Buddies 98 VTR seized
 

It has 20k miles and it started making some noise and seized up. I haven't seen it yet and he hasn't pulled it apart so I'm not sure whats going on. One thing I would like to know is the VTR uses an interference engine. I'm thinking it'll have a broken cam chain from what he's told me.

If its an intereference engine I'm guessing atleast half the valves are bent and the cam chain wrapped around the crankshaft to seize the motor.

Is this an interference engine?

If it is, does it "usually" do any damage to the pistons or just to the valves when the cam chain breaks?

Re: Buddies 98 VTR seized
 

Pardon my ignorance,, but I've only been wrenching on, racing, riding and driving cars, trucks, road race street and dirt bikes for 35 years or so,,, And I must admit,,,, I have no idea what an "interference engine" is. If you could explain that term,, perhaps, I might be able to answer :P

interference engine means if the main chain broke, then the valve would go down and hit the piston on it way up and break the piston and usually bend the valves. In the non interference engine, even if the belt/chain breaks, none if that will happen.

Re: Buddies 98 VTR seized
 

OK,, we look at that,,I lernd somting :P I've been building motors for bikes and autos for a long time,,working with and for some great shops.. Never heard the term before. :wink:

bronco78, I hadn't learned that until long after starting wrenching. When you start replacing broken timing belts on jap cars you hear it alot.

We pulled the valve covers today and found a loose chain on the front cylinder caused by a broken cam chain tensioner spring.

I guess I need to pull the head and check for valve/piston damage now.

I hope the front cam chain isn't a bitch to replace.

So is it an interference engine or not?

Good Call!!

Great question,, I just assumed it was,,as every bike I've ownerd for the last 10 few years, and many of the cars, and or motors I've built,, have been of interference design.. Just never new that term before. Heck,, I was not aware,, any modern motorcycle motor made in the last dozen years or so,, was not an interference engine . I do know who to ask though,, be back with an answer soon.

Before pulling the head I'm going to check the valve clearances. Excessive clearance should tell me if I have any bent valves. I might get lucky with the valves and hopefully if the chain looks good I can just re-time the cams and install a new tensioner and away we go. Although I think that may be an optimistic outcome.

Re: Buddies 98 VTR seized
 

The word is yes.. from a guy I trust... He is the guy road racers, trail riders, and race teams bring motors to. Yes the VTR motor is an Interference engine." A car term for sure... as it can or can not apply to an auto motor. Not really so in bikes. Nothing made in recipient history has enough piston/valve clearance to not have interference if the cams were to go out of time. Some it takes only a few deg, some it would have to be way out. The real question is.. how far out do the VTR cams need to be before the valves will smack the piston

Well because the tensioner broke I think my cams stopped moving for atleast a few revolutions and if either the intake or exhaust valves were fully extended at the time the piston would have smacked the them.

Hopefully I got lucky and the feeler gauge yields good news.

Thanks for the help bronco78!

Yes,, do that,, when they bend the valves.. they of course do not fully seat,, and you'll find a clearance you can measure with your thumb... Honestly.. It takes so little valve/piston contact to bend a valve....and having had several motors drop valves, and cause so much destruction. If it were my motor,, I'd pull the heads no matter what I found under the valve cover. A set of gaskets and some inspection time is a small price to pay.. to ensure the rest of the motor is ok,, and not going to grenade if you just retime the cams, and go.

I think your right but it the valves are within spec they have to be fine. We're talking about hundredths of a mm. Most likely they'll be damaged and I'll have to pull the head though. After looking at the manual I'm not too worried about changing the cam chain. Looks to be easier than previously speculated.

Re: Buddies 98 VTR seized
 

Its very common for the older CCT springs to break around 20-30k. Thats why some of us have gone to the manual aftermarket kind. Honda has also addressed the problem by updating them (a couple of times).

Be warned people who've never changed them.

If I order a set for a 98 VTR will I get the latest set of the same old junk? I think I might just order two 919 units to be sure they are the latest and greatest. This kid knows little about bikes and I don't think he would want to hastle with the manual (ape style) tensioners.

Thanks for the info!

Re: Buddies 98 VTR seized
 

I'm sure you would get the lastest ones which I believe have a pink painted dot on them but am not sure.

Maybe someone else on here can speak up. I think its time for a sticky on this issue.

The one we pulled out had a pink painted dot. I think that just means which end is up.

Re: Buddies 98 VTR seized
 

You could use a leakdown test to help determine the ability of your valves to seal.

It tells which revision it is. It went from no dot, to a white dot, to a pink dot to something else, I think. Anyway, I don't rightly remember. But I don't think the pink dot is the latest revision.

The current revision on the Blackbird/X11 is a Blue dot, if that helps. Haven't checked into the VTR ones yet, but I have an engine to rebuild shortly, so I'll be looking into it as well.

Welp here it is. Bent exhaust valves on the front cylinder but the piston looks good. I think we have a head lined up but if any of you have a good one for a good price let me know. We also need a cam chain (better safe than sorry, a head gasket, and a set of the updated tensioners.

I'll try to remember to take some pics to show you guys what a bad tensioner or broken cam chain does to valves.

Its pretty impressive how large the pistons are. Bigger than my fist! From now on I'm going to refer to the vtr engine as the double donkey puncher.

Re: Buddies 98 VTR seized
 

Looks like latest CCT have orange dot...well - in Europe.
I've been told to buy latest one with partnumber that ends with -013, and that one indeed was latest Honda had and it had orange dot on it.
could be of course that in US that part have pink dot, this is why I loked at partnumber instead of color....

Re: Buddies 98 VTR seized
 

The parts fiche lists two PN's 14520-MBB-013 and 14520-MBB-003

But they both default to the 14520-MBB-013 part number when selected.
Part Number: 14520-MBB-013
Description: LIFTER, TENSIONER
Source: HONDA
Price: $53.57

Re: Buddies 98 VTR seized
 

All this CCT horror makes me a bit nervous. My 98 has 11,000 miles

Re: Buddies 98 VTR seized
 

Mine were still fine at 40,000 km's but I replaced them just in case. Too many horror stories.

Going 250kmh with the engine wound out, I couldn't stand the thought of it seizing under me.

Hey all, i am the guy with the bike that is being discussed. I have pix of the broken valves. I will be posting them. Thanks for all the great input.
-Josh

Well he finally got all the parts and we put it together last weekend. He said it ran like crap and wouldn't idle before. Now it runs flawlessly. Actually better than mine.

Re: Buddies 98 VTR seized
 

Yeah, Thanks much mike. It was fun to ride last night. It finally doesnt idle awefully. ANd it didnt seem to have any cold start issues. I am very happy!

Re: Buddies 98 VTR seized
 

how hard are these tensioners to replace my 99 has 20,000 miles and I am planning on getting the valve clearence checked this spring would this be a good time to replace them I can handle minor repairs but major teardown scares me to death!!!!!!!!!!!!!!!!!!!!

THey are kinda fussy, but not challenging. Just have to be careful. If you do it wrong, you will have bent valves. It is a good time to do it though. I had 20,100 miles on mine when it went. We changed the tensioners out with ones from a 10k miles engine.