "crank compression". if it's blowing it needs fixing.

//John

alan · « **Reply #5 on:** July 07, 2005, 09:07:38 AM »

Now see that is the problem with those d**ned 4 strokes, just to many parts!

5dracing · « **Reply #6 on:** July 08, 2005, 03:11:45 AM »

Thanks everyone. I'll do the couple of checks listed here before I go inside. I found out these bikes take special tools just to set the valves. 4 strokes arrggg. I'll take reed valves over this.

John · « **Reply #7 on:** July 08, 2005, 05:36:36 AM »

Sorry, I can't keep silent...

If the oil-seals on the valve steerings are worn engine oil seaps through. The symptoms are typically blue smoke when it's started after standing for a while. Run the engine hot, let it stand for 15 min and start it. This problem won't show up as poor compression. The fix are new valve seals.

You should (don't know the english terms here) also wear in the valves in the seats (rotate with carborundum). This does address poor compression.

If there is constant blue smoke, it's more likely the piston rings.

//John

5dracing · « **Reply #8 on:** July 10, 2005, 11:12:36 PM »

I had the chance to look it over some more this week end and it's about as bad as it can get. I started it cold and the blue smoke rolled out the pipe. I then opened the oil fill and I believe I could take a compression check there. So I'm in for the long haul or overhaul as it might be called.

Thanks for the info on checking things.