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Post by ypvsjohn on Jun 18, 2021 23:19:34 GMT 1
Evening all
Sorted my suspension after previous post with a nitron shock and racetech linear springs. But after going out to test it it's clear theit's best I have emailed mutts just awaiting a reply, those of you with big bore motors have you gone with Athena or serval? I know this will be expensive as my bike is completely stock including exhausts but the power valves rattle aswell as the crank so may aswell go with a 421 imo Which cylinders would you all go for? Not fussed about chasing bhp just want a nice fun road motor to use occasionally
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Post by JonW on Jun 19, 2021 1:28:53 GMT 1
Lots of info on this forum about big bores, have a look with the search function as you'll find info and builds.
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Post by Tobyjugs on Jun 19, 2021 8:41:36 GMT 1
I've experienced three different set ups. One that I own and two from other people. The other two systems were 421 and tuned. They are difficult to ride on the road. My set up which is tame is less demanding but still a handful.
I like the Assasin cylinders made by Driveline they make lots of torque. They are 443 cc.
The most important part of your choice will be knowing what type of engine performance you want that suits your riding needs.
Once you know this get the exhaust pipes made to suit the tune of the cylinders.
One last thing if it's for public road use try to get some good silencers fitted. Most of my village know if I start my project bike up due to the noise it makes.
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Post by dusty350 on Jun 19, 2021 9:03:14 GMT 1
I think Dave (Mutts) did as ride in, ride out service on a big bore set up. He is the right person to do the whole kit and set up for sure Dusty
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Post by oldbritguy on Jun 19, 2021 9:59:00 GMT 1
Yes Dave is the man however he is absolutely buried in work just now. Spoke to him last week and he has about a 4 month wait for work. Best bet would be to email him (check his website Mutts Nuts 2 Strokes) with what you are looking to do and he will get back to you, not immediately, but he will get back. Like all good things, be prepared to wait but his knowledge and work are second to none. John
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Post by chrisg on Jun 19, 2021 10:16:08 GMT 1
Yes Dave is the man however he is absolutely buried in work just now. Spoke to him last week and he has about a 4 month wait for work. Best bet would be to email him (check his website Mutts Nuts 2 Strokes) with what you are looking to do and he will get back to you, not immediately, but he will get back. Like all good things, be prepared to wait but his knowledge and work are second to none. John I suppose that's a good sign that he's busy. It means he's good. Like a good builder, if he can come round and start next week, keep clear.
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Post by midlifecrisisrd on Jun 19, 2021 10:36:46 GMT 1
Before you go and splurge £5k on a 421 with all the bits needed to get the best out of it look at dyno curves from other people who have done them
Then think what it will be like riding it in the real world and how where the power is and the transition of power will make it ride
Most have impressive peak figures but no bottom end and a very savage delivery. A good few experienced riders have trashed their bikes due to this
Tobyjugs's 443 is an exception in that it is tuned for midrange but still brutal and in a chassis that is more than capable
A good tuned and set up 350 ypvs will make over 70hp at the wheel with standard carbs
So that's a crank, top end refresh, porting (Mick abbey), ignition and either mutts or tsa pipes.
Half the price too
If you still want to go more hp with a 421 then good on you 👍
Steve
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Post by mintyfresh on Jun 19, 2021 10:40:43 GMT 1
Before you go and splurge £5k on a 421 with all the bits needed to get the best out of it look at dyno curves from other people who have done them Then think what it will be like riding it in the real world and how where the power is and the transition of power will make it ride Most have impressive peak figures but no bottom end and a very savage delivery. A good few experienced riders have trashed their bikes due to this Tobyjugs's 443 is an exception in that it is tuned for midrange but still brutal and in a chassis that is more than capable A good tuned and set up 350 ypvs will make over 70hp at the wheel with standard carbs So that's a crank, top end refresh, porting (Mick abbey), ignition and either mutts or tsa pipes. Half the price too If you still want to go more hp with a 421 then good on you 👍 Steve
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Post by mintyfresh on Jun 19, 2021 10:47:16 GMT 1
A well serviced, standard 350 ypvs putz out 47ish bhp, at the wheel.
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Post by Tobyjugs on Jun 19, 2021 10:50:20 GMT 1
Steve has a very good point. Which I didn't really get across in my reply. There have been remarks on this forum from members going back to the Steve's reccomendations due to the rideability factor. Two weeks ago I got a call out of the blue from a man in Belgium. After chatting for a while with I suggested the +4mm crank with a stronger clutch and different ratio primaries. I don't think he liked my answer, I was just trying to be practicle for his needs.
