VTR250 cam chain replacement

**SS90** · 30th September 2012, 23:28

This is the second time I have seen a VT250 throw a rod, not unheard of it would seem.
An old girlffriend had a 89 VT250, imported (way back in 94) with 4,000 km oit, regular (4,000km) oil changes, it never missed a beat, and she sold it with 30,000km on board.

Go figure.

I am wondering if all that gasket goo round the cases has something to do with it?
Possibly blocking off an oil feed?

**328FTW** · 1st October 2012, 05:04

There was plenty of oil, like I said I checked the cam chains and stuff. The valve was in the sump and the bearings are PERFECT, bottomend looks like a new motor and the piston skirts have no signs of oil not being in the bores causing a dry seize, I'd of also expected to see that that piston hadn't been going up and down so much if a rod broke outright, there are many many marks in the top of it from the valve bouncing off it quite a few times a second till it collapsed.

The oil feed to the head is also external, I drilled, tapped and flushed those lines. I ran diesel through them with a pump to get any rouge metal swarth my greased drill missed and it was free flowing. The engine was crashed however, and the camchain was snapped from the impact with the frame. I should perhaps check the head for a sign of a valve impact cause I just turfed it and had a quick look at the piston, all looked good. It's a stretch but maybe a couple valves gave the piston a smack giving it a hairline crack that somehow collapsed it.

Not the only motor I've had a hand in blowing up with style

At this point I'm more interested in sourcing some new parts for the motor I'm getting from bogan, guy is meant to be putting a deposit on the commodore today. All going well in the next couple weeks he will of paid me in full and I can throw money at it like it's a stripper in the hopes it'll give me the ride of my life.

**actungbaby** · 1st October 2012, 11:45

[QUOTE=328FTW;1130406912]There was plenty of oil, like I said I checked the cam chains and stuff. The valve was in the sump and the bearings are PERFECT, bottomend looks like a new motor and the piston skirts have no signs of oil not being in the bores causing a dry seize, I'd of also expected to see that that piston hadn't been going up and down so much if a rod broke outright, there are many many marks in the top of it from the valve bouncing off it quite a few times a second till it collapsed.

honestly dude it be the crank bearings they all do it on early motors if not cared for

my vt 250 motor the con rod shells where paper think on the front cylinder second motor ditto

if you need spare heads i got 4 of them and two engines both with shaged cranks

U can have 2 heads for free dude just junk to me i was going sell to scrap dealer

**328FTW** · 1st October 2012, 12:51

Might take you up on that later if I find issues with my own spare heads. The rod only broke in half, the bolts didn't snap so I got a good look at the motor, I'm aware they do bearings but this motor had a solid bottomend, it's definitely a valve that came down through the top first then the rod followed. I've had a good look over it.

I will do a proper motor for this thing though, use new OEM bearings of the correct code, check the bores with a micrometer as well as the crank, I'm weighing up the pros/cons of gapless rings. Might cost me a bit more than just a used engine but I should have a solid motor. Building engines is somewhat what I do, I've just never done a bike motor however a cheap bike which I own is a great place to start; I'm keen to get into it as well.

However I'd like to do the valves this time

Maybe there is an option for dome top valves out there for the VT motor? A compression bump while I'm at it would be sweet

**ducatilover** · 2nd October 2012, 14:05

Just buy a Spada motor and put the good F2 Integra cams in it? If you can find some...

**328FTW** · 2nd October 2012, 14:29

I put the crank in a spare block and have been caining the shit out of it some more around town. I dunno how that's even possible, nor do I care anymore. Same bearings, different rods, if I get a thousand km's out of it then whatever, already done 100 on it and I'm not taking it easy in the slightest. I can do a motor in a few short hours now.

Seems kinda noisy from the topend at full noise, dunno if that's normal or if I'm just more aware of it after the last one went bang. I had the last few days free to relax a bit and instead I've built my second motor up and fluffed around. I need to clean and balance the carbs, flatspots in a couple places. Only riden it a few days and I'm already blowing shit up, I'm fucking terrible

**ducatilover** · 2nd October 2012, 14:35

Champ.
Oil pressure cam tensioner or mechanical? My Spada always had a bit of top end noise

**bogan** · 2nd October 2012, 14:45

Originally Posted by 328FTW

Only riden it a few days and I'm already blowing shit up, I'm fucking terrible

Originally Posted by ducatilover

Champ.

You guys must be two of the four riders of the motorcyclalocalypse

**328FTW** · 2nd October 2012, 18:44

Need the dethklok bike to ride around in.

The tensioners are just mechanical, down low it's pretty quiet. Once it gets past about 9 it starts to sound pretty harsh though. Maybe I just need a louder exhaust.