Valve adjustment no good? - Page 5

The_big_dill · September 29th, 2013, 09:58 AM

Quote:

Originally Posted by Motofool

Once the chain is loose, everything produces noise: the top guard, the sprockets, the guides and even the CCT.

I assume that paint is some form of identification; maybe someone worked in that area before you bought the bike.

Same for the rocker screw, it may be a substitute; but I would leave it alone if it is doing its function so far.

My priority would be find a way to keep that chain under tension at all times, anything else is secondary because, as has been explained earlier, jumping teeth and losing the valve's timing at high rpms' would be a catastrophe.

Could you measure the chain with 0.10 mm precision?

I will try to get a vernier caliper to check, but i am afraid that will have to wait... school is getting intense and i have been putting more time in the bike than i should.

I understand the catastrophe, sometimes i wish i didn't know what was happening in the engine as i cringe my teeth with the smallest sound that appears, kinda ruins my day :\

In any case, i really appreciate you two answering so many questions and helping me out the entire time. Hopefully this thing lasts me for a while, if not, i will probably rebuild or buy a new engine, all depends on whats cheaper, time is really not a factor at my age, at least not when i am out of school.

The_big_dill · September 30th, 2013, 05:52 PM

I pictured the operation of the chain in its current state and now i can see why its clicking. As i mentioned, the slack varies throughout the revolutions of the engine and when the chain slacks, it is instantly pulled tight again because of the high revving engine, forcing the chain to slap against the top chain guard.

A rebuild is my decision and am now gathering information on what i need. I am planning to replace all the gaskets (I will print the ones n4mwd kindly provided), seals, bearings, chains, sprockets, journals, rings, etc. As well as lapping the valves.

But i guess this depends on what exactly needs replacing, and that will need the engine torn apart.

Can you guys give me a quick list of what i will have to replace, just to start compiling an order?

Thanks.

n4mwd · September 30th, 2013, 07:49 PM

You can't really tell for sure until you get in there, but what you need for sure are the gaskets, HondaBond RT for sealing it back up, head gaskets, connecting rod bolts and nuts (4 sets), big nut for clutch basket, 4 wrist pin keepers.

When you get inside you need to check the bearings to see if they are in tolerance. Its hard to get a micrometer that measures in microns, but that's what you need. I have found its cheaper and better in the long run to just get some plastiguage and use that to make sure the bearing clearance is proper. The connecting rod bolts are made out of some kind of rubberized steel so its imperative that you don't overtorque them. For plastiguaging and eperimenting, use the old ones, and then use the new ones for final assembly.

You might be able to test the rod bearings by twisting and shaking the rods on the crank without removing the bolts. If you don't remove the bolts, you don't need new ones. But you are just guessing as to their condition. Its up to you as to whether you remove them for a real inspection or just guess.

If you need new engine bearings, they run about $10 a half so normally, you just change the out of spec ones. If you need to change a set, they come in different sizes and are matched by colors on the crank and housing. THEY DO NOT COME OVERSIZED! So if the crank is bad, its bad, it cannot be turned like automobile cranks. Actually, there are racing machine shops that can do it, but they will return the crank to OEM spec by different processes and the cost is usually greater than what the dealer charges for a brand new crank. Having said that, you have said nothing that would make me think that your crank is bad.

Of course, you probably need a new timing chain and sprockets.

One thing that you might consider is a small engine stand to hold the engine while you work on it - and the brackets to hold it to the stand. Its not required, but it makes it a lot easier. And a tub to catch all the oil that was stuck in it (cat littler box?).

An engine that old, you should examine the pistons and rings to make sure they are still in spec. The cylinder also needs to be measured with a special tool to make sure its still even.

If your cylinder is fine, then you might need some new piston rings. If your cylinders are too worn, then you'll need to either get new ones or have the old ones bored and go with oversized pistons and rings. The cost is about the same either way, but you'll get a smidgen more power with bigger pistons.

Make no mistake that what you propose is a costly endevour. Be prepared to spend about $500. It may be more in Canada.

The_big_dill · October 2nd, 2013, 10:58 AM

Thanks for the details n4mwd, I will get back with a thread on the rebuild. I was planning to get a stand for rebuilding this engine. Rebuilding will more than likely be more expensive here, considering all the things I payed for like $3-4 for each cam cap bolt.
Posted via Mobile Device

The_big_dill · October 2nd, 2013, 11:31 AM

Thanks for the details n4mwd, I will get back with a thread on the rebuild. I was planning to get a stand for rebuilding this engine. Rebuilding will more than likely be more expensive here, considering all the things I payed for like $3-4 for each cam cap bolt.
Posted via Mobile Device

juliusmichaelhonrada · June 16th, 2016, 08:53 AM

hello guys i have a 1988 ninja 250 , im also having the same problem , after i adjusted the timing , it would not start anymore even with the choke on which it did before the adjustment .

i verified all 2T mark in the peephole , with IN/EX mark lined up in the head surface , with 33 piece of rivets .

My flywheel nut become loose when i was turning the engine counterclockwise is it possible that i messed it up and now my spark timing is off and 2T mark is not really 2 TDC?