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Post by midlifecrisisrd on Jun 19, 2021 12:57:01 GMT 1
I'm not dissing 421, 443 or whatever size is used
It totally depends on what you want from the bike
As said some people are disappointed that despite it making 90 - 100 at the top end it will be making about 30 around 7k
The lack of power valves is the cause
If you hit the kill switch on a ypvs then switch off the ignition the valves will be in the open position
Now pull the ypvs fuse and take it for a ride
That will give you half an idea of how a motor ported for top end and no valves rides like
Steve
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Post by JonW on Jun 19, 2021 14:02:03 GMT 1
Not all builds are outright bhp numbers and not all big cyls are the same, some are more torquey than others your tuner can also help with this.
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Post by ypvsjohn on Jun 19, 2021 15:17:33 GMT 1
Lots of interesting feed back as I said I've emailed Dave at mutts just waiting on a reply. I want a useable Street bike not bothered about big bhp at all the only reason I am looking at the cylinder kits and cranks is because after looking it's around the same price and less work than fixing mine that has rattly powervalves needs pistons and probably a bore. And the crank bearing are definitely shot I can move the crank up and down via the flywheel very slightly and feel it knock. I bought the bike cheap at £2000 so not bothered about throwing a couple quid at it and will only use it a few times a year I have quite a few bikes to choose from
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Post by reedpete on Jun 19, 2021 21:50:54 GMT 1
Another thing to understand when you drool over all the big bore stuff is that the primary market that drove the development of it all is the banshee in the USA . Making the power and putting in down to the tarmac with a single rear wheel in a fun and safe way are two different things.
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Post by ypvsjohn on Jun 19, 2021 22:12:20 GMT 1
Another thing to understand when you drool over all the big bore stuff is that the primary market that drove the development of it all is the banshee in the USA . Making the power and putting in down to the tarmac with a single rear wheel in a fun and safe way are two different things. I know from reading that they make no power low down and it comes in with a real hit, my.only reason for looking at these kits is my ypvs top end is basically scrap it needs rebore pistons power valves all the bushes etc aswell as the bottom end going over for a refresh and new crank bearings if not a crank aswell. If I thought the top end was salvageable I would do it and run a stock motor I will ride this bike a couple times a year that's all. I also have a KTM 1290 super adventure and a gen 4 susperstock zx10r that I would much rather ride all the time the ypvs is just for nipping out on when I have an hour to kill
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Post by muttsnuts on Jun 20, 2021 12:45:50 GMT 1
ok, I am slowly getting back on top of things, I'll post up something shortly on the situation
With regards the original question, I've seen your email John and I'll try and get to it today (alot of info to supply), think I did suggest you send me your number and I'll call you to discuss as it will be quicker
But basically, you can pretty much have built whatever you want (within reason), you can have a 100bhp monster with massive bottom end as well, but you need deep pockets, I was working on one of the projects yesterday and hitting 100bhp at 8k rpm, with 112bhp at just over 9k, makes in the realm of 40bhp (Stock 350LC power) at 5.5k rpm, or you can have a very flexible and powerful 385 pushing in the region of 75bhp reliably for thousands of miles and a whole host of other configurations depending upon riding style, requirements and of course budget
HTH
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Post by muttsnuts on Jun 20, 2021 13:00:00 GMT 1
good example of a nice mix of biggish power and good bottom end
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Post by Tobyjugs on Jun 20, 2021 17:00:00 GMT 1
Dave's graph above is nice but you should try searching for other graphs from the +4mm crank used with the standard YPVS cylinders they will give better bottom end presentations with a real 2 stroke feeling (higher reving). Only a little bit less peak torque. This set up i suggest does depend on the size of your cylinders due to limited piston sizes. The dyno graphs from Yogi and midlifecrises are worth looking at. I'm not sure if it's cheaper to buy the Athena equipment and get it tuned and set up or go the +4mm route get that tuned and set up correctly. Maybe Steve or Matt could post up their dyno graphs for a comparison. Another thing I like about the plus 4 set up is the wolf in sheep's clothing
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Post by midlifecrisisrd on Jun 20, 2021 18:34:25 GMT 1
This isn't mine or Matt's but I thought I'd use this one as it was done by Dave and tested on his dyno so the nearest to a direct comparison you will get It is running stock 26mm carbs and airbox so motor looks standard Steve
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Post by ypvsjohn on Jun 20, 2021 22:51:10 GMT 1
Thanks for the reply Dave I have not received an email off you for some reason mustn't have come through I'll fire you over my number in a moment.
