YZF600 engine stuffed into a 90 blaster
- Thread starter rshutchinson
- Start date
Can't lower the engine. It's not about the work of modding the frame. I'd have to lower it 2 inches or so which would make it useless for what I'm going to use it for. Also, this bike will only get maybe a few miles a year so I'm not worried about longevity necessarily on some things such as chain life.
I'll be making a skidplate as well for sure just to protect the oil pan from stumps or rocks.
Thanks for the picture! I'm thinking it's best to go around the pivot point. Adding the stationary roller I've got just below the pivot *should* make it act no different than if it had a large sprocket on the engine that was in line with the pivot point. I'll have to move the top factory roller location up on the frame since the chain will now go higher but that's not a big deal.
Also noticed that someone has already done some work to the rear shock mount and is using a different rear shock which I think is why it seems the rear of the bike sits lower than normal. I'll take a picture, maybe its a known mod? I'm not familiar with these bikes at all.
I'll be making a skidplate as well for sure just to protect the oil pan from stumps or rocks.
Thanks for the picture! I'm thinking it's best to go around the pivot point. Adding the stationary roller I've got just below the pivot *should* make it act no different than if it had a large sprocket on the engine that was in line with the pivot point. I'll have to move the top factory roller location up on the frame since the chain will now go higher but that's not a big deal.
Also noticed that someone has already done some work to the rear shock mount and is using a different rear shock which I think is why it seems the rear of the bike sits lower than normal. I'll take a picture, maybe its a known mod? I'm not familiar with these bikes at all.
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Here is the rear lower shock mount. That stock is also welded to the bottom of the original shock mount. The shock itself is nice though.
The rollers are not designed as chaintensioers, their purpose it to arrest chain slap.
The chain is tensioned at the carrier.
Unless the final drive is in the same plane as the swingarm pivot, the chain will be constantly be changing its properties of slack as the suspension compresses/de-compresses and chain breakage will be imminent.
The chain is tensioned at the carrier.
Unless the final drive is in the same plane as the swingarm pivot, the chain will be constantly be changing its properties of slack as the suspension compresses/de-compresses and chain breakage will be imminent.
This is a recipe for disaster, broken cases, torn off chain rollers, maybe even limb damage.
Each time the suspension changes its position the chain will either tighten drastically and attempt to tear a roller off.
Or will will flap around like Grannies undies on the line in a strong wind.
Be advised that something is gonna break unless the final drive is the same plane as the pivot bolt.
Each time the suspension changes its position the chain will either tighten drastically and attempt to tear a roller off.
Or will will flap around like Grannies undies on the line in a strong wind.
Be advised that something is gonna break unless the final drive is the same plane as the pivot bolt.
Thanks for the reply, blaaster. I do understand what you are saying about chain tension and I had the same worries.
Now I'm pretty sure you know what I was talking about but just incase we aren't on the same page, when I say chain roller I didn't mean the stock chain roller. I meant a fixed, bearing loaded sprocket that I have that I'll picture below. It would not act as a tensioner, it would act merely as another gear to bring the trailing side of the chain away from the bottom of the swingarm. I see what you mean by the swingarm trying to rip it off as it travels up.
I'm thinking that option 2 I listed is the only real viable option at this point. Add in a spring loaded tensioner to keep the chain from flopping as well as the moving the factory rollers/arrestors.
I haven't measured how much swingarm travel this bike really has at the rear sprocket.
Now I'm pretty sure you know what I was talking about but just incase we aren't on the same page, when I say chain roller I didn't mean the stock chain roller. I meant a fixed, bearing loaded sprocket that I have that I'll picture below. It would not act as a tensioner, it would act merely as another gear to bring the trailing side of the chain away from the bottom of the swingarm. I see what you mean by the swingarm trying to rip it off as it travels up.
I'm thinking that option 2 I listed is the only real viable option at this point. Add in a spring loaded tensioner to keep the chain from flopping as well as the moving the factory rollers/arrestors.
I haven't measured how much swingarm travel this bike really has at the rear sprocket.
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A spring loaded tensioner may be the answer but it would have to be above the pivot bolt.
Every time the suspension gets compressed the chain will tear the guts out of the pivot roller.
Ideally the sprockets should be positioned that the rear one decsribes a perfect arc.
Every time the suspension gets compressed the chain will tear the guts out of the pivot roller.
Ideally the sprockets should be positioned that the rear one decsribes a perfect arc.
Why do you say it would have to be on the top run of chain? I've never saw a tensioner on the top side. The engine sprocket would always want to pull the chain in a straight line from the rear sprocket under power and I feel that the tensioner wouldn't really do much on the top, meaning it would still allow slack on the bottom run.
Thinking about it, if I route the chain between the shift-shaft and pivot, use the stationary roller just below and aft the pivot, then place a spring loaded tensioner in front of the rear sprocket on the bottom of the swinger it should take out any play in the chain through it's movement. This will best simulate the correct design and should eliminate the slack.
I'm only taking what I know from my experience with motorcycles. I run a pretty loose chain and on the bottom run of chain there isn't nearly the tension that there is on the top. The bottom run only gets tight when the suspension compresses. What I'm getting at is that there won't be all that much pressure on the stationary roller all the time.
Please don't take anything I'm saying the wrong way, I'm not arguing, simply trying to understand.
Also, if anyone is interested I can throw up some pictures of the motorcycle build I'm currently working on for myself as well as the XS400 I built this summer for my wife.
