The '97 engine repair

See the pictures
Disclaimer
Why did I open the engine?
Tools you will need
Prepairing
What I found out
Parts'n'prices
Reassembling the engine
Torques

Disclaimer

If you decide to open an engine, you should know, what you´re doing, and you should know about basics like how to properly adjust valves timing. If you´re not sure, better ask a qualified mechanic. Also, I do my very best to tell the correct things, but of course I can't give any warranty!

Why did I open the engine?

It began during the ´97 summer holiday in Sweden: An occasionally audible slight clankering noise, when the engine was cold. As soon as the engine got warmer, first after some hundred meters, the noise disappeared. However - during the months the noise got louder and louder, and the time befor it disappeared, got longer and longer. At last it was very loud and it took up to 6-7 km to disappear. I suspected at least one worn out camshaft chain. Also I noticed a very high oil consumption (> 1 ltr/1,000 km), so in November I decided to disassemble the engine. First I´ve been about to write a complete "howto disassemble a TA engine", but this would be a huge document, and it is described in any maintenance book. So I decided to confine to some special hints you probably will find nowhere else, and better tell you of what I found inside my engine.

This is my second engine - the first is standing in my garage. It still runs, just the oil consumption after exactly 100,000 km made me think of disassembling it in ´95. But then I found this engine - with 38,000 km on it, and together with a carb set and a rear shock, I gave DEM 750.- for it. So I thought, that it would be a good idea, just to change the engines, and the other time to overhaul the original engine. The first thing I did, the second one I did not. And now, after this engine has also run 91,000 km all in all, it´s time again to do something.

Tools you will need

• 8, 10, 12, 14, 17, 19, 27 mm wrenches (or nuts, respectively)
• 5, 6, 10 mm Allen head wrenches (Inbus-Schlüssel)
• screwdrivers
• torque wrench (required)
• engine blocking tool (not really necessary, there are many ways to do it ...)
• pulling-off tool for generator´s rotor (M22*1.5 thread) (required)
• high precision gauging tools
• a U-shaped piece of wood for supporting the pistons, when cylinders are removed
• scraper for removing old gaskets
• rubber hammer
• lots of clean and non-fluffy pieces of cloth

Prepairing

When being about to pull the engine out of the frame, be sure not to put your bike on any kind of stand, neither a centerstand nor any other bike stand. Put it on a suitable chest - I used a mineral water chest. Why that? Simply, because the engine is lying safely on the chest, once you have losen all the connections to the frame, and because it´s much easier to get it out of the frame now.

Before losening the engine-frame connections, remove the following things:

• all the fairings
• the seat
• the tank
• crashbars, if mounted
• the battery (always disconnect the ground lead first ...)
• the carburator set (incl. the black plastic dome)
• the ignition coils of the front cylinder
• the left radiator (in fact, losening it is enough. There´s no real need to remove it.)
• the bar, the engine guard is fixed to
• the rear swingarm
• the complete exhaust pipe
• and of course you must disconnect all electrical connections and the cooling liquid and airing tubes. Don´t forget the lead coming out of the clutch housing (maybe country dependent). The connector you´ll find beside the right radiator. To reach it, you´ll have to losen the right radiator.

When being about to replace the cam chains, you have to dismount the generator´s rotor and the clutch. For dismounting the rotor, you´ll need an engine blocking tool and a special pulling-off tool with a M22*1.5 mm thread. If lacking a blocking tool, you may put a piece of cloth between the gearwheels on the clutch side. When losening the screw holding the rotor on the crankshaft, please note, that it´s left-threaded.
When losening the 24 mm screw fixing the clutch on the crankshaft (right-threaded), be sure not to block the gear at the clutch basket, but better via the sprocket with a gear engaged. I´m lucky enough to have a frame fragment (the guy I bought the second engine from, gave it to me), so it´s easy to block it. Or you may remount the springs without the clutch plate, using suitable disks between the springs and the bolts, and then block the engine with a piece of cloth as described above.

What I found

The adjusting screws of both the exhaust rockers showed pitting, so they were replaced.

Outlet valves and seats were slightly burned, but besides that, seats seemed to be ok. They have been smoothed. Input seats were ok.

