Topic: K2/K5 Drag project

[dragracer]

So my neighbor just stopped by and helped me put the motor on the bench. Pulled the cylinder and head as a whole and man.. I ran this thing hard this year.. Screaming for a rebuild.. Worn piston skirts, #3 and #4 had broken compression rings and #4 has had some decent contact with the valve at some point..

So what should I do fellas?

Time to look for a decent set of 836 pistons and bore that cylinder. Its likely no use now for stock pistons anyway if the original pistons are as bad as you detailed. The head sto be looked at and i don't mean just lap the valves. Send it to a machine shop to get the seats cut and the valves faced- any decent automotive machine shop can do a basic 5 angle valve job for under $150. Seek out one that works on a lot of imports. You need to replace those worn out valve springs and get seals also. Now that you have the engine off the frame, go ahead and split the cases to get that tranny out, mail it this way and i'll get it taken care of for you. You'll need to put in a new cam chain- makes no sense to cut that corner at this point. Plastiguage the rod and mains bearings to see if they need replacing.

Yes, all of what i said is going to cost you some $$ but take your time and try to find the least expensive way to rebuild the engine. Its just not practical to half azz get this bike back up and running if you expect it to last, pass after pass down the dragbstrip. It shouldn't matter that you miss a race- its more important that it done right so wait till the funds come. Its a hobby, not a must!!

[Bill/BentON Racing]

Fix it. Hehe. You play, you pay! Time to pay up! Lol. The gods of maintenence/racing are calling!. Call me today and we'll discuss options. You need to build top and bottom end.

[NalleyRacing]

Okay.. So heres where were at today..

Pulled the APE tensioner off the cylinder and out popped my missing bolt!! What a relief! Dosent even look chewed up or anything.

So here's what I wanna know.. Should I tear into this bottom end and do the check up and transmission work. Or get the top end secure and go back at it. I was never able to fully eliminate the trans as my cause for popping out of gear, but would foot shift just fine..

I dont have alot of time or cash to put into it right now. Just not sure which route to take

[Bill/BentON Racing]

You...fix that one. You need the "practice" and it needs it,especially the undercut gears, not going finish many runs popping out of gear! Then ....well I'll let George give you the news!! Lol, Bill

[Sam Green Racing]

Trey, if it shifts fine with your foot and don't pop out of gear, it's probably your air shifter that is not set up properly.

Sam.

[TurboD]

^ Agreed..

[Sam Green Racing]

Do you really need the air shifter, it's just another thing to go wrong ?

Sam.

[gschuld]

I imagine it all depends on how far you really want to go in the quest for Street ET consistency.  Assuming the equipment is working properly, the air shifter should offer you more consistent shifts.  But you already know this

George

[scottly]

Trey, how worn are the pistons? How about the cylinder bores? Have you made any actual measurements? Concerning the bottom end, did the bike have any indications of low oil pressure? If the trans doesn't pop out of gear under load when foot-shifted, the trans is fine. (seems I've said this before? ). You aren't building a motor for ultimate power nor for 100,000 mile durability! Race motors are built with looser clearances to reduce friction. Sam, IIRC, the auto tended to get quicker as more runs were put on it?
Put the top end back together with a ring and valve job, and make sure you clay the pistons if you are going to use a non-stock cam.

[NalleyRacing]

Pistons have all had some contact with the valves. Skirts have quite a bit of wear. Still havent seperated the cylinder from the head to measure clearances yet

[scottly]

Pistons have all had some contact with the valves.

So did all of my pistons. This pic was taken in 1979, and about 3 weeks later, I rode the bike on a 3000+ mile road trip. The same motor has also recently survived over 100 dyno runs. How many trips down the strip can you do in a season? Measure your parts before you start throwing cubic dollars into the project....
 

[gschuld]

If I recall right, you put a higher lift cam (41?) in an otherwise stock motor right?  I'm pretty sure the stock piston valve reliefs don't leave much room for extra cam lift.  For example, the RC 240 cam was designed to work in a stock piston motor(modest lift increase) but the 295, 315, 327 cams ...not so much.

That may well have at least contributed to your pistons touching valves issue.

George

[dragracer]

Pistons have all had some contact with the valves. Skirts have quite a bit of wear. Still havent seperated the cylinder from the head to measure clearances yet

Skirts likely have wear because those rings are worn out and have never been replaced. Nothing to keep them from slapping around in the bore. If thats all you've got to work from, hopefully a light cylinder hone and a fresh set of rings will keep you running for a little while longer. If you put that cam in with an adjustable cam chain sprocket and didn't degree it, there a chance you could have tagger a piston, especially in light of the bolt missing and possible slippage.

[kmb69]

Maybe tagging the pistons caused the cam bolts to come loose. ALWAYS gotta check timing and clearances with AM cams.

Or...maybe, forgetting to tighten the cam bolts is certainly one way to achieve "variable cam timing"! 

[NalleyRacing]

So all I need to get back in action is a set of std piston rings and a light hone for the cylinder..

The head is another story.. Really needs the seats cut and a new set of valves and guides.. I have a set of springs and guide seals.. Thats about it. Lots of seals and o rings for the rebuild too along with a few sets of nice base and head gaskets..

No one locally seems to be able to do the valve job, who should I send it off too?

[dragracer]

So all I need to get back in action is a set of std piston rings and a light hone for the cylinder..

The head is another story.. Really needs the seats cut and a new set of valves and guides.. I have a set of springs and guide seals.. Thats about it. Lots of seals and o rings for the rebuild too along with a few sets of nice base and head gaskets..

No one locally seems to be able to do the valve job, who should I send it off too?

Talk to William Baxter. He can find someone in
Texas. Or I bet Keith knows someone in Houston. There was a few shops down there when I lived in Texas. Can't recall them at the moment.

[Jerry Rxman Griffin aka MuthaF'er]

Big Jay comes to mind.

[cbr954]

Have you checked with Buzz at Dynoman, he is in your neck of the woods.

[kmb69]

.....
Or I bet Keith knows someone in Houston. There was a few shops down there when I lived in Texas. Can't recall them at the moment.

Actually, I am also trying to find someone local with a Serdi.
There is a local shop with a Peterson, but I have always believed the Serdi was better.
Late last year, I missed out buying an almost new Serdi by one frickin day. It went cheap and up North. 
Amazing as big as Houston is, no one is advertising Serdi work.

[Bill/BentON Racing]

Keith what did it go for?

[kmb69]

Keith what did it go for?

$12k

[Bill/BentON Racing]

That would have paid for itself pretty quick.

[NalleyRacing]

Say a prayer..
Test and tune all day today at the track.. Spent the last 48 hours in the shop finishing up the new motor

F3 top end put on the K bottom end for now while the machine work gets done on the K model parts.. Hoping for some deep 12s and maybe 105..

Wish me luck!

[Bill/BentON Racing]

K, G'luck. Keep us posted.

[Jerry Rxman Griffin aka MuthaF'er]

Looking good Trey    Keeping fingers crossed for your 12's. been a long time coming for you.