Not a pro but option 2 looks like the way to go and is how the blaster is set up, since when your on the Gas all the tension will be on the top, the chain going over a roller on the bottom front seems to be the ticket. I would think the chain would be easier to adjust if it you were able to set it a bit tight when unloaded and normal chain slack with you sitting on it, the roller in front and the chain guide In the back both o n the bottom should do a good job of controlling any looseness wit the swing arm Compressed.
If you were to choose option 1 then the chain would have to be loosest when you were sitting on it and cruising around only getting tight when the suspension is compressed. It might be a pain to figure out how loose it needed to be, if something happens you don't get it loose enough then land hard enough on the back wheels, it could be bad news for the chain, output shaft bearings, or axle bearings.
Just my 2 cents, I am sure on e of the more experienced guys will chime in with what they know will work.
looks like someone experienced did beat me to it , and plus one to his thinking.
If the chain went under the roller, when the suspension compressed and the chain got tight it would shred the roller first, which if your lucky might loosen the it up enough to keep from stressing the Chain and bearings.
If you were to choose option 1 then the chain would have to be loosest when you were sitting on it and cruising around only getting tight when the suspension is compressed. It might be a pain to figure out how loose it needed to be, if something happens you don't get it loose enough then land hard enough on the back wheels, it could be bad news for the chain, output shaft bearings, or axle bearings.
Just my 2 cents, I am sure on e of the more experienced guys will chime in with what they know will work.
looks like someone experienced did beat me to it , and plus one to his thinking.
If the chain went under the roller, when the suspension compressed and the chain got tight it would shred the roller first, which if your lucky might loosen the it up enough to keep from stressing the Chain and bearings.
I do not think I said that the tensioner should be on top of the chain, I said the tensioner should be above the pivot bolt, in meaning, higher than the pivot roller.
I really think that to save any hassles that the engine must be mounted lower so that the final drive is at least as close as possible to the same height as the swinger pivot.
I can only see problems when the swinger makes great excursions.
I really think that to save any hassles that the engine must be mounted lower so that the final drive is at least as close as possible to the same height as the swinger pivot.
I can only see problems when the swinger makes great excursions.
I believe the OP understands the problem and has decided to live with it. He just wants to take up the slack on the bottom side of the chain the best he can .. to correctly solve the core problem would be the biggest challenge of the swap .. regardless of the devices used on the bottom (slack) side of the chain, when you get out of the throttle the rear sprocket will try to drive the front sprocket and the top side of the chain will become the slack side .. how effective will the tensioner be on the load side? .. I have no real measurements to go by but my very crude guesstimate of the distance between the top side tangents of the two sprockets in a 15 deg. swing could be around 3/8" .. take a 24" piece of string, pull it tight, then close the distance 3/8" and see the slack .. thats just one side ..
Hope I'm way off base on this .. good luck .. burp
Hope I'm way off base on this .. good luck .. burp
one other thought .. with the huge power, added weight and sprocket configuration this bike will likely want to squat or compress the rear suspension under acceleration .. won't be running any sag
Sorry, you're right, you did say that. I said top side of the chain because after the stationary roller the chain will be below the pivot, so I automatically assumed it would have to have been the top run of chain.
Exactly. Thank you. The only real difference here is the chain will be pivoting above the swingarm pivot. The problem is how much is this difference going to affect the chain slack as the swingarm moves. Won't know until I try or test it out or get real mathematical with it. I can make a spring loaded tensioner with quite a lot of travel if needed.
Thanks guys! Will get back to work on it this week.
No progress yet, but I am going to look at a dirt cheap blaster with all the extended suspension and brake parts I'd wanted. If it's decent I'll pick it up, swap out the stock stuff from this bike and resell it and make some money off it.
Hey, no progress with this yet. Been busy swapping parts to get the other bike ready to resell and fixing my dad's co-workers motorcycle. Now that that's done I can get back to this.
Had to go to a niece's birthday but got a little done. Got both side pieces bent up to clear the carbs but only time to tack one side in.
4" Extended swinger on. Diamond J a-arm extensions on. Had to order new 12mm tie-rod extensions since I've got some moose tie rods so the bike is pigeon-toed for now. Another big plus was the hydraulic brake hubs. Got these and the front plastic with headlight. Only paid $100 for all that after I sold the bike last night.
Still not sure what I'm going to do for a fuel tank since the carbs take up the area where it would normally go. Thinking it may have to go under the seat somehow.
Total wheelbase is 51" which is only about an inch longer than the stock banshee and a Polaris Trailboss I had before this one.
4" Extended swinger on. Diamond J a-arm extensions on. Had to order new 12mm tie-rod extensions since I've got some moose tie rods so the bike is pigeon-toed for now. Another big plus was the hydraulic brake hubs. Got these and the front plastic with headlight. Only paid $100 for all that after I sold the bike last night.
Still not sure what I'm going to do for a fuel tank since the carbs take up the area where it would normally go. Thinking it may have to go under the seat somehow.
Total wheelbase is 51" which is only about an inch longer than the stock banshee and a Polaris Trailboss I had before this one.
Sorry didn't look good enough, the carbs aren't on so the the hairdryer thing ain't gonna cut it.
Tank instead of stock airbox, nice and tugged away.
But is the fuelpump able to pump fuel up? Don't know if it makes a difference tank above the carbs. as stock on the bike, or the tank lower as the carbs
if the bike uses a fuelpump?
Tank instead of stock airbox, nice and tugged away.
But is the fuelpump able to pump fuel up? Don't know if it makes a difference tank above the carbs. as stock on the bike, or the tank lower as the carbs
if the bike uses a fuelpump?
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