The pistons were wearing nice little black coke caps - an aftereffect of the high oil consumption, caused normally by worn out piston rings and valve seals. The piston rings I did not check, they simply were replaced ...
Also replaced: both the cam chains and the oilpump chain. And, of course, all gaskets.

Cam chain tensioners and guides seemed to be ok, so they are remounted.

Parts´ prices

pieces	part	part#	price/piece	total
2	camshaft chain	14401-MM9-003	159.-	328.-
2	alternatively: aftermarket cam chain by Detlev Louis	10047526	82.- (incl.VAT)	164.- (incl. VAT) *
2	camshaft chain tensioner	14510-MM-000	120.-	240.- **
2	camshaft chain guide	14522-MM9-000	34.51	69.02 **
1	oilpump chain	15136-MF5-013	33.93	33.93
2	exhaust valve	14721-MF5-010	59.02	118.04
4	inlet valve	14711-MV1-000	28.26	113.04
2	valve adjusting screw	90014-MF5-000	4.86	9.72
4	valve seals for inlet valves	12208-413-003
2	valve seals for exhaust valves	12209-413-003		57.40 (all 6 seals together)
2	set of piston rings	13011-MS6-305	62.17	124.34
2	cylinder foot gasket	12191-MM9-850	8.54	17.08
2	cylinder head gasket	12251-MM9-851	40.69	81.38
1	gasket for clutch cover	11394-MM9-850	19.25	19.25
1	gasket for generator cover	11395-MM9-850	13.90	13.90
2	O-ring (cooling liquid pipe -> cylinder)	91315-ME9-003	3.91	7.82
	div. copper seal rings		7.10	7.10
1	fairing nut	90111-MM9-000	7.17	7.17

* took this instead. But attention! The ´97 Detlev Louis catalogue offers two chains:
1. part# 10047509, DEM 85.-, for ´86-´87 Transalp (Seen it? There never were a TA in 1986...)
2. part# 10047526, DEM 82.-, for ´88-´93 Transalp
If you have an ´88 TA, you have to take the first chain (10047509), the other one is too small.
** not needed

Reassembling the engine

Before reassembling your engine, carefully remove all remnants of old gaskets. Use a special scraper for this, don´t use a knife or a screwdriver, else you will destroy the surfaces. Oil all gaskets before using, else they will leak.

Piston rings are mounted in following order:

• lowest groove: oil ring (3 parts). First mount the waved ring, then the flat ones.
• middle groove: the dark grey one
• uppermost groove: the light grey one

When remounting valve springs, the narrow windings must point down (towards the cylinderhead)

Be sure to mount the fixed cam chain guides before mounting the cylinder head! The cam chain tensioners can be mounted, if cylinderhead is already fixed. Cam chain tensioners have to be released before mounting. To do so, push the wedge and secure it with a small nail. You don´t really need to take off the spring, as to be seen on the picture, pushing the wedge is a little bit easier. Just don´t forget to remount the spring!

Don´t mix up the camshafts! Before mounting the camshafts, grease all bearings with MoS2 grease. Use Loctite, when fixing the sprocket to the camshaft.

When fixing the cylinderhead, tighten all screws in prescribed order and with prescribed torque (see below).

Torques

It´s not so important, to tighten screws with a tenth of Nm (Newtonmeter) torque, but it´s important, to tighten a set of screws with the same torque. For example, the cylinderhead screws #1-4 you may tighten with any torque between 35-45 Nm, but all with the same torque.
Number of screws is for one cylinder!

	number	thread diameter (mm)	torque (Nm)	remarks
cylinderhead screws
nut 1-4	4	10	35-45
nut 5	1	8	20-25
bolt 6-7	2	8	20-25
bolt 8 (Allen head (Inbus))	1	6	8-12
camshaft
holder: bolts	3	8	20-25
holder: nut	1	8	20-25
holder: bolts	2	6	8-12
sprocket: bolts	2	7	20-25	use Loctite
clutch
primary gearwheel: bolt	1	12	80-100
clutch hub nut	1	18	80-100	secure by hitting the secure sheet
clutch operational sheet (or whatever that is called ...): bolts	4	6	8-12
oil pump sprocket holder: bolt	1	6	13-17	use Loctite
generator
rotor bolt	1	12	100-120	left threaded!

Detlev Müller
all b&w: from "Reparaturanleitung Honda XL600V" by Bucheli Verlag, Zürich

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