Pulled the motor today removed cylinder head bores are 0.75 over plug looks lean on one pot but all stock bike with stock carbs so no idea what's going on there. Definitely need a power dynamo as bike runs and rides but isn't charging the battery. Removed one cylinder but the other is stuck solid on one stud possibly a rusty Dowl left it Soaking in oil overnight. The 385 graph looks really good tbh as said in an earlier post I'm not bothered about chasing bhp in a steel fram that can't handle the bhp just wanting to build a nice street motor why it's got to come apart anyway and I know it needs everything including exhausts as it's a completely standard bike
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Post by muttsnuts on Jun 21, 2021 8:25:03 GMT 1
the 385 copnversion is the best bang for buck in my opinion, they can be pushed to very good BHP but you are then losing reliability, a sensible tune and setup running between 70bhp and 75bhp gives you a strong motor and thousands of miles (have several out there that have covered good mileage so far)
But if you don't have the PV barrels etc, then the Athena is a cheap route to market for decent power and reliability
As I say, it all comes down to budget and what you want
I could post graphs all day (not that I have the time at the moment), but it still comes down to what you want really
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Post by ypvsjohn on Jun 21, 2021 22:46:59 GMT 1
the 385 copnversion is the best bang for buck in my opinion, they can be pushed to very good BHP but you are then losing reliability, a sensible tune and setup running between 70bhp and 75bhp gives you a strong motor and thousands of miles (have several out there that have covered good mileage so far) But if you don't have the PV barrels etc, then the Athena is a cheap route to market for decent power and reliability As I say, it all comes down to budget and what you want I could post graphs all day (not that I have the time at the moment), but it still comes down to what you want really Dave I've messaged you my number give me a call whenever you can but the 385 route sounds pretty good to keep the ypvs system, and will leave plenty on the budget for straight cut gears ignition pipes etc so I can get it back built up asap. Pulled the cylinder today it's on .75 bore but will definitely need a rebore the pistons and cylinders are scored badly. Looking at this it probably needs a full overhaul all bearings seals etc aswell
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Post by jon on Jun 21, 2021 23:48:10 GMT 1
I favour the 385 route also. Trackable power for the road, and no vicious power band at the wrong moment in the wet.
Still I know it’s not cheap, I reckon my 385 cylinder owe me around £1000.
Jon
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Post by ypvsjohn on Jul 1, 2021 21:22:30 GMT 1
Rebuilding the motor completely standard none of the reputable builders are answering phone calls/emails so just boring to 1mm over and stock everything else. Crank and gearbox bearings off pjme And gaskets etc
Tried to email Kenny twice for a set of exhaust no answer so if anyone is selling any get in touch?
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Post by Bobthebuilder on Jul 2, 2021 6:21:11 GMT 1
Try alonze for the pipes usually a quick turn round . I’m collecting my 385 from Dave today I’m sure he’ll post dyno figures I can’t upload photos. The whole package isn’t cheap once you start adding all the parts and you’ve got to be prepared to wait and I mean a lot of months but so far the dyno sheet looks impressive
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Post by dusty350 on Jul 2, 2021 7:54:17 GMT 1
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Post by midlifecrisisrd on Jul 2, 2021 9:07:10 GMT 1
A fresh ypvs motor with either Alonze/Mutts or TSA pipes is quite fruity
Got TSA's on my 385 and a new pair of Alonze hanging in the garage
Both works of art
Steve
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Post by ypvsjohn on Jul 2, 2021 9:21:18 GMT 1
Thanks I'll try alonze for the exhausts, just waiting for a clutch holding tool then I can start the rebuild. I have no issues rebuilding the motor but it's hard for me to move the bike around to get someone to set up a 421 motor. If I build it standard I can just bolt it all back together and run it. Nothing will need setting up if it's standard it ran fine just noisey on the bottom end.
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Post by 3tj6 on Jul 2, 2021 9:44:03 GMT 1
I got some alonze pipes for my lc ypvs hybrid, ordered direct , 2 weeks later a pair of fantastic pipes arrived 👍
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Post by muttsnuts on Jul 2, 2021 20:38:54 GMT 1
John, where did you send the number, did you send an email as well ? I am, working through emails etc, but some people are still sending stuff to my old phone number, so I won't be getting them, the new number is on the website, don't use google as it won't let me update the telephone number for some reason, stupid bloody thing, so use my website to get the correct number
I can't see anything from you on email etc, PM me on here isn't a bad idea, at least I do see those messsges when I logon
If you have sent stuff and I've not responded sorry about that, but its stupid at the moment, last week in 4 days I had 102 phone calls, not exactly sure what the hell people expect me to do, can't respond to that many, I'd never get any work done !
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