September 30th, 2013, 07:49 PM	#163
n4mwd ninjette.org certified postwhore Name: D Location: Palm Beach, FL Join Date: Oct 2010 Motorcycle(s): 2006 Ninja 250R, 2007 EFI Ninja 250R Posts: A lot. Blog Entries: 1	You can't really tell for sure until you get in there, but what you need for sure are the gaskets, HondaBond RT for sealing it back up, head gaskets, connecting rod bolts and nuts (4 sets), big nut for clutch basket, 4 wrist pin keepers. When you get inside you need to check the bearings to see if they are in tolerance. Its hard to get a micrometer that measures in microns, but that's what you need. I have found its cheaper and better in the long run to just get some plastiguage and use that to make sure the bearing clearance is proper. The connecting rod bolts are made out of some kind of rubberized steel so its imperative that you don't overtorque them. For plastiguaging and eperimenting, use the old ones, and then use the new ones for final assembly. You might be able to test the rod bearings by twisting and shaking the rods on the crank without removing the bolts. If you don't remove the bolts, you don't need new ones. But you are just guessing as to their condition. Its up to you as to whether you remove them for a real inspection or just guess. If you need new engine bearings, they run about $10 a half so normally, you just change the out of spec ones. If you need to change a set, they come in different sizes and are matched by colors on the crank and housing. THEY DO NOT COME OVERSIZED! So if the crank is bad, its bad, it cannot be turned like automobile cranks. Actually, there are racing machine shops that can do it, but they will return the crank to OEM spec by different processes and the cost is usually greater than what the dealer charges for a brand new crank. Having said that, you have said nothing that would make me think that your crank is bad. Of course, you probably need a new timing chain and sprockets. One thing that you might consider is a small engine stand to hold the engine while you work on it - and the brackets to hold it to the stand. Its not required, but it makes it a lot easier. And a tub to catch all the oil that was stuck in it (cat littler box?). An engine that old, you should examine the pistons and rings to make sure they are still in spec. The cylinder also needs to be measured with a special tool to make sure its still even. If your cylinder is fine, then you might need some new piston rings. If your cylinders are too worn, then you'll need to either get new ones or have the old ones bored and go with oversized pistons and rings. The cost is about the same either way, but you'll get a smidgen more power with bigger pistons. Make no mistake that what you propose is a costly endevour. Be prepared to spend about $500. It may be more in Canada. __________________________________________________ My Ninja Blog Proud member of ABATE.My NYC Road Rage documentary - CENSORED!
	1 out of 1 members found this post helpful.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Valve adjustment help	jgcable	1986 - 2007 Ninja 250R Tech Talk	5	July 22nd, 2014 09:25 PM
Valve adjustment	ninjaryda	1986 - 2007 Ninja 250R Tech Talk	6	April 6th, 2013 06:02 PM
Valve Adjustment	fredhsu	2008 - 2012 Ninja 250R Tech Talk	7	August 7th, 2012 03:57 PM
valve adjustment	little fish	1986 - 2007 Ninja 250R Tech Talk	8	November 4th, 2011 10:10 AM
Valve Adjustment-Really Tight adjustment screw?	mikesova	1986 - 2007 Ninja 250R Tech Talk	5	May 2nd, 2010 04:57 AM

September 30th, 2013, 05:52 PM	#162
The_big_dill ninjette.org member Name: Phil Location: Aurora, ON, Canada Join Date: Jan 2013 Motorcycle(s): 1987 Ninja 250 custom gold Posts: 218	I pictured the operation of the chain in its current state and now i can see why its clicking. As i mentioned, the slack varies throughout the revolutions of the engine and when the chain slacks, it is instantly pulled tight again because of the high revving engine, forcing the chain to slap against the top chain guard. A rebuild is my decision and am now gathering information on what i need. I am planning to replace all the gaskets (I will print the ones n4mwd kindly provided), seals, bearings, chains, sprockets, journals, rings, etc. As well as lapping the valves. But i guess this depends on what exactly needs replacing, and that will need the engine torn apart. Can you guys give me a quick list of what i will have to replace, just to start compiling an order? Thanks.

October 2nd, 2013, 10:58 AM	#164
The_big_dill ninjette.org member Name: Phil Location: Aurora, ON, Canada Join Date: Jan 2013 Motorcycle(s): 1987 Ninja 250 custom gold Posts: 218	Thanks for the details n4mwd, I will get back with a thread on the rebuild. I was planning to get a stand for rebuilding this engine. Rebuilding will more than likely be more expensive here, considering all the things I payed for like $3-4 for each cam cap bolt. Posted via Mobile Device

October 2nd, 2013, 11:31 AM	#165
The_big_dill ninjette.org member Name: Phil Location: Aurora, ON, Canada Join Date: Jan 2013 Motorcycle(s): 1987 Ninja 250 custom gold Posts: 218	Thanks for the details n4mwd, I will get back with a thread on the rebuild. I was planning to get a stand for rebuilding this engine. Rebuilding will more than likely be more expensive here, considering all the things I payed for like $3-4 for each cam cap bolt. Posted via Mobile Device

June 16th, 2016, 08:53 AM	#166
juliusmichaelhonrada ninjette.org guru Name: Julius Michael Location: Philippines Join Date: May 2016 Motorcycle(s): GPX250-RII Posts: 296	hello guys i have a 1988 ninja 250 , im also having the same problem , after i adjusted the timing , it would not start anymore even with the choke on which it did before the adjustment . i verified all 2T mark in the peephole , with IN/EX mark lined up in the head surface , with 33 piece of rivets . My flywheel nut become loose when i was turning the engine counterclockwise is it possible that i messed it up and now my spark timing is off and 2T mark is not really 2 